Sensory Processing Disorders Academic Notes

Introduction to Sensory Processing Disorders

• Sensory processing disorders (SPD) represent a condition affecting many children, often occurring as a primary diagnosis or in association with other conditions.

• Common diagnoses associated with sensory processing issues include:

  • Autism.

  • Cerebral Palsy (CP).

  • Attention Deficit Hyperactivity Disorder (ADHD).

  • Primary Sensory Processing Disorder (which can stand alone without another condition).

  • Genetic conditions including Fragile X, Rhett syndrome, Down syndrome, and Parader Willi.

Neural Activity and Perception

• Sensation is defined as a neural activity. As stated by Hayward, it is "neural activity triggered by a stimulus that activates a sensory receptor and results in sensory nerve pathways to the brain."

• A sensory threshold must be met for a receptor to fire and send a signal through the pathways.

• Children with SPD often have threshold-related issues:

  • The threshold fires too quickly (hypersensitivity).

  • The system requires significant sensory input to fire (hyposensitivity).

• Perception is described by Hayward as a "multi-stage process that takes place in the brain which includes selecting, processing, organizing, and integrating that information that's received from the senses."

• In children with SPD, the brain may receive the neural input but fail to process it correctly, leading to functional and behavioral problems.

• Standard sensory processing is automatic, efficient, and effective. Atypical processing disrupts motor activities because the child cannot make sense of input to produce a correct motor outcome. This affects tasks at school and home.

The Williams and Shellenberger Pyramid of Learning

• The Pyramid of Learning demonstrates that sensory systems and sensory processing serve as the foundation for higher-level skills.

• Difficulties in sensory processing directly impact:

  • Perceptual motor development.

  • Cognitive development.

• Areas evaluated in the pyramid during examination include:

  • Eye-hand coordination.

  • Visual perceptual development.

  • Activities of Daily Living (ADLs).

  • Behavior.

  • Classroom learning.

Classification of Sensory Impairments

• Children may struggle with one, two, or all sensory systems.

• Physical Therapy (PT) focuses primarily on:

  1. Tactile system.

  2. Proprioceptive system.

  3. Vestibular system.

• Impairment groups are divided into two main categories: Hyposensitive and Hypersensitive.

Hyposensitivity (Low Response/Registration)

• Characterized by partial or poor/low registration.

• Results in a high sensory threshold.

• Manifests as "sensory craving" as the child seeks input to raise the threshold enough for receptors to fire.

• Leads to impaired sensory discrimination, where children find it confusing to distinguish between different textures or movements.

Hypersensitivity (High Response/Over-response)

• Receptors fire too quickly due to a sensory threshold that is too low.

• Leads to "sensory defensiveness," where the child actively avoids sensory input.

Detailed Examples of Sensory Defensiveness (Hypersensitivity)

• Tactile System:

  • Avoids being touched or touching objects.

  • Dislikes "messy" play (e.g., mud, sand, water splashes in bathtubs or water tables).

  • Lack of exploration affects fine motor skill development and object manipulation.

• Vestibular System (Gravitational Insecurity):

  • A strong desire to be "grounded" to the floor.

  • Distress when feet do not touch the ground.

  • Fearful of swings or slides.

  • Triggers a "fight or flight" response, affecting Physical Education (PE), sports, and playground involvement.

• Auditory System:

  • Aversion to loud or unexpected noises (e.g., fire drills, noisy classrooms, busy playgrounds).

  • Results in agitation and difficulty concentrating.

• Oral Motor System:

  • Development of "picky eater" habits.

  • Preference for specific textures or tastes.

  • Overwhelmed by mixed textures (e.g., stews or soups containing multiple ingredients).

  • Implications include nutritional concerns and social discomfort during family or group meal times.

Detailed Examples of Hyposensitivity (Low Registration)

• Tactile System:

  • High pain threshold; may not register pain or feel material (e.g., food) on their face or hands.

  • Delayed reaction to touch.

  • Seeks input by reaching for and grabbing everything to "wake up" or alert themselves.

• Proprioception System:

  • Lack of awareness of body position in space.

  • Results in poor motor planning and decreased motor coordination.

  • Seeking behaviors include crashing into things, bumping, jumping, and seeking deep pressure.

• Vestibular System:

  • Under-reaction to movement input.

  • Takes a long time to get dizzy or show clumsiness after spinning.

  • Craves spinning and high-movement activities.

• Auditory System:

  • Failure to respond to their name initially; may take several attempts or several seconds to respond.

  • Impacts communication, social skills, and classroom learning due to missing key information.

• Oral Motor System:

  • Often presents as low muscle tone in the oral musculature.

  • Craving for intense flavors (sour, spicy) to "wake up" the mouth.

  • Craving for crunchy or chewy items to provide tactile and proprioceptive input.

Observations and Clinical Examination

• Observational cues for sensory seeking:

  • Proprioceptive Seeking: Pushing hard against a wall; pushing a heavy cart (joint compression); joint distractions/compressions (push-pull games like "Row Row Your Boat").

  • Rotary Vestibular Seeking: Spinning around in a circle.

  • Linear Vestibular Seeking: Swinging on a standard swing.

