A person with > autism experiences sensory perceptions differently than someone without autism. Often, autistic brains receive too much sensory stimulation and are unable to integrate and modulate information in a neurotypical way. Each individual’s experience of it will vary.

In her book, Thinking in Pictures, > Temple Grandin reports the results of a survey about sensory integration in a relatively small population with autism spectrum disorders from one center:

"A survey of sensory problems in 30 adults and children was conducted by Neil Walker and Margaret Whelan from the Geneva Centre for Autism in Toronto. Eighty percent reported hypersensivity to touch. Eighty-seven percent reported hypersensivity to sound. Eighty-six percent had problems with vision. However, thirty percent reported taste or smell sensivities."

A growing number of experts, including Stanley Greenspan, M.D., Ph.D., and autism specialist Ricki Robinson, M.D., believe that sensory related disorders are frequently misdiagnosed as Attention Deficit/Hyperactivity Disorder, as well as emotional problems, aggressiveness and speech-related disorders such as Apraxia. Sensory processing, they argue, is foundational, like the roots of a tree, and gives rise to a myriad of behaviors and symptoms such as hyperactivity and speech delay. For example, a child with an under-responsive vestibular system may need extra input to his "motion sensor" in order to achieve a state of quiet alertness. To get this input, the child might fidget or run around, appearing ostensibly to be hyperactive, when in fact, he suffers from a sensory related disorder.

Sensory integration therapy is a type of occupational therapy that places a child in a room specifically designed to stimulate and challenge all of the senses. During the session, the therapist works closely with the child to encourage movement within the room. Sensory integration therapy is driven by four main principles (Schaaf 2004):

• Just Right Challenge (the child must be able to successfully meet the challenges that are presented through playful activities)
• Adaptive Response (the child adapts his behavior with new and useful strategies in response to the challenges presented)
• Active Engagement (the child will want to participate because the activities are fun)
• Child Directed (the child's preferences are used to initiate therapeutic experiences within the session)

 

Not everybody agrees with the notion that hypersensitive senses is necessarily a disorder. However, sensory integration dysfunction, sometimes called sensory processing disorder, is only diagnosed when the sensory behavior interferes significantly with learning, playing, and activities of daily living (ADL). Sensory issues can be on a spectrum. Being annoyed and distracted by the sound of a noisy ventilation system or the scratchiness of a sweater is considered to be a typical sensory response. However, when a child is so strongly affected by background noise or tactile sensations that he totally withdraws, becomes hyperactive and impulsive, or lashes out as part of a primitive fight-or-flight response, the child's sensory issues are severe enough to warrant intervention.

In addition to experiencing hypersensitivity, a person can experience hyposensitivity (undersensitivity to sensory stimuli). One example of this is insensitivity to pain. A child with sensory integration dysfunction may giggle when given an injection or not even blink when receiving a second-degree burn.

There is no proof for the idea that hypersensitivity would necessarily be a result of sensory integration issues. However, there is anecdotal evidence that sensory integration therapy results in a more typical sensory responses and sensory processing. For example, Temple Grandin has claimed that the deep pressure created by a cattle squeeze machine she used in her youth resulted in her being able to tolerate the affectionate hugs and touches she craved. Additionally, over 130 articles on sensory integration have been published in peer-reviewed (mostly occupational therapy) journals. The difficulties of designing double-blind research studies of sensory integration dysfunction have been addressed by Temple Grandin and others. More research is needed.

It is possible Sensory Integration Dysfunction can be misdiagnosed, just as with any other disability. Some experts claim that occupational therapists and other professionals incorrectly apply this label to individuals with attention difficulties or who simply don't put forth any effort during assessments.^{[citation needed]} For example, a student who fails to repeat what has been said in class (due to boredom or distraction) might be referred for evaluation for sensory integration dysfunction (although many, many school teachers, therapists, and administrators are unfamiliar with sensory integration dysfunction or don't believe in it, this sometimes happens).^{[citation needed]} The student might then be evaluated by an occupational therapist to determine why he is having difficulty focusing and attending, and perhaps also evaluated by an audiologist or a speech-language pathologist for auditory processing issues or language processing issues. As part of the auditory evaluation, the student may be asked to listen to signals coming from either side of a pair of headphones and identify where they are coming from. If the student is bored or distracted, or confused by the oral directions given, the test may be inconclusive and may not isolate what the problem is. The assessor must consider sensory and language factors in evaluating the student's performance on the test. Diagnoses based on single tests are unreliable, and integrated assessment utilizing multiple sources of information is the preferred means of diagnosis.

Similarly, a child may be mistakenly labeled "ADHD" or "ADD" because impulsivity has been observed, when actually this impulsivity is limited to sensory seeking or avoiding. A child might regularly jump out of his seat in class despite multiple warnings and threats because his poor proprioception (body awareness) causes him to fall out of his seat, and his anxiety over this potential problem causes him to avoid sitting whenever possible. If the same child is able to remain seated after being given an inflatable bumpy cushion to sit on (which gives him more sensory input), or, is able to remain seated at home or in a particular classroom but not in his main classroom, it is a sign that more evaluation is needed to determine the cause of his impulsivity. Children with FASD (Fetal Alcohol Spectrum Disorders)display many sensory integration problems.

And while the diagnosis of sensory integration dysfunction is accepted widely among occupational therapists and also educators, these professionals have been criticized for overextending a model that attempts to explain emotional and behavioral problems that could be caused by other conditions. Children who receive the diagnosis of sensory integration dysfunction should also be observed for signs of anxiety problems, ADHD, food intolerances, and behavioral disorders, as well as for autism (note that contrary to popular belief, autistic children may be social, have a sense of humor, and make eye contact). Genetic problems such as Fragile X syndrome should be looked into as well. While the DSM-IV lists sensory issues as a secondary characteristic of autism, sensory integration dysfunction is not considered to be on the autism spectrum, and a child can receive a diagnosis of sensory integration dysfunction without any comorbid conditions. However, because comorbid conditions are common with sensory integration issues, it is important to investigate whether the child has other conditions as well which make him or her reactive, "touchy", or unpredictable, and manifest in a manner similar to that characterized by occupational therapists as sensory integration dysfunction. The theory of SI points out that children learn through their senses. If a child seems to have difficulty processing sensory information, it makes sense to observe whether he or she is developmentally on track (in terms of social skills, fine motor skills, gross motor skills, language, etc.)

While the physical methods employed by occupational therapists as treatment for SID are often palliative (they make the child feel better--much as a nice massage or physical contact would make anyone feel better), it is important that children diagnosed with sensory integration dysfunction be observed closely so that any other conditions will not be overlooked. Moreover, SI therapy is not "one size fits all." According to SI theory, children with sensory integration issues have their own unique set of sensory responses that need to be addressed. What is calming and focusing for one child may be overstimulating for another, and vice versa. The child's unique set of sensory responses must be considered when designing a sensory diet.

Some adults identify themselves as having sensory integration dysfunction; that is, they report that their hypersensitivity, hyposensitivity, and related sensory processing issues, such as poor self-regulation, continue to cause significant interference in their daily lives at home, at work, and at school.