Sensory issues are a common feature of autism which can cause difficulties with understanding and tolerating a normal environment. Autistic people are also more likely than the general population to have difficulty with movement (motor skills). Delays in motor skills and general clumsiness are especially characteristic of Asperger Syndrome but are found in other forms of autism as well.
Autistic people are often oversensitive to sensory input. This can cause them to be overwhelmed by common sensory experiences such as stores and swimming pools. Undersensitivity can also be a problem. People who are undersensitive to sensory input may self-stimulate (stim) or even self-injure in order to get the input their nervous system requires. Commonly there is a mix between oversensitivity and undersensitivity which may fluctuate randomly. Sensory issues are frequently the cause of negative or odd behaviours.
1. Dyspraxia/Apraxia/Developmental Coordination Disorder
Dyspraxia (UK definition), also called apraxia or Developmental Coordination Disorder, is an impairment in the development of motor coordination which may affect the acquisition of motor skills such as walking, crawling, buttoning, etc. People with this condition are usually clumsy and may have difficulty with building models, playing ball, and printing or writing. People with dyspraxia are usually clumsy, drop things frequently, may bump into objects or people, spill often, and are accident prone. Developmental Coordination Disorder (DCD) is not diagnosed when the criteria are met for a Pervasive Developmental Disorder but many people with autistic spectrum disorders have the same kinds of difficulties and may be diagnosed with dyspraxia. Those with Asperger Syndrome, particularly, often have difficulty with coordination and appear clumsy.
2. Tourette Syndrome
A motor disorder characterized by motor and verbal tics. Tics are uncontrolled, repetitive movements or speech. Tics can be simple twitches, more complex movements, or even complete phrases. The person with Tourette Syndrome is usually unable to control tics although sometimes they can be suppressed briefly (similar to stifling a sneeze). Tics are usually worse when the person is under stress, even if the stress is from trying to control the tics. Most people with Tourette's also have Attention Deficit Hyperactivity Disorder (ADHD) and many have Obsessive Compulsive Disorder (OCD). Tics (whether or not they meet the full criteria for Tourette Syndrome) are much more common in people on the autistic spectrum than in the general population.
3. Central Auditory Processing Disorder (CAPD)
Central Auditory Processing Disorder (CAPD) is a problem with the way incoming sounds are processed by the brain. Sounds are received properly by the ear, but are not processed and interpreted correctly by the brain. This disorder primarily affects language sounds and can cause problems with paying attention to auditory input, descriminating between sounds, remembering and recalling auditory information, and higher level thinking skills involving auditory information. CAPD may lead to language and behaviour problems and often looks like Attention Deficit (Hyperactivity) Disorder(ADHD).
4. Sensory Integration Dysfunction (SID)
Characterized by oversensitivity, undersensitivty, or difficulty descriminating sensory information. Can lead to clumsiness and coordination difficulties.
5. Scotopic Sensitivity Syndrome (SSS, aka "Irlen Syndrome")
Scotopic Sensitivity Syndrome is a controversial theory, first identified in dyslexics, which is gaining support from the mainstream scientific community.
Thought to be a problem in how the visual cortex processes information, it is said to cause visual problems, hypersensitivity to light and difficulties with depth perception. This leads to problems with literacy, apparent clumsiness, headaches and irritability; and indirectly to behaviour problems and low self-esteem.
Treatment involves the use of special coloured lenses and coloured acetate sheets, that improve reading skill.
Disclaimer: Although the Irlen organisation is most famous for marketing treatments for Scotopic Sensitivity Syndrome, please be aware that there are many other ways of obtaining coloured lenses etc, including dyslexia organisations. This FAQ does not recommend or promote any particular source for the equipment.
6. Other Sensory Conditions
Because autism is due to unusual "brain wiring", it is not uncommon to have other neurological conditions along with it. Two little known sensory related conditions which appear to be more common in autistics are:
Synaesthesia Sometimes called "cross-sensory perception", synaesthesia is when input from one sense is interpreted in another. (eg. seeing sound, hearing light, tasting colour). It is very rare, but more common in people with atypical neurology, including those with autistic spectrum disorders.
Prosopagnosia Also known as "face blindness", this condition impairs a person's ability to recognize human faces. It appears to be somewhat more common in autistic spectrum disorders, but is usually a result of brain damage. It is not the same as being able to connect a name to a person. In autistic people, what appears to be prosopagnosia may actually be due to lack of eye contact or social interest.
Originally compiled by Anna Hayward on behalf of the alt.support.autism newsgroup, November 2000. Original site design and HTML by Kalen Molton. Please address any general queries to Mike Stanton. Broken links and problems of a technical nature should be addressed to John Muggleton by entering details in the comments box of the form here. Any opinions expressed in this article are personal and should not be construed as medical advice. We are not representatives of any of the companies discussed, nor do we receive any form of commission.