Harry was an 8-year-old boy who loved basketball but couldn’t manage to go to more than two or three practices without leaving early and deciding to quit. He could rarely manage to make his shoes the perfect level of tightness so that his foot felt just squeezed enough, but even when he did, he couldn’t help but think about the seam in his socks rubbing against the tops of his toes. The sound in the gym was piercingly loud with all of the other boys screaming and their sneakers making squeaking noises when they rubbed against the floor. The fluorescent lights gave him a pounding headache. Harry’s mother decided that his intense bad moods after practice were too stressful, and she let him give the sport up. Maybe baseball would work out better…
Sensory integration was defined by Anna Jean Ayres, an occupational therapist and educational psychologist, in 1972 as “the neurological process that organizes the sensation from one’s own body from the environment and makes it possible to use the body effectively within the environment.” How we process sensory information affects our ability to discriminate sensory information from our bodies and our environments in order to physically interact with people and our surroundings. Sensory processing also affects our ability to modulate sensory information to maintain an optimal level of arousal for the task at hand.
The concept of Sensory Processing Disorder (SPD) has both proponents and detractors (see final paragraph). Basically, the concept references a group conditions in which the neurological process known as multisensory (or multimodal) integration fails to organize input coming from multiple sensory modalities. In other words, the brain has difficulties perceiving, categorizing, interpreting and responding to different sensory modalities (five basics: touch, sound, sight, taste, smell; and the other two: vestibular, or movement and balance sense, and proprioception, or joint and muscle sense). It has been compared to a “neurological traffic jam” in which sensory signals become mixed up and disorganized. People with SPD lack coherence in the processing of sensory perceptions, so they experience a wide range of difficulties when input comes from multiple senses. The difficulties they experience are significant enough to get in the way of daily functioning.
There are several different types of SPDs, which may involve oversensitivity or under-sensitivity to stimulation of any of the five senses. SPDs can be further categorized as Sensory Modulation Disorder is over- or under-responding to sensory stimuli or seeking sensory stimulation; Sensory-Based Motor Disorder describes when motor output is disorganized as a result of incorrect processing of sensory information affecting postural control and/or developmental coordination; Sensory Discrimination Disorder is characterized by incorrect processing of sensory information.
Causes of SPD have been studied by electroencephalography (EEG; recording of electrical brain activity along the scalp) and event-related potentials (ERP; measurement of brain response by EEG that is the direct result of a specific sensory event). One hypothesis is that people with SPD have less sensory “gating” than typical subjects. In other words, they have less opening/activation or closing/deactivation of ion (salt) channels when electrical transmissions are conducted in the nervous system. Another hypothesis is that there are increased dopamine D2 receptors in the striatum, which is the part of the brain that regulates pleasurable sensations/feelings.
SPDs are typically diagnosed by standardized tests, questionnaires, observational scales, parent interview, and observation of daily activities at school and home or in an occupational therapy gym. Therapists who make diagnosis may be occupational therapists, psychologists, learning specialists, and physiotherapists. However, neuropsychological, neurological and neurophysiological evaluations are helpful to define the issue and clarify a diagnosis. In particular, such evaluations can determine if there is an identifiable and treatable biological cause, which can be overlooked if the diagnosis is based solely on the evaluation of a therapist.
Some people think children “grow out” of sensory problems, but really, they just learn to compensate for their difficulties. Various therapies can help to structure a child’s environment and teach compensatory skills. There are some proponents of “sensory integration therapy, ” but it is controversial; it is a type of occupational therapy that stimulates and challenges the senses. Therapists provide a level of sensory stimulation that the child can cope with and teach the child to learn self-regulation skills in a controlled, safe, and fun environment. Therapists provide the perfect level of challenge so that the child can develop increasingly adaptive responses to environmental challenges. Therapy may take place in a sensory gym, which is a room with suspended equipment that allows for varying movement and sensory experiences. In some cases, sensory over-responsivity can be part of autonomic (or “automatic”) nervous system dysfunction, and can be amenable to medical therapies.
Even though the concept of SPD has been around for a long time and currently sensory processing issues are getting a lot of attention in schools, Sensory Processing Disorders are not recognized in widely accepted medical and psychological diagnostic manuals. In 2012, the American Academy of Pediatrics (AAP) stated the sensory integration therapies had insufficient data to support their use, and felt that SPD should not be used as a diagnosis. Additionally, SPDs were rejected for inclusion in the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM5).
The main argument is that altered sensory responsiveness is a feature of other many other disorders (e.g. Autism Spectrum Disorder or ADHD) rather than a separate and distinct diagnosis. Others argue that the increase in this phenomenon is occurring because we ask more of children than ever before; for example, they say that not being able to sit quietly in circle time is perfectly normal for a 4-year-old child, and children that have trouble should not be diagnosed. Overall, much of the controversy exists because sensory processing disorders have not been well researched and defined.
Research on SPD is very limited, and more is needed. Regardless though, an accurate diagnosis is crucial in identifying the source of the complaints and the most effective therapeutic approach.
Katie Davis, M.S.
Neuropsychology Pre-Doctoral Intern
The Center for Neurological and Neurodevelopmental Health (CNNH)
250 Haddonfield-Berlin Rd., Suite 105
Gibbsboro, NJ 08026
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