Concept evolution in sensory integration: a proposed nosology for diagnosis.

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).