Cerebellar-Induced Aphasia and Related Language Disorders

Several studies have implicated the cerebellum in cognitive and behavioral-affective functions, including language. Clinical evidence and imaging studies point to a cerebellar involvement in motor speech production; verbal fluency and lexical/semantic retrieval; grammatical/syntactical processing; reading, writing, and metalinguistic skills; and verbal working memory. These observations have led to the hypothesis of a cerebellar-induced aphasia. Support for this concept is provided by reports of case studies with aphasia-like symptoms following acute cerebellar damage and imaging studies demonstrating impaired language performance in groups with cerebellar damage compared to healthy control groups. However, the concept of a cerebellar-induced aphasia is still a matter of debate because the underlying mechanism has yet to be elucidated. Some have argued that the cerebellum is involved in language through cerebellocerebral diaschisis or that it has a temporal/sequencing role in linguistic functioning, whereas others ascribe linguistic deficits following cerebellar damage to impaired motor control. To determine whether cerebellar-induced aphasia is a fact or a fallacy, it is of vital importance to determine the underlying mechanisms.