Neurocognitive impairments associated with ambiguous handedness in the chronically mentally ill

One form of atypical handedness, ambiguous handedness, is found in roughly one-quarter of chronic schizophrenic patients. Despite its prevalence, relatively little is known about the neurocognitive underpinnings of ambiguous handedness. In the present study we examined the performance of ambiguous (n = 19) and non-ambiguous (n = 39) handed chronically mentally ill inpatients on selected measures of verbal learning, motor learning and manual dexterity. The results revealed that ambiguous handers were more impaired than non-ambiguous handers in verbal learning, but not motor learning. Group differences in manual dexterity were significant for the entire sample, but not when analyses were limited to males. These findings suggest that impairments in verbal learning may be linked to the pathogenesis of ambiguous handedness in chronic psychiatric patients.