Autism Spectrum Disorder

Prevalence

•Neurodevelopmental disorder with a prevalence of 1 in every 31 children being diagnosed with ASD at age 8 in 2022 (CDC, 2025)

•3 times more common in boys than girls

•Earliest diagnosis by 18 months of age although commonly age 4 and over

•Spectrum disorder with wide variation in skill levels of individuals

Diagnostic Criteria: DSM 5 Social

Deficits in social communication and social interactions across multiple contexts

Diagnostic Criteria: DSM 5 Behavior Restrictions

Restricted, repetitive patterns of behavior, interests, or activities

Diagnostic Criteria for ASD: DSM 5

•Symptoms present in early development (may become manifest only when social demands exceed limited capacities) – some children mask by learned strategies

•Clinically significant impairment in social, occupational, and other areas of functioning

•Not explained by intellectual disability or global developmental delay

Specifiers –

•With or without accompanying intellectual impairment

•With or without accompanying language impairment

•Associated with a known medial or genetic condition or environmental factor

•Associated with other neurodevelopmental, mental, or behavioral disorders

•With catatonia

Marked deficits in social communication but do not meet criteria of ASD – social communication (pragmatic) disorder

Three Functional Levels

ASD Level 1: Requiring Support. Difficulty initiating social interactions, organization, and planning problems can hamper independence

ASD Level 2: Requiring Substantial Support. Social interactions limited to narrow special interests, frequent restricted/repetitive behaviors. 

ASD Level 3 Requiring Very Substantial Support. Severe deficits in verbal and nonverbal social communication and skills, great distress, difficulty changing actions or focus

Diagnostic Criteria for ASD: DSM4

Etiology

No single known cause – but neuropathology of ASD begins in prenatal or perinatal period

Combination of genetic and environmental factors

Genetic component

• Increased risk in families

• Twin studies – identical twin also having ASD – 31-95% greater risk 

• Siblings of children with ASD – 25-50% chance of some delays - ~20% ASD, ~30% Broader Autism Phenotype (social, language, motor delays, unusual sensory interests)

Other populations at risk for ASD: Premature infants, children born to older parents, exposure to prescription medications like valproic acid and thalidomide

Associated genetic disorders: Fragile X, Tuberous Sclerosis, Down syndrome, Angelman, etc.

Specific environmental factors have not been identified 

Brain Pathology 1

Early overgrowth followed by arrested development and early degeneration from adolescence to middle ages

Brain Pathology 2

Long-distance under-connectivity and short-distance over-connectivity – poor integration of sensorimotor, social communication and cognitive functions

Brain Pathology Continued

•Cortex: Frontal and temporal lobes – planning, executive function, social communication skills

•Amygdala: Emotional processing

•Hippocampus: Learning and memory 

•Basal ganglia and cerebellum: Coordination, clumsy gait, motor learning

•Mirror Neuron system deficits: Problems with imitation and empathy

Impairments Part 1 Social

Social and attentional – difficulties with eye contact, turn taking, joint attention, delayed response to name, attention more on non-social cues, difficulty disengaging attention 

Communication –

Poor pragmatic language skills (use of nonverbal cues to communicate: eye gaze, facial expressions, body language),

Poor prosody (rhythm, stress, intonation)

Poor phonology (Word articulation)

Atypical language – echolalia (immediate or delayed imitation of words)

Cognition – Executive functioning deficits

Set of mental processes that allow problem-solving to achieve a goal

Includes response inhibition, interference control (selective attention), working memory, cognitive flexibility

Impairments Part 2 Sensory/Perceptual

Sensory-perceptual –

Sensory modulation –

Difficulty regulating and organizing nature and intensity of responses to specific sensory stimuli – tactile, olfactory, visual, auditory, proprioceptive, and vestibular inputs

Under-responsive – slow to respond, fail to react to pain

Over-responsive – Exaggerated responses to input

Sensory seeking – craves for sensory input – stereotypical movements of arm flapping, body rocking etc.

