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A 10-year-old left-handed girl with a developmental stutter and agenesis of the corpus callosum with associated hydrocephalus ceased stuttering immediately upon initiation of steroid therapy for colitis. Steroid taper resulted in a recurrence of the stutter and resumption for treatment of recrudescent colitis caused its disappearance again. Baseline agenesis of the corpus callosum with hydrocephalus and the patient's course in the face of the known effects of steroids on white matter lend support to the hypothesis that stuttering reflects anomalous dominance and/or atypical interhemispheric connectivity, as evidenced by the fact that presumed alterations of white matter tracts affected speech rhythms/stuttering.

Patients with left hemisphere lesions deep in parietal or parietal-occipital regions close to the lateral ventricles have been reported to have impaired performance on left ear speech stimuli in dichotic listening tests. This loss has been termed "paradoxical" because it presents at the ear ipsilateral to the lesion. Two patients with infiltrating tumors which involved the corpus callosum demonstrated that effect, but also demonstrated right ear extinction on a complex-pitch discrimination test that required right hemisphere processing. Since the side at which the impairment will be demonstrated depends upon the type of test used, the term "paradoxical extinction" does not clearly describe this phenomena. It is suggested that the so-called paradoxical loss is better referred to as callosal extinction.