9.2 Autism Spectrum Disorder & Sensory Processing Interventions

Autism Spectrum Disorder & Sensory Processing Interventions

Occupational therapy practitioners evaluating and treating pediatric clients with Autism Spectrum Disorder (ASD) and sensory processing differences operate at the intersection of neurobiology, behavioral science, and occupational engagement. Clinical success requires mastery of DSM-5-TR diagnostic criteria, Ayres Sensory Integration (ASI) core principles, sensory system physiology, Winnie Dunn's sensory quadrants, and structured visual communication strategies.

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1. Autism Spectrum Disorder: Diagnostic Architecture & Severity Levels

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) defines ASD through two core diagnostic domains:

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|                               DSM-5-TR CORE DIAGNOSTIC DOMAINS                                    |
+-------------------------------------------------+-------------------------------------------------+
| DOMAIN A: Social Communication & Interaction    | DOMAIN B: Restricted, Repetitive Behaviors      |
| (All 3 criteria required):                      | (At least 2 of 4 criteria required):            |
+-------------------------------------------------+-------------------------------------------------+
| 1. Deficits in social-emotional reciprocity     | 1. Stereotyped or repetitive motor movements,   |
|    (e.g., abnormal social approach, failure     |    use of objects, or speech (echolalia).       |
|    of normal back-and-forth conversation).      | 2. Insistence on sameness, inflexible adherence |
| 2. Deficits in nonverbal communicative behaviors|    to routines, or ritualized verbal/nonverbal  |
|    (e.g., poorly integrated verbal/nonverbal    |    behavior patterns.                           |
|    communication, atypical eye contact/gestures)| 3. Highly restricted, fixated interests abnormal|
| 3. Deficits in developing, maintaining, and     |    in intensity or focus.                       |
|    understanding relationships (e.g., difficulty| 4. Hyper- or hypo-reactivity to sensory input   |
|    adjusting behavior to social contexts).      |    or unusual interest in sensory aspects.      |
+-------------------------------------------------+-------------------------------------------------+

DSM-5-TR Severity Levels for ASD

• Level 1 ('Requiring Support'): Without supports, social communication deficits cause noticeable impairments. Difficulty initiating social interactions; inflexible behavior interferes with functioning in one or more contexts; struggles with organization and planning.
• Level 2 ('Requiring Substantial Support'): Marked deficits in verbal and nonverbal social communication skills; social impairments apparent even with supports in place; limited initiation of social interactions; simple sentences; distress or difficulty changing focus or action.
• Level 3 ('Requiring Very Substantial Support'): Severe deficits in verbal and nonverbal social communication causing severe functional impairments; very limited social initiation and minimal response to overtures; extreme difficulty coping with change; repetitive behaviors markedly interfere with functioning in all spheres.

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2. Ayres Sensory Integration (ASI) Core Principles & Fidelity

Developed by Dr. A. Jean Ayres, Ayres Sensory Integration (ASI) is an evidence-based neurobiological approach predicated on the brain's capacity for neuroplasticity. ASI is defined by specific fidelity criteria that differentiate it from generic sensory techniques.

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|                         AYRES SENSORY INTEGRATION (ASI) CORE TENETS                               |
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| • Active, Child-Led Engagement: The child drives activity selection based on inner drive; the     |
|   therapist never forces passive participation.                                                   |
| • The 'Just-Right Challenge': The therapist dynamically grades environmental demands so that the   |
|   task requires effort but ensures successful completion.                                         |
| • Adaptive Response: An active, goal-directed, purposeful action in response to a sensory demand  |
|   (e.g., successfully balancing on a bolster swing while catching a beanbag); drives neuroplasticity.|
| • Specialized Clinic Architecture: Requires certified safety equipment, including multi-point     |
|   suspended ceiling hooks, rotary rotational devices, crash mats, climbing structures, and varied  |
|   proprioceptive/tactile materials.                                                               |
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Specialized ASI Suspended Equipment

• Platform Swing: Provides linear, back-and-forth vestibular input; facilitates prone extension and seated equilibrium reactions.
• Bolster / Log Swing: Straddled by the child to promote core co-contraction, bilateral adductor activation, and vestibular-proprioceptive integration.
• Rotary / Tire Swing: Delivers high-intensity angular and rotational vestibular acceleration (requires high caution for autonomic signs).
• Lycra / Hammock Swing: Envelops the body, delivering total-body deep tactile pressure alongside linear vestibular oscillation for calming down-regulation.
• Scooter Board on Ramp: Combines rapid linear vestibular acceleration with active neck/upper back extension and proprioceptive impact into crash pillows.

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3. Sensory Systems Neurobiology & Critical Precautions

Understanding sensory processing requires parsing specific neurological channels, their physiological functions, and their emotional/arousal modulation capacities.

