S ensory integration is a long-standing and growing area of practice in occupational therapy. Debate and discussion with colleagues have led us to develop a proposed taxonomy reflecting a new classification scheme to enhance diagnostic specificity. The nosology proposed here is rooted in empirical data first published by Ayres (Ayres, 1972b, 1989) that has evolved based on empirical and theoretical information. This new nosology provides a viewpoint for discussion and research. Two sociopolitical trends contribute to the timeliness of the ideas presented. First, a call exists throughout health and developmental services for evidence-based practice (Sackett, Richardson, Rosenberg, & Haynes, 1997). Diagnostic precision is crucial for homogeneity of samples in empirical research, affecting the validity of the research findings. Second, the condition of sensory processing disorders (SPD) has recently been acknowledged outside the occupational therapy profession in three diagnostic classification references: the Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood, Revised (known as the DC: 0-3R) (Zero to Three, 2005), the Diagnostic Manual for Infancy and Early Childhood of the Interdisciplinary Council on Developmental and Learning Disorders (ICDL, 2005), and the Psychodynamic Diagnostic Manual (PDM Task Force, 2006). Both manuals include diagnostic taxonomies with subtypes of SPD suggested by a committee of occupational therapists, who assisted in developing guidelines for diagnostic specificity related to sensory-based disorders (Miller, Cermak, Lane, Anzalone, & Koomar, 2004).

The fragile X mutation and fragile X syndrome are associated with hyperarousal, hyperactivity, aggression, and anxiety. These may be related to strong reactions to auditory, tactile, visual, and olfactory stimuli [Hagerman, 1996b; Hagerman and Cronister, 1996]. However, almost no data exist describing hyperarousal and sensory sensitivity in individuals with the fragile X mutation. This study establishes a reliable laboratory paradigm for examining reactions to sensory stimuli. We found the pattern of electrodermal responses (EDRs) to stimulation in one sensory modality predicted the pattern of EDRs in four other sensory systems. In addition, the EDR pattern of individuals with the fragile X mutation was related to their FMR-protein expression. Finally, EDRs in individuals with fragile X syndrome were significantly different from those of normal controls, demonstrating greater magnitude, more responses per stimulation, responses on a greater proportion of trials, and lower rates of habituation. The findings support the theory that individuals with fragile X syndrome have a physiologically based enhancement of reactions to sensations. Because electrodermal activity indexes sympathetic nervous system activity, the data suggest that the over-arousal to sensation may involve the sympathetic system.

This study is the first to systematically examine estimated rates of sensory processing disorders using survey data. Parents of incoming kindergartners from one suburban U.S. public school district were surveyed using the Short Sensory Profile, a parent-report screening tool that evaluates parents' perceptions of functional correlates of sensory processing disorders (McIntosh, Miller, Shyu, & Dunn, 1999a). A total of 703 completed surveys were returned, which represents 39% of the kindergarten enrollment (n = 1,796) in the district for the 1999-2000 school year. Of the 703 children represented by the surveys, 96 children (13.7% of 703) met criteria for sensory processing disorders based upon parental perceptions. A more conservative prevalence estimate of children having sensory processing disorders based on parental perceptions was calculated by assuming that all non-respondents failed to meet screening criteria. This cautious estimate suggests that based on parents' perceptions, 5.3% (96 of 1796) of the kindergarten enrollment met screening criteria for sensory processing disorders. These percentages are consistent with hypothesized estimates published in the literature. Findings suggest a need for rigorous epidemiological studies of sensory processing disorders.

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This study investigates the presence of sensory modulation dysfunction (SMD) among children with attention-deficit-hyperactivity disorder (ADHD). Twenty-six children with ADHD (mean age 8.3 years, 18 males, 8 females), and 30 typically developing children (mean age 8.2 years, 21 males, 9 females) were tested using a laboratory procedure that gauges responses to repeated sensory stimulation by measuring electrodermal reactivity (EDR). Parental report measures of limitations in sensory, emotional, and attentional dimensions were administered using the Short Sensory Profile, the Leiter International Performance Scale-Revised, Parent Rating subscales, and the Child Behavior Checklist (CBCL). Compared to the typical sample, the children with ADHD displayed greater abnormalities in sensory modulation on both physiological and parent-report measures. The children with ADHD also displayed more variability in responses. Within the group with ADHD, levels of SMD were highly correlated with measures of psychopathology on the CBCL. Implications of findings relate to the importance of considering sensory processing abilities in a subgroup of children with ADHD.