 

Enhanced/atypical visual and auditory perception –

Enhanced local processing compared to global processing of perceptual information

Unable to understand the “big picture” – get caught up in the details

Enhanced auditory and visual perception – heightened pitch perception, greater pitch discrimination 

Impairments Part 3 - Motor

Motor – large effect sizes for motor impairments based on a meta-analysis

Motor stereotypies –

Movements with bodies (rocking, twirling, flapping, bouncing)

Object-related behaviors (spinning, poking, twirling, smelling, atypical peering at objects)

Inflexible routines

Recognize this could be a way to modulate their senses or as a form of communication

Motor delays – GM, FM, and oro-motor delays:

Delayed head holding, rolling, sitting, crawling, walking

Delayed reaching, clapping, scribbling, pointing – FM delays predictive of later communication delays

Limited movement repertoire and transitions 

Gait and balance –

Toe walking

Deficits in feedback and feedforward balance

Motor planning, praxis, and imitation

Complex sports, handwriting,

Self-care – dressing, tying laces

Strength and tone

Persistence of abnormal reflexes

Truncal hypotonia

Poor strength – grip strength

Endurance and physical activity levels

High risk for developing obesity (3 times more likely than healthy peers)

Retrospective study – 23.4% older children & adolescents obese; 19% overweight; 35.7% at-risk for obesity

Lower physical activity levels, greater sedentary time

Dietary patterns

Social and motor impairments

Motor Deficits in ASD

Co-occurring Conditions

•ADHD: 30-61%

•Gastrointestinal disorders (diarrhea, constipation, food regurgitation, food selectivity): 42%

•Sleep disturbances: 50-80%

•Communication disorders: 63.4%

•Motor planning disorders/dyspraxia: 34%

•Obesity & overweight: 32% overweight & 16% obese (2-5-year-olds)

•Toe-walking: 20%

•Sensory processing disorders: 15.7%

•Developmental Coordination Disorder: 18% (although 86.9% fail on the DCDQ)

•Intellectual disability: 18.3%

•Anxiety: 11-40%

•Depression: 7% children, 26% adults

•Schizophrenia: 4-35% adults

•Learning disabilities: 6.3%

•Epilepsy: 16-44%

Diagnosis: Early Screening

Early identification and intervention is related to better outcomes

Earliest signs within the first 2 years in the perceptuo-motor system:

•Gross motor delays –

•Delayed motor milestones, poor head and trunk control, reduced movement repertoire

•Fine motor delays –

•Poor fine motor & object manipulation skills, primitive repetitive manipulation of objects 

Commonly used screening tools –

Modified Checklist for Autism in Toddlers (MCHAT) – 16-48 months

Ages and Stages Questionnaire (ASQ) – 1 month to 5.5 years

Social Communication Questionnaire (SCQ) > 4 years

Screening Tool for ASD in Two-year olds (STAT) – 24-36 months

Pervasive Developmental Disorders Screening Test (PDDST-II) – 18-48 months

Diagnosis

Earliest diagnosis by 18 months

Interdisciplinary team – clinical psychologist, developmental pediatrician, psychiatrist, PT, OT, SLP, special educator

Motor

Sensory

Social emotional

Communication – speech, language

Cognition

Adaptive and functional skills

Diagnosis Cont.

History – ask about birth history, family history of ASD, milestones in different domains (motor, communication, social)

Interviews with caregivers – child’s current level of functioning

Observation of child in multiple, naturalistic settings –

Nature of play - variability

Exploration of objects – typical use versus fixated on certain parts

Gross motor skills – positions, transitions, balance, fundamental motor skills, navigating stairs, kicking a ball, ball skills

Fine motor skills – reaching, grasping, in-hand manipulation 

Child’s mode of communication (verbal and nonverbal; spontaneous and responsive)

Sensory responses

Intellectual level, cognition, attention 

Tools for Diagnosis

Autism Diagnostic Interview- Revised (ADI-R) – parent interview that gains information in language/communication, reciprocal social interactions, and restricted/repetitive behaviors

Autism Diagnostic Observation Schedule (ADOS) – 4 modules + Toddler module

Based on language level and age

Direct observation while making social presses (standardized qualitative assessment)

Score social communication and repetitive behaviors (0-3 scale with 0 being typical or near typical performance)

