For the similarly-named personality trait distinct from the disorder, see Sensory processing sensitivity. Sensory integration was defined by occupational sensory development of young children in preschool Anna Jean Ayres in 1972 as “the neurological process that organizes sensation from one’s own body and from the environment and makes it possible to use the body effectively within the environment”.
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. Sensory-based motor disorder shows motor output that is disorganized as a result of incorrect processing of sensory information affecting postural control challenges, resulting in postural disorder, or developmental coordination disorder. Sensory discrimination disorder involves the incorrect processing of sensory information. Incorrect processing of visual or auditory input, for example, may be seen in inattentiveness, disorganization, and poor school performance. Symptoms may vary according to the disorder’s type and subtype present.
SPD can affect one sense or multiple senses. While many people can present one or two symptoms, sensory processing disorder has to have a clear functional impact on the person’s life. Dislike of textures such as those found in fabrics, foods, grooming products or other materials found in daily living, to which most people would not react. Serious discomfort, sickness or threat induced by normal sounds, lights, movements, smells, tastes, or even inner sensations such as heartbeat. Sucking or biting fingers, clothing, pencils, etc. Delays in crawling, standing, walking or running.
The exact cause of SPD is not known. However, it is known that the mid-brain and brain stem regions of the central nervous system are early centers in the processing pathway for multisensory integration, these brain regions are involved in processes including coordination, attention, arousal, and autonomic function. Current research in sensory processing is focused on finding the genetic and neurological causes of SPD. Differences in tactile and auditory over responsivity show moderate genetic influences, with tactile over responsivity demonstrating greater heritability. Bivariate genetic analysis suggested different genetic factors for individual differences in auditory and tactile SOR. People with sensory over-responsivity might have increased D2 receptor in the striatum, related to aversion to tactile stimuli and reduced habituation. In animal models, prenatal stress significantly increased tactile avoidance.
Different neural generators could be activated at an earlier stage of sensory information processing in people with SOR than in typically developing individuals. The automatic association of causally related sensory inputs that occurs at this early sensory-perceptual stage may not function properly in children with SOR. Recent research found an abnormal white matter microstructure in children with SPD, compared with typical children and those with other developmental disorders such as autism and ADHD. Diagnosis is primarily arrived at by the use of standardized tests, standardized questionnaires, expert observational scales, and free play observation at an occupational therapy gym.
Observation of functional activities might be carried at school and home as well. Some scales that are not exclusively used in SPD evaluations are used to measure visual perception, function, neurology and motor skills. SIT is “ineffective and that its theoretical underpinnings and assessment practices are unvalidated. Moreover, the authors warned that SIT techniques exist “outside the bounds of established evidence-based practice” and that SIT is “quite possible a misuse of limited resources. The main form of 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 provide a level of sensory stimulation that the child can cope with, and encourage movement within the room.
Children with hypo-reactivity may be exposed to strong sensations such as stroking with a brush, vibrations or rubbing. Play may involve a range of materials to stimulate the senses such as play dough or finger painting. Children with hyper-reactivity may be exposed to peaceful activities including quiet music and gentle rocking in a softly lit room. Treats and rewards may be used to encourage children to tolerate activities they would normally avoid.