developmental disabilities and autism in early childhood

hp252 exam 2

Developmental Disabilities

Umbrella term that includes intellectual disabilities and other conditions that affect a person’s ability to independently complete major life activities in 3 or more areas before age 22.

intellectual Disability (ID)

A developmental disorder diagnosed before age 18 with an IQ below 70 and significant functional limitations.

Difference between DD and ID

DD begins before age 22 and limits 3+ life activities; ID begins before age 18 and requires an IQ < 70.

Major Life Activities (for DD diagnosis)

Self-care, learning, communication, mobility, self-direction, independent living, and economic self-sufficiency.

Prevalence of Developmental Disabilities

More common in boys; less prevalent among Asian individuals.

Causes of Intellectual Disability

35% genetic, 33% environmental (trauma or toxins), 33% unknown.

Down Syndrome

Chromosomal condition caused by Trisomy 21; most common chromosomal ID. Traits: low muscle tone, short stature, upward eye slant, single palm crease. Life expectancy ~60 years.

Fragile X Syndrome (FXS)

Most common inherited cause of ID; FMR1 gene on X chromosome doesn’t make needed protein. Traits: long face, large ears, flexible joints, anxiety, speech delay, hand flapping.

Fetal Alcohol Spectrum Disorder (FASD)

Caused by prenatal alcohol exposure; affects ~40,000 babies/year. Traits: facial malformations, growth <10th percentile, hyperactivity, aggression, ID. Preventable.

Phenylketonuria (PKU)

Genetic metabolic disorder where body can’t break down phenylalanine; leads to brain damage without dietary treatment.

Klinefelter Syndrome (47-XXY)

Males with extra X chromosome; traits include tall height, reduced body hair, sterility, mild ID, and social/language challenges.

Prader-Willi Syndrome

Deletion on chromosome 15; causes insatiable hunger, short stature, low muscle tone, mild ID, and behavioral challenges.

Autism Spectrum Disorder (ASD)

Neurodevelopmental disorder characterized by persistent deficits in social communication and restricted, repetitive behaviors.

Evolution of Autism Terminology

Autism was once grouped under schizophrenia (1950s); DSM-5 (2013) unified subtypes under ASD spectrum model.

Prevalence of Autism

More common in boys and Black individuals.

Social Communication Deficits (ASD)

Trouble with back-and-forth conversation, emotion sharing, eye contact, and forming relationships.

Repetitive Behaviors (ASD)

Repetitive speech/movements, insistence on routines, fixated interests, unusual sensory responses.

Echolalia

Repetition of words/phrases heard; can be immediate or delayed; up to 75% of verbal individuals with ASD show it.

Early Signs of ASD

Lack of eye contact, joint attention, or reciprocal conversation; unusual sensory focus; rigid routines.

Diagnosing Autism

Reliable by 18–24 months; median diagnosis age still around 4–5.7 years.

Autism “Epidemic” Misconception

rise in diagnoses due to better awareness, broader criteria, and improved detection — not an actual epidemic.

Cognitive Characteristics of ASD

Strong visual processing, weak abstract thinking, focus on details.

Social Characteristics of ASD

Difficulty with joint attention, reading emotions, and perspective-taking.

Communication Characteristics of ASD

Delayed speech or none, literal language use, echolalia, limited eye contact.