Intellectual Disability & Developmental Delay

Intellectual Disability & Developmental Delay pdf


If your child has an intellectual disability or a developmental delay, these challenges can impact his or her cognition, social development and learning as well as his or her day-to-day functioning, including self-care, community living skills and communication of wants and needs. A developmental delay includes characteristics of an intellectual disability, but this diagnosis is reserved for children younger than five who may not be able to be reliably assessed in cognitive domains. These children have a number of weaknesses in meeting developmental milestones. An intellectual disability (ID) is a disability that impacts both intellectual and adaptive development and functioning. ID is present first in the developmental period. Challenges must be conceptual, social and practical, according to the current Diagnostic and Statistical Manual (DSM-5). Children with intellectual disabilities tend to learn much more slowly than would be typical. These children can and do make progress, but this progress is not at the same rate as the progress of other learners. Speaking, walking, kicking a ball, playing and engaging with others may all be delayed. You may describe your child as a really hard worker who struggles. You may see that he or she is more immature than peers, needs more help than others and just doesn’t get it as quickly as other children.


The primary deficits in an intellectual disability are discussed below. Individuals may have trouble with reasoning, problem solving, verbal comprehension, retaining information, abstract thinking, academic skills and adaptive skills. Challenges must be obvious in both clinical evaluation and standardized intelligence testing (IQ). Challenges must be evident across multiple settings; in other words, challenges in school alone would not be enough to meet criteria. Difficulties must be evident in the child’s school, home, and community.

Conceptual. An individual with ID may have difficulty learning academic information, recalling conceptual information, and processing new information. Despite lots of support, a child may not be learning reading and math like peers. Using repetition, visual strategies, small group or one-on-one support may be most successful, but progress may still be markedly slow. Children with more severe IDs may have challenges understanding and communicating with language and also with understanding concepts like time, numbers and money. With very severe deficits, understanding anything symbolic may be challenging. Children may need to learn only within the physical world, and language could be severely impacted.

Social. The social domain considers spoken language as an integral part of understanding, conversation and social interaction. Mildly impaired children may seem just a bit immature. Language may be more concrete, and understanding of social dynamics may be as well. Individuals with ID may be easier to manipulate or take advantage of because of their more concrete understanding of social situations. For individuals with ID, making and having social opportunities and social connections is very important. Research shows us that individuals who have strong social connections are much happier and more productive in life. Social groups, activities and community centers are very important for people with ID. The support of family is invaluable so that children and adults with ID will feel connections and have relationships to rely on for support.

Practical. Individuals with ID typically need support planning and organizing a schedule, budgeting, shopping for groceries, and keeping track of appointments. Individuals can often learn lots of self-care skills, community skills and home care. They may struggle to live completely independently, preferring an apartment close to a family member, a group home with built in social opportunities or having a caregiver. Mild and Moderately impaired individuals can handle a lot of personal and self-care tasks and may be very successful at jobs that are more concrete in nature or may excel in concrete tasks at school. Extra support from supervisors, teachers, paraprofessionals, and others will greatly impact progress. Severe and profoundly impacted individuals will be more reliant on others for self-care. Sometimes, toileting, bathing, eating, dressing, and other daily skills require comprehensive support. A small percentage of individuals may have self-injuring behaviors, such as biting or hitting themselves. Individuals with more significant impairments need a great deal more support than do those with mild to moderate challenges.

Severity Levels. ID is characterized as having four different severity levels. Severity level Mild includes traits that are subtle and may not be obvious to those who are not trained to diagnose, but the child’s challenges are significant enough to lead to a referral. Severity level Moderate is noted for individuals who might have more challenges communicating, speaking in simple sentences, and maybe more obviously impaired. Severity level Severe is for individuals who have significant deficits, and Profound is the level for individuals who are most impacted.


It is important to explore and consider an assessment as concerns arise. The services that diagnosed young children qualify for can enable them to make greater gains and strides in developing the cognitive and adaptive skills they will need to function independently. Children with DD or ID do make progress. This progress may be slower and more challenging to reach, and so starting early can be a great help to your child. Taking all this information into consideration, it is important to assess children at a young age and to determine whether services are warranted.


Cognitive/Intellectual Assessment. Cognitive assessment provides information on thinking and reasoning skills. The WISC-V is the most commonly used assessment measure for school aged children ages 6 to 16. This measure is divided into Verbal Comprehension, Visual Spatial, Fluid Reasoning, Working Memory and Processing Speed. Each measure is a bit different, but they all assess cognitive or intellectual abilities. Other measures include the DAS-2, Stanford Binet, KABC-2, WJ Cognitive, and CAS. Some measures like the TONI and UNIT only use nonverbal stimuli, making them more multi-culturally useful in some cases of children who do not speak English. Scores within the standard error of measurement that include Standard Scores of 70 or below indicate a significant cognitive deficit. Compared to challenges in working memory and processing speed, challenges in verbal and nonverbal reasoning are more significant because they are more associated with general intelligence.

