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Concern is growing about the danger of sports-related concussions and their long-term impact on athletes. But physicians and healthcare providers acknowledge that the science is evolving, leaving questions about rehabilitation and treatment options.

Currently, guidelines recommend that traumatic brain injury patients get plenty of rest and avoid physical and cognitive activity until symptoms subside.

But a new pilot study looking at athletes with concussions suggests total inactivity may not be the best way to recover after all, say scientists at Southern Methodist University, Dallas, where the research was conducted.

The study found that a simple cognitive task as early as four days after a brain injury activated the region that improves memory function and can guard against two hallmarks of concussion -- depression and anxiety.

"Right now, if you have a concussion the directive is to have complete physical and cognitive rest, no activities, no social interaction, to let your brain rest and recover from the energy crisis as a result of the injury," said SMU physiologist Sushmita Purkayastha, who led the research, which was funded by the Texas Institute for Brain Injury and Repair at UT Southwestern Medical Center, Dallas.

"But what we saw, the student athletes came in on approximately the third day of their concussion and the test was not stressful for them. None of the patients complained about any symptom aggravation as a result of the task. Their parasympathetic nervous system -- which regulates automatic responses such as heart rate when the body is at rest -- was activated, which is a good sign," said Purkayastha, an assistant professor in the SMU Department of Applied Physiology and Wellness.

The parasympathetic nervous system is associated with better memory function and implicated in better cardiovascular function. It also helps to regulates stress, depression and anxiety -- and those are very common symptoms after a concussion.

"People in the absolute rest phase after concussion often experience depression," Purkayastha added. "In the case of concussion, cutting people off from their social circle when we say 'no screen time' -- particularly the young generation with their cell phones and iPads -- they will just get more depressed and anxious. So maybe we need to rethink current rehabilitation strategy."

The new study addresses the lack of research upon which to develop science- and data-based treatment for concussion. The findings emerged when the research team measured variations in heart rate variability among athletes with concussions while responding to simple problem-solving and decision-making tasks.

While we normally think of our heart rate as a steady phenomenon, in actuality the interval varies and is somewhat irregular -- and that is desirable and healthy. High heart rate variability is an indicator of sound cardiovascular health. Higher levels of variability indicate that physiological processes are better controlled and functioning as they should, such as during stressful (both physical and challenging mental tasks) or emotional situations.

Concussed athletes normally have lowered heart rate variability.

For the new study, Purkayastha and her team administered a fairly simple cognitive task to athletes with concussions. During the task, the athletes recorded a significant increase in heart rate variability.

The study is the first of its kind to examine heart rate variability in college athletes with concussions during a cognitive task.

The findings suggest that a small measure of brain work could be beneficial, said co-investigator and neuro-rehabilitation specialist Kathleen R. Bell, a physician at UT Southwestern Medical Center, Dallas.

"This type of research will change fundamentally the way that patients with sports and other concussions are treated," said Bell, who works with brain injury patients and is Chair of Physical Medicine and Rehabilitation at UT Southwestern. "Understanding the basic physiology of brain injury and repair is the key to enhancing recovery for our young people after concussion."

The researchers reported their findings in the peer-reviewed Journal of Head Trauma Rehabilitation, in the article "Reduced resting and increased elevation of heart rate variability with cognitive task performance in concussed athletes."

Co-authors from SMU Simmons School include Mu Huang and Justin Frantz; Peter F. Davis and Scott L. Davis, from SMU's Department of Applied Physiology and Wellness; Gilbert Moralez, Texas Health Presbyterian Hospital, Dallas; and Tonia Sabo, UT Southwestern.
Concussion symptom improved with simple brain activity
Volunteer subjects for the study were 46 NCAA Division I and recreational athletes who participate in contact-collision sports. Of those, 23 had a physician-diagnosed sports-related concussion in accordance with NCAA diagnostic criteria. Each of them underwent the research testing within approximately three to four days after their injury.

Not surprisingly, compared to the athletes in the control group who didn't have concussions, the athletes with concussions entered answers that were largely incorrect.

More importantly, though, the researchers observed a positive physiological response to the task in the form of increased heart rate variability, said Purkayastha.

"It's true that the concussed group gave wrong answers for the most part. More important, however, is the fact that during the task their heart rate variability improved," she said. "That was most likely due to the enhancement of their brain activity, which led to better regulation. It seems that engaging in a cognitive task is crucial for recovery."

Heart rate variability is a normal physiological process of the heart. It makes possible a testing method as noninvasive as taking a patient's blood pressure, pulse or temperature. In the clinical field, measuring heart rate variability is an increasingly common screening tool to see if involuntary responses in the body are functioning and being regulated properly by the autonomic nervous system.
The parasympathetic is blunted or dampened by concussion
Abnormal fluctuations in heart rate variability are associated with certain conditions before symptoms are otherwise noticeable.

Monitoring heart rate variability measures the normal synchronized contractions of the heart's atriums and ventricles in response to natural electrical impulses that rhythmically move across the muscles of the heart.

After a concussion, an abnormal and unhealthy decline in heart rate variability is observed in the parasympathetic nervous system, a branch of the autonomic nervous system. The parasympathetic is in effect blunted or dampened after a concussion, said Purkayastha.

As expected, in the current study, heart rate variability was lower among the athletes with concussions than those without.

New findings add evidence suggesting experts rethink rehab

But that changed during the simple cognitive task. For the athletes with concussions, their heart rate variability increased, indicating the parasympathetic nervous system was activated by the task.

Heart rate variability between the concussed and the controls was comparable during the cognitive task, the researchers said in their study.

"This suggests that maybe we need to rethink rehabilitation after someone has a concussion," Purkayastha said.

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heart disease; sports medicine; stroke prevention; diseases and conditions; brain injury; intelligence; stroke; disorders and syndromes

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Mild problem-solving task improves brain function after a concussion, new study suggests

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A mild problem-solving task improves brain functioning after a concussion, according to a new study. Currently there are many questions about rehabilitation and treatment options, with absolute rest often the go-to treatment. But the new study suggests that a simple cognitive task as early as four days after a brain injury activates the region that improves memory function, and may guard against developing depression or anxiety.

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Problem Solving and Decision Making (Solving Problems and Making Decisions)

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Learn about problem solving in this topic from the Free Management Library.

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In Yasunari Kawabata's unsettling short story, Yumiura, a novelist receives an unexpected visit from a woman who says she knew him 30 years earlier. They met when he visited the town of Yumiura during a harbor festival, the woman explains. But the novelist cannot remember her. Plagued recently by other troublesome memory lapses, he sees this latest incident as a further sign of mental decline. His discomfort turns to alarm when the woman offers more revelations about what happened on a day when he visited her room. "You asked me to marry you," she recalls wistfully. The novelist reels while contemplating the magnitude of what he had forgotten. The woman explains that she had never forgotten their time together and felt continually burdened by her memories of him.

After she finally leaves, the shaken novelist searches maps for the town of Yumiura with the hope of triggering recall of the place and the reasons why he had gone there. But no maps or books list a town called Yumiura. The novelist then realizes that he could not have been in the part of the country the woman described at the time she remembered. Her detailed, heartfelt and convincing memories were entirely false.

Kawabata's story dramatically illustrates different ways in which memory can get us into trouble. Sometimes we forget the past and at other times we distort it; some disturbing memories haunt us for years. Yet we also rely on memory to perform an astonishing variety of tasks in our everyday lives. Recalling conversations with friends or recollecting family vacations; remembering appointments and errands we need to run; calling up words that allow us to speak and under stand others; remembering foods we like and dislike; acquiring the knowledge needed for a new job -- all depend, in one way or another, on memory. Memory plays such a pervasive role in our daily lives that we often take it for granted until an incident of forgetting or distortion demands our attention.

Memory's errors have long fascinated scientists, and during the past decade they have come to occupy a prominent place in our society. Forgotten encounters, misplaced eyeglasses and failures to recall the names of familiar faces are becoming common occurrences for many adults who are busily trying to juggle the demands of work and family, and cope with the bewildering array of new communications technologies. How many passwords and "PINs" do you have to remember just to manage your affairs on the Internet, not to mention your voice mail at the office or on your cell phone?

In addition to dealing with the frustrations of memory failures in daily life, the awful specter of Alzheimer's disease looms large on the horizon. As the general public becomes ever more aware of its horrors, the prospects of a life dominated by catastrophic forgetting further increase our preoccupations with memory.

Although the magnitude of the woman's memory distortion in Yumiura seems to stretch the bounds of credulity, it has been equaled and even exceeded in everyday life. Consider the story of Binjimin Wilkomirski, whose Holocaust memoir, Fragments, won worldwide acclaim for portraying life in a concentration camp from the perspective of a child. Wilkomirski presented readers with raw, vivid recollections of the unspeakable terrors he witnessed as a young boy. Even more remarkable, Wilkomirski had spent much of his adult life unaware of these traumatic childhood memories, only becoming aware of them in therapy. Because his story and memories inspired countless others, Wilkomirski became a sought-after international figure and a hero to Holocaust survivors.

