# data[].attributes.headline
Types of  strokes (John Hopkins Medicine)

# data[].attributes.subject
Types of  strokes (John Hopkins Medicine)

# data[].attributes.attachment_link.readable_text
What are the different types of stroke?

Strokes can be classified into 2 main categories:

Ischemic strokes. These are strokes caused by blockage of an artery (or, in rare instances, a vein). About 87% of all strokes are ischemic.

Hemorrhagic stroke. These are strokes caused by bleeding. About 13% of all strokes are hemorrhagic.

What is an ischemic stroke?

An ischemic stroke occurs when a blood vessel that supplies the brain becomes blocked or "clogged" and impairs blood flow to part of the brain. The brain cells and tissues begin to die within minutes from lack of oxygen and nutrients. Ischemic strokes are further divided into 2 groups:

Thrombotic strokes. These are caused by a blood clot that develops in the blood vessels inside the brain.

Embolic strokes. These are caused by a blood clot or plaque debris that develops elsewhere in the body and then travels to one of the blood vessels in the brain through the bloodstream.

Thrombotic stroke

Thrombotic strokes are strokes caused by a thrombus (blood clot) that develops in the arteries supplying blood to the brain. This type of stroke is usually seen in older persons, especially those with high cholesterol and atherosclerosis (a buildup of fat and lipids inside the walls of blood vessels) or diabetes.

Sometimes, symptoms of a thrombotic stroke can occur suddenly and often during sleep or in the early morning. At other times, it may occur gradually over a period of hours or even days.

Thrombotic strokes may be preceded by one or more "mini-strokes," called transient ischemic attacks, or TIAs. TIAs may last for a few minutes or up to 24 hours, and are often a warning sign that a stroke may occur. Although usually mild and transient, the symptoms caused by a TIA are similar to those caused by a stroke.

Another type of stroke that occurs in the small blood vessels in the brain is called a lacunar infarct. The word lacunar comes from the Latin word meaning "hole" or "cavity." Lacunar infarctions are often found in people who have diabetes or high blood pressure.

Embolic stroke

Embolic strokes are usually caused by a blood clot that forms elsewhere in the body (embolus) and travels through the bloodstream to the brain. Embolic strokes often result from heart disease or heart surgery and occur rapidly and without any warning signs. About 15% of embolic strokes occur in people with atrial fibrillation, a type of abnormal heart rhythm in which the upper chambers of the heart do not beat effectively.

Surviving Stroke at a Young Age | Sam's Story

What is a hemorrhagic stroke?

Hemorrhagic strokes occur when a blood vessel that supplies the brain ruptures and bleeds. When an artery bleeds into the brain, brain cells and tissues do not get oxygen and nutrients. In addition, pressure builds up in surrounding tissues and irritation and swelling occur, which can lead to further brain damage. Hemorrhagic strokes are divided into 2 main categories, including the following:

Intracerebral hemorrhage

Intracerebral hemorrhage is usually caused by high blood pressure. Bleeding occurs suddenly and rapidly. There are usually no warning signs and bleeding can be severe enough to cause coma or death.

Subarachnoid hemorrhage

Subarachnoid hemorrhage results when bleeding occurs between the brain and the membrane that covers the brain (meninges) in the subarachnoid space. This type of hemorrhage is often due to an aneurysm or an arteriovenous malformation (AVM). It can also be caused by trauma.

An aneurysm is a weakened, ballooned area on an artery wall and has a risk for rupturing. Aneurysms may be congenital (present at birth), or may develop later in life due to such factors as high blood pressure or atherosclerosis.

An AVM is a congenital disorder that consists of a disorderly tangled web of arteries and veins. The cause of AVM is unknown, but it is sometimes genetic or part of certain syndromes.

What are recurrent strokes?

Recurrent strokes occur in about 1 in 4 people who have had a stroke within 5 years after a first stroke. The risk is greatest right after a stroke and decreases over time. The likelihood of severe disability and death increases with each recurrent stroke. About 3% of people who have had a stroke have a second stroke within 30 days of their first stroke, and about one-third have a second stroke within 2 years.

Rehabilitation After a Stroke: Mary's Story

# data[].attributes.attachment_link.description
Strokes are classified as either ischemic or hemorrhagic. Ischemic strokes are caused by blockage of an artery. Hemorrhagic strokes are caused by bleeding in the brain.

