Intellectual Disability

By: Dariko Danielyan, MS, SLP-CCC

Summary of condition:

Intellectual disability or ID impacts 1-3% of the world’s population (Cleveland Clinic, 2023). ID is a disability that limits a person’s ability to “learn at an expected level and function in daily life” (CDC, 2024). Individuals with ID may develop more slowly compared to others. It may take them longer to learn skills such as eating, dressing, speaking, walking, and learning in school (CDC, 2024).

There are many signs/symptoms of intellectual disability (ID). It is important to note that severity of ID can vary among individuals (CDC, 2024).

Some common signs include:

Delayed/slowed learning
Slowed reading speed
Difficulties with several skills such as reasoning and logic, critical thinking, problem-solving, planning, focusing, recalling information, and making appropriate judgements
Slower social development compared to peers
Difficulty understanding social expectations, boundaries and appropriate social interactions with friends, peers, and romantic partners (Cleveland Clinic, 2023)
Learning to speak later than other children or having difficulty speaking

Onset of ID occurs anytime before an individual turns 18. ID can be caused before birth, after birth, or in early childhood.

Causes of ID before birth can include genetics, infections, substances that disrupt fetal development such as tobacco or alcohol, medical conditions such as hypothyroidism (Cleveland Clinic, 2023)
Causes of ID after birth include: Premature birth, hypoxia (lack of oxygen to the fetus’ brain), and/or any other brain injuries
Causes of ID in early childhood include: brain injury, toxic exposures to heavy metals, infections such as measles or meningitis, tumors in the brain, medical conditions such as seizures and various types of epilepsy

Types (Cleveland Clinic, 2023): ID is typically classified by 4 severity levels: mild, moderate, severe, and profound

Characteristics of mild ID:

Average mental age of 9-12 years of age
Impact learning and completion of complex tasks
Often work and live independently with support from specialized interventions and assistance in early childhood
Most common type of ID (about 85% of people with ID are classified as “mild”)

Characteristics of moderate ID:

Average mental age of 6-9 years of age
Typically acquire an elementary school level education and often communicate using simple language
Can learn to live independently, however, most need varying levels of support (such as support from a group home) with day-to-day activities, tasks, and self-care

Characteristics of severe ID:

Average mental age of 3-6 years of age
Typically communicate using single words, phrases, and/or gestures
Typically require daily support with day-to-day activities, tasks, and self-care

Characteristics of profound ID:

Average mental age of 3 years old and below
Mainly communicate nonverbally and can often comprehend gestures/emotional expressions
Typically require 24/7 medical care and support with all aspects of life

Role of Rehabilitation:

Occupational Therapy (OT) (Johnson, Blaskowitz & Mahoney, 2019):

Support with activities of daily living (ADLs) such as bathing, dressing, toileting, eating, etc.
Support with instrumental activities of daily living (IADLs) such as managing finances, cooking, shopping, housekeeping, transportation, and medication management
Vocational training
Health management skills intervention
Community engagement programs

Physical Therapy (PT) (Friedman & Feldner, 2018):

Pain management
Postural support
Respiratory support
Assistive technology support
Environmental modifications
Prevention of secondary impairments
Functional mobility training

Speech-Language-Pathology (SLP) (ASHA, 2019):

Conceptual skills (receptive and expressive language, reading, writing)
Social skills (interpersonal skills, understanding and applying social skills, problem solving)
Practical skills (organizing and following job tasks or tasks of daily living, accessing and using technology for communication (e.g., phone, Zoom), using money and transportation, completing personal care procedures

Evaluations for ID typically include several components (Cleveland Clinic, 2023):

Evaluation of intelligence (which include skills such as planning, recalling information, problem-solving, attention, critical thinking, etc,)
Evaluation of completion of daily-life skills (such as eating, dressing, etc.)
Evaluation of social skill knowledge and application
Laboratory tests of urine, blood or more
Genetic counseling
Imaging tests to determine differences in brain structure that may cause ID

Interventions (Cleveland Clinic, 2023):

Education support: providing necessary accommodations and supports. One such example is an Individualized Education Plan (IEP)
Behavioral support: learning life skills, social skills, and important executive functioning skills (e.g., problem-solving, recall, etc.)
Vocational training: learn work-related skills
Family education: helping family, friends, and loved ones learn more about ID and how to support those with ID
Community support: helping individuals with ID access resources that may provide support with daily life skills, work skills, and social groups

Helpful Resources:

References:

American Speech-Language-Hearing Association (ASHA). (2019). Intellectual Disability. (2019). https://www.asha.org/practice-portal/clinical-topics/intellectual-disability/?srsltid=AfmBOoqhvyvskwqKDUaMjj95JNAq9H37EWsB8JZLDiy5DYS7xgWlZssf
Cleveland Clinic. (2023). Intellectual disability. https://my.clevelandclinic.org/health/diseases/25015-intellectual-disability-id
Center for Disease Control and Prevention (CDC). (2024). Facts About Intellectual Disability. https://www.cdc.gov/disability-and-health/media/pdfs/2024/12/IntellectualDisability.pdf
Friedman, C., & Feldner, H. A. (2018). Physical Therapy Services for People With Intellectual and Developmental Disabilities: The Role of Medicaid Home- and Community-Based Service Waivers. Physical Therapy, 98(10), 844–854. https://doi.org/10.1093/ptj/pzy082
Johnson, K. R., Blaskowitz, M., & Mahoney, W. J. (2019). Occupational Therapy Practice with Adults with Intellectual Disability: What More Can We Do? The Open Journal of Occupational Therapy, 7(2). https://doi.org/10.15453/2168-6408.1573

Intellectual Disability

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