Adaptive Assessment. Adaptive assessment is often in the form of teacher and parent report rating scales of adaptive behaviors demonstrated in school, the community or at home. The Vineland, SIB-R or ABAS may be provided as a rating scale or may be given as an interview. Scores within the standard error of measurement that include Standard Scores of 70 or below indicate a significant adaptive deficit. Parents should be sure they are rating a child’s independent skills. Talking with the clinician who provided and administered the measure can help a parent determine if a skill is being rated as mastered when actually much help is required to complete the task.

Looking across measures at various symptoms, the clinician is going to determine whether or not the symptoms are significant and how they might be explained. For example, understanding where cognitive and adaptive challenges have the most impact can be helpful in treatment. At the same time, understanding your child’s relative learning strengths can be helpful to make progress in treatment. For example, identifying good fine motor skills or solid visual processing can help identify ways to improve learning.


A referral for a comprehensive neuropsychological evaluation is most appropriate when concerns are suspected about ID. This type of assessment includes an evaluation of your child’s cognitive ability, adaptive skills, language skills, social skills and sensory processing. Other areas may be evaluated as concerns arise. Referrals may include Applied Behavior Analysis (ABA) therapy, speech therapy, occupational therapy, parent consultations, and an Individualized Educational Plan (IEP).

ABA Therapy. ABA therapy refers to behavioral therapy that is used to increase communicative behaviors or decrease problem behaviors. A therapist often comes into your home or preschool to do this therapy and takes extensive data on your child’s progress.

Speech Therapy. Speech therapy may be recommended to increase expressive, receptive and pragmatic language or to help if Speech & Language articulation challenges or problems are present. It is great to have your speech therapist collaborate with any other therapist so that everyone is working together to meet your child’s needs.

Occupational Therapy. Occupational therapy addresses any deficits in fine motor skills. Occupational therapy can be very helpful for some children with ID who are working to develop fine motor skills like writing, drawing, building with blocks, feeding, dressing, self-help, cooking, and cleaning.

Parent Consult. Parent consultation can follow an ABA or a Family Systems model and can provide guidance to parents on strategies to use and principles of reinforcement. Consultation can also focus on the parent’s experience and emotional well-being.

School Services. School-based supports like an IEP can help your child receive accommodations and modifications that they may require to access learning in the classroom setting. Taking a comprehensive neuropsychological report to any of these professionals will help them to get an understanding of your child. It will be important to think about how these therapies fit together and about how different skills are being built and addressed to best support your child.


Organizations that work with individuals who have IDs stress the point that learning and progress are possible and can be steady and marked. Progress tends to be slow, but individuals with IDs and DDs can learn. It is important that we as a society, including families, schools and community organizations, understand this progression and work to support members of our society who may need a bit more teaching and patience but who are valuable members of our community. Community skills training and opportunities to find jobs and roles in the community have a huge impact on quality of life. Providing social outlets and community supports can go a long way in helping individuals with ID succeed. Taken together, it is valuable to obtain a diagnosis and to engage in the appropriate therapies as early as is feasible. With these supports in place, it is possible to see growth in skills, the ability to form meaningful relationships, and the potential to live a fulfilling life.


  • Intelligence
  • Verbal Comprehension
  • Non-Verbal
  • Fluid Reasoning
  • Processing Speed
  • Sequencing
  • Spatial
  • Auditory Processing
  • Learning problems
  • Achievement
  • Reading Comprehension
  • Basic Reading Skills
  • Writing
  • Math
  • Presence
  • Parallel Play
  • Interacting
  • Conversation
  • Empathy
  • Intimacy
  • Adaptive Skills
  • Functional Communication
  • Toilet training
  • Hygiene
  • Sleep Problems
  • Manners
  • Disordered eating
  • Motor Planning
  • Coordination
  • Perseverating


[1] The Arc

[2] American Association of Intellectual and Developmental Disabilities.

[3] Kroncke, Anna P., & Willard, Marcy & Huckabee, Helena (2016). Assessment of autism spectrum disorder: Critical issues in clinical forensic and school settings. Springer, San Francisco.



[4] Anderman, Eric M. & Anderman, Lynley Hicks (2009). Classroom motivation. Anderman/dp/0131116975/

[5] Sattler, Jerome (2014). Foundations of behavioral, social, and clinical assessment of children.

[6] Bell, Nanci (2013). Seeing stars: Symbol imagery for phonological and orthographic processing in reading and spelling.

[7] Bell, Nanci (2007). Visualizing and verbalizing: For language comprehension and thinking.

[8] Lindamood, Patricia (2011). LiPS: The Lindamood phoneme sequencing program for reading, spelling, and speech — 4th edition, complete kit (LIPS, 4th).

[9] Orlassino, Cheryl (2012). Blast off to reading!: 50 Orton-Gillingham based lessons for struggling readers and those with dyslexia.

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