# data[].attributes.headline
The effects of the COVID-19 pandemic on students' academic performance and mental health: An overview

# data[].attributes.subject
The effects of the COVID-19 pandemic on students' academic performance and mental health: An overview

# data[].attributes.body
https://doi.org/10.1016/j.rspp.2024.100046

# data[].attributes.attachment_link.title
Association of Women's Health, Obstetric and Neonatal Nurses

# data[].attributes.attachment_link.description
Return to Learn > Professional Resources and News Releases > Partners and Projects > Association of Women’s Health, Obstetric and Neonatal Nurses

# data[].attributes.attachment_link.readable_text
Feeling tired as the sun starts to set may be a sign of a synchronized circadian rhythm. Since circadian rhythms are closely related to environmental cues like light, they can affect how a person feels throughout the day.

Understanding circadian rhythms and how they work can be essential for maintaining a healthy sleep-wake cycle. We discuss what circadian rhythms are, how they are affected by different factors, and how to prevent related sleep issues.

Circadian rhythms are 24-hour cycles that are part of the body's internal clock, running in the background to carry out essential functions and processes. One of the most important and well-known circadian rhythms is the sleep-wake cycle.

Different systems of the body follow circadian rhythms that are synchronized with a biological clock in the brain. This internal clock is directly influenced by environmental cues, especially light, which is why circadian rhythms are tied to the cycle of day and night.

When properly aligned, a circadian rhythm can promote consistent and restorative sleep. But when this circadian rhythm is thrown off, it can create significant sleep problems, including insomnia. Research is also revealing that circadian rhythms play an integral role in diverse aspects of physical and mental health.

Circadian rhythms work by helping to make sure that the body's processes are optimized at various points . The term circadian comes from the Latin phrase "circa diem," which means "around a day."

Circadian rhythms exist in all types of organisms. For example, they help flowers open and close at the right time and keep nocturnal animals from during the daytime when they would be exposed to more predators.

In people, circadian rhythms throughout the body. The digestive system produces proteins to match the typical timing of meals, and the endocrine system regulates hormones to suit normal energy expenditure.

The circadian rhythms throughout the body are connected to an internal clock located in the brain. Specifically, it is found in the suprachiasmatic nucleus (SCN), which is in a part of the brain called the hypothalamus. At different times of the day, clock genes in the SCN send signals to regulate activity throughout the body.

The SCN is highly sensitive to light, which serves as a critical external cue that influences the signals sent by the SCN to coordinate circadian rhythms in the body. For this reason, circadian rhythms are closely connected to day and night. While other cues, like exercise, social activity, and temperature, can affect the internal clock, light is the most powerful influence on circadian rhythms.

Is a Circadian Rhythm the Same As a Biological Clock?

Biological clocks help regulate the timing of bodily processes, including circadian rhythms. A circadian rhythm is an effect of a biological clock, but not all biological clocks are circadian. For instance, plants adjust to changing seasons using a biological clock with timing that is distinct from a 24-hour cycle.

When people talk about circadian rhythm, it is most often in the context of sleep. The sleep-wake cycle is one of the most clear and critical examples of the importance of circadian rhythms.

During the day, light exposure causes the internal clock to send signals that generate alertness and help keep us awake and active. As night falls, the internal clock initiates the production of melatonin, a hormone that promotes sleep, and then keeps transmitting signals that help us stay asleep through the night.

In this way, circadian rhythms align sleep and wakefulness with day and night to create a stable cycle of restorative rest that enables increased daytime activity.

While the sleep-wake cycle is one of the most prominent circadian rhythms, these 24-hour cycles play a vital role in virtually all systems of the body.

Research continues to uncover details about circadian rhythms, but evidence has to metabolism and weight through the regulation of blood sugar and cholesterol. Circadian rhythms influence mental health as well, including the risk of psychiatric illnesses like depression and bipolar disorder as well as the potential for like dementia.

There are indications that circadian rhythms have an important influence on the immune system as well as processes of DNA repair that are involved in . Early-stage research indicates that circadian cycles can influence the and that new medications may be used more strategically.

