SUBTYPING OF DEVELOPMENTAL MOTOR DEFICITS

The purpose of this study was to investigate whether subtypes of devel opmental motor deficits could be identified: specifically, one with im pairments in motor planning that would be characterized by deficits in gestural performance and motor sequencing and a second with impairmen ts in the execution of motor skills that would be characterized by def icits in balance and coordination. Subjects included 102 children betw een the ages of 6 years and 10 years, 11 months, 51 who had been ident ified as displaying deficits in motor skills and 51 normal controls. H ierarchical-agglomerative and iterative partitioning cluster analyses using measures of balance, bilateral coordination, upper limb coordina tion, transitive gestures, and motor sequencing revealed four subtypes . One group displayed deficits in motor sequencing, whereas another de monstrated deficits in balance, coordination, and gestural performance . In addition, a third group of children showed severe deficits in all motor skill areas, and a final group had no motor deficits compared w ith the other groups. Examination of performance on measures of academ ic, language, visual-perceptual, visual-motor skills revealed that the se four groups displayed different patterns of nonmotor performance. T hese findings suggest that different subtypes of developmental motor d eficits can be identified among children who have been labeled ''clums y.''