The story began to unravel, however, when Daniel Ganzfried, a Swiss journalist and himself the son of a Holocaust survivor, published a stunning article in a Zurich newspaper. Ganzfried revealed that Wilkomirski is actually Bruno Dossekker, a Swiss native born in 1941 to a young woman named Yvone Berthe Grosjean, who later gave him up for adoption to an orphanage. His foster parents, the Dossekkers, found him there. Young Bruno spent all of the war years in the safe confines of his native Switzerland. Whatever the basis for his traumatic "memories" of Nazi horrors, they did not come from childhood experiences in a concentration camp. Is Dossekker/Wilkomirski simply a liar? Probably not: he still strongly believes his recollections are real.

Memory's errors are as fascinating as they are important. They can be divided into seven fundamental transgressions or "sins," which I call transience, absentmindedness, blocking, misattribution, suggestibility, bias and persistence. Just like the ancient seven deadly sins -- pride, anger, envy, greed, gluttony, lust and sloth -- the memory sins occur frequently in everyday life and can have serious consequences for all of us.

Transience, absentmindedness and blocking are sins of omission: we fail to bring to mind a desired fact, event or idea. Transience refers to a weakening or loss of memory over time. It is a basic feature of memory, and the culprit in many memory problems. Absentmindedness involves a breakdown at the interface between attention and memory. Absentminded memory errors -- misplacing your keys or eyeglasses, or forgetting a lunch appointment -- typically occur because we are preoccupied with distracting issues or concerns, and don't focus attention on what we need to remember.

The third sin, blocking, entails a thwarted search for information we may be desperately trying to retrieve. We've all had the experience of failing to produce a name to a familiar face. This frustrating experience happens even though we are attending carefully to the task at hand, and even though the desired name has not faded from our minds -- as we become acutely aware when we unexpectedly retrieve the blocked name hours or days later.

The next four sins of misattribution, suggestibility, bias and persistence are all sins of commission: some form of memory is present, but it is either incorrect or unwanted. The sin of misattribution involves assigning a memory to the wrong source: mistaking fantasy for reality, or incorrectly remembering that a friend told you a bit of trivia that you actually read about in a newspaper. Misattribution is far more common than most people realize, and has potentially profound implications in legal settings. The related sin of suggestibility refers to memories that are implanted as a result of leading questions, comments or suggestions when a person is trying to call up a past experience. Like misattribution, suggestibility is especially relevant to -- and sometimes can wreak havoc within -- the legal system.

The sin of bias reflects the powerful influences of our current knowledge and beliefs on how we remember our pasts. We often edit or entirely rewrite our previous experiences -- unknowingly and unconsciously -- in light of what we now know or believe. The result can be a skewed rendering of a specific incident, or even of an extended period in our lives, that says more about how we feel now than about what happened then.

The seventh sin -- persistence -- entails repeated recall of disturbing information or events that we would prefer to banish from our minds altogether: remembering what we cannot forget, even though we wish that we could. Everyone is familiar with persistence to some degree: Recall the last time you suddenly awoke at 3 a.m., unable to keep out of your mind a painful blunder on the job or a disappointing result on an important exam. In more extreme cases of serious depression or traumatic experience, persistence can be disabling and even life-threatening.

New discoveries, some based on recent breakthroughs in neuroscience that allow us to see the brain in action as it learns and remembers, are beginning to illuminate the basis of the seven sins. These studies allow us to see in a new light what's going on inside our heads during the frustrating incidents of memory failure or error that can have a significant impact on our everyday lives. But to understand the seven sins more deeply, we also need to ask why our memory systems have come to exhibit these bothersome and sometimes dangerous properties: Do the seven sins represent mistakes made by Mother Nature during the course of evolution? Is memory flawed in a way that has placed our species at unnecessary risk? I don't think so. To the contrary, I contend that each of the seven sins is a byproduct of otherwise desirable and adaptive features of the human mind. Let's consider two of the most common memory sins: transience and absentmindedness.

TRANSIENCE

Take, for example, the conclusion of the most publicized trial in recent history: a jury acquitted O.J. Simpson of murder. Word of the verdict spread quickly, nearly everyone reacted with either outrage or jubilation, and many people could talk about little else for days and weeks afterward. The Simpson verdict seemed like just the sort of momentous event that most of us would always remember vividly: how we reacted to it, and where we were when we heard the news.

Now, can you recall how you found out that Simpson had been acquitted? Chances are that you don't remember, or that what you remember is wrong. Several days after the verdict, a group of California undergraduates provided researchers with detailed accounts of how they learned about the jury's decision. When the researchers probed students' memories again 15 months later, only half recalled accurately how they found out about the decision. When asked again nearly three years after the verdict, less than 30% of students' recollections were accurate; nearly half were dotted with major errors.

The culprit in this incident is the sin of transience: forgetting that occurs with the passage of time. Research has shown that minutes, hours or days after an experience, memory preserves a relatively detailed record, allowing us to reproduce the past with reasonable if not perfect accuracy. But with the passing of time, the particulars fade and opportunities multiply for interference -- generated by later, similar experiences -- to blur our recollections.

Consider the following question: If I measure activity in your brain while you are learning a list of words, can I tell from this activity which words you will later remember having studied, and which words you will later forget? In other words, do measurements of brain activity at the moment when a perception is being transformed into a memory allow scientists to predict future remembering and forgetting of that particular event? If so, exactly which regions allow us to do the predicting?

Our group at the imaging center of Massachusetts General Hospital came up with an experiment to answer the question. Holding still in this cacophonous tunnel [the magnetic resonance imaging or MRI scanner], participants in our experiment saw several hundred words, one every few seconds, flashed to them from a computer by specially arranged mirrors. To make sure that they paid attention to every word, we asked our volunteers to indicate whether each word refers to something abstract, such as "thought," or concrete, such as "garden." Twenty minutes after the scan, we showed subjects the words they had seen in the scanner, intermixed with an equal number of words they hadn't seen, and asked them to indicate which ones they did and did not remember seeing in the scanner. We knew, based on preliminary work, that people would remember some words and forget others. Could we tell from the strength of the signal when participants were making abstract/concrete judgments which words they would later remember and which ones they would later forget?

We could. Two regions of the brain showed greater activity when people made abstract/concrete judgments about words they later remembered compared with those they later forgot. One was in the inner part of the temporal lobe, a part of the brain that, when damaged, can result in severe memory loss. The other region whose activity predicted subsequent memory was located further forward, in the lower left part of the vast territory known as the frontal lobes.

This finding was not entirely unexpected, because previous neuroimaging studies indicated that the lower left part of the frontal lobe works especially hard when people elaborate on incoming information by associating it to what they already know.

These results were exciting because there is something fascinating, almost science fiction-like, about peering into a person's brain in the present and foretelling what she will likely remember and forget in the future. But beyond an exercise in scientific fortune-telling, these studies managed to trace some of the roots of transience to the split-second encoding operations that take place during the birth of a memory. What happens in frontal and temporal regions during those critical moments determines, at least in part, whether an experience will be remembered for a lifetime, or drop off into the oblivion of the forgotten.

ABSENTMINDEDNESS

On a brutally cold day in February 1999, 17 people gathered in the 19th floor office of a Manhattan skyscraper to compete for a title known to few others outside that room: National Memory Champion. The winner of the U.S. competition would go on to challenge for the world memory championship several months later in London.

The participants were asked to memorize thousands of numbers and words, pages of faces and names, lengthy poems and decks of cards. The victor in this battle of mnemonic virtuosos, a 27-year-old administrative assistant named Tatiana Cooley, relied on classic encoding techniques: generating visual images, stories and associations that link incoming information to what she already knows. Given her proven ability to commit vast amounts of information to memory, one might also expect that Cooley's everyday life would be free from the kinds of memory problems that plague others. Yet this memory champion considers herself dangerously forgetful. "I'm incredibly absentminded," Cooley told a reporter. Fearful that she will forget to carry out everyday tasks, Cooley depends on to-do lists and notes scribbled on sticky pads. "I live by Post-its," she admitted ruefully.

The image of a National Memory Champion dependent on Post-its in her everyday life has a paradoxical, even surreal quality: Why does someone with a capacity for prodigious recall need to write down anything at all? Can't Tatiana Cooley call on the same memory abilities and strategies that she uses to memorize hundreds of words or thousands of numbers to help remember that she needs to pick up a jug of milk at the store? Apparently not: The gulf that separates Cooley's championship memory performance from her forgetful everyday life illustrates the distinction between transience and absentmindedness.

The kinds of everyday memory failures that Cooley seeks to remedy with Post-it notes -- errands to run, appointments to keep and the like -- have little to do with transience. These kinds of memory failures instead reflect the sin of absentmindedness: lapses of attention that result in failing to remember information that was either never encoded properly (if at all) or is available in memory but is overlooked at the time we need to retrieve it.

To appreciate the distinction between transience and absentmindedness, consider the following three examples:

A man tees up a golf ball and hits it straight down the fairway. After waiting a few moments for his partner to hit, the man tees up his ball again, having forgotten that he hit the first drive.

