LDs involve deficits in acquiring and performing basic academic skills. Currently, LDs are categorized into disorders of reading, mathematics, and written expression (Tables 21–4, 21–5, and 21–6). Developmental coordination disorder (DCD), the only motor skills disorder in DSM, is defined in DSM-IV-TR by significant impairment in gross or fine motor coordination, including delays in motor milestones or difficulty with other expected motor tasks during development (Table 21–7). It is often co-occurring and closely related to LD of written expression. The presence of neurological soft signs in individuals with LD of written expression is evidence of problems in the regulation of sensorimotor functions that may lie on a continuum with motor skill disorders (Rourke et al. 2003).