When circadian rhythm is thrown off, the body's systems do not function optimally. A disturbed sleep-wake circadian rhythm can give rise to serious sleep problems. Without the proper signaling from the body's internal clock, a person can have difficulty falling asleep, wake up more often throughout the night, or be unable to sleep as long as they want into the morning. Their total sleep can be reduced, and a disrupted circadian rhythm can also mean shallower, fragmented, and lower-quality sleep.

In addition, studies have identified circadian rhythm disruptions as to obstructive sleep apnea (OSA), a sleep disorder marked by repeated lapses in breathing. OSA reduces the body's oxygen levels and causes numerous sleep interruptions through the night.

As a whole, a misaligned circadian rhythm can negatively affect sleep in many ways, increasing a person's risk of insomnia and excessive daytime sleepiness. Given the essential role of sleep for productivity and overall health, there are often significant consequences when a person's circadian rhythm is off.

Circadian Rhythms

Disruptions to circadian rhythm can occur over the short- or long-term. Experts have identified a number of types of circadian rhythm sleep-wake disorders (CRSWD) based on their characteristics and causes.

Jet lag disorder: This occurs when a person travels across multiple time zones in a short period of time. Until a person's circadian rhythm can acclimate to the day-night cycle of their new location, they are likely to suffer sleeping problems and fatigue from jet lag.

Shift work disorder: Work obligations can cause major disruptions in a person's circadian rhythm. Shift work, which requires having to work through the night and sleep during the day, puts a person's sleep schedule directly at odds with the local daylight hours.

Advanced sleep phase disorder: People with this rare type of disruption find that they get tired early in the evening and wake up very early in the morning. Even if they want to be up later at night or sleep later in the morning, people with an advanced sleep phase disorder usually cannot do so.

Delayed sleep-wake phase syndrome: This type of circadian rhythm disruption is associated with staying up late at night and sleeping in late in the morning. The exact cause is unknown, but delayed sleep-wake phase syndrome may be related to genetics, underlying physical conditions, and a person's behavior.

Non-24-hour sleep wake disorder: Non-24-hour sleep wake disorder occurs primarily in people who are blind and are not able to receive light-based cues for their circadian rhythm. Their body still follows a 24-hour cycle, but their sleeping hours constantly shift backward by minutes or hours at a time.

affect the brain National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. Irregular sleep-wake rhythm disorder: People with this rare disorder have no consistent pattern to their sleep and may have many naps or short sleeping periods throughout a 24-hour day. Irregular sleep-wake rhythm disorder is frequently connected to conditions that View Source , such as dementia or traumatic brain injury.

Some circadian disruptions are related to individual behavior, such as for travel or work, that makes sleep-wake schedules inconsistent with normal daylight hours. Other disorders stem from an underlying issue that causes an inability to receive or process environmental cues that regulate the body's biological clock. In certain situations, genetic causes may be involved, or the cause may be unknown.

How To Maintain a Healthy Circadian Rhythm

While it is not possible to have full control over circadian rhythms, there are healthy sleep tips that can be followed to better entrain these 24-hour sleep cycles.

Seek out sun: Exposure to natural light, especially early in the day, helps reinforce the strongest circadian cue.

Follow a consistent sleep schedule: Varying your bedtime or morning wake-up time can hinder your body's ability to adjust to a stable circadian rhythm.

Get daily exercise: Activity during the day can support your internal clock and help make it easier to fall asleep at night.

Avoid caffeine: Stimulants like caffeine can keep you awake and throw off the natural balance between sleep and wakefulness. Everyone is different, but if you are having trouble sleeping at night, you should avoid caffeine after noon.

Limit light before bed: Artificial light exposure at night can interfere with circadian rhythm. Experts advise dimming the lights and putting down electronic devices in the lead-up to bedtime.

Keep naps short and early in the afternoon: Late and long naps can push back your bedtime and throw your sleep schedule off-kilter.

Make the bedroom conducive to sleep: Your bedroom setting can influence your sleep habits and the quality of your sleep at night. Invest in a comfortable mattress, bedding, and sleep accessories.

These steps to improve sleep hygiene can be an important part of supporting a healthy circadian rhythm, but other steps may be necessary depending on the situation. If you have persistent or severe sleeping problems, daytime drowsiness, or a problematic sleep schedule, it is important to talk with a doctor who can best diagnose the cause and offer the most appropriate treatment.

Eric Suni has over a decade of experience as a science writer and was previously an information specialist for the National Cancer Institute.