A man puts his glasses down on the edge of a couch. Several minutes later, he realizes he can't find the glasses, and spends a half-hour searching his home before locating them.

A man temporarily places a violin on the top of his car. Forgetting that he has done so, he drives off with the violin still perched on the roof.

Superficially, all three examples appear to reflect a similar type of rapid forgetting. To the contrary, it is likely that each occurred for very different reasons.

The first incident took place back in the early 1980s, when I played golf with a patient who had been taking part in memory research conducted in my laboratory. The patient was in the early stages of Alzheimer's disease, and he had severe difficulties remembering recent events. Immediately after hitting his tee shot, the patient was excited because he had knocked it straight down the middle; he realized he would now have an easy approach shot to the green. In other words, he had encoded this event in a relatively elaborate manner that would ordinarily yield excellent memory. But when he started teeing up again and I asked him about his first shot, he expressed no recollection of it whatsoever. This patient was victimized by transience: he was incapable of retaining the information he had encoded, and no amount of cueing or prodding could bring it forth.

In the second incident, involving misplaced glasses, entirely different processes are at work. Sad to say, this example comes from my own experience -- and happens more often that I would care to admit. Without attending to what I was doing, I placed my glasses in a spot where I usually do not put them. Because I hadn't fully encoded this action to begin with -- my mind was preoccupied with a scientific article I had been reading -- I was at a loss when I realized that my glasses were missing. When I finally found them on the couch, I had no particular recollection of having put them there. But unlike the golfing Alzheimer's patient, transience was not the culprit: I never adequately encoded the information about where I put my glasses and so had no chance to retrieve it later.

The third example, featuring the misplaced violin, turned into far more than just a momentary frustration. In August 1967, David Margetts played second violin in the Roth String Quartet at UCLA. He had been entrusted with the care of a vintage Stradivarius that was owned by the department of music. After Margetts put the violin on his car's roof and drove off without removing it, UCLA made massive efforts to recover the instrument. Nonetheless, it went missing for 27 years before resurfacing in 1994 when the Stradivarius was brought in for repair and a dealer recognized the instrument. After a lengthy court battle, the violin was returned to UCLA in 1998.

There is, of course, no way to know exactly what Margetts was thinking about when he put the violin on his car's roof. Perhaps he was preoccupied with other things, just as I was when I misplaced my glasses. But because one probably does not set down a priceless Stradivarius without attending carefully to one's actions, I suspect that had Margetts been reminded before driving off, he would have remembered perfectly well where he had just placed the violin. In other words, Margetts was probably not sabotaged by transience, or even by failure to encode the event initially. Rather, forgetting in Margett's case was likely attributable to an absent-minded failure to notice the violin at the moment he needed to recall where he had put it. He missed a retrieval cue -- the violin on the car's roof -- which surely would have reminded him that he needed to remove the instrument.

Even though they often seem like our enemies, the seven sins are an integral part of the mind's heritage because they are so closely connected to features of memory that make it work well. The seven sins are not merely nuisances to minimize or avoid. They illuminate how memory draws on the past to inform the present, preserves elements of present experience for future reference, and allows us to revisit the past at will. Memory's vices are also its virtues, elements of a bridge across time that allows us to link the mind with the world.
Adapted from Daniel Schacter, Ph.D.'s The Seven Sins of Memory: How the Mind Forgets and Remembers (Houghton-Mifflin, 2001)

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Seven different ways that memory can mess with your head and your life, and ways to identify them.

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Memory, Encoding Storage and Retrieval | Simply Psychology

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Often, the tasks participants are asked to perform can appear artificial and meaningless. Few, if any, people would attempt to memorize and recall a list of unconnected words in their daily lives. And it is not clear how tasks such as this relate to the use of memory in everyday life.

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Surprising new research about the act of remembering may help people with post-traumatic stress disorder

Sitting at a sidewalk café in Montreal on a sunny morning, Karim Nader recalls the day eight years earlier when two planes slammed into the twin towers of the World Trade Center. He lights a cigarette and waves his hands in the air to sketch the scene.

At the time of the attack, Nader was a postdoctoral researcher at New York University. He flipped the radio on while getting ready to go to work and heard the banter of the morning disc jockeys turn panicky as they related the events unfolding in Lower Manhattan. Nader ran to the roof of his apartment building, where he had a view of the towers less than two miles away. He stood there, stunned, as they burned and fell, thinking to himself, "No way, man. This is the wrong movie."

In the following days, Nader recalls, he passed through subway stations where walls were covered with notes and photographs left by people searching desperately for missing loved ones. "It was like walking upstream in a river of sorrow," he says.

Like millions of people, Nader has vivid and emotional memories of the September 11, 2001, attacks and their aftermath. But as an expert on memory, and, in particular, on the malleability of memory, he knows better than to fully trust his recollections.

Most people have so-called flashbulb memories of where they were and what they were doing when something momentous happened: the assassination of President John F. Kennedy, say, or the explosion of the space shuttle Challenger. (Unfortunately, staggeringly terrible news seems to come out of the blue more often than staggeringly good news.) But as clear and detailed as these memories feel, psychologists find they are surprisingly inaccurate.

Nader, now a neuroscientist at McGill University in Montreal, says his memory of the World Trade Center attack has played a few tricks on him. He recalled seeing television footage on September 11 of the first plane hitting the north tower of the World Trade Center. But he was surprised to learn that such footage aired for the first time the following day. Apparently he wasn't alone: a 2003 study of 569 college students found that 73 percent shared this misperception.

Nader believes he may have an explanation for such quirks of memory. His ideas are unconventional within neuroscience, and they have caused researchers to reconsider some of their most basic assumptions about how memory works. In short, Nader believes that the very act of remembering can change our memories.

Much of his research is on rats, but he says the same basic principles apply to human memory as well. In fact, he says, it may be impossible for humans or any other animal to bring a memory to mind without altering it in some way. Nader thinks it's likely that some types of memory, such as a flashbulb memory, are more susceptible to change than others. Memories surrounding a major event like September 11 might be especially susceptible, he says, because we tend to replay them over and over in our minds and in conversation with others-with each repetition having the potential to alter them.

For those of us who cherish our memories and like to think they are an accurate record of our history, the idea that memory is fundamentally malleable is more than a little disturbing. Not all researchers believe Nader has proved that the process of remembering itself can alter memories. But if he is right, it may not be an entirely bad thing. It might even be possible to put the phenomenon to good use to reduce the suffering of people with post-traumatic stress disorder, who are plagued by recurring memories of events they wish they could put behind them.

Nader was born in Cairo, Egypt. His Coptic Christian family faced persecution at the hands of Arab nationalists and fled to Canada in 1970, when he was 4 years old. Many relatives also made the trip, so many that Nader's girlfriend teases him about the "soundtrack of a thousand kisses" at large family gatherings as people bestow customary greetings.

He attended college and graduate school at the University of Toronto, and in 1996 joined the New York University lab of Joseph LeDoux, a distinguished neuroscientist who studies how emotions influence memory. "One of the things that really seduced me about science is that it's a system you can use to test your own ideas about how things work," Nader says. Even the most cherished ideas in a given field are open to question.

Scientists have long known that recording a memory requires adjusting the connections between neurons. Each memory tweaks some tiny subset of the neurons in the brain (the human brain has 100 billion neurons in all), changing the way they communicate. Neurons send messages to one another across narrow gaps called synapses. A synapse is like a bustling port, complete with machinery for sending and receiving cargo-neurotransmitters, specialized chemicals that convey signals between neurons. All of the shipping machinery is built from proteins, the basic building blocks of cells.

One of the scientists who has done the most to illuminate the way memory works on the microscopic scale is Eric Kandel, a neuroscientist at Columbia University in New York City. In five decades of research, Kandel has shown how short-term memories-those lasting a few minutes-involve relatively quick and simple chemical changes to the synapse that make it work more efficiently. Kandel, who won a share of the 2000 Nobel Prize in Physiology or Medicine, found that to build a memory that lasts hours, days or years, neurons must manufacture new proteins and expand the docks, as it were, to make the neurotransmitter traffic run more efficiently. Long-term memories must literally be built into the brain's synapses. Kandel and other neuroscientists have generally assumed that once a memory is constructed, it is stable and can't easily be undone. Or, as they put it, the memory is "consolidated."

According to this view, the brain's memory system works something like a pen and notebook. For a brief time before the ink dries, it's possible to smudge what's written. But after the memory is consolidated, it changes very little. Sure, memories may fade over the years like an old letter (or even go up in flames if Alzheimer's disease strikes), but under ordinary circumstances the content of the memory stays the same, no matter how many times it's taken out and read. Nader would challenge this idea.

In what turned out to be a defining moment in his early career, Nader attended a lecture that Kandel gave at New York University about how memories are recorded. Nader got to wondering about what happens when a memory is recalled. Work with rodents dating back to the 1960s didn't jibe with the consolidation theory. Researchers had found that a memory could be weakened if they gave an animal an electric shock or a drug that interferes with a particular neurotransmitter just after they prompted the animal to recall the memory. This suggested that memories were vulnerable to disruption even after they had been consolidated.

To think of it another way, the work suggested that filing an old memory away for long-term storage after it had been recalled was surprisingly similar to creating it the first time. Both building a new memory and tucking away an old one presumably involved building proteins at the synapse. The researchers had named that process "reconsolidation." But others, including some prominent memory experts, had trouble replicating those findings in their own laboratories, so the idea wasn't pursued.

Nader decided to revisit the concept with an experiment. In the winter of 1999, he taught four rats that a high-pitched beep preceded a mild electric shock. That was easy-rodents learn such pairings after being exposed to them just once. Afterward, the rat freezes in place when it hears the tone. Nader then waited 24 hours, played the tone to reactivate the memory and injected into the rat's brain a drug that prevents neurons from making new proteins.

If memories are consolidated just once, when they are first created, he reasoned, the drug would have no effect on the rat's memory of the tone or on the way it would respond to the tone in the future. But if memories have to be at least partially rebuilt every time they are recalled-down to the synthesizing of fresh neuronal proteins-rats given the drug might later respond as if they had never learned to fear the tone and would ignore it. If so, the study would contradict the standard conception of memory. It was, he admits, a long shot.

"Don't waste your time, this will never work," LeDoux told him.

It worked.

When Nader later tested the rats, they didn't freeze after hearing the tone: it was as if they'd forgotten all about it. Nader, who looks slightly devilish in his earring and pointed sideburns, still gets giddy talking about the experiment. Eyes wide with excitement, he slaps the café table. "This is crazy, right? I went into Joe's office and said, 'I know it's just four animals, but this is very encouraging!'"

After Nader's initial findings, some neuroscientists pooh-poohed his work in journal articles and gave him the cold shoulder at scientific meetings. But the data struck a more harmonious chord with some psychologists. After all, their experiments had long suggested that memory can easily be distorted without people realizing it.

In a classic 1978 study led by Elizabeth Loftus, a psychologist then at the University of Washington, researchers showed college students a series of color photographs depicting an accident in which a red Datsun car knocks down a pedestrian in a crosswalk. The students answered various questions, some of which were intentionally misleading. For instance, even though the photographs had shown the Datsun at a stop sign, the researchers asked some of the students, "Did another car pass the red Datsun while it was stopped at the yield sign?"

Later the researchers asked all the students what they had seen-a stop sign or yield sign? Students who'd been asked a misleading question were more likely to give an incorrect answer than the other students.

To Nader and his colleagues, the experiment supports the idea that a memory is re-formed in the process of calling it up. "From our perspective, this looks a lot like memory reconsolidation," says Oliver Hardt, a postdoctoral researcher in Nader's lab.

Hardt and Nader say something similar might happen with flashbulb memories. People tend to have accurate memories for the basic facts of a momentous event-for example, that a total of four planes were hijacked in the September 11 attacks-but often misremember personal details such as where they were and what they were doing at the time. Hardt says this could be because these are two different types of memories that get reactivated in different situations. Television and other media coverage reinforce the central facts. But recalling the experience to other people may allow distortions to creep in. "When you retell it, the memory becomes plastic, and whatever is present around you in the environment can interfere with the original content of the memory," Hardt says. In the days following September 11, for example, people likely repeatedly rehashed their own personal stories-"where were you when you heard the news?"-in conversations with friends and family, perhaps allowing details of other people's stories to mix with their own.

Since Nader's original experiment, dozens of studies with rats, worms, chicks, honeybees and college students have suggested that even long-standing memories can be disrupted when recalled. Nader's goal is to tie the animal research, and the clues it yields about the bustling molecular machinery of the synapse, to the everyday human experience of remembering.

Some experts think he is getting ahead of himself, especially when he makes connections between human memory and these findings in rats and other animals. "He oversells it a little bit," says Kandel.

Daniel Schacter, a psychologist at Harvard University who studies memory, agrees with Nader that distortions can occur when people reactivate memories. The question is whether reconsolidation-which he thinks Nader has demonstrated compellingly in rat experiments-is the reason for the distortions. "The direct evidence isn't there yet to show that the two things are related," Schacter says. "It's an intriguing possibility that people will now have to follow up on."

A real-world test of Nader's theory of memory reconsolidation is taking place a few miles from his Montreal office, at the Douglas Mental Health University Institute. Alain Brunet, a psychologist, is running a clinical trial involving people with post-traumatic stress disorder (PTSD). The hope is that caregivers might be able to weaken the hold of traumatic memories that haunt patients during the day and invade their dreams at night.

Brunet knows how powerful traumatic memories can be. In 1989, when he was studying for a master's degree in psychology at the University of Montreal, a man armed with a semiautomatic rifle walked into an engineering classroom on campus, separated the men from the women and shot the women. The gunman continued the massacre in other classrooms and hallways of the university's École Polytechnique, shooting 27 people and killing 14 women before killing himself. It was Canada's worst mass shooting.

Brunet, who was on the other side of campus that day, says, "this was a very powerful experience for me." He says he was surprised to discover how little was known at the time about the psychological impact of such events and how to help people who've lived through them. He decided to study traumatic stress and how to treat it.

Even now, Brunet says, the drugs and psychotherapy conventionally used to treat PTSD do not provide lasting relief for many patients. "There's still plenty of room for the discovery of better treatments," he says.

In Brunet's first study, PTSD patients took a drug intended to interfere with the reconsolidation of fearful memories. The drug, propranolol, has long been used to treat high blood pressure, and some performers take it to combat stage fright. The drug inhibits a neurotransmitter called norepinephrine. One possible side effect of the drug is memory loss. (In a study similar to Nader's original experiment with rats, researchers in LeDoux's lab have found that the drug can weaken fearful memories of a high-pitched tone.)

The patients in Brunet's study, published in 2008, had each experienced a traumatic event, such as a car accident, assault or sexual abuse, about a decade earlier. They began a therapy session sitting alone in a nondescript room with a well-worn armchair and a television. Nine patients took a propranolol pill and read or watched TV for an hour as the drug took effect. Ten were given a placebo pill.

Brunet came into the room and made small talk before telling the patient he had a request: he wanted the patient to read a script, based on earlier interviews with the person, describing his or her traumatic experience. The patients, all volunteers, knew that the reading would be part of the experiment. "Some are fine, some start to cry, some need to take a break," Brunet says.

A week later, the PTSD patients listened to the script, this time without taking the drug or a placebo. Compared with the patients who had taken a placebo, those who had taken the propranolol a week earlier were now calmer; they had a smaller uptick in their heart rate and they perspired less.

Brunet has just completed a larger study with nearly 70 PTSD patients. Those who took propranolol once a week for six weeks while reading the script of their traumatic event showed an average 50 percent reduction in standard PTSD symptoms. They had fewer nightmares and flashbacks in their daily lives long after the effects of the drug had worn off. The treatment didn't erase the patients' memory of what had happened to them; rather, it seems to have changed the quality of that memory. "Week after week the emotional tone of the memory seems weaker," Brunet says. "They start to care less about that memory."

Nader says the traumatic memories of PTSD patients may be stored in the brain in much the same way that a memory of a shock-predicting tone is stored in a rat's brain. In both cases, recalling the memory opens it to manipulation. Nader says he's encouraged by the work so far with PTSD patients. "If it's got any chance of helping people, we have to give it a shot," he says.

Among the many questions that Nader is now pursuing is whether all memories become vulnerable when recalled, or only certain memories under certain circumstances.

Of course, there is the even bigger question: why are memories so unreliable? After all, if they were less subject to change we wouldn't suffer the embarrassment of misremembering the details of an important conversation or a first date.

Then again, editing might be another way to learn from experience. If fond memories of an early love weren't tempered by the knowledge of a disastrous breakup, or if recollections of difficult times weren't offset by knowledge that things worked out in the end, we might not reap the benefits of these hard-earned life lessons. Perhaps it's better if we can rewrite our memories every time we recall them. Nader suggests that reconsolidation may be the brain's mechanism for recasting old memories in the light of everything that has happened since. In other words, it just might be what keeps us from living in the past.

Greg Miller writes about biology, behavior and neuroscience for Science magazine. He lives in San Francisco. Gilles Mingasson is a photographer based in Los Angeles.

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Sitting at a sidewalk café in Montreal on a sunny morning, Karim Nader recalls the day eight years earlier when two planes slammed into the twin towers of the World Trade Center. He lights a cigarette and waves his hands in the air to sketch the scene.

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Sleep deprivation: Causes, symptoms, and treatment

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Sleep deprivation occurs when a person does not get enough sleep. A lack of sleep can harm mental and physical health. Learn more about it can here.

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Understanding Brain, Mind and Soul: Contributions from Neurology and Neurosurgery

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Treatment of diseases of the brain by drugs or surgery necessitates an understanding of its structure and functions. The philosophical neurosurgeon soon encounters difficulties when localising the abstract concepts of mind and soul within the tangible ...

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Abstract

Background

Many studies on vision and driving cessation have relied on measures of sensory function, which are insensitive to the higher order cognitive aspects of visual processing. The purpose of this study was to examine the association between traditional measures of visual sensory function and higher order visual processing skills with incident driving cessation in a population-based sample of older drivers.

