Agenesis of the corpus callosum: report of two pre-school children and review of the literature.

The results of neuropsychological examinations of two patients with agenesis of the corpus callosum showed low intelligence-test performance, impared visuo-motor co-ordination and impaired bimanual co-ordination. The most striking deficits were observed in Case A, particularly in her inability to identify objects verbally when placed in the non-dominant hand, and in her ability to complete a task with the non-dominant hand without vision, when she was unable to complete the same task with vision. This patient is unusual insofar as she manifests deficits noted in acallosal patients, as well as some noted in split-brain patients but not previously ascribed to acallosal patients.