Language disorders subsequent to left cerebellar lesions: A case for bilateral cerebellar involvement in language?

Background: Crossed cerebello-cerebral diaschisis, reflