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The diagnostic category of learning disabilities is a heterogeneous one, but few empirical attempts have been made to distinguish subgroups. Recent research, however, suggests that it may be meaningful to discriminate between "hyperactive" and "nonhyperactive" learning-disabled children. In the present study, 21 learning-disabled children identified as "hyperactive" through teacher nominations and ratings were compared to 15 learning-disabled children identified as "nonhyperactive" in the same manner. The two groups differed on rated behavior, birth order, amount of prescribed stimulant medication, amount of psychosocial stress, and Verbal, Performance, and Full Scale WISC-R IQ scores. They did not differ, however, on several demographic variables, the number of perinatal complications, reading achievement, and a number of tonic and phasic measures of autonomic activity. These findings support the distinction between "hyperactive" and "nonhyperactive" subgroups of learning-disabled children, but suggest that the two subgroups may have a similar biological substrate.