Intellectual Disability

intellectual disability

1. Intellectual functioning (intelligence)

2. Standardized assessment of intelligence (IQ)

2. Adaptive behavior

3. Onset must be before age 18

• Not an appropriate diagnosis for an adult with similar limitations due to a TBI experienced at age 21

characteristics of intellectual disabilty

• IQs that are 2SDs below the mean (i.e., 70 vs a mean of 100)

• Research suggests a range of 65-75, measurement variance

• Use clinical judgment to interpret scores

• Intelligence is unable to be tested by standard tests with a strong presumpton of this disability: Severity Unspecifed

adaptive behavior

The collecton of conceptual, social, and practical skills that people have learned so they can function in their everyday live

• Conceptual: communicaton (spoken, writen, read), $, time, numbers

• Social: naivete, rule following, interpersonal skills

• Practical: ADLs, IADLs (Rx, meals, money and home management), health and safety

global developmental delay (GDD)

• Children who are younger than 5 years

• Delayed achievement of developmental milestones

• Temporary diagnosis

•Reassessment needed after age 5

signs of delay (2-4 months)

Failure to interact with the environment

signs of delay (6-18 months)

Decreased gross motor skills

signs of delay (18 months- 5 yrs)

Decreased language development

sings of delay (3-5 yrs)

• Decreased or abnormal play and social skills

• Below age level fine motor skills

signs of delay (5+ years)

• Decreased academic achievement

• Abnormal attention, anxiety levels, mood and conduct

classification of ID

Categorization by severity levels

• DSM-5: mild, moderate, severe, profound

• Move away from DSM-IV (limitatons focused)

• AAIDD considers the level of supports needed to improve function (standardized tool used): intermittent (as needed), limited (a limited period of tme), extensive (daily in a life area), pervasive (daily, all life areas, all contexts)

• Strengths-focused, limitatons assist in developing support profle

incidence of ID

ID is not a rare developmental disability – 1-3% of the global populaton

• Males are more likely than females to be diagnosed with ID

• Recent estimates that ~1% of the populaton is affected

• This is reduced from previous years now that IQ is not the only factor that contributes to the diagnosis

prevalance of ID

• Prevalance increases with age: 3-7 yr: 1.39%; 13-17 yr: 2.35%

• Black children (2.82%) more likely to be diagnosed than hispanic (1.77%), white (1.76%) and asian (0.72%)

• Asian children least likely to be diagnosed

• In WV- 2.78% (ages 6-21); 17.6% receive education services

• Nationally- 0.94%; 7.4% receive education services

causes of ID

• Cause is often unknown in the case of mild ID (IQs 50-70)

• Causes more likely to be known in the case of individuals who are severely impacted (IQs <50)

• Differing origins

• Differing points in the developmental cycle

• More than one causal factor for >=50% of individualas

etiology of mild ID

• Environmental factors such as socioeconomic status and neglectful or abusive caregivers.

• See communication barriers and decreased motor coordinaton.

• Diagnosis may be late

etiology of severe ID

• Biomedical origin (genetc, non-genetc congenital birth anomalies)

• Greater number of associated impairments

• Cerebral palsy, seizures, sensory issues, psychological and behavioral disorders (depression, bipolar disorders), communicaton, feeding difcultes, ADHD, ASD, stereotypic movement, limitatons in impulse control, INC rates of mental illness (up to 40%-70% of individuals)

• Diagnosis as a newborn or infant due to signifcant number of red flags

biomedical etiology

Genetic causes (prenatal)

• Single gene disorders

  • Autosomal dominant: Tuberous sclerosis

  • Autosomal recessive: Tay-Sachs, phenylketonuria

  • X-linked: Fragile X syndrome

• Chromosomal disorders – missing or extra chromosomes

  • Down syndrome (trisomy 21)

  • Trisomy 18, 13

Congenital anomalies (aka “birth defects”) that are not genetc

• CNS malformatons

  • Cortcal atrophy, hydrocephaly, spina bifda, craniostenosis, cardiac anomalies

environment etiology 

Environmental Influences – external to the person, impact brain development/function.

May occur:

• Prenatally

  • Intrauterine exposure to substances (primarily FAS)

  • Material conditons: “rubella, syphilis, hypertension, diabetes, toxemia, hyperphenylalaninemia, cytomegalovirus”

• Prematurity or intrauterine growth retardaton resultng in low birth weight

  • Maternal contributors to low birth weight: smoking, lack of prenatal care and poor nutriton, infecton, chemical exposure, use of certain substances including legal medicatons

• Especially during the first trimeste

• Perinatally

  • Mechanical birth injuries during difcult labors

    • Meningeal tears (CSF leaks)

    • Blood vessel tears

• Acquire HIV-1 encephalopathy, herpes simplex II during birth

• Hypoxia (decreased oxygen supply) or anoxia

• Preterm birth’ risk of impaired respiratory hemorrhage

known risks for ID

• smoking, drinking, other drugs during pregnancy 

• having certain medical conditions, such as uncontrolled diabetes 

• taking certain medications, such as isotretinoin 

• having someone in your family with a birth defect 

• getting certain infections during pregnancy, such as cytomegalovirus or zika 

• having fever greather than 101 or elevated body temperature 

signs and symptoms of ID

In a young child, symptoms may include delays in GM/FM skills, communicaton, limitatons in recalling informaton including understanding consequences, social rules, difculty problem solving

• Those with mild ID may not be identfed untl they reach school

• Intellectual limitatons (2 SD below mean)

• Adaptve behavior limitatons – skills required to safely and responsibly live on one’s own (2 SD below mean in one’s performance contexts

signs and symptoms of mild ID

• A child may have difculty learning an academic skill, challenges with abstracton, EF, STM

• Adults may have a concrete approach to problem solving

• Immature social interactons

• May be IND in ADLs and may be employable

signs and symptoms of moderate ID

• A child may have slow development of language/academic skills in pre-K

• Adults may have an elementary-level educaton

• Language skills below peers and decreased social skills may limit friendships and relatonships

• Need for supports and assistance for academic, personal, employment actvites

• May require repetton of teaching and reminders to support ADLs and recreatonal skills

signs and symptoms of severe ID

• Expressive language – single words, phrases, AAC means

• Receptve language – simple speech, gestures

• High level of support needed for problem solving

• Require SPV and supports for ADLs

• Long-term teaching can assist with acquiring skills

signs and symptos of profound ID

• Expressive and receptve language very limited, gestures and emotonal cues may be used and understood

• Recreaton may include water actvites, walking, listening to music, watching movies

• Dependent in ADLs or may be able to assist caregiver

• May be able to functonally use objects

course and prognosis of ID

• Usually considered a lifelong conditon

• Can increase adaptve functon skills of an individual with mild ID

• Do not predict outcome by the IQ score

• Life expectancy is similar to general populaton for those with mild ID

• Generally nonprogressive

• Muscular dystrophy and Tay-Sachs are progressive

• Those with Down syndrome develop progressive dementa around 40 y.o.

• At risk of stigma, isolaton, discrimination --- anxiety, depression

behaviors of ID

• Assess the behavior according to cognitve age rather than chronological age.

• Modifcatons to environment

• Behaviors due to communicaton barriers, to gain atenton, or to avoid frustraton.

• Medication for psychiatric-based disorders.

• Doctor may reevaluate every 2 years

• Behavior management techniques

• Varies by state regarding coverage