Methods

Two thousand licensed drivers aged ≥70 were enrolled and followed-up for three years. Tests for central vision and visual processing were administered at baseline and included visual acuity, contrast sensitivity, sensitivity in the driving visual field, visual processing speed (Useful Field of View (UFOV) Subtest 2 and Trails B), and spatial ability measured by the Visual Closure Subtest of the Motor-free Visual Perception Test. Participants self-reported the month and year of driving cessation and provided a reason for cessation. Cox proportional hazards models were used to generate crude and adjusted hazard ratios with 95% confidence intervals between visual functioning characteristics and risk of driving cessation over a three-year period.

Results

During the study period, 164 participants stopped driving which corresponds to a cumulative incidence of 8.5%. Impaired contrast sensitivity, visual fields, visual processing speed (UFOVand Trails B), and spatial ability were significant risk factors for subsequent driving cessation after adjusting for age, gender, marital status, number of medical conditions, and miles driven. Visual acuity impairment was not associated with driving cessation. Medical problems (63%), specifically musculoskeletal and neurological problems, as well as vision problems (17%) were cited most frequently as the reason for driving cessation.

Conclusion

Assessment of cognitive and visual functioning can provide useful information about subsequent risk of driving cessation among older drivers. In addition, a variety of factors, not just vision, influenced the decision to stop driving and may be amenable to intervention.

Keywords: Driving cessation, higher order visual processing, older drivers, visual sensory function

For many older adults, remaining a current driver is important for maintaining independence and well-being. Driving cessation is associated with a number of poor health outcomes including decreased quality of life, increased depression, reduced access to healthcare services, declines in physical and social functioning, admission to long-term care facilities, and mortality. Population aging is taking place in nearly all countries of the world. As such, millions of older adults will stop or restrict their driving after a lifetime of depending on driving for autonomy and mobility. Identifying risk factors for driving cessation will be important given the potentially serious consequences of driving cessation among this growing demographic.

A number of risk factors that precede driving cessation have been identified in the literature including older age, being female, lower levels of education, and poor health. While social support has not been explored in depth, two prospective studies suggest that living with other drivers is associated with driving cessation, although, other studies suggest older adults who continue to drive tend to be married. Former drivers often report having activity limitations or having conditions which can limit mobility such as paralysis or weakness from a stroke or Parkinson's disease. Furthermore, it is well-established that older adults who cease driving are more likely to be cognitively impaired, though cognitively impaired individuals may also be unaware of their deficits and perceive no reason to stop driving.

Vision is also an important risk factor for driving cessation and is a commonly reported health problem among older drivers; many older drivers may stop driving or restrict driving once their visual sensory function has become impaired in an effort to ensure their safety or to comply with state licensing renewal regulations. In a population-based prospective study of older drivers in Maryland, baseline visual acuity, contrast sensitivity, and peripheral visual field and changes in visual function of these measures were predictive of cessation. Other studies have examined vision impairment and driving cessation, but have been constrained by a cross-sectional design so were not able to address the issue of temporality of whether these impairments occurred prior to cessation or as a result of the cessation itself. Many of the studies on vision impairment relied on measures of sensory function, which are not assessments of the higher order or cognitive aspects of visual processing. Several longitudinal studies of driving cessation among community-dwelling older adults have examined the role of higher order visual processing. Anstey et al. reported that those having slowed processing speed as measured by the Digit Symbol Substitution were 3.03 times more likely to cease driving. Two prospective studies from the ACTIVE clinical trial found that slower cognitive speed of processing as measured by the Useful Field of View test (UFOV) was a significant factor for 3-year (HR=1.37) and 5-year (HR=1.18) risk of driving cessation, even after adjusting for age, vision, health, and physical functioning. Similarly, a 10-year study by Edwards et al. conducted in a Maryland-based Department of Motor Vehicles (DMV) demonstrated that those with impaired scores on the UFOV (HR=1.76) and Trails B (HR=1.21) test were more likely to stop driving compared to those with normal scores. While the previous work has established the association between visual processing speed and driving cessation, few were population-based. Furthermore, few reports have described the strength of the association with a range of visual functioning and other higher order visual processing tests in the same sample. This is helpful in order to compare the relative strengths of each measure which can be difficult to do across studies when characteristics vary from sample to sample. Identifying the types of visual function loss that lead to driving cessation are important to better understand the relationship between vision and driving.

To address these gaps, the purpose of this study is to examine the association between traditional measures of visual sensory as well as higher order visual processing skills with incident driving cessation in a population-based sample of older drivers.

Methods

Study sample

The study consisted of a population-based sample of adults aged 70 years or older who resided in north central Alabama, as described previously. Potential participants were randomly selected from a list obtained from Pinpoint Technologies, a direct marketing company in Tustin, CA. The researchers confirmed driver's license status through the Alabama Department of Public Safety, and eliminated those from the target population who did not hold an Alabama license. Those who were selected from the list received a letter about the study, followed by a telephone call to confirm eligibility. Persons were excluded if they had not driven in the last 3 months, were younger than 70 years, lived in a nursing home, or did not speak English. For those who were eligible and agreed to participate, an appointment was scheduled in the Clinical Research Unit (CRU) in the Department of Ophthalmology at the University of Alabama at Birmingham. Following written informed consent, participants were enrolled between October 2008 and August 2011. The protocol involved a single in-person visit to the CRU and a follow-up telephone survey conducted at 1-year intervals for three subsequent years. This study was approved by the Institutional Review Board of the University of Alabama at Birmingham. The final sample consisted of 2,000 older drivers.

For the current analysis, participants' driving status could reasonably switch multiple times (e.g. current driver, then former driver, then back to current driver) over the study period; participants were censored at the time of the first report of driving cessation in order to examine time after the baseline visit to the first report of driving cessation. There were 210 participants who died, were not able to complete the interview or could not be reached, or refused to participate and were right censored at the time of the last interview. For those who completed all three follow-up surveys (n=1621), they were right censored at the time of the last interview. In addition, during the telephone interview, there were 5 participants who reported a driving cessation date prior to study enrollment despite being a current driver at enrollment and were excluded from the analysis. Therefore, baseline and follow-up data from 1995 participants were included in this analysis.

Data Collection

At the baseline visit, a trained interviewer confirmed demographic (age, gender, race), socioeconomic, and marital status information and administered a general health questionnaire about the presence versus absence of chronic medical conditions (i.e., "has a doctor ever told you that you have..."). The mini-mental status examination (MMSE) was administered to estimate cognitive status. Reduced cognitive status was defined as a MMSE score <24. The Driving Habits Questionnaire was used to collect information about annual mileage and the number of places, trip and days driven per week.

Tests for central vision and visual processing were administered at the baseline visit. Testing was done under habitual correction, so participants wore whatever spectacles or contact lenses they normally wear when driving. All tests were administered under binocular viewing unless noted.

Visual acuity

Distance visual acuity was assessed using the Electronic Visual Acuity (EVA) system, which was expressed as logarithm of the minimum angle resolvable (logMAR). Visual acuity impairment was defined as 0.3 logMAR or greater.

Contrast sensitivity

Contrast sensitivity was estimated using the Pelli-Robson Contrast Sensitivity Chart and was scored using the letter-by-letter method and expressed as log sensitivity. Contrast sensitivity impairment was defined as <1.5 log sensitivity.

Driving visual field

Visual field sensitivity was measured with the Humphrey Field Analyzer (HFA) Model II-I (Carl Zeiss Meditec, Dublin, CA, USA) using a 20-point custom test design to include test target locations that are relevant when a driver gazes toward the roadway environment through a vehicle's windshield or dashboard. A detailed description of the test rationale and procedure has been published. Light sensitivity was measured in each eye separately using the HFA's full-threshold procedure using a white stimulus-size III target at each of the 20 monocular visual field locations. The monocular visual fields from each participant were combined to form a binocular field consisting of 21 points spanning 60° to the right and left, 15° to the superior field, and 30° to the inferior field. The sensitivity at each test location was defined by the more sensitive point (higher value) for the two eyes. A participant was defined as having severe visual field impairment if the average sensitivity across all points was in the lowest quartile of sensitivity (worse sensitivity).

Driving cessation

At each telephone survey, the interview included questions about driving status and cessation. Driving cessation was defined as a negative response to the question "Do you currently drive?" If no, participants were asked to explain why they stopped driving and the month and year they had stopped driving. Since participants were not asked to choose one main reason, it is possible participants responding to this question provided more than one reason or diagnosis. Authors CH and CO read through the explanations for why they stopped driving to get a general impression of the comments made by the participants. Comments were grouped into nine broad categories according to the theme of the comment 1) medical problem, 2) vision problem, 3) no car to drive or cannot afford to maintain the car, 4) personal choice to stop driving or didn't feel safe when driving anymore, 5) doctor told the participant not to drive, 6) family member told the participant not to drive, 7) the participant was involved in a motor vehicle collision, 8) someone else is able to drive the participant, and 9) other. For the largest category (medical conditions), the comments were further summarized according to the medical system: musculoskeletal (e.g. fracture, bone break, arthritis, hip or knee replacement surgery, or problems with neck, shoulder, arm), neurological problems (e.g. stroke, dementia, Amyotrophic lateral sclerosis, Parkinson's disease, nerve problems, slow reactions, bad reflexes, syncope, lose consciousness, tremors), heart problems (e.g. heart attack, bypass surgery), cancer (e.g. cancer in any location, chemotherapy), pulmonary problems (e.g. low oxygen, fluid in lungs), syndrome of aging (e.g. too old, lose balance, falls, trouble walking), in rehab or long term care (e.g. in rehab, assisted living, hospital), or other medical problem or unspecified illness. Categories were not mutually exclusive.

