What Exactly Is Sensory Integration Dysfunction?
About 10% of people are estimated to have sensory integration dysfunction. Sensory integrative problems are found in up to 70% of children with learning difficulties. Sensory integrative difficulties have been identified in people with autism and other developmental disabilities. But what exactly is sensory integration dysfunction?
The theory of Sensory Integration Dysfunction (SID) was formulated by A. Jane Ayres (1979), an occupational therapist, to describe a variety (!) of neurological disorders. It attempts to account for the relationship between sensory processing and behavioral deficits. At present SID still remains a theory and has not much recognition and support from the fields outside occupational therapy (OT). Below I will try to answer the 'why is it so' question and see whether skepticism is justifiable or not.
There seem to be several reasons to account for criticism received by the theory of SID. To start with, the choice of the term 'sensory integration dysfunction/disorder' was very unfortunate. On the one hand, SID allows a very broad interpretation as it was introduced to cover a variety of neurological disorders. On the other hand, it effectively narrows the investigation, as it excludes any other disorder labeled by a different term, for example, sensory processing disorders. As a result, despite the theory having been actively developed within the field of OT, it has inevitably ignored a great amount of research in the field of sensory and information processing, as being outside the scope of OT interests. It is no wonder, therefore, to find such statements as "the state of knowledge regarding modulation of sensation was in its infancy during the 1980s" in a review of OT literature. To the contrary of this statement, quite a lot of research was being carried out in the field of sensory dysfunction, including sensory modulation problems, in the 1960s-80s.
Thus, already in the 1960s, Bernard Rimland wrote about impairments in perceptual abilities of autistic children. Edward Ornitz described disorders of perception in autism. In the early 1970s, Carl Delacato put forward the theory of sensory dysfunction in autism, and proposed a classification of abnormal sensory experiences of autistic children. Delacato also pioneered the treatment of sensory abnormalities by 'normalizing' the sensory processing. Though his book The Ultimate Stranger: The Autistic Child (1974) was published more than three decades ago, the basic ideas about sensory dysfunction described in this book are still relevant today. Actually, these ideas 're-appeared' in many works of OT research in the 1980s-90s as 'new discoveries'.
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