Transient "cerebellar" mutism in lesions of the mesencephalic-cerebellar region.

Four patients aged from 20 to 48 years with transient mutism are presented: 3 patients underwent surgery for midline tumours of the mesencephalic-cerebellar region (medulloblastoma in two cases and pinealoblastoma in one), at times attached to one or both lateral recesses of the IV ventricle. One patient was hospitalized and treated for brain-stem ischemia. All patients developed mutism 48 to 72 hours after surgery; in the patient with brain-stem softening mutism appeared 72 hours after admission. All the patients had unimpaired consciousness and no deficits of lower cranial nerves. Speech, always normal in the first hours after surgery, was regained after a period of 6-16 weeks. Various hypotheses for this speech disorder are analyzed.