  • Oral Motor Seeking: Chewing on wristbands; eating sour or chewy foods.

• Examination Components:

  1. Parent and Child Interview: Essential to understand sensory processing throughout the day (feeding, dressing, school, play).

  2. Objective Tests and Measures:

     • Test of Sensory Function in Infants: For ages $4$ to $18$ months. Uses basic objects and tactile input. Takes approximately $20$ minutes to administer.

     • Short Sensory Profile: Developed by Winnie Dunn (OT). Screens tactile sensitivity, taste/smell, movement, under-responsiveness/seeking, auditory filtering, low energy/weak, and visual/auditory sensitivity. Scores indicate typical performance, probable difference, or definite difference.

     • Sensory Integration and Practice Test (SIPT): Designed by Jean Ayres (OT). For children ages $4$ years to $8$ years and $11$ months. A lengthy test taking approximately $2$ hours. Assesses tactile, visual, proprioceptive, and vestibular function. Requires specialized training and qualifications to administer.

Intervention Concepts and Clinical Practice

• Sensory processing is an internal experience; clinicians must respect a child's desire to proceed slowly.

• For nonverbal children, observation of external behavior is the primary guide.

• General Concept:

  • If hyperactive/over-responding: Add calming activities.

  • If lethargic/non-responsive: Add alerting activities.

• Avoid the "rebound effect" by not providing too much input; follow up with families to check behavior later in the day.

• Interventions should be integrated into normal daily routines and focus on functional outcomes and skills.

• Neuroplasticity vs. Compensation: While PT aims for neuroplasticity (brain rewiring), compensatory treatments involving environmental modification are used if neuroplasticity is not achieved.

  • Environmental Modifications: Quiet rooms for noise/visual sensitivity; removing tags from clothes for tactile defensiveness; avoiding crowded areas.

  • Compression Tools: SPIO, Benik, and Theratogs garments; weighted vests and blankets. These help the child know where their body is in space.

Specific Intervention Programs

Sensory Integration Therapy (SIT)

• Developed in the 1970s by Jean Ayres.

• AOTA supports its use, though high-level research is limited; evidence is supported by extensive anecdotal data and lower-level studies.

• Goal: Promote the child's ability to organize increasingly complex adaptive responses to sensory input.

• Setup: One-on-one therapy using suspended equipment (vestibular/proprioceptive), ball pits (tactile/proprioceptive), jumping on trampolines, and various tactile toys.

Sensory Diets

• Metaphorical comparison to a nutritional diet.

• Provides scheduled sensory experiences throughout the day based on individual needs.

• Case Example: The lecturer's son used a sensory diet involving $10$ pull-ups, running around the house $2$ times, and jumping on a trampoline for $10$ minutes to facilitate sitting still for dinner or homework.

Wilbarger Brushing Program

• Developed by Wilbarger using a surgical scrub brush.

• Involves firm, rhythmical strokes down arms and legs ($10$ times), followed by gentle joint compressions.

• Performed every $2$ hours throughout the day to reduce tactile hypersensitivity.

"How Does Your Engine Run?"

• A self-regulation program.

• Teaches children to identify their level of alertness.

• Color-coded system: Red/Fast car (hyperactive/hypersensitive) vs. Low/Slow car (under-registration).

• Goal: Helping the child reach the "just right place."

Alerting vs. Calming Activities per System

• Tactile:

  • Alerting: Exploring bins of rice, beans, and varied textures.

  • Calming: Crawling through tunnels (deep, heavy, compressive work).

• Proprioception:

  • Alerting: Quick, fast, bumpy, or arhythmical movements (e.g., jumping on a trampoline).

  • Calming: Slow, consistent, deep pressure (e.g., crawling through tubes that provide downward force/compression).

• Vestibular:

  • Alerting: Rotary input (Sit and Spin), irregular, fast, or arhythmical movements (bicycles, merry-go-rounds).

  • Calming: Slow, rhythmical, linear, and regular movement (e.g., rocking chair).

• Visual:

  • Alerting: Bright lights, primary colors, high contrast, cluttered environments, flashing lights (caution: seizures).

  • Calming: Pastels, dim lighting, low contrast, minimal patterns, lack of clutter (e.g., white-walled tents or quiet "cozy places").

• Oral Motor:

  • Alerting: Cold, spicy, or sour foods (e.g., Sour Patch gummy candies); textured foods; blowing whistles or bubbles; spinning pinwheels.

  • Calming: Deep pressure and "hard work" (e.g., chewing on a chewy tube); sucking on hard candies; bland foods.

• Auditory:

  • Alerting: Loud, irregular, or arhythmical sounds; shaking or tapping toys.

  • Calming: Soft, regular, rhythmical sounds; white noise machines (e.g., settings for rain or water found on Amazon sound machines).

Final Clinical Considerations

• SPD is a real issue affecting participation in school, home, and community.

• Impairments range from mild to severe and temporary to permanent.

• Interventions must be highly individualized.

• Provide consistent, graded sensory input to avoid over- or under-stimulation.

• The most important goal is helping children and families understand how input affects behavior and function to promote self-regulation and independence.