Statistical Analysis

Characteristics of the study sample at baseline were summarized for the overall sample. Cox proportional hazards models were used to generate crude and adjusted hazard ratios (HRs) these characteristics and incident driving cessation. Potential confounding factors were selected because of their statistical association with risk of driving cessation in the crude analysis and included age, gender, marital status, number of medical conditions, and miles driven in the crude analysis. A log(-log) plot was used for each survival analysis to validate the proportionality assumption for each vision measurement. In a secondary analysis, a competing risks model by Fine and Gray was used to calculate the cumulative incidence of driving cessation after accounting for the burden of mortality.

Results

Descriptive statistics of the study sample are presented in by driving cessation status. The risk of driving cessation was higher for those who were older, female, not married, and those who reported having more medical comorbidities. In addition, poorer vision scores in terms of contrast sensitivity, visual fields, visual processing speed as measured by UFOV and Trails B, and spatial ability were risk factors for incident cessation. Participants who ceased driving in subsequent years were also driving fewer days per week and miles per year at baseline. The risk of driving cessation did not differ in terms of race, education, hearing impairment, or visual acuity, and MMSE impairment status.

Table 1

During the study period, 164 older drivers stopped driving which corresponds to a cumulative incidence of driving cessation, accounting for competing mortality, of 8.5% (). Of the 164 who stopped driving during the study period, 44 (27%) resumed driving at least once. The results of the crude and adjusted models are summarized in . In terms of visual functioning, those with impaired contrast sensitivity (HR = 1.73, 95% CI 1.10-2.72, p=0.018) and severe visual field impairment (HR = 1.78, 95% CI 1.29-2.46, p=0.0004) had a significantly increased risk of driving cessation compared to those without impairment after adjusting for age, gender, marital status, number of medical conditions, and miles driven. Impaired visual acuity was not significantly associated with driving cessation, even in the crude analysis. Participants with impaired higher order visual processing as measured by UFOV and Trails B, and impaired spatial ability were more likely to cease driving compared to those without impairment. The strength of the crude associations weakened after adjustment; however, these associations remained statistically significant. In addition, the association between UFOV scores and driving cessation increased in a stepwise fashion such that older adults were more likely to stop driving as UFOV scores became worse (UFOV scores 150-350, HR = 1.52, 95% CI 1.07-2.16, p=0.021; UFOV scores >350, HR = 1.79, 95% CI 1.16-2.78, p=0.0092).

Table 2

Respondents who stopped driving were asked to explain why they stopped driving. Medical problems (63%) and vision problems (17%) were mentioned most frequently (). The most common medical problems were related to the musculoskeletal system, neurological problems, and syndromes of aging. Beyond medical and visual, several other reasons for driving cessation were reported. In a similar proportion of responses, participants mentioned not having a car to drive, or not being able to afford to maintain a car, or not feeling safe when driving, or it was a personal choice to stop driving. About one-fifth reported giving up driving based on advice from a family member or doctor. Eight percent specified a reason for stopping was involvement in a motor vehicle crash. Only 5% reported that someone else could always drive them. Less than 2% said their license expired or had some other reason that did not fit in the other categories.

Discussion

In the current study, we examined measures of visual sensory as well as higher order visual processing skills as risk factors for driving cessation over a 3-year prospective study of older adults. In this population-based sample, the vast majority were still driving at the end of the study. Of those who stopped, impaired contrast sensitivity, visual fields, visual processing speed as measured by UFOV and Trails B, and spatial ability were significant risk factors for subsequent driving cessation after adjusting for demographic characteristics, number of medical conditions, and miles driven. The strength of the association between each visual characteristic and driving cessation was similar in magnitude. The association with contrast sensitivity and visual fields has been previously observed. In more recent longitudinal studies, various measures of cognitive functioning, UFOV in particular, have been associated with driving cessation. The results of this study extend these findings to include visual processing speed measured by Trails B and spatial ability.

In contrast to other studies, visual acuity was not associated with driving cessation. At the time of this study, Alabama did not have a vision rescreening policy in place when one renews their license. This means that participants' visual acuity had not been screened for licensure since their initial application as a young adult or when they moved to the state. Most state regulations implement a vision rescreening test and require a visual acuity of 20/40 or better for licensure. As one would expect, individuals with impaired visual acuity would fail the DMV screening test and would not be able to renew their licenses which would require them to stop driving. While this may be the case in many other states, it does not apply to Alabama, so our lack of association is not due to vision standard laws, but more likely that visual acuity impairment does not seem to impact the decision to stop driving. This result may not be surprising since visual acuity is not associated with crash risk, so drivers' assessment of risk remains low and the individual continues to drive. In contrast, many of the other visual factors examined in this study assess one's ability to recognize hazards and divide their attention effectively while driving and have been associated with crash involvement. The observed associations with driving cessation suggest that in the absence of visual acuity licensing renewal laws, some older adults may still self-regulate their driving when their visual skills necessary for safe driving become impaired.

When demographic and health characteristics of driving cessation were examined prospectively, the pattern of results was somewhat consistent with the literature. Older age and number of medical conditions have been observed in prior studies. The present results suggest that female gender is a risk factor for driving cessation, but these results are not consistent with more recent cohorts. We did not observe an association between MMSE impairment and driving status. It is possible that those with cognitive impairment were unaware of their deficit and perceived no reason to stop driving or that deterioration in cognitive ability may have occurred after the baseline assessment. Finally, we found those who were not married were more likely to stop driving. This is in contrast to other reports that found those with other drivers in the household were more likely to stop driving or found no association. It is possible those who were not married were living with other drivers or had adequate social support from family and friends, though this was not assessed.

The present study also found that for those who stopped driving, about one-quarter returned to driving at a later point. In prior studies, return to driving was often assessed in the setting of specific diseases such as stroke or head injury. We did not assess the reasons older drivers returned to driving or whether anything was done to improve their driving skills (e.g. additional driver training, cognitive speed of processing training, cataract surgery). It is possible that they self-regulated their driving in a postoperative phase (e.g. hip replacement, knee replacement). Another explanation for return to driving may be that they had inadequate support and had to resume driving due to lack of transportation.

The reasons for driving cessation cited by our participants seemed logical and represented the range of physical, visual, cognitive skills required in driving. Medical problems were the most common reason to stop driving. Specifically muscle-skeletal problems may suggest that the problem lead to loss in gross motor skills or limited activities. Recent studies by Edwards et al. and Anstey et al. suggest that physical abilities are better predictors of driving outcomes than presence or absence of chronic medical conditions. Almost one-fifth admitted a neurological problem as a factor in their decision to cease driving, supporting the idea that cognitive functioning plays an important role in a sample of community-dwelling adults where the vast majority did not have dementia. Other reasons reported do not reflect driver competence, but rather social and economic issues of continued driving. For some, the decision to stop driving was prompted by costs related to maintaining a vehicle. For many elderly living on fixed income, costs related to maintaining a vehicle or paying for alternative transportation may be prohibitive. Others were influenced by family and physicians or had other transportation options available to them.

Overall, these findings suggest a variety of factors, not just vision, influence the decision to stop driving. However, grouping the reasons for driving cessation by body system identifies specific systems that may be amenable to intervention to prolong driving. Visual processing speed is particularly relevant given that prior research has demonstrated that cognitive difficulties in some older adults can be remediated through speed of processing training and speed of processing training may delay driving cessation. In addition, clinicians could have a dialogue with older patients with impaired vision to discuss ways to optimize satisfaction after driving stops. In terms of public health, more research is needed to understand whether prolonging driving mobility among older adults could potentially avoid other negative health consequences of not being a driver.

The results of this study must be interpreted in light of strengths and limitations. The large, population-based nature of the sample increases the external validity of the observed results for the segment of the population who are licensed and are actually driving the vehicle. Another strength includes the assessment of several different visual and processing measures in the same sample in order to evaluate their ability to predict driving cessation. In particular, this is the first study to report an association with light sensitivity in the driving visual field and driving cessation. The prospective design provides insight into driving cessation, namely to understand the temporal order of events, which is not available from cross-sectional analyses. In addition, information on a miles driven which would have likely affected driving status was collected each year of this study in order to adequately assess driving exposure.

