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Definition

An intellectual disability is defined as significantly below average general intellectual and adaptive functioning manifested during the developmental period, with significant delays in academic skills. Developmental period refers to birth to eighteen (18) years of age.The corresponding definition is found in State Board of Education Rule 6A-6.03011, Florida Administrative Code ( F.A.C.)

State Lead Contact

Florida Rule

Florida Department of Education Resources

Bureau of Exceptional Student Education Discretionary Projects

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Definition An intellectual disability is defined as significantly below average general intellectual and adaptive functioning manifested during the developmen.

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Overview of Intellectual and Developmental Disabilities

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IEP Team Members

The members of the multidisciplinary team who write your child's IEP include:

You, the parents, who have the most information about your child's strengths and needs

General education teacher(s) who can share information about classroom expectations and your child's performance

A special education teacher who has training and experience in educating children with disabilities and in working with other educators to plan accommodations

An individual who can interpret the results of your child's evaluation and use results to help plan an appropriate instructional program

A representative of the school system who knows about special education services and has the authority to commit resources

Individuals with knowledge or special expertise about your child that are invited by you and/or the school district

Representatives from transition services agencies, when such services are being discussed

Anyone invited by you that you feel would be helpful during the IEP process. Often it is helpful to ask a friend, another parent or an advocate to attend the meeting with you. Let the school know if you have invited someone.

Your child, when appropriate, and whenever transition is discussed

Contents of the IEP

The IEP is a document that is designed to meet your child's unique educational needs. It's not a contract, but it does guarantee the necessary supports and services that are agreed upon and written for your child.

At the least, the IEP must contain these pieces of information:

Present levels of educational performance

Goals

Special education and related services

In Florida, another required component of the IEP for students who are Deaf or hard of hearing is the Communication Plan. The communication plan helps to gather all data to guide the IEP team discussion on supports and services needed in the areas of language, communication, reading, assistive technology, listening and more. This should be completed prior to the IEP meeting. The plan should be discussed at the IEP meeting so that the team can consider the appropriate communication and language needs of the student. This document drives the development of the IEP.
Once the IEP is written, the team has to decide how to put it into action. The school district is obligated to provide a free appropriate public education (FAPE) in the least restrictive environment (LRE). So the IEP team considers the way - to the maximum extent appropriate for both - to educate your child alongside kids without a disability. Special education is a set of services, rather than a specific place for your child to go. The services your child needs to reach the goals and objectives and how they'll be delivered are identified. For most kids, the general education classroom will be the preferred setting, but a range of options is available, including special day classes. In addition to the above, the following are part of the IEP:

The extent, if any, to which your child will not participate with nondisabled kids in the regular class and other school activities

When services will begin, where and how often they'll be provided, and how long they'll last

Necessary transition services (age 16 or the first IEP that will be in effect when the child turns 16)

These special factors will be considered and addressed in the IEP, depending on your child's needs:

Supports and strategies for behavior management, if behavior interferes with her learning or the learning of others

Language needs as related to the IEP as outlined in the communication plan

Communication needs as outlined in the communication plan

Assistive technology devices or s ervices required in order to receive FAPE

Necessary accommodations in the general education classroom

When you sign the IEP, it does not mean you agree with it. Your signature on the IEP form means that you attended the IEP team meeting. You will be asked to sign a different form to give your permission for services to begin for your child.

If you do not agree with the IEP, you can write "not in agreement" on the IEP beside your signature. The school may want to meet again to go over your concerns, or bring in educational professionals to consult, or hold a facilitated meeting. If you still feel that your concerns are not being addressed, you can choose to seek mediation, file a state complaint with the Florida Department of Education, or ask for a due process hearing.

The IEP is reviewed at least once a year. Parents will also receive a progress report regarding your child's progress towards their IEP goals when report cards out. However, if you or the teacher believe that your child isn't learning or making progress or has achieved the goals sooner than expected, a meeting may be scheduled at any time to revise the IEP. If you feel that an IEP review meeting is needed, put your request in writing and send it to the school and/or district administrator.

Work collaboratively with the staff responsible for your child's IEP. Listen and ask questions. Ask what you can do to reinforce skills at home. You know your child best, so it is helpful to consider yourself the team leader. Have a positive attitude- even when you disagree. Remember, the team is there to help your child succeed.

Keep all relevant evaluations in a binder and bring them to the IEP meeting. There are many assessments that parents can do at home which can give you a sense of your child's strengths and weaknesses as related to the educational setting. Parents are encouraged and should feel comfortable writing goals for their child, both academic and social. Remember that this is a team effort, so keep the channels of communication open so that you all are working towards the same goals.

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Individualized Education Program (IEP) Resources for Parents

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Information for Parents of a student who is Deaf/Hard of Hearing

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13 Categories of Disability Under IDEA Law:

There are 13 different disability categories as defined by the Individuals with Disabilities Education Act (IDEA), under which 3- through 22-years-olds may be eligible for services.

In order to qualify for special education, the IEP Team must determine that a child has a disability in one of the 13 categories and it must adversely affect their educational performance:

Autism Spectrum Disorder

Deaf-Blindness

Deafness

Emotional Disturbance

Hearing Impairment

Intellectual Disability

Multiple Disabilities

Orthopedic Impairment

Other Health Impairment

Specific Learning Disability

Speech or Language Impairment

Traumatic Brain Injury

Visual Impairment, including Blindness

Preschool children, ages 3 to 5 years old, may qualify for special education services if they have one of the the previously listed eligible disabilities or an "established medical disability." An "established medical disability" is a disabling medical condition or congenital syndrome very likely to require special education services.

In California, children with disabilities younger than three (3) years of age may also qualify for early instruction and intervention. Children younger than three (3) years of age who qualify for early services will receive services from the District only if they have a visual, hearing, or severe orthopedic impairment. All other children in this age range who exhibit developmental delays or have established risk conditions with harmful developmental consequences will receive early intervention services from their local regional center.

The law requires that to the maximum extent appropriate, children with disabilities be educated with children without disabilities. This placement is called "the least restrictive environment."

The federal definitions guide how states define who is eligible for a free appropriate public education (FAPE) under special education law:

AUTISM SPECTRUM DISORDER: Is a neurodevelopmental disorder that impairs a child's ability to communicate and interact with others. It also includes restricted repetitive behaviors, interests and activities. These issues cause significant impairment in social, occupational and other areas of functioning. It is defined as a single disorder that includes disorders that were previously considered separate - autism, Asperger's syndrome, childhood disintegrative disorder and pervasive developmental disorder not otherwise specified.

DEAF-BLINDNESS: Concomitant (simultaneous) hearing and visual impairments, the combination of which causes such severe communication and other developmental and educational needs that they cannot be accommodated in special education programs solely for children with deafness or children with blindness.

DEAFNESS: a hearing impairment so severe that a child is impaired in processing linguistic information through hearing, with or without amplification, that adversely affects a child's educational performance.