Dr. Singh is the Medical Director of the Indiana Sleep Center. His research and clinical practice focuses on the entire myriad of sleep disorders.

Learn more about our Editorial Team

References

1. Brainard, J., Gobel, M., Scott, B., Koeppen, M., & Eckle, T. (2015). Health implications of disrupted circadian rhythms and the potential for daylight as therapy. Anesthesiology, 122(5), 1170-1175.
https://pubmed.ncbi.nlm.nih.gov/25635592/

2. Vitaterna, M. H., Takahashi, J. S., & Turek, F. W. (2001). Overview of circadian rhythms. Alcohol Research & Health, 25(2), 85-93.
https://pubmed.ncbi.nlm.nih.gov/11584554/

3. Sollars, P. J., & Pickard, G. E. (2015). The Neurobiology of Circadian Rhythms. The Psychiatric clinics of North America, 38(4), 645-665.
https://pubmed.ncbi.nlm.nih.gov/26600101/

4. Jagannath, A., Taylor, L., Wakaf, Z., Vasudevan, S. R., & Foster, R. G. (2017). The genetics of circadian rhythms, sleep and health. Human molecular genetics, 26(R2), R128-R138.
https://pubmed.ncbi.nlm.nih.gov/28977444/

5. MedlinePlus: National Library of Medicine (US). (2021. December 8). Degenerative nerve diseases., Retrieved February 16, 2023, from
https://medlineplus.gov/degenerativenervediseases.html

6. Sancar, A., Lindsey-Boltz, L. A., Gaddameedhi, S., Selby, C. P., Ye, R., Chiou, Y. Y., Kemp, M. G., Hu, J., Lee, J. H., & Ozturk, N. (2015). Circadian clock, cancer, and chemotherapy. Biochemistry, 54(2), 110-123.
https://pubmed.ncbi.nlm.nih.gov/25302769/

7. Sulli, G., Rommel, A., Wang, X., Kolar, M. J., Puca, F., Saghatelian, A., Plikus, M. V., Verma, I. M., & Panda, S. (2018). Pharmacological activation of REV-ERBs is lethal in cancer and oncogene-induced senescence. Nature, 553(7688), 351-355.
https://pubmed.ncbi.nlm.nih.gov/29320480/

8. Butler, M. P., Smales, C., Wu, H., Hussain, M. V., Mohamed, Y. A., Morimoto, M., & Shea, S. A. (2015). The Circadian System Contributes to Apnea Lengthening across the Night in Obstructive Sleep Apnea. Sleep, 38(11), 1793-1801.
https://pubmed.ncbi.nlm.nih.gov/26039970/

9. Zee, P. C., & Vitiello, M. V. (2009). Circadian rhythm sleep disorder: Irregular sleep wake rhythm type. Sleep Medicine Clinics, 4(2), 213-218.
https://pubmed.ncbi.nlm.nih.gov/20160950/

# data[].attributes.attachment_link.title
What Is Circadian Rhythm? | Sleep Foundation

# data[].attributes.attachment_link.description
Circadian rhythms promote quality sleep and overall health. Learn about the body's internal clock and how its 24-hour cycles affect sleep.

# data[].attributes.attachment_link.readable_text
Autism exists on a spectrum, which means that while all people on the spectrum will experience some of the differences mentioned above, the degree to which each autistic person experiences them and the amount of support they need, will vary. This is sometimes influenced by whether the person on the autism spectrum has any co-occurring health conditions . It is also influenced by the accessibility and relative safety of the environment and society autistic people inhabit; a society that we all contribute to and live in.

For more information about autism, check out the Autism Self Advocacy Network's (ASAN)online book, Welcome to the Autistic Community .

What Autism Isn't

In March 2018, the  (NASS) released the most up-to-date Canadian prevalence rate:  approximately 1 - 2% of the Canadian population is on the autism spectrum which means there are National Autism Spectrum Disorder Surveillance System 1 in 66 Canadian children and youth (ages 5-17) are diagnosed with Autism Spectrum Disorder (ASD). According to the  Canadian Medical Association Journal ,  approximately 135,000 autistic people in Ontario.

Having these numbers helps us advocate to the appropriate government ministries for the individual needs of all people on the autism spectrum ;and their families throughout the life course.

Download a PDF version of our language statement.

