Sensory Integration Dysfunction
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Sensory Integration Dysfunction is a neurological disorder causing difficulties with processing information from the five senses (vision, auditory, touch, olfaction, and taste), the sense of movement (vestibular), and/or the positional sense (propioception)[1]. Sensory information is sensed normally, but perceived abnormally. This is not the same as blindness or deafness because sensory information is sensed but tends to be analyzed by the brain in an unusual way that may cause pain or confusion [2].
Sensory integration dysfunction can be a disorder on its own, but it can also be a characteristic of other neurological conditions, including autism spectrum disorders, dyslexia, dyspraxia, pervasive developmental disorder, multiple sclerosis and speech delays, among many others [3] Unlike many other neurological problems that require validation by a licensed psychiatrist or physician, this condition can only be properly diagnosed by an occupational therapist. There is no known cure, however there are many treatments available.
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Meaning of sensory integration
Sensory integration is the ability to take in information through the senses of touch, movement, smell, taste, vision, and hearing, and to combine the resulting perceptions with prior information, memories, and knowledge already stored in the brain, in order to derive coherent meaning from processing the stimuli. The mid-brain and brainstem regions of the central nervous system are early centers in the processing pathway for sensory integration. These brain regions are involved in processes including coordination, attention, arousal, and autonomic function. After sensory information passes through these centers, it is then routed to brain regions responsible for emotions, memory, and higher level cognitive functions.
Sensory integrative disorders
- Vestibular processing disorders
- Dyspraxia
- Sensory discrimination and perception problems
Sensory modulation
Sensory modulation refers to a complex central nervous system process by which neural messages that convey information about the intensity, frequency, duration, complexity, and novelty of sensory stimuli are adjusted. Behaviorally, this is manifested in the tendency to generate responses that are appropriately graded in relation to incoming sensations, neither underreacting nor overreacting to them.
Sensory Modulation Problems
- Sensory registration problems - This refers to the process by which the central nervous system attends to stimuli. This usually involves an orienting response. Sensory registration problems are characterized by failure to notice stimuli that ordinarily are salient to most people.
- Sensory defensiveness - A condition characterized by overresponsivity in one or more systems.
- Gravitational insecurity - A sensory modulation condition in which there is a tendency to react negatively and fearfully to movement experiences, particularly those involving a change in head position and movement backward or upward through space.
(Case-Smith, (2005)
Hyposensitivities and hypersensitivities
Sensory integration disorders vary between individuals in their characteristics and intensity. Some people are so mildly afflicted, the disorder is barely noticeable, while others are so impaired they have trouble with daily functioning.
Children can be born hypersensitive or hyposensitive to varying degrees and may have trouble in one sensory modality, a few, or all of them. Hypersensitivity is also known as sensory defensiveness. Examples of hypersensitivity include feeling pain from clothing rubbing against skin, an inability to tolerate normal lighting in a room, a dislike of being touched (especially light touch) and a dislike in looking directly into the eyes of another person.
An example of a child with hyposensitivity is one who constantly gets up and down in a classroom and is constantly seeking sensory stimulation.
In treating sensory dysfunctions, a "just right" challenge is used. This involves active movement, and an inner drive or motivation. The "just right" challenge is absent if the activity and the child's perception of activity do not match. In addition, deep pressure is calming for children who have sensory dysfunctions. It is recommended that therapists use a variety of tactile materials, a quiet, subdued voice, and slow, linear movements.
Sensory integration and autism spectrum disorders
Sensory integration dysfunction is a common symptom of autism [4]. Often, autistic children receive too much sensory stimulation through one or more of their senses, and in order to turn down the volume, they tend to avoid people, noises and bright lights. Autistic children do not develop the neurotypical capacity to integrate and modulate information from the five senses.
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."
Alternative views
Not everybody agrees with the notion that hypersensitive senses is necessarily a disorder. Even if hypersensitivity is the most common in autism, insensitivity to pain is also common. Additionally, there is no proof for the idea that hypersensitivity would necessarily be a result of sensory integration issues.
It is possible that misdiagnosis is also a problem with the construct of Sensory Integration Dysfunction. Some experts claim that occupational therapists incorrectly apply this label to individuals with attention difficulties or who simply don't put forth any effort during assessments. For example, a student who fails to repeat what has been said in class (due to boredom or distraction) is referred for evaluation for sensory integration dysfunction. The student is asked to listen to signals coming from either side of a pair of headphones and combine them to form words. The student is still bored or distracted, and so does poorly on the test. The assessor concludes that the student has sensory integration dysfunction, while, in fact, he may have a disorder of auditory processing (also overdiagnosed), poor auditory attention, a mood problem, or may fail to put forth adequate effort on the task for other reasons. Diagnoses based on single tests are unreliable, and integrated assessment utilizing multiple sources of information is the preferred means of diagnosis, especially in children.
And while this diagnosis is accepted widely among occupational therapists and also educators, these professionals have been criticized for overextending an already-poorly-supported model that attempts to explain emotional and behavioral problems that are better (and more simply) explained in other ways. A large percentage of children who receive the diagnosis of sensory integration dysfunction might be better understood as having anxiety problems or even behavioral disorders. These problems can make a child look reactive, "touchy", or unpredictable, and manifest in a manner similar to that characterized by occupational therapists as sensory integration dysfunction.
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), children misdiagnosed with sensory integration dysfunction will not receive appropriate psychological treatment (e.g., cognitive behavioral therapy) if they remain misdiagnosed.
It should also be understood that there is general agreement that some children do have oversensitivity to many physical stimuli, the existence of this relatively small subset of children has lead to a general pattern of overdiagnosis in children who "look the same" but have other problems. There are relatively few medical and psychological practictioners who agree that sensory integration dysfunction is the foundational problem in most children with this diagnosis.
See also
External links
- Incredible Horizons: S.I.D.
- Sensory Nation
- Autism.org - 'Sensory Integration', Cindy Hatch-Rasmussen, MA, OTR/L
- Genetic.org - 'Sensory Integrative Dysfunction', Linda C. Stephens, MS, OTR/L, FAOTA
- quackwatch.org - 'Why Sensory Integration Disorder Is a Dubious Diagnosis', by Peter L. Heilbroner, MD, PhD
- Quirky Kids - 'Quirky Kids: Understanding and helping your child who doesn't fit in - when to worry and when not to worry', Perri Klass, M.D., and Eileen Costello, M.D.
- SensoryInt.com - Sensory Integration International
- AdultSID.com - E-mail list for adults with Sensory Integration Dysfunction
- The SPD Network - Resources for the Sensory Processing Disorder community
References
- Case-Smith, Jane. Occupational Therapy for Children. [Fifth Edition] (2005). Elesevier Mosby: St. Louis, MO.