EMOTIONAL DISTURBANCE: A condition exhibiting one or more of the following characteristics over a long period of time and to a marked degree that adversely affects a child's educational performance:

(a) An inability to learn that cannot be explained by intellectual, sensory, or health factors; (b) An inability to build or maintain satisfactory interpersonal relationships with peers and teachers; (c) Inappropriate types of behavior or feelings under normal circumstances; (d) A general pervasive mood of unhappiness or depression; (e) A tendency to develop physical symptoms or fears associated with personal or school problems.

The term includes schizophrenia. The term does not apply to children who are socially maladjusted, unless it is determined that they have an emotional disturbance.

(Examples: Anxiety disorder, schizophrenia, bipolar disorder, obsessive-compulsive disorder and depression)

HEARING IMPAIRMENT: An impairment in hearing, whether permanent or fluctuating, that adversely affects a child's educational performance but is not included under the definition of "deafness."

(* Being hard of hearing is not the same thing as having auditory processing disorder)

INTELLECTUAL DISABILITIES: Significantly sub-average general intellectual functioning, existing concurrently [at the same time] with deficits in adaptive behavior and manifested during the developmental period, that adversely affects a child's educational performance.

(Note: "Intellectual Disability" is a new term in IDEA. Until October 2010, the law used the term "mental retardation.")

(Example: Down Syndrome)

MULTIPLE DISABILITIES: Concomitant (simultaneous) impairments (such as intellectual disability-blindness, intellectual disability-orthopedic impairment, etc.), the combination of which causes such severe educational needs that they cannot be accommodated in a special education program solely for one of the impairments. The term does not include deaf-blindness.

ORTHOPEDIC IMPAIRMENT: Severe orthopedic impairment that adversely affects a child's educational performance. The term includes impairments caused by a congenital anomaly, impairments caused by disease (e.g., poliomyelitis, bone tuberculosis), and impairments from other causes.

(Examples: Cerebral palsy, amputations, and fractures or burns that cause contractures).

OTHER HEALTH IMPAIRMENT: Having limited strength, vitality, or alertness, including a heightened alertness to environmental stimuli, that results in limited alertness with respect to the educational environment, that-

(a) is due to chronic or acute health problems such as asthma, attention deficit disorder or attention deficit hyperactivity disorder, diabetes, epilepsy, a heart condition, hemophilia, lead poisoning, leukemia, nephritis, rheumatic fever, sickle cell anemia, and Tourette syndrome;

and, (b) adversely affects a child's educational performance

(Example: Attention Deficit Hyperactivity Disorder)

SPECIFIC LEARNING DISABILITY: A disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may manifest itself in the imperfect ability to listen, think, speak, read, write, spell, or to do mathematical calculations. The term includes such conditions as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia. The term does not include learning problems that are primarily the result of visual, hearing, or motor disabilities; of intellectual disability; of emotional disturbance; or of environmental, cultural, or economic disadvantage.

(Examples: Dyslexia, Dysgraphia, Dyscalculia, Auditory processing disorder, and Nonverbal learning disability)

SPEECH OR LANGUAGE IMPAIRMENT: A communication disorder such as stuttering, impaired articulation, language impairment, or a voice impairment that adversely affects a child's educational performance.

(Examples: Stuttering, impaired articulation, language impairment or voice impairment)

TRAUMATIC BRAIN INJURY: An acquired injury to the brain caused by an external physical force, resulting in total or partial functional disability or psychosocial impairment, or both, that adversely affects a child's educational performance. The term applies to open or closed head injuries resulting in impairments in one or more areas, such as cognition; language; memory; attention; reasoning; abstract thinking; judgment; problem-solving; sensory, perceptual, and motor abilities; psychosocial behavior; physical functions; information processing; and speech.

The term does not apply to brain injuries that are congenital or degenerative, or to brain injuries induced by birth trauma.

VISUAL IMPAIRMENT, INCLUDING BLINDNESS: An impairment in vision that, even with correction, adversely affects a child's educational performance. The term includes both partial sight and blindness.

(Examples: Partial sight and blindness)

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13 Categories of Disability Under IDEA Law - B.I.G. Solutions, LLC

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13 Categories of Disability Under IDEA Law: There are 13 different disability categories as defined by the Individuals with Disabilities Education Act (IDEA), under which 3- through 22-years-olds may be eligible for services. In order to qualify for special education, the IEP Team must determine that a child has a disability in one of the [...]

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The diagnosis of an intellectual disability is typically made through a test of intelligence or cognition, often assessed by the range of scores on an Intelligence Quotient (IQ) test. This type of test will help the health care provider examine the abilities of a person to learn, think, solve problems, and make sense of the world. Average IQ test score is around 100, and 85% of children with an intellectual disability score in the range of 55 to 70. More severe cases of intellectual disability generally have lower IQ scores.

Clinicians will also observe a child's behavior for signs of a disability and assess adaptive behavior. Adaptive behaviors include coping skills and other behaviors that show how a child interacts with other people. Health care providers can use this information to assess whether the individual has the skills needed to care for oneself and interact with others.

Some conditions that lead to IDDs may be diagnosed with a blood test, ultrasound, or another method, depending upon the condition. These tests may be conducted after birth or during pregnancy.

Newborn screening relies on testing blood samples taken from newborns while they are still in the hospital to help identify certain serious or life-threatening conditions, including some that lead to IDDs. Most tests use a few drops of blood obtained by pricking the infant's heel. If a screening test suggests a problem, the infant's doctor will follow up with further testing.

Prenatal Screening

Health care providers recommend that certain pregnant women, including those who are older than 35 years of age and those with a family history of certain conditions, have their fetuses tested prenatally, while still in the womb, for conditions that cause IDD. There are two main types of prenatal tests.

Amniocentesis is a test that is usually performed to determine whether a fetus has a genetic disorder. In this test, a doctor takes a small amount of fluid from the womb using a long needle. The fluid, called amniotic fluid, contains cells that have genetic material that is the same as the fetus's genetic material. A laboratory grows the cells and then examines their genetic material for any problems. Some IDDs that can be detected with amniocentesis are Down syndrome and certain types of muscular dystrophy.

Because amniocentesis can cause a miscarriage in about 1 out of 200 cases, it is usually only recommended for pregnancies in which the risk of genetic disorders or other problems is high.

This test extracts cells from inside the womb to determine whether the fetus has a genetic disorder. Using a long needle, the doctor takes cells from the chorionic villi, which are tissues in the placenta, the organ in the womb that nourishes the fetus. The genetic material in the chorionic villus cells is identical to that of the fetal cells.

Like amniocentesis, CVS can be used to test for chromosomal disorders such as Down syndrome and other genetic problems. CVS can be done earlier in pregnancy than amniocentesis, but it is also associated with a higher risk of miscarriage-about 1 in 100 cases. Healthcare providers usually only recommend CVS in women who are at high risk for a condition or IDD.