At Autism Ontario, our goal is to support and advocate alongside all autistic individuals across the province, regardless of race, ethnicity, income, religion, sexual orientation, or gender identity. We aim to actively and deliberately listen to and include all autistic community members to guide our choices relating to language.

Identity-first language reflects the belief that being autistic is an important part of a person's identity. Person-first language, including phrases such as "living with autism", reflects the idea that autism can be separated from a person. Results from a recent survey of over 7,000 autistic people suggest that approximately 90% of autistic people prefer identity-first language with a smaller proportion preferring person-first language. According to the Canadian Autism Spectrum Disorder Alliance (CASDA), there is a growing body of scientific and community literature documenting the dislike, amongst autistic individuals, of person-first language and its potential for increasing stigma. Disability scholars have also objected to the use of person-first language.

With the aim of being inclusive, respectful, and representative of the many people within our diverse community, we will use both identity-first and person-first referential language. We acknowledge that the use of language evolves rapidly and will continue to be an ongoing discussion within the autism community.

Four Directions Autism (a parent-to-parent support group for First Nations, Inuit, and Metis parents who have autistic children):

# data[].attributes.attachment_link.description
What is Autism? The clinical model defines autism, or Autism Spectrum Disorder, as a lifelong neurodevelopmental disorder that affects the way a person communicates and relates to people and the world around them. It can affect body language and posture, social interactions and relationships, how you engage with your interests, and sensory processing capacities.

# data[].attributes.attachment_link.description
Most microbes in and around our bodies are harmless, but some evolve to become deadly threats to individual and public health.

# data[].attributes.attachment_link.title
Chronic Traumatic Encephalopathy (CTE) | Brain Injury Canada

# data[].attributes.attachment_link.description
Chronic Traumatic Encephalopathy an occur in people who have a history of multiple head injuries. Learn more about what could happen with CTE and how it’s diagnosed.

# data[].attributes.attachment_link.readable_text
Diagnosing ADHD is a process with several steps.

If you think someone might have ADHD, the first step is to talk with a healthcare provider.

How is ADHD diagnosed?

Deciding if a person has ADHD is a process with several steps. There is no single test to diagnose ADHD, and many other problems, such as sleep disorders, anxiety, depression, and certain types of learning disabilities, can also have symptoms similar to ADHD.

When to talk with a doctor‎

Diagnosing ADHD in children

The healthcare provider will look to determine whether the child has another condition or conditions that might explain the symptoms better, or that can often occur at the same time as ADHD.

For children, the American Academy of Pediatrics (AAP) recommends that healthcare providers ask parents, teachers, and other adults who care for the child about the child's behavior in different settings, including at home, school, or with peers. Read more about recommendations for the diagnosis and treatment of children and adolescents with ADHD.

Diagnosing ADHD in adults

ADHD often lasts into adulthood. Symptoms might look different at older ages. For example, in adults, hyperactivity may appear as extreme restlessness or wearing others out with their activity.

For more information about diagnosis and treatment throughout the lifespan, please visit the websites of the National Resource Center on ADHD and the National Institutes of Mental Health.

DSM-5 criteria for ADHD

Healthcare providers use the guidelines in the American Psychiatric Association's Diagnostic and Statistical Manual, Fifth edition (DSM-5), to help diagnose ADHD. This diagnostic standard helps ensure that people are appropriately diagnosed and treated for ADHD. Using the same standard across communities can also help determine how many children have ADHD, and how public health is impacted by this condition.

The number of symptoms required for an ADHD diagnosis (by age group) are as follows:‎

People with ADHD show a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development:

DSM-5 criteria for ADHD diagnosis ‎

In addition to the above criteria, the following conditions must also be met:

Several inattentive or hyperactive-impulsive symptoms were present before age 12 years.

Several symptoms are present in two or more settings, (such as at home, school or work; with friends or relatives; in other activities).

There is clear evidence that the symptoms interfere with, or reduce the quality of, social, school, or work functioning.

The symptoms are not better explained by another mental disorder (such as a mood disorder, anxiety disorder, dissociative disorder, or a personality disorder). The symptoms do not happen only during the course of schizophrenia or another psychotic disorder.

For more information about diagnosis and treatment throughout the lifespan, please visit the websites of the National Resource Center on ADHD and the National Institutes of Mental Health.

# data[].attributes.attachment_link.description
Diagnosing ADHD is a process with several steps.