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4. Winnie Dunn's Sensory Processing Framework

Winnie Dunn's model categorizes sensory processing based on the interaction between a child's Neurological Threshold (high vs. low) and their Behavioral Response Strategy (passive vs. active).

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|                         WINNIE DUNN'S SENSORY PROCESSING QUADRANTS                                |
+-----------------------------------+---------------------------------------------------------------+
|                                   |                    BEHAVIORAL RESPONSE STRATEGY               |
|                                   +-------------------------------+-------------------------------+
|                                   | PASSIVE (Acts in accordance)  | ACTIVE (Acts to counteract)   |
+-------------------+---------------+-------------------------------+-------------------------------+
|                   | HIGH          | 1. LOW REGISTRATION           | 2. SENSATION SEEKING          |
|                   | (Needs MORE   |    (Bystander)                |    (Seeker)                   |
| NEUROLOGICAL      | sensory input | • Misses salient sensory cues | • Craves high-intensity input |
| THRESHOLD         | to respond)   | • Appears sluggish, lethargic | • Fidgets, rocks, crashes     |
|                   |               | • Slow processing speed       | • Touches everything/everyone |
|                   +---------------+-------------------------------+-------------------------------+
|                   | LOW           | 3. SENSORY SENSITIVITY        | 4. SENSATION AVOIDING         |
|                   | (Needs LESS   |    (Sensor)                   |    (Avoider)                  |
|                   | sensory input | • Easily distracted/startled  | • Actively retreats/escapes   |
|                   | to respond)   | • Distressed by noise/lights  | • Covers ears, elopes, hides  |
|                   |               | • Hyperactive/complaining     | • Rigid, resistant to changes |
+-------------------+---------------+-------------------------------+-------------------------------+

Targeted Environmental & Classroom Interventions by Quadrant

• Low Registration (High Threshold / Passive): Increase sensory intensity and contrast; provide bright visual cues, tactile highlighting, movement breaks, and frequent verbal prompts with rich multi-sensory demonstrations.
• Sensation Seeking (High Threshold / Active): Provide purposeful, structured heavy work (carrying heavy books, pushing loaded carts, chair push-ups, wiggle cushions) so the child receives required sensory volume without disrupting classroom routine.
• Sensory Sensitivity (Low Threshold / Passive): Reduce environmental clutter; dim overhead fluorescent lighting; provide noise-dampening ear protection; place desk away from busy doorways and high-traffic corridors.
• Sensation Avoiding (Low Threshold / Active): Provide predictable routines with advance warnings for transitions; establish a quiet sensory 'calm-down corner'; allow the child to leave class 2 minutes before the bell to avoid hallway chaos.

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5. Behavioral, Visual, and Communication Interventions

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|                         EVIDENCE-BASED VISUAL & BEHAVIORAL TOOLS                                  |
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| 1. TEACCH STRUCTURED TEACHING:                                                                    |
|    • Physical Structure: Clear visual boundaries demarcating distinct areas (work, play, snack).  |
|    • Visual Work Systems: Left-to-right organization (Finished bin on right) answering 4 questions:|
|      What work? How much work? When am I finished? What comes next?                               |
|                                                                                                   |
| 2. PICTURE EXCHANGE COMMUNICATION SYSTEM (PECS) PHASES:                                           |
|    • Phase I (Physical Exchange): Child exchanges picture for highly desired item (2 trainers).    |
|    • Phase II (Distance & Persistence): Child travels to communication binder and persistence.    |
|    • Phase III (Picture Discrimination): Child discriminates between preferred and non-preferred.  |
|    • Phase IV (Sentence Structure): Builds 'I want [item]' sentence strip.                         |
|    • Phase V (Responding to 'What do you want?'): Answering direct inquiries.                     |
|    • Phase VI (Commenting): Spontaneous commenting on environment ('I see...', 'I hear...').    |
|                                                                                                   |
| 3. CAROL GRAY SOCIAL STORIES:                                                                     |
|    • Purpose: Describe social situations, social cues, and expected behaviors to build perspective.|
|    • The Social Story Sentence Formula:                                                           |
|      Maintain at least 2 to 5 DESCRIPTIVE, PERSPECTIVE, or AFFIRMATIVE sentences for every        |
|      0 to 1 DIRECTIVE or COACHING sentence.                                                       |
|    • Avoid demanding directives (e.g., use 'I will try to...' instead of 'You must...').          |
|                                                                                                   |
| 4. FIRST-THEN BOARDS & VISUAL TIMERS:                                                             |
|    • First-Then Board (Premack Principle): Pairs non-preferred task with immediately following    |
|      preferred reinforcer ('First handwriting, Then swing').                                      |
|    • Visual Timers (Time Timer): Provides concrete visual countdown of remaining activity duration.|
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