Many young people with Asperger’s (AS) and High-functioning Autism (HFA) have a dysfunctional sensory system. Oftentimes, one or more senses are either over-reactive or under-reactive to stimulation. Such sensory issues may be the underlying reason for certain behaviors associated with autism spectrum disorders (e.g., rocking, spinning, hand-flapping, etc.). Although the receptors for the senses are located in the peripheral nervous system, the problem appears to stem from neurological dysfunction in the central nervous system.
Sensory integration refers to the accurate interpretation of sensory stimulation from the environment by the child’s brain. Conversely, sensory integrative dysfunction is a disorder in which sensory input is not organized appropriately in the brain, thus producing varying degrees of problems in development, information processing, and behavior.
Sensory integration focuses primarily on 3 basic senses: (1) proprioceptive, (2) vestibular, and (3) tactile. Their interconnections start forming before birth and continue to develop as the child matures and interacts with his environment. These 3 senses are also connected with other systems in the brain, and even though they are less familiar than other senses (i.e., taste, smell, sight, and hearing), they are critical to basic survival.
Dysfunction within these 3 senses manifests itself in many ways. For example, the child:
- has an activity level that is either unusually high or unusually low
- is in constant motion or fatigues easily
- is over- or under-responsive to sensory input
- becomes impulsive, easily distractible, or shows a general lack of planning
- experiences gross and/or fine motor coordination problems
- has difficulty adjusting to new situations and may react with frustration, aggression, or withdrawal
- has speech and/or language delays
Let’s look at each of these 3 senses in greater detail...
The proprioceptive system refers to components of muscles, joints, and tendons that (a) provide the child with a subconscious awareness of her body position, which is automatically adjusted in different situations (e.g., sitting properly in a chair, stepping off a curb smoothly, etc.), and (b) allow the child to manipulate objects using fine motor movements (e.g., writing with a pen, using a spoon, buttoning a shirt, tying shoe laces, etc.). In addition, proprioception involves motor planning, which is the ability to plan and execute different motor tasks.
Some common signs of proprioceptive dysfunction include the following:
- tendency to fall
- resistance to new motor movement activities
- odd body posturing
- minimal crawling when young
- lack of awareness of body position in space
- eating in a sloppy manner
- difficulty manipulating small objects (e.g., buttons, snaps)
Therapy may include:
- bouncing on a trampoline or a large ball
- skipping or pushing heavy objects
- wearing weighted belts
- weighted blankets
- weighted vests
The vestibular system refers to structures within the inner ear that detect movement and changes in the position of the head (e.g., tells the child when his head is upright or tilted, even with the eyes closed).
Dysfunction within the vestibular system may manifest itself in two different ways:
- Hyposensitivity: The AS or HFA youngster may actively seek very intense sensory experiences (e.g., excessive body whirling, jumping, spinning, etc.). This type of youngster demonstrates signs of a hypo-reactive vestibular system (i.e., he is trying constantly to stimulate himself).
- Hypersensitivity: The youngster may (a) be extremely susceptible to vestibular stimulation; (b) have fearful reactions to ordinary movement activities (e.g., swings, slides, inclines, ramps. etc.); (c) have trouble learning to climb or descend stairs or hills; (d) be apprehensive about walking or crawling on uneven or unstable surfaces; and (e) appear clumsy.
Therapy can include:
- hanging upside down
- rocking chairs
All of these actions involve the head moving in different ways that stimulate the vestibular system. The therapist will observe the youngster carefully to be sure the movement is not over-stimulating. The most stimulating movement tends to be rotational (i.e., spinning) and should be used carefully by the therapist. Merry-go-rounds, being tossed on to cushions, or jumping on trampolines can be favorite activities with some AS and HFA kids. Back and forth movement is typically less stimulating than side-to-side movement. A rocking motion will usually calm a youngster, while vigorous motions like spinning will be stimulating. Ideally, therapy will provide a variety of these movements.
The tactile system includes nerves under the skin's surface that send information to the brain (e.g., light touch, pain, pressure, temperature, etc.), which plays an important role in perceiving the environment – and protective reactions for survival.
Dysfunction in the tactile system can be seen in the following:
- avoiding getting one's hands dirty (e.g., with glue, sand, mud, finger-paint, etc.)
- complaining about having one's hair or face washed
- refusing to eat certain textured foods
- refusing to wear certain types of clothing
- using one's finger tips rather than whole hands to manipulate objects
- walking with heels of the feet off the floor
- withdrawing when being touched
A dysfunctional tactile system can lead to a misperception of touch and pain, and may lead to self-imposed isolation, general irritability, hyperactivity, and distractibility. Tactile defensiveness is a condition in which the child is extremely sensitive to touch, which can result in behavior problems, inability to concentrate, and negative emotional response to touch sensations.
Therapy may include the following:
For AS and HFA kids who enjoy the feel of sticky textures, the therapist may use certain materials (e.g., glue, stickers, play dough, rubber toys, sticky tape, water, beans, rice, and sand). On the other hand, kids who are very sensitive to touch may go through a brushing program that attempts to desensitize them to touch by systematically brushing their body at regular intervals throughout the day.
Some AS and HFA kids enjoy a sense of firm overall pressure. This can be provided by weighted blankets, weighted belts, being squeezed by pillows, and firm hugs. Also, making tunnels or tents from blankets over furniture can be soothing to these “special needs” children.
Other therapeutic approaches for AS and HFA children with dysfunctional sensory systems may include the following:
- Difficulty with using both sides of the body simultaneously can occur in some of these young people. The therapist may encourage the youngster with hopscotch, crawling, skipping, playing musical instruments, playing catch, or bouncing balls with both hands to help with bilateral integration.
- Hand and eye coordination can be improved with activities such as popping bubbles, hitting a ball with a bat, beanbags and balloons, and throwing/catching balls.
- Skills such as riding a bike or tying shoe laces can be difficult for some AS and HFA children, because they involve sequences of movements. Therapy to help in this area may include obstacle courses, swimming, mazes, constructional toys, and building blocks.
Evaluation and treatment of sensory integrative dysfunction is performed by an occupational and/or physical therapist. The therapist's general goals are to:
- assist the youngster in inhibiting and/or modulating sensory information
- assist the youngster in processing a more organized response to sensory stimuli
- provide the youngster with sensory information which helps organize the central nervous system
Sensory processing functions on a continuum. Everyone has difficulty processing certain sensory stimuli (e.g., a certain touch, taste, smell, sound, movement etc.) – and everyone has sensory preferences. Processing difficulties only become a Sensory Processing Disorder when an individual is on extreme ends of the continuum or experiences disruptive, unpredictable fluctuations which significantly impact developmental skills and everyday functioning.
If you believe your AS or HFA child may be experiencing some form of sensory integration dysfunction, ask your child’s doctor for a referral to an occupational and/or physical therapist for treatment.
The Aspergers Comprehensive Handbook