I. Description of the problem. Sensory processing refers to the way the nervous system receives messages from the senses and turns these messages into appropriate motor and behavioral responses. Sensory processing disorder (SPD, formerly referred to as sensory integration disorder, or SID) refers to problems in organizing and using sensory information from both the environment and the child’s own body, specifically impairments in detecting, modulating, interpreting, or responding to sensory stimuli. The ability to integrate or process sensory information is a temperament-related process that varies in children and, if problematic, may interfere with the child’s ability to participate in activities and relationships and affect learning capacities.

II. Epidemiology. Estimates place the prevalence as high as 1 in every 20 children who may experience symptoms significant enough to impact their daily life. The only study thus far conducted on prevalence of sensory integration found the incidence of SPD to be 13.9% in kindergarteners. Clinicians report higher incidence of SPD disorders in boys than girls. Families often report similar untreated traits in parents of identified children, but again, no genetic studies have been conducted. In addition, SPD may be present in children with varying diagnoses including autism spectrum disorders, nonverbal learning disabilities, attention deficit hyperactivity disorder (ADHD), and developmental coordination disorder.

III. Etiology/contributing factors. The etiology of SPD is not known. Some evidence has been found that children with sensory modulation disorder, specifically those with over responsivity (see preceding text) have heightened sympathetic arousal. It is hypothesized that children with SPD have atypical autonomic (both sympathetic and parasympathetic) responses to sensory challenges. The evidence supporting parasympathetic and cortisol differences in children with SPD and no co-occurring diagnoses is not convincing. It is hypothesized, but not verified, that the underlying processes contributing to SPD are temperamentally related differences in the way sensory input is processed in the central nervous system. While individual temperamental differences are considered the basis of SPD, the ultimate expression of that challenge is often dependent upon the children’s interaction with their environments. Social environments that are responsive to the child’s cues and thereby provide an optimal goodness-of-fit with the child’s sensory needs and motor capacities can decrease behavioral disorganization, thus forming the theoretical basis of intervention.