Limitations much be acknowledged. Driving cessation was based on self-report, a common problem in studies on this topic. Some participants may not recall the precise month and year of driving cessation. It is unlikely this was differential between those who had vision loss and those who did not. Still, this could result in measurement error and would bias the findings toward the null, making our results conservative. Individuals with normal visual function at baseline may have developed an impairment during follow-up, which may have influenced the decision to cease driving. This potential source of information bias would have made these estimates more conservative. Some participants may have been reluctant to discuss reasons for cessation if it was a stressful life transition or was perceived as undesirable. Therefore, not all reasons for driving cessation may have been reported or may have been underreported. Another potential source of bias is loss to follow up, especially if there was differential loss according to visual characteristics and driving cessation. However, about 10% of participants did not participate in the third follow-up interview, and it is unlikely this would have greatly impacted the results. Finally, Ragland et al. and later Ackerman et al. provided empirical support that older adults cease driving due to physical functioning status, which was not collected in this analysis, so we cannot rule out residual confounding.

Conclusion

Assessment of visual functioning can provide valuable information about subsequent risk of driving cessation among older adults. A variety of factors influence the decision to stop driving, suggesting that programs could be developed to target areas which are amenable to intervention in order to prevent or delay driving cessation since driving is primary mode of transportation for older adults.

Acknowledgments

None

Funding Sources: This research was funded by the National Eye Institute (R01-EY18966) and the National Institute on Aging (P30-AG22838) of the National Institutes of Health; the American Recovery and Reinvestment Act of 2009; the EyeSight Foundation of Alabama; the Able Trust; and Research to Prevent Blindness, Inc.

Footnotes

Conflicts of Interest: None

References

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Association of visual sensory function and higher order visual processing skills with incident driving cessation

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Many studies on vision and driving cessation have relied on measures of sensory function, which are insensitive to the higher order cognitive aspects of visual processing. The purpose of this study was to examine the association between traditional measures ...

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The question of how our how our brains memorize daily experiences has intrigued cognitive psychologists and neuroscientists for decades. Amongst a range of theories attempting to explain how we encode and later recall information, a curious influence over memory encoding has been observed: our emotional state at the time of an event occurring can affect our ability to memorize details of it.

Moreover, emotions are believed to play a role in determining whether we can recall a stored memory at the time we try to revisit it. Coaxing ourselves into the same mood we were experiencing when we witnessed an event, for instance, has been found to often have a positive effect on our chances of recalling specific details relating to it.

It appears that emotionally charged situations can lead us to create longer lasting memories of the event. When we are led to experience feelings of delight, anger or other states of mind, vivid recollections are often more possible than during everyday situations in which we feel little or no emotional attachment to an event.

The findings of a series of studies have implied that emotion plays a role at various specific stages of remembering ( encoding) information, consolidating memories and during the recall of experiences at a later date. For instance, cognitive psychologist Donald MacKay and a team of researchers asked participants to take part in an emotional Stroop test, in which they were presented with different words in quick succession. Each word was printed in a different color, and subjects were asked to name the color. They were also later asked to recall the words after the initial test. MacKay found that taboo words, which were intended to elicit an emotional response, were recalled more frequently than words which carried less emotional connotations (MacKay et al, 2004).

The results of MacKay's experiment, and others with similar outcomes, suggest that an emotive state at the time we perceive and process an observation can positively affect the encoding of information into the short or even long-term memory.

Although the emotional Stroop test demonstrates this link between emotion and memory, the role of emotion has been long suspected.

In 1977, researchers at Harvard published a paper entitled Flashbulb Memories, in which they noted that people are often able to vividly recollect where they were when an event occurred that was significant to them. They used the example of the assassination of U.S. president John F. Kennedy, but many people will hold similarly detailed memories of what they were doing when they learned of the terrorist attacks of September 11th, 2001 or the death of a famous person such as Elvis Presley or Michael Jackson. Unlike a photographic memory, these "flashbulb memories" tend only to occur only when the event is felt to be of particular significance to a person or when it causes a state of surprise, supporting the idea that a person's emotional state at the time of an event can influence whether or not it is encoded as a memory (Brown and Kulik, 1977).

Now, the idea that we would be more likely to remember an event of historical significance than a mundane observation during a commute to work may seem obvious. The assassination of JFK is often considered to have been one of the most significant events in U.S. 20th Century history, even by those who were born after the event and only learnt of it in history classes. However, another study in which participants were asked to complete questionnaires to gauge their recollection of the attempted assassination of Ronald Reagan suggested that the significance of an event tends to be less influential than the emotions experienced at the time of encoding. Pillemer (1984) found that people's reported emotional state at the time of the assassination attempt helped to influence whether memories would be stored more than whether or not they merely rehearsed - considered or discussed - the memory afterwards.

Why Would Emotions Influence Memory?

Whilst there appears to be mounting evidence in support of emotions' role in memory, the question remains of why emotions, over judgements we exercise more control over, affect our encoding of events in this way. What purpose is served by being able to recall a distressing occasion that we would rather forget, better than the facts that we need to learn for an exam?

First, let us remember the evolutionary purpose served by emotional experiences. One theory suggests that our ability to experience distressing emotions, fear and anxiety is an inherited trait which has historically given our ancestors a survival advantage. Öhman and Mineka (2001) claimed that, as emotions tend to operate beyond our conscious control, their intuitive nature gives us an early warning of impending threats or dangers in our external environment (Öhman and Mineka, 2001). For example, whilst crossing through the powerful currents of a river, the feeling of fear alerts us to the danger to our lives and helps to ensure that we pay attention to hazards. Negative emotions may also deter us from engaging in such activities in the first place! Similarly, feelings of happiness created by a secure environment, such as a home, warm and free from threats, may encourage us to continue risk-averse, adaptive behavior.

Attention, Emotion and Memory

Whilst the emotional distortion of memory encoding and recall seems to be counter-productive to the maintenance of an accurate view of the outside world, their influence may be better understood in terms of how it affects our attention, and how subject of our focus in turn affects what our memories encode.

Research suggests that our brains are more likely to focus on stimuli of emotional significance. This was demonstrated in a study in which participants were shown a control set of emotionally neutral images with pictures such as those depicting various injuries, eliciting an emotional response. Schupp et al (2007) found that subjects' attention increased when emotional images were displayed to them, suggesting that our attention is instinctively drawn to emotive subjects.

As we tend to remember by focussing and elaborating on an observation, this may go some way to helping us to understand why emotions influence memories.

Although emotions can draw our attention to subjects, their influence on our conscious experience of the world does not end here. After switching our attention from one subject to another, a brief phenomenon may occur, known as an attentional blink, during which we are unable to fully focus on the second stimuli.

As a result, we may remember something less well if we have been focussing on something else immediately beforehand. Studies have suggested that there is an emotional component to this attentional blink.

In one experiment, researchers were able to limit participants' ability to remember neutral information by presenting them with an emotive stimuli very shortly beforehand (Smith et al, 2006).

Mood Congruence Effect

A person's focus of attention will inevitably affect what they remember during an experience, but emotions appear to affect memory encoding more profoundly than simply drawing attention to a particular emotive subject over a neutral one.

Your emotional state at the time of an event can help to determine whether or not your observations during it will be stored ready for recall later on.

One study found that the subjects of an experiment were more able to associate with stories whose content matched their moods at the time of them being recounted to them. A happy person, for example, may associate more with characters who are positive and enthusiastic, whilst a sad person may identify with a character who is the subject of persecution. Gordon Bower, who conducted the study, found that this mood congruence effect - an association with stimuli which reflect our current mood - influenced people's ability to remember information (Bower, 1981). The result of this effect is that you may be more able to recall having read a negative report in a newspaper if you were in a low mood, rather than happy, at the time of reading it.

Role of the Amygdalae

The means by which emotions are able help determine which memories are processed is also the subject of ongoing studies.

Whilst the process is still not fully understood, it is believed that the hippocampus and two amygdalae regions in the brain play key roles in processing both memories and emotions, and that interactions between the two may reinforce the link between memory and emotions.

One study which used tomography to monitor the amygdala found increased activity when remembering emotive stimuli, whether they were of a positive or negative nature.

Hamann et al (1999) also proposed that one role of the amygdala is to "modulate" activity in the hippocampus, which is believed to play a role in the formation of new memories (Hamann et al, 1999).

Rehearsal and Retrieval

Whilst emotions are believed to affect the transformation of events into memories at the point of encoding, our mood whilst trying to recall events at a later date can affect our ability to access those memories.

In a joyous mood, we may be able to better remember past events that brought joy to us. For example, whilst on a beach, you may be able to recall happy memories of a memorable family gathering over a negative event. In contrast but following the same principle, whilst in a low mood, you may recall sad memories more easily. This correlation between our mood at the point of recall and the type of memories we able to recall is known as the mood-state dependent memory.

James Laird of Clark University demonstrated this effect in a series of experiments, in which they were able to artificially induce moods by varying participants' facial expressions accordingly.

When subjects were asked to perform expressions which would create a fearful expression, for instance, they reported increased feelings of fear. Laird and his fellow researchers found that the induced mood then affected the memories that a participant was able to access - someone experiencing some emotions, such as fear, may be better able to remember other memories of similarly fearful events than when they are in a more emotional neutral state (Laird et al, 1989). This research appears to support the idea that memory recall is often mood-state dependent.

