Transient "cerebellar" mutism.

The term "cerebellar mutism" refers to a specific disorder in which a complete but transient loss of speech, followed by dysarthria, occurs following resection of intrinsic posterior cranial fossa tumors or cerebellar hemorrhages, or upon trauma. Although it is well known that the lack of long-tract findings and cranial nerve (CN) involvement is the rule, the pathophysiology of cerebellar mutism has not been clearly elucidated. A review of the relevant literature disclosed 93 patients with this condition, the majority of these being in the pediatric age group. The neuropathological findings were as follows: 57 primitive neuroectodermal tumors (PNET), 19 astrocytomas, 10 ependymomas, 5 vascular malformations, 1 metastatic tumor, and 1 traumatic injury. The interval before the onset of mutism ranged from 0 to 168 h (mean 40.9 h). The mutism lasted from 1 to 168 days (mean 37.6 days). Subsequent dysarthria was present in 75 (80%) of the 93 patients. In this article, some specific recent illustrative reports are presented, and the concept of the role of the cerebellum in language and cognition is discussed. With these data as our point of departure, various hypotheses that have been advanced to explain the pathogenesis of this transient speech disorder are analyzed. The findings of the study suggest that the cause of the cerebellar mutism is the ischemia caused by vasospasm, as it usually developed after a latent period.