MUTISM AND CEREBELLAR DYSARTHRIA AFTER BRAIN-STEM SURGERY - CASE-REPORT

TRANSIENT MUTISM RESOLVING to cerebellar speech after posterior fossa surgery is a well-recognized phenomenon, particularly in pediatric pat ients. The anatomic basis for this postoperative functional change is unclear but may reside in the dominant superior cerebellar hemisphere or the medial deep cerebellar nuclei. We report a case of an 8-year-ol d girl who presented for surgical resection of a cavernous malformatio n of the right pens (at the level of the middle cerebellar peduncle) a fter hemorrhage. Preoperatively, her complaints consisted of contralat eral motor deficits. She had normal speech. Her lesion was resected th rough a subtemporal approach to the pens. She awoke unable to speak. S he was able to communicate through a variety of verbal cues, including sign language. Her mutism lasted 12 days after which she underwent a prolonged period of slowly resolving cerebellar dysarthria. Her preope rative motor deficits also slowly resolved. This is the first reported case of mutism resolving to cerebellar dysarthria after a supratentor ial approach to the brain stem. We discuss the anatomic basis for post operative mutism in light of previous observations combined with the u nusual finding of mutism after pontine surgery. In particular, reports of mutism after bilateral cerebellar hemispheric injury, bilateral or unilateral medial deep nuclear injury, and, now, pontine tegmental in jury implicate the superior cerebellar hemispheres, the deep cerebella r nuclei, and the nuclear outflow through the superior cerebellar pedu ncle as the anatomic bases for cerebellar participation in the product ion of human speech.