SPEECH, LANGUAGE, AND THE CEREBELLUM

The cerebellum can affect speech and language in a number of ways. The most obvious is dysarthria when motor movements are deprived of the r egulatory control, which is one of the main functions of the cerebellu m. Less well-known is cerebellar mutism, which most often occurs after the removal of a cerebellar tumour. It is unlikely that this is simpl y the result of dysarthria. The most controversial aspect of cerebella r function, and the main stress of this paper, ir the contribution it may make to language production. A number of studies have suggested th at the cerebellum can, indeed, be involved in both cognition and langu age. A number of these are reviewed, in particular, the results of dif fuse and focal lesions of the cerebellum, and how these can affect the function of the cerebrum; and conversely how cerebral lesions can cau se changes in the cerebellum. Positron emission tomography (PET) has b een essential in the assessment of these patients. During human evolut ion parts of the cerebellum and their connections have enlarged enormo usly, and it would be surprising if these parts of the brain had not t aken on new roles. To regard the cerebellum as only serving motor func tion is too narrow a concept.