Citations

1. American Academy of Pediatrics. (July 30, 2012). Health issues: Outlook for children with intellectual disabilities. Retrieved August 9, 2012, from http://www.healthychildren.org/English/health-issues/conditions/developmental-disabilities/Pages/Outlook-for-Children-with-Intellectual-Disabilities.aspx

2. National Dissemination Center for Children with Disabilities (NICHCY). (January, 2011). NICHCY disability fact sheet #8: Intellectual disabilities. Retrieved August 9, 2012, from https://www.parentcenterhub.org/intellectual/

3. American Academy of Pediatrics. (July 30, 2012). Health issues: Children with intellectual disabilities. Retrieved August 9, 2012, from http://www.healthychildren.org/English/health-issues/conditions/developmental-disabilities/Pages/Intellectual-Disability.aspx

4. National Library of Medicine, Medline Plus. (2012). On newborn screening. Retrieved August 25, 2012, from https://medlineplus.gov/newbornscreening.html

5. The Patient Education Institute. (2011, March 01). X-plain: Amniocentesis - Reference summary. Retrieved July 24, 2012, from https://medlineplus.gov/ency/presentations/100192_1.htm

6. Simpson, J. L., & Otano, L. (2007). Prenatal genetic diagnosis. In S. G. Gabbe, J. R. Niebyl, & J. L. Simpson (Eds.), Obstetrics: Normal and problem pregnancies (5th ed.). New York, NY: Churchill Livingstone.

7. American College of Obstetricians and Gynecologists. (2007). Invasive prenatal testing for aneuploidy. Washington, DC: Author. Retrieved September 14, 2014, from https://pubmed.ncbi.nlm.nih.gov/18055749/

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How do healthcare providers diagnose intellectual and developmental disabilities (IDDs)?

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A test of intelligence or cognition is typically used to diagnose an intellectual disability. Clinicians will also observe a child's behavior for signs of a disability and assess adaptive behavior.

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List of resources for persons with disabilities.

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It is important to implement strategies that address the needs of the individual. We recommend that you apply these strategies across home, school, and community contexts.
Go to the Site Map for a full list of resources and activities!

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picture exchange communication system cards

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Do2Learn: Educational Resources for Special Needs

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picture communication cards, songs, games and learning activities for autism, aspergers, fetal alcohol syndrome and disabilities

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Continuing Education Activity

Individuals with an intellectual disability have neurodevelopmental deficits characterized by limitations in intellectual functioning and adaptive behavior. This activity reviews the evaluation and management of intellectual disability, including the genetic and environmental etiologies of intellectual disability, various disease manifestations, and appropriate evaluation strategies. This activity also highlights the needs of individuals with intellectual disabilities and suggests an interprofessional approach to the management of intellectual disability, and recognizes the interprofessional team element in managing these cases.

Objectives:

Summarize the epidemiology of intellectual disability.

Outline the etiology of intellectual disability.

Explain the treatment considerations for patients with intellectual disabilities.

Review the importance of improving care coordination amongst the interprofessional team to enhance the delivery of care for patients affected by intellectual disability.

Access free multiple choice questions on this topic.
Introduction

Individuals with an intellectual disability have neurodevelopmental deficits characterized by limitations in intellectual functioning and adaptive behavior. These disabilities originate at birth and manifest before the age of 18 and can be associated with a considerable number of related and co-occurring problems, including mental health (e.g., depression and anxiety), neurodevelopmental (e.g., autism spectrum disorders, and attention deficit hyperactivity disorder), as well as neurological (e.g., infantile cerebral palsy) and medical conditions (e.g., meningitis).

Intellectual Functioning

Intellectual functioning is generally called intelligence and includes a wide range of mental activities such as the ability of logical reasoning and practical intelligence (problem-solving), ability in learning, verbal skills, and so on. It manifests and expresses itself through numerous sets of capabilities, behaviors, thoughts, and emotions. In other words, intellectual functioning is definable as the global ability that allows the individual to understand reality and interact with it.

Intellectual functioning is commonly measured by the intelligence quotient (IQ), which represents a total score obtained from standardized tests (IQ tests) developed for evaluating human intelligence. IQ test score has a median of 100 and a standard deviation of 15. A score of 70 or below (two standard deviations below the median) indicates intellectual limitations.

Adaptive Behavior

These disabilities express as lacking competence in social, conceptual, and practical skills. Social skills include interpersonal skills, social responsibility, self-esteem, gullibility, naivety, resolution of social problems, and the ability to follow the rules of society and obey the laws. Conceptual skills include the ability to understand time, finance, and language. Practical skills include the ability to use tools, carry out activities of daily living, and interact with other people. All these skills are learned throughout development and performed in response to common problems and simple/complex tasks, as well as expectations from our community and society. Obviously, these behavioral responses become progressively more complex with age. Several validated tools are useful for assessing limitations in adaptive behavior.

Etiology

While many causes of intellectual disability are not known, the etiology of intellectual disability mainly divides into genetic abnormalities and environmental exposure. Genetic abnormality can be a single gene mutation, copy number variation, or chromosomal abnormality that causes an inborn error of metabolism, neurodevelopmental defect, and neurodegeneration. Environment exposure can be maternal exposure to toxin/infectious agents, uncontrolled maternal medical conditions, delivery complications, and post-natal trauma and exposure to toxin/infectious agents. The most common known preventable or environmental cause of intellectual disability is fetal alcohol syndrome, the most common chromosomal cause is Down syndrome, and the most common genetic cause is Fragile X syndrome.

Genetic

The genetic abnormality may cause an inborn error of metabolism, neurodevelopmental defect, or neurodegeneration. With an inborn error of metabolism, toxic by-products accumulate, causing intellectual disability and other behavioral problems. Phenylketonuria (PKU) is one of the inborn errors of metabolism that occurs in approximately 0.01% of newborns. PKU most commonly results from phenylalanine hydroxylase defect inherited in an autosomal recessive fashion. The defect disables the liver from converting phenylalanine to para-tyrosine. The consequent accumulation of phenylalanine is the culprit of intellectual disability. Neurological damage from PKU is irreversible but preventable. Therefore, newborn screening for PKU is mandatory in the U.S. and other countries. Early screening followed by prompt initiation of a low phenylalanine diet before the age of 3 may prevent intellectual disability.[1] Recently, different rare types of hyperphenylalaninemia were described, including the deficiency of the enzyme dihydropyridine reductase and a deficiency of a cofactor, biopterin.[2]

Lesch-Nyhan syndrome is an X-linked inborn error of metabolism caused by purine metabolism enzyme deficiency. This condition results from a mutation in HGPRT.[3] This mutation leads to a buildup of uric acid, which causes severe self-mutilating behavior of biting mouth and finger as well as intellectual disability.[4] Other known inborn errors of metabolism that result in intellectual disability are Niemann-Pick disease, Hunter disease, Hurler disease, maple syrup urine disease, Hartnup disease, homocystinuria, and galactosemia.

A neurodevelopmental defect presents in Fragile X syndrome, a leading genetic cause of intellectual disability. It results from a single gene mutation in the FMR1 (Xq27.3) gene. In most cases, CGG repeat of the FMR1 gene expands to over 200 times. The expansion leads to a phosphorylated CG pattern, causing methylation imprinting of the gene, thereby silencing FMR1 gene expression. FMR1 is a transcription factor of hundreds of genes expressed in the central nervous system, and its disruption causes intellectual disability as well as behavioral disturbance, and seizure.[5] Neurodevelopment defect also presents in neurofibromatosis type 1, also known as von Recklinghausen syndrome, an autosomal dominant condition caused by mutations of NF1. Its characteristic presentation is abnormal neural cell migration leading to cafe au lait spot, movement disorder, and intellectual disability.[6]

Neurodegeneration leading to intellectual disability presents in Rett syndrome (RS), an X-linked dominant degenerative condition only seen in females secondary to mutation of the MeCP2 gene. In patients with RS, cerebral atrophy occurs at the substantia nigra, causing defects in the dopaminergic nigrostriatal pathway, starting at 6 to 18 months of age.[7]

IQ alterations can also occur as part of a clinical picture in other genetic syndromes. In many cases, the intellectual deficit appears to be limited and can occur at different stages of neurodevelopment, also in terms of cognitive decline. For example, in chromosome 22q11.2 deletion syndrome, DiGeorge syndrome, or velocardiofacial syndrome, which is one of the most common multiple anomaly syndromes in humans, is usually described as a cognitive decline rather than an early onset intellectual disability.[8]

Environmental

Environmental exposure during pregnancy may lead to intellectual disability, which can be caused by maternal exposure to a toxin, infectious agent, uncontrolled maternal condition, and birth complications.

One common toxic substance that leads to an intellectual disability during pregnancy includes alcohol. Alcohol exposure, indeed, commonly causes intellectual disability along with other developmental abnormalities, in a condition known as fetal alcohol syndrome.[9] Fetal exposure to alcohol inhibits the production of retinoic acid, which is an essential signaling molecule for the development of the nervous system. Even a small amount of alcohol in any trimester of pregnancy may cause fetal alcohol syndrome.[10]. Exposure to opioids, cocaine, and teratogenic medications may also lead to intellectual disability.

Common, well-known infectious agent that causes intellectual disability are rubella and HIV. Maternal rubella infection in the initial trimester of pregnancy leads to intellectual disability approximately 10 to 15% of the time; it can rise to above 50% with infection during the first month. Immunization may prevent the mother from rubella infection.[11] HIV may be transferred vertically from mother to infant. Infants with HIV may develop encephalopathy, seizures, and intellectual disability within the first year of life secondary to microcephaly, immunosuppression, and Pneumocystis jiroveci pneumonitis (PCP) infection.[12] Excessive neuro-inflammation causes overstimulation of the N-methyl-D-aspartate type receptor (NMDAR) system, which leads to neuronal injury. Antiretroviral therapy for the mother and prophylactic treatment with zidovudine for newborn exposed to HIV has significantly reduced the transmission.[12] Other known infectious exposures to mothers that may cause intellectual disability in the newborn are cytomegalic inclusion disease, syphilis, and toxoplasmosis.

Uncontrolled maternal medical conditions may lead to intellectual disability. Pregnancy hypertension, asthma, urinary tract infection, pre-pregnancy obesity, and pre-gestational diabetes were shown to increase the risk significantly.[13] Furthermore, uncontrolled maternal diabetes, malnutrition, and obstetrical complications causing anoxia (placenta previa, placenta abruption, and umbilical cord prolapse) may also cause intellectual disability.[14]

An intellectual disability is acquirable during early childhood. Causes include infection (notably encephalitis and meningitis), head trauma, asphyxia, intracranial tumor (either directly or indirectly through seizure, surgery, and chemotherapy), malnutrition, and exposure to toxic substances.[15]

Epidemiology

The prevalence of intellectual disability in developing countries is estimated to range from 10 to 15 per 1000 children; of those, about 85% have a mild intellectual disability. From 1 to 3% of the Western population is estimated to have an intellectual disability. Incidence is challenging to accurately calculate as mild disabilities may be under-recognized until later in childhood. Intellectual disability is reported to peak at the ages of 10 to 14 years and is 1.5 times more prevalent in males than females.[16]

History and Physical

Keeping up with daily functions is often challenging for individuals with different degrees of intellectual disability. They may have difficulty feeding themselves, going to the bathroom, and dressing. They also may have difficulty getting along with their family and friends because of a problem with communication as well as poor impulse control. They may have trouble excelling academically and socially at school.

Concerning clinical history, symptoms of intellectual disability usually begin during childhood or adolescence. Moreover, delays in language or motor skills may be observed by age two. Nevertheless, a significant number of children with mild levels of intellectual disability may not get identified until school age.

A comprehensive history of patients with intellectual disability must include the following:

Information about the mother's pregnancy, labor, and delivery

Mother's use of substances or medications during pregnancy

Mother suffered any uncontrolled medical condition

Was there any issue with delivery?

Patient's sensory, social, language, and motor developments to detect any developmental delay

Patient's exposure to infection, trauma, and toxin

Patient's medical conditions

Patient's psychiatric conditions

Medications that the patient is taking

Patient's family history of psychiatric and medical conditions

Patient's living situation, caretaker

Patient's behavior toward caretaker, parents, and siblings

Patient's academic performance at school

Patient's behavioral disturbance reported at school

Physical examination is vital to differentiate intellectual disorders from other conditions. A full neurological exam should be performed to identify any deficit that may mimic intellectual disability and comorbid symptoms. Visual and hearing tests are particularly important as abnormal vision or hearing causes difficulty with communication, leading to a delay in developing language and social skills, closely mimicking intellectual disability. Motor dysfunctions such as spasticity, hypotonia, hyperreflexia, and involuntary movements are commonly present in individuals with intellectual disabilities.[17]

Some physical characteristics are closely associated with a specific diagnosis as follows:

Down syndrome: slanted eyes, flat nasal bridge, protruding tongue, small chin, and single crease palm

Fragile X syndrome: long and narrow face, prominent forehead and jaw, large ears, and large testicles in male

Fetal alcohol syndrome: smooth philtrum, thin vermilion, and small palpebral fissures

Prader-Willi: obesity secondary to compulsive eating behavior, hypogonadism, small hands, and feet

Cat's cry (Cri-du-chat) syndrome: microcephaly, hypertelorism, low-set ears, and micrognathia

Phenylketonuria: bizarre movements such as twisting hand mannerisms, poor motor coordination, and perceptual difficulties

Evaluation

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the diagnosis of intellectual disability requires deficits in intellectual function, deficits in adaptive function, and onset before the age of 18. The IQ test is widely used to assess the intellectual function of individuals. IQ test derives from Stanford-Binet Intelligence Scales, used for school placement in France. Lewis Terman adapted the test to measure general intelligence. Scores were reported as "mental age" divided by chronological age, multiplied by 100. The current version of the IQ test is standardized, and two standard deviations below the test taker's group calculate as an IQ of 70. An IQ of 70 or below suggests an intellectual disability diagnosis. Based on the IQ score, the severity grading appears below.