Childhood Autism Rating Scale (CARS-2) – Direct observation

Physical Therapy Assessment - Motor

Motor:

•Peabody Developmental Motor Scales (0-5 years)

•Bruininks Oseretsky Test of Motor Proficiency (4-21 years)

•Test of Gross Motor Development (3-10 years)

•Movement Assessment Battery for Children (3-16 years)

•Developmental Coordination Disorder- Questionnaire (5-15 years)

•Gait

•Functional skills

Physical Therapy Assessment - Sensory

Sensory:

•Sensory Integration and Praxis Test (4-8 years 11 months)

•Sensory Profile (birth-15 years)

•Sensory Processing Measure (5-12 years)

Physical Therapy Assessment - Participation and Adaptive Function

Participation:

•Children’s Assessment of Participation & Enjoyment (CAPE) (6-21 years)

•Preferences for Activities of Children (PAC) (6-21 years)

•School Function Assessment (SFA) (5-12 years)

•Pediatric Evaluation of Disability Inventory (PEDI) (6 months-7.5 years)

Adaptive Function:

Vineland Adaptive Behavior Scales (VABS) (0-90 years)

Communication modality

Method of instruction – visual, gestural, manual

Sensory preferences

Need for structure and familiar routines

Choice of environment

Transitions

Additional factors – self-injurious behaviors, reinforcers, sensory overload, group vs. individual

PT Interventions

Early intervention is associated with better outcomes

Individualized treatment program involving families (Individualized Education Program) – focus on child’s strengths and preferences and set goals in collaboration with family

Structured/predictable environments – consistency in environment, therapist, activities, schedule

Use of appropriate communication supports, behavioral supports, reinforcement schedules, motivating activities 

Use of modeling strategies, graded prompting, varied practice, peer teaching

Remember multiple professionals – OT, PT, SLP, Special Educator, Behavioral therapist

PT Interventions - ABA

Applied Behavior Analysis (ABA) – based on principles of operant conditioning

Reinforce desirable behaviors and reduce undesirable behaviors

Effective in reducing negative behaviors, increasing communication, teaching new skills

Task analysis of skill and teaching individual steps of the skill and providing reinforcement in a predictable manner

Systematic reinforcement schedules

Practice of components as

Discrete trials (discrete trial training – 1:1 blocked practice, controlled environments) 

In naturalistic environments (incidental teaching – use child-preferred activities and natural rewards, more motivating)

Ongoing evaluation

Intensive – 40 hours/week one-on-one training

PT Interventions

Picture Exchange Communication System (PECS)

Treatment and Education of Autistic & Related Communication-Handicapped Children (TEACCH) – consistency and predictability in environment, therapists, space, supplies, schedule

Visual Schedules

Augmentative & Alternative Communication

Sensory Integration Approaches

Input modulated by child’s needs – use activities sought by the child

Sensory diet

Use of deep pressure (push-pull, weighted vests, hug machine), activities providing vestibular input (swings, vestibular ball) 

Social stories

Targets

Balance

Bilateral coordination

Imitation and praxis

Sensory needs

Strength – core strength

Aerobic capacity and endurance

BMI

Novel modalities

Rhythm and music therapies

Use of technology – Exergaming, Robots

Aquatic interventions

Equine therapies

Yoga, Tai-chi, Martial arts

Cognizant of needs of adults with ASD – continuing needs

Interventions – vocational training, social skill training, behavioral supports

Need for PT interventions directed towards functional training and promotion of physical health, endurance, and fitness

Strategies

Structure in interactions – space, props, people, time of the day

Use picture schedules to help with transitions, rules sheet for behavior

Mode of communication – gestures/sign, AAC, verbal (brief, clear instructions  - “Do this”, “copy me”, etc.)

Use props to help clarify instructions, wait for response, give them time to process

Least-to-most prompting (verbal, gestural, physical prompting)

Ensure optimal sensory state – warm-up activities, use of music 

Provide modeling, hand-on-hand assistance, as needed

Repetition important, provide opportunities for free play, movement exploration

Provide reinforcement (verbal, gestural, token, earned breaks, healthy edibles)

Progression – start with just-right challenge, look for signs that activity may be too much

If…then

First we work, then we take a break…