Developmental manual dyspraxia: a lesson in mind and brain.

For decades, pediatricians assiduously documented "soft neurologic signs" in children referred for school learning difficulties, although pediatric neurologists, including Charles F. Barlow, pointed out the dissociation between most neuropsychological abnormalities and the motor findings in question. Later, large epidemiologic studies confirmed the independence of soft signs from other neuropsychological defects. We used a standardized dyspraxia battery to study 164 schoolchildren 5 to 12 years old. We found that in the group as a whole there was a positive correlation between motor performance in the dyspraxia battery and IQ on the Wechsler Intelligence Scale for Children--revised (Full-Scale, Verbal, and Performance). In terms of dyspraxia subscales, we found that Performance IQ and Full-Scale IQ correlated with imitation of nonsense gestures and use of actual objects, whereas Verbal IQ correlated positively only with pantomime on command. In contrast, for the group of 24 subjects whose scores on the battery designated them as dyspraxic, there was no correlation between dyspraxia scores and IQ. Together with the existence of specific, dramatically different, types of dyspraxia among the 24 dyspraxic subjects, present findings uphold the earlier neurologic opinion that "motor soft signs" are not evidence for fixed "brain damage" or even for other types of motor dysfunction, and that dissociation of different specific cognitive dysfunctions is the rule within individual patients.