IQ 50 to 70: mild intellectual disability (85% of cases)

IQ 35 to 50: moderate intellectual disability (10% of cases)

IQ 20 to 35: severe intellectual disability (4% of cases)

IQ below 20: Profound intellectual disability (1% of cases)

However, it is no longer a standard to classify intellectual disability by IQ score alone. For instance, if an individual has IQ below 70 but has a good adaptive function, the subject does not have an intellectual disability. On the other side, individuals with a normal or even higher than normal IQ may manifest severe deficits in adaptive functions and are, therefore, classified as having an intellectual disability. In turn, the current diagnosis of intellectual disability also considers a person's adaptive function.[18] The Adaptive Behaviour Assessment System can measure adaptive function.[19] It encompasses the social and practical domains. Adaptive function measures ability in communication, social participation, and independent living.

The DSM-5 also has "Unspecified Intellectual Disability" (Intellectual Developmental Disorder) to describe individuals over the age of 5 suspected of having an intellectual disability who has difficulty completing required tests, usually because of limitations resulting from blindness, deafness, or concurrent mental illness.

Chromosomal analysis, urine and blood tests, and neuroimaging techniques have been used to elucidate the etiology of intellectual disability.

Traditionally, chromosomal analysis has been done by parents' choice before the birth of a child via amniocentesis (performed at 15 weeks of gestation) or chorionic villi sampling (8 to 10 weeks of gestation). It is a highly specific test for Down syndrome, and early detection of chromosomal abnormalities allows a decision to terminate the pregnancy. Recently, a cell-free fetal DNA test has appeared as a noninvasive prenatal test for Down syndrome. It has demonstrated a higher detection rate, positive predictive value, and false-positive rate.[20] Another current technique of chromosomal analysis is fluorescent in situ hybridization (FISH), which is useful to identify the microscopic deletion of the chromosome.[21]

Urine and blood analysis allow the evaluation of enzyme activities and detection of inborn errors of metabolism, including PKU, Lesch-Nyhan syndrome, galactosemia, and Hurler syndrome, with the help of advanced techniques such as tandem mass spectroscopy and gas chromatography.[22]

As for neuroimaging techniques, computerized tomography (CT) or magnetic resonance imaging (MRI) has been useful to identify microcephaly, cerebral developmental delay, and cerebral palsy.[23] Functional MRI and diffusion tensor imaging are being researched to identify abnormalities in neural circuit pathways. For example, Fragile X syndrome with aberrant frontal-striatal pathways has been found associated with ADHD symptoms. Electroencephalography (EEG) is used to detect seizures that often accompany intellectual disability, though findings do not direct to specific diagnoses.[24]

Treatment / Management

Management of intellectual disability must begin promptly with the goals to prevent further worsening, minimize the symptoms of disability, and improving the quality of everyday life. When initiating therapy, a healthcare provider must be aware of the various avenues of treating intellectual disability to orchestrate a multidisciplinary and individually tailored treatment appropriately. This section will discuss some examples of the multiple interventions available.

Educational support is a crucial component of intellectual disability management. Upon diagnosis of intellectual disability in children, healthcare providers must contact the school promptly to set up special education arrangements. What special education entails may vary slightly among schools, but it typically aids comprehensively with providing academic modifications as well as transition planning from childhood to adulthood with a focus on promoting self-sufficiency. It also teaches them how to seek assistance, behavioral skills, vocational skills, communication skills, functional living skills, and social skills based on individual needs in the least restrictive environment. Creating the least restrictive environment for students with an intellectual disability means placing them in general classrooms as much as tolerated. While segregated classrooms for special needs may be helpful for those who need them, implementing the least restrictive environment policy has been shown to improve student outcomes. It is important to monitor the patients' progress in school because education solely from classroom settings may not be sufficient. If an individual with an intellectual disability requires assistance beyond what is available at school, the family can meet the need at home through family education or other outside resources. For example, a disabled student who needs extra attention with social skills may be referred to participate in the Special Olympics programs that have been shown to improve social competence in intellectual disability subjects. Lastly, other causes of learning difficulties need to be ruled out, and appropriate hearing and vision screenings are necessary for individuals with intellectual disabilities.

Behavioral intervention is another important aspect of intellectual disability management, and it can occur in a few different ways. Behavioral therapy aims to encourage positive behaviors while discouraging undesirable behaviors. Providing positive reinforcement and benign punishments (e.g., time-outs) is an effective method of behavioral training. Other supplemental methods may include avoiding triggers of negative demeanor, shunning misconduct, and redirecting to prevent or curtail any troublesome behavior. Cognitive therapy is another mode of behavioral training that has been effective for eligible intellectual disability patients. Cognitive therapy has its basis on the principle that one's behavior, emotions, and cognitions are connected, and it aims to correct one's negative behaviors by identifying and adjusting negative thoughts and emotional stress. Although many other approaches to behavioral intervention exist, the implementation of behavioral therapy, cognitive therapy, or a combination of the two is the most widely used method that has been shown to be an effective means of behavioral intervention for intellectual disability patients.

Vocational training helps teenagers and young adults to obtain the necessary skills to enter the labor market. In vocational training, patients carry out pre-scheduled activities under the supervision of a multi-disciplinary team consisting of a social worker, occupational therapist, teacher, counselor, and psychologist. Patients learn to keep themselves clean, wear appropriate clothes, and carry out their responsibilities. A study has shown that patients who underwent vocational training had reduced support requirements compared to their peers.

Family education is an essential service provided by healthcare providers for family members of intellectually disabled patients. The first part of this is assisting the family members in understanding intellectual disability: definition, management, and prognosis. Then, healthcare providers can help the family through placement decisions, refer them to appropriate services and equipment, and provide caregiver training. In addition to preparing the family for the patient, physicians must recognize that family members also often bear a significant amount of stress as well. The medical team must support the whole family through psychosocial problems such as the need for respect, feeling helpless, depression, and anxiety. There are also outside resources to which the family can obtain a referral. American Association on Intellectual and Developmental Disabilities (AAIDD), The Arc of the United States, and Family-to-family Health Information and Education Centers are some of the nationally available resources, and social workers can help with connecting the families with local resources. Establishing strong support for the family, in turn, creates a caring home environment for the patient.

Government resources are available for patients with intellectual disabilities and their families. Patients with intellectual disabilities are eligible to benefit from social security income. Patients also may benefit from various community services that provide housing and food delivery. The government also provides education and employment opportunities as outlined under the "Disability Resources" section of the US Department of Labor website.