Emotions and Forgetting

If emotions help to determine whether or not a memory is consolidated into the long-term memory, it seems equally plausible that the emotions associated with a memory may influence a person's ability to access it.

Psychoanalyst Sigmund Freud was one of the first people in the field of psychology to investigate the emotional associations linked to memories. Freud felt that memories of particularly traumatic events, or those which would cause distress to a person if dwelled upon them, may be repressed.

Such memories are not entirely forgotten, but the conscious mind is prevented from recalling them in case, according to Freud, they created feelings of guilt or shame. Instead, they remain in the unconscious mind and affect us in ways that we do not realise. In a series of studies, Freud identified repressed feelings and memories as being the source of various phobias, for instance.

Using regression in a state of hypnosis, along with techniques such as free association, Freud believed that these memories could be brought back into the conscious mind so that a person may accept them and resolve issues associated with such repressed memories.

Rose-Tinted Glasses? The Fading Affect Bias

More recently, the effect of emotions on the memories that we forget has been identified in the form of the fading affect bias. This bias leads us to tend to forget memories of negative emotional valence and focus on memories which affect us more positively. Idealised memories of childhood, for instance, may be due to our minds focussing on the positive, rather than negative, events that occurred whilst growing up.

This fading affect bias was demonstrated in a 2009 study which tested the memory recall of hundreds of participants, and found that memories of a positive valence, when recalled to others, are more likely to remain accessible than those of a negative valence (Walker et al, 2009).

The findings of these experiments support the results of a separate study in which hundreds of nuns were questioned regarding prior life events. Researchers found that the older participants were, the more they tended to recall memories of a positive valence than negative events (Kennedy, Mather and Cartensen, 2004). The older we get, it appears, the more we may view the past through 'rose-tinted glasses'.

Effect of Suppressing Emotions

Can our conscious efforts to change our emotions during an event alter the way in which they affect our memories' encoding of the experience?

Researchers at Stanford university tested this idea with experiments in which participants were shown varying stimuli such as a video. During the experiments, some participants were asked to suppress their emotions and not allow them to show to others. Afterwards, their ability to recall the stimuli presented to them was measured. Interestingly, people who had attempted to suppress their emotions tended to demonstrate an impaired ability to recall their experience afterwards compared to those who allowed their emotional state to show (Richards and Gross, 2000). One explanation for the results of this study is that a conscious focus on, and self-awareness of, one's emotional state may detract from a person's observation of their environment, including external stimuli such as the video.

Gender Differences

The way in which we allow signs of our emotions to show is not the only factor to affect the link between memory and emotional state. Gender differences, too, seem to influence memory, with males and females handling emotive memories differently.

fMRI scans conducted on people carrying our memory tasks whilst in a negative emotional state have revealed differences in how the brain processes information whilst a particular emotional state is being experienced. The scans revealed that activity may be focussed in the amygdala, as discussed earlier, in females compared to males (Koch et al, 2007).

Further gender differences between the way memories are handled in males and females in an emotional state have also been found. Sabrina Kuhlmann and her colleagues carried out a study which tested the effect that cortisol, which is often released during stressful experiences, has memory recall. After inducing a state of stress and conducting a memory task, Kuhlmann found that the release of cortisol had a significant effect on male participants' memories which did not occur to the same extent in females (Kuhlmann et al, 2001).

Implications

The role that emotions play in our ability to encode and recall information may seem an inevitable, uncontrollable aspect of everyday life. However, the way in which emotions distort our perception and recollection of reality has implications beyond the study of psychology.

Take eyewitness testimonies in court cases, for example. Such valuable forms of evidence can play a key role in the legal process and in securing convictions. The reliability of eyewitness testimonies has become a subject of focus in recent years, with the influence of interrogation techniques and other factors being found to sometimes affect witnesses' recall of events.

References

1. Mackay, D.G., Shafto, M., Taylor, J.K., Marian, D.E., Abrams, L and Dyer, J.R. (2004). Relations between emotion, memory, and attention: Evidence from taboo Stroop, lexical decision, and immediate memory tasks. Memory & Cognition. 32(3). 474-488.

2. Brown, R. and Kulik, J. (1977). Flashbulb Memories. Cognition. 5(1). 73-99.

3. Pillemer, D.B. (1984). Flashbulb memories of the assassination attempt on President Reagan. Cognition. 16(1). 63-80.

4. Öhman, A. and Mineka, S. (2001). Fears, Phobias, and Preparedness: Toward and Evolved Module of Fear and Fear Learning. Psychological Review. 108(3). 483-522.

5. Schupp, H.T., Stockburger, J., Codispoti, M., Junghöfer, M., Weike, A.I. and Hamm, A.O. (2007). Selective Visual Attention to Emotion. The Journal of Neuroscience. 27(5). 1082-1089.

6. Smith, S.D., Most, S.B., Newsome, L.A. and Zald, D.H. (2006). An Emotion-Induced Attentional Blink Elicited by Aversively Conditioned Stimuli. Emotion. 6(3). 523-527.

7. Bower, G.H. (1981). Mood and Memory. American Psychologist. 36(2). 129-148.

8. Hamann, S.B., Ely, T.D., Grafton, S.T. and Kilts, C.D. (1999). Amygdala activited related to enhanced memory for pleasant and aversive stimuli. Nature Neuroscience. 2. 289-293.

9. Laird, J.D., Cuniff, M., Sheehan, K., Shulman, D. and Strum, G. (1989). Emotion Specific Effects of Facial Expressions On Memory for Life Events. Journal of Social Behavior and Personality. 4(2). 87-98.

10. Walker, W.R., Skowronski, J.J., Gibbons, J.A., Vogl, R.J. and Ritchie, T.D. (2009). Why people rehearse their memories: Frequency of use and relations to the intensity of emotions associated with autobiographical memories. Memory. 17(7). 760-773.

11. Kennedy, Q., Mather, M. and Carstensen, L.L. (2004). The Role of Motivation in the Age-Related Positive Bias in Autobiographical Memory. Psychological Science. 15(3). 208-214.

12. Richards, J.M. and Gross, J.J. (2000). Emotion Regulation and Memory: The Cognitive Costs of Keeping One's Cool. Journal of Personality and Social Psychology. 79(3). 410-424.

13. Koch, K., Pauly, K., Kellermann, T., Seiferth, N.Y., Reske, M., Backes, V., Stöcker, T., Shah, N.J., Amunts, K., Kircher, T., Schneider, F. and Habel, U. (2007). Gender differences in the cognitive control of emotion: An fMRI study. Neuropsychologia. 45. 2744-2754.

14. Kuhlmann, S., Piel, M. and Wolf, O.T. (2001). Impaired Memory Retrieval after Psychosocial Stress in Healthy Young Men. The Journal of Neuroscience. 25(11). 2977-2982.

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Emotion And Memory: How Do Your Emotions Affect Your Ability To Remember Information And Recall Past Memories?

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The question of how our how our brains memorize daily experiences has intrigued cognitive psychologists and neuroscientists for decades. Amongst a range of theories attempting to explain how we encode and later recall information, a curious influence over memory encoding has been observed: our emotional state at the time of an event occurring can affect our ability to memorize details of it.

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The Neuropsychotherapist - The Neuroscience of Psychotherapy

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Definition

The prefrontal cortex (PFC) is the cerebral cortex which covers the front part of the frontal lobe. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behaviour. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals. The most typical psychological term for functions carried out by the prefrontal cortex area is executive function. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable outcomes). The frontal cortex supports concrete rule learning, while more anterior regions along the rostro-caudal axis of the frontal cortex support rule learning at higher levels of abstraction. ( adapted from Wikipedia)

Prefrontal cortex of left cerebral hemisphere. Shown in red. Polygon data were generated by Database Center for Life Science(DBCLS)Polygon data are from BodyParts3D[2]. - [1]

The Prefrontal Cortex in 60 seconds from The Neuropsychotherapist on Vimeo.

Clinical Relevance

Reduced volume and interconnections of the frontal lobes with other brain regions has been observed in people diagnosed with mental disorders; those subjected to repeated stressors; suicides; those incarcerated; criminals; sociopaths; those affected by lead poisoning; and daily cannabis users.

Feeling guilt or remorse, and to interpret reality, may be dependent on a well-functioning prefrontal cortex.

The size and number of connections in the prefrontal cortex could relate directly to sentience, as the prefrontal cortex in humans occupies a far larger percentage of the brain than any other animal.

The left and right halves of the prefrontal cortex appear to become more interconnected in response to consistent aerobic exercise.

Practicing mindfulness can enhance prefrontal activation, which is correlated with increased well-being and reduced anxiety.

Resources

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Prefrontal Cortex | The Neuropsychotherapist - The Neuroscience of Psychotherapy

# data[].attributes.attachment_link.description
Prefrontal Cortex Definition The prefrontal cortex (PFC) is the cerebral cortex which covers the front part of the frontal lobe. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behaviour. The basic activity of this brain region is considered to be orchestration of thoughts and actions ...