Psychopharmacologic interventions may not be the main component of intellectual disability treatment, but they play a significant role in treating behavioral abnormalities associated with intellectual disorders and comorbid conditions. Aggressive behavior is not uncommon among individuals with intellectual disabilities and causes admission to institutional settings. Risperidone is well-documented to treat disruptive, aggressive, and self-injurious behaviors in children with intellectual disabilities with good safety and tolerability profile.[25] Risperidone is an atypical antipsychotic that is less likely to cause tardive dyskinesia, which commonly results in a typical antipsychotic. Aripiprazole is another atypical antipsychotic that is used to manage aggression.

Treatment of comorbid conditions is an important aspect of adequate therapy. Attention-deficit/hyperactivity disorder (ADHD), depression, and movement disorders are some of the comorbid conditions accompanying intellectual disability that require evaluation and treatment. Methylphenidate, clonidine, and atomoxetine are shown in randomized control trials to reduce ADHD symptoms. Methylphenidate significantly improved the maintenance of attention to complete a task; however, there was no long-term improvement in learning and social skills.

Depressive symptoms can be easily overlooked in individuals with intellectual disabilities when other behavioral problems are prominent; this requires careful evaluation. Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, and sertraline were shown in multiple studies to help with depressive symptoms in this patient population.

Involuntary movements, repetitive self-stimulatory behaviors, and obsessive-compulsive symptoms may be harmful to the patients. Antipsychotic medications have been anecdotally reported to diminish these symptoms, although there was no observation of improvement in adaptive behavior.[26] SSRIs are useful in treating obsessive-compulsive symptoms and stereotyped motor movements.[27]

Studies have shown that patients with intellectual disabilities are at risk for polypharmacy, and providers should be cautious when prescribing medications as some patients may be at a higher risk of side effects and may need lower dosages.

Differential Diagnosis

Several diseases or conditions can be mistaken for intellectual disability:

Child abuse: childhood abuse may cause developmental delays in language and socialization, causing a defect in adaptive function. The child may have difficulty communicating her needs and developing trust and social responsibility. Unlike intellectual disability, symptoms are often reversible when the environment improves.

Debilitating medical disease: Individuals with normal intelligence may experience depression and delay in the development of chronic, debilitating medical illnesses.

Cerebral palsy: poor muscle coordination, problems with vision, hearing, and speaking may imitate symptoms of intellectual disability.

Sensory disability: deafness or blindness may lead to a flaw in diagnostic testing, causing a false-positive diagnosis of intellectual disability.

Speech disorder: expressive and receptive aphasia may be mistaken for intellectual disability.

Prognosis

The cognitive deficit of intellectual disability is permanent damage; thus, the prognosis of intellectual disability depends on the severity of cognitive impairment and the supportive environment provided. If provided adequate support, individuals with mild intellectual disabilities may achieve adequate language and social competency to live independently and raise their own families. Individuals with moderate intellectual disabilities are not likely to achieve academic levels greater than second grade; however, they may acquire language and communicate their needs. They may be able to get a job under supervision. Individuals with severe intellectual disabilities usually have difficulty acquiring language. They may be able to develop alternative communication skills and recognize words that are critical to functioning. Adults with a severe intellectual disability usually require supervised living situations, such as group homes, and supervision to perform any work-related tasks. Individuals with profound intellectual disabilities have significant difficulty with communication and social functioning.

Complications

Most individuals with intellectual disabilities have comorbid psychiatric conditions. Individuals are at higher risk of developing depression because they are prone to developing negative self-images as they have difficulty interacting with others and meeting social expectations. Other psychiatric comorbid symptoms frequently observed in these individuals are hyperactivity, self-injurious behaviors, and repetitive stereotypical behaviors. Management of complications is discussed above in the "Treatment" section.

Deterrence and Patient Education

Among the most challenging aspects of intellectual disability is the patient's sense of social skill deficit and social isolation. Educating the family for support to improve social competence and self-esteem is critical. Special Olympics International program is an example program that helps with improving social interactions, friendships, and self-esteem.[28] Individuals with a disability need to be continuously encouraged to learn and interact with other people. The family of individuals with intellectual disabilities should understand that they are more prone to experience failures and rejections and make sure to provide a supportive environment that is not discouraging. Family therapy can help with resolving any feeling of guilt, despair, or anger that may occur in the family relationship.

Enhancing Healthcare Team Outcomes

The management of patients with intellectual disabilities is best with an interprofessional team. When treating individuals with intellectual disabilities, a healthcare provider may find communication with the patients difficult and may coerce the treatments. It is important to act professionally and make sure that patients do not get excluded from fundamental rights and are not coerced into specific therapies, as emphasized in the United Nations Convention for Intellectual Disability.[29] Healthcare providers must carefully listen to the patient's needs and provide treatments that are in the patient's best interest. To serve the patient's best interest, an interprofessional, an interprofessional approach is essential; it has been shown to reduce the healthcare cost by decreasing the number of tests for the diagnosis of intellectual disability and the frequency of hospitalization.[30] Core members of the interprofessional team are primary care physicians, psychiatrists, psychologists, neurologists, speech pathologists, special nurse educators, social workers, and pharmacists. To maintain the best collaborative care, communication among the members of the team be effective. Each healthcare provider must promptly and accurately document diagnosis, assessment, services provided, and follow-up plans. In the current healthcare system, it is efficient and effective for primary care physicians and nurse practitioners to refer to specialists based on the patient's needs, collect evaluations and reports, and coordinate care.

The array of treating physicians will manage the overall case, but they must rely on the input of other team members. Specialty-trained mental health nurses can provide a great deal of valuable information as they engage with the patient. They are also excellent resources for verifying medication and other therapeutic intervention compliance, which can be challenging in such cases, as well as evaluating the effectiveness of the current regimen. Pharmacists must weigh in with medication reconciliation, assist in agent selection for comorbidities, and verify dosing. Pharmacists can also educate patients and/or their families regarding the medications used. Medication adverse events should be reported to the treating physician promptly by either the pharmacist or nursing staff. Thus, an interprofessional approach is the optimal means by which to address patients with intellectual disabilities. [Level 5]

References

Disclosure: Keun Lee declares no relevant financial relationships with ineligible companies.

Disclosure: Marco Cascella declares no relevant financial relationships with ineligible companies.

Disclosure: Raman Marwaha declares no relevant financial relationships with ineligible companies.

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Individuals with an intellectual disability have neurodevelopmental deficits characterized by limitations in intellectual functioning and adaptive behavior. These disabilities originate at birth and manifest before the age of 18 and can be associated with a considerable number of related and co-occurring problems, including mental health (e.g., depression and anxiety), neurodevelopmental (e.g., autism spectrum disorders, and attention deficit hyperactivity disorder), as well as neurological (e.g., infantile cerebral palsy) and medical conditions (e.g., meningitis).

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The Florida Inclusion Network (FIN) provides services to schools and districts to increase and improve inclusive practices for students with disabilities in general education classrooms and other natural settings. FIN services are provided by a number of facilitators who have experience and expertise in planning and implementing inclusive practices at the school and district levels.

FIN facilitators are organized into five regions and work in partnership with districts and schools within a specified geographic area: Region 1, Region 2, Region 3, Region 4 and Region 5. FIN facilitators serve districts and schools by developing and increasing opportunities for meaningful inclusion of students with disabilities. Services provided to schools and districts are identified through a collaborative, problem solving process focused on increasing outcomes for ALL students in inclusive environments. Listen to this short video about services and supports that FIN has for families.

When contacted for support and assistance, FIN can provide families with a variety of information and resources and may, upon request, contact the district's exceptional student education (ESE) office or school to discuss concerns on behalf of the family. Family concerns and needs are always carefully considered as part of FIN's planning and problem-solving with districts and/or schools.

While FIN facilitators do not attend IEP meetings, they can provide information about the following: effective inclusive practices, family-school collaboration and communication, opportunities for networking with other families, and ways to access local resources and support. For information about your child's educational program or Individual Education Plan (IEP), please contact your child's teacher or school administrator.

Following is a list of FIN resources that are available, at no cost, to families and educators. For more information, please click on the links provided or contact your local FIN facilitator.

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The Florida Inclusion Network (FIN) provides services to schools and districts to increase and improve inclusive practices for students with disabilities in general education classrooms and other natural settings. FIN services are provided by a number of facilitators who have experience and expertise in planning and implementing inclusive practices at the school and district levels.

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Intellectual Disability | Center for Parent Information and Resources

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Link checked and current as of June 2017

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Improve Outcomes for Students with Disabilities by listening to this Teacher Nook podcast episode with Maya Bechi M.Ed. We talk about how to improve educational and transition outcomes for students with disabilities including Autism. We also discuss how to talk to parents about their child when you see them out in the community or when they come to your classroom.

Have you ever wondered if the IEP goals that you are writing actually connect with the outcomes and life a student is preparing for post-secondary? This interview with Maya Bechi helps special education teachers in the classroom by explaining the difference between IEP goals and student outcomes. This helps you make meaningful plans for the students in your classroom. Be sure to check out Maya's parent interview form for FREE! It helps you talk with parents about the plans they have in place for their child's future. Check that link out below.
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Improve Outcomes for Students with Disabilities (Podcast)

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Improve Outcomes for Students with Disabilities- The Teacher Nook podcast interview with Maya Bechi on teaching students in special education.

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Collaborative Teaching Virtual Instruction Tips With shifts to virtual instruction, teachers in collaborative partnerships will likely encounter challenges in providing co-teaching or support facilitation models to students with disabilities. This Tip Sheet provides a framework to assist teachers in making adjustments to their instruction to continue collaborative efforts.

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Five Tips for Helping Students with Special Needs

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They say that teaching is a thankless job - not only are teachers underpaid, but many of them dedicate countless hours of their free time to do extra work for their students. Being a teacher, in general, can be very difficult, but being a special needs teacher comes with its own unique set of challenges.

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Developmental disabilities are common in children in the United States, and the prevalence has increased in recent years ( 1). Timely estimates are necessary to assess the adequacy of services and interventions that children with developmental disabilities typically need ( 2). This report provides updated prevalence estimates for diagnosed autism spectrum disorder, intellectual disability, and other developmental delay among children aged 3-17 years from the 2019-2021 National Health Interview Survey (NHIS), with differences in prevalence examined between years and by sex, age group, and race and Hispanic origin. Estimates are also presented for any developmental disability, defined as having had one or more of these three diagnoses.

Keywords: autism spectrum disorder, intellectual disability, other developmental delay, developmental disability, National Health Interview Survey (NHIS)

The prevalence of any developmental disability, including other developmental delay, increased from 2019 to 2021.

Figure 1. Prevalence of children aged 3-17 years ever diagnosed with selected developmental disabilities, by year: United States, 2019-2021

¹Linear increase from 2019 to 2021 is significant ( p < 0.05).
NOTES: Developmental disability includes autism spectrum disorder, intellectual disability, and any other developmental delay. As children could be diagnosed with multiple developmental disabilities, "any developmental disability" is not the combined sum of intellectual disability, autism spectrum disorder, and other developmental delay. Estimates are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. .
SOURCE: National Center for Health Statistics, National Health Interview Survey, 2019-2021.

The prevalence of any developmental disability varied by sex and race and Hispanic origin but not age group.

Figure 2. Prevalence of children aged 3-17 years ever diagnosed with any developmental disability, by sex, age, and race and Hispanic origin: United States, 2019-2021

¹Significantly different from girls ( p < 0.05).
²Significantly different from Asian, non-Hispanic children ( p < 0.05).
³Children of Hispanic origin may be of any race.
NOTES: Developmental disability includes autism spectrum disorder, intellectual disability, and any other developmental delay. Estimates are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. .
SOURCE: National Center for Health Statistics, National Health Interview Survey, 2019-2021.

The prevalence of intellectual disability varied by sex, age group, and race and Hispanic origin.

Figure 3. Prevalence of children aged 3-17 years ever diagnosed with intellectual disability, by sex, age, and race and Hispanic origin: United States, 2019-2021

¹Significantly different from girls ( p < 0.05).
²Significant linear trend by age group ( p < 0.05).
³Significantly different from Asian, non-Hispanic children ( p < 0.05).
⁴Significantly different from Black, non-Hispanic children ( p < 0.05).
⁵Children of Hispanic origin may be of any race.
NOTES: Estimates are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. .
SOURCE: National Center for Health Statistics, National Health Interview Survey, 2019-2021

The prevalence of autism spectrum disorder varied by sex and age group.

During 2019-2021, the prevalence of autism spectrum disorder was higher in boys (4.66%) than girls (1.50%) (Figure 4).

Children aged 3-7 years (2.62%) were less likely to have been diagnosed with autism spectrum disorder than children aged 8-12 years (3.36%) and 13-17 years (3.35%).

While the prevalence of autism spectrum disorder was highest in Black children (3.56%), a significant difference was not observed between any of the race and Hispanic-origin groups.

Figure 4. Prevalence of children aged 3-17 years ever diagnosed with autism spectrum disorder, by sex, age, and race and Hispanic origin: United States, 2019-2021

¹Significantly different from girls ( p < 0.05).
²Significant linear trend by age group ( p < 0.05).
³Children of Hispanic origin may be of any race.
NOTES: Estimates are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. .
SOURCE: National Center for Health Statistics, National Health Interview Survey, 2019-2021.

The prevalence of developmental delay other than autism spectrum disorder or intellectual disability varied by sex, age group, and race and Hispanic origin.

Figure 5. Prevalence of children aged 3-17 years ever diagnosed with other developmental delay, by sex, age, and race and Hispanic origin: United States, 2019-2021

¹Significantly different from girls ( p < 0.05).
²Significant linear trend by age group ( p < 0.05).
³Significantly different from Asian, non-Hispanic children ( p < 0.05).
⁴Children of Hispanic origin may be of any race.
NOTES: Estimates are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. .
SOURCE: National Center for Health Statistics, National Health Interview Survey, 2019-2021.

Summary

During 2019-2021, a significant increase in the prevalence of any diagnosed developmental disability was observed. However, no significant change in the prevalence of diagnosed autism spectrum disorder or intellectual disability was observed over the same period. The increase in the prevalence of any developmental disability was largely the result of the significant increase in prevalence of any other developmental delay.

Estimates presented in this report are the first on developmental disabilities from NHIS since the survey was redesigned in 2019. While the prevalence reported in this report was higher for each selected condition than in a previous report from NHIS ( 3) with estimates from 2014-2016, these estimates may not be comparable with pre-redesign estimates. Boys were more likely to be diagnosed with a developmental disability than girls, younger children were less likely to be diagnosed with intellectual disability, and older children were less likely to be diagnosed with a developmental delay. This report did not find Black and Hispanic children to be more likely to be diagnosed with autism spectrum disorder compared with White children, unlike recent reports ( 4).

Definitions

Diagnosed developmental disabilities: Children were considered to have a developmental disability if they were diagnosed with one or more of the three selected developmental disabilities:

Autism spectrum disorder: Based on a "yes" response to the survey question, "Has a doctor or other health professional ever told you that [sample child] had autism, Asperger's disorder, pervasive developmental disorder, or autism spectrum disorder?" Children diagnosed with autism spectrum disorder could also be diagnosed with intellectual disability.

Intellectual disability: Based on a "yes" response to the survey question, "Has a doctor or other health professional ever told you that [sample child] had an intellectual disability, also known as mental retardation?" Children diagnosed with intellectual disability could also be diagnosed with autism spectrum disorder.

Other developmental delay: Based on a "yes" response to the survey question, "Has a doctor or other health professional ever told you that [sample child] had any other developmental delay?" Parents who affirmed that their child had autism spectrum disorder or intellectual disability were asked to exclude those conditions when asked about any other developmental delay. Children who were diagnosed with either or both autism spectrum disorder and intellectual disability and had a "yes" response to this survey question were considered to have been diagnosed with both or all three conditions.

Race and Hispanic origin: Categories shown for non-Hispanic children are for those who selected only one racial group; respondents had the option to select more than one racial group. Children categorized as Hispanic may be of any race or combination of races. Estimates for non-Hispanic children of races other than White only, Black only, or Asian only are not shown but are included in total estimates. Analyses were limited to the race and Hispanic-origin groups for which data were reliable and sufficiently powered for group comparisons based on National Center for Health Statistics presentation standards ( 5).

Data source and methods

Data from the 2019-2021 NHIS were used for this analysis. NHIS is a nationally representative household survey of the U.S. civilian noninstitutionalized population. It is conducted continuously throughout the year by the National Center for Health Statistics. Interviews are typically conducted in respondents' homes, but follow-ups to complete interviews may be conducted over the telephone. Because of the COVID-19 pandemic, interviewing procedures were disrupted, and 68.0% of 2020 and 61.4% of 2021 Sample Child interviews were conducted at least partially by telephone ( 6, 7). In 2019, 31.7% of Sample Child interviews were conducted at least partially by telephone ( 8). For more information about NHIS, visit https://www.cdc.gov/nchs/nhis.htm. The NHIS questionnaire was redesigned in 2019, which may impact the ability to compare estimates from this report with previous years. For more information on the NHIS redesign, visit https://www.cdc.gov/nchs/nhis/2019_quest_redesign.htm.

Point estimates and the corresponding confidence intervals were calculated using SAS-callable SUDAAN software ( 9). All estimates are based on parent or guardian report and meet National Center for Health Statistics data presentation standards for proportions ( 5). Estimates are presented at two decimal places to allow comparability with reports from the Autism and Developmental Disabilities Monitoring Network ( 4) and previous National Center for Health Statistics reports ( 3). Differences between percentages were evaluated using two-sided significance tests at the 0.05 level via logistic regression. Linear and quadratic trends by age group were evaluated using two-sided significance tests at the 0.05 level.

About the authors

Benjamin Zablotsky, Amanda E. Ng, Lindsey I. Black, and Stephen J. Blumberg are with the National Center for Health Statistics, Division of Health Interview Statistics.

References

1. Zablotsky B, Black LI, Maenner MJ, Schieve LA, Danielson ML, Bitsko RH, et al. Prevalence and trends of developmental disabilities among children in the United States: 2009-2017. Pediatrics 144(4):e20190811. 2019.

2. Cogswell ME, Coil E, Tian LH, Tinker SC, Ryerson AB, Maenner MJ, et al. Health needs and use of services among children with developmental disabilities-United States, 2014-2018. MMWR Morb Mortal Wkly Rep 71(12):453-8. 2022.

3. Zablotsky B, Black LI, Blumberg SJ. Estimated prevalence of children with diagnosed developmental disabilities in the United States, 2014-2016. NCHS Data Brief, no 291. Hyattsville, MD: National Center for Health Statistics. 2017.

4. Maenner MJ, Warren Z, Williams AR, Amoakohene E, Bakian AV, Bilder DA, et al. Prevalence and characteristics of autism spectrum disorder among children aged 8 years-Autism and Developmental Disabilities Monitoring Network, 11 sites, United States, 2020. MMWR Surveill Summ 72(2):1-14. 2023.

5. Parker JD, Talih M, Malec DJ, Beresovsky V, Carroll M, Gonzalez JF Jr, et al. National Center for Health Statistics data presentation standards for proportions. National Center for Health Statistics. Vital Health Stat 2(175). 2017.

6. National Center for Health Statistics. National Health Interview Survey, 2020 survey description. 2021.

7. National Center for Health Statistics. National Health Interview Survey, 2021 survey description. 2022.

8. National Center for Health Statistics. National Health Interview Survey, 2019 survey description. 2020.

9. RTI International. SUDAAN (Release 11.0.3) [computer software]. 2018.

Suggested citation

Zablotsky B, Ng AE, Black LI, Blumberg SJ. Diagnosed developmental disabilities in children aged 3-17 years: United States, 2019-2021. NCHS Data Brief, no 473. Hyattsville, MD: National Center for Health Statistics. 2023. DOI: https://dx.doi.org/10.15620/cdc:129520.

Copyright information

All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.

National Center for Health Statistics

Brian C. Moyer, Ph.D., Director
Amy M. Branum, Ph.D., Associate Director for Science

Division of Health Interview Statistics

Stephen J. Blumberg, Ph.D., Director
Anjel Vahratian, Ph.D., M.P.H., Associate Director for Science

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Products - Data Briefs - Number 473 - July 2023

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List of Accommodations and Modifications

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The site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape closes them as well.

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Center for Parent Information and Resources

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Supports, Modifications, and Accommodations for Students - Center for Parent Information and Resources

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Your Central Hub for Parent Centers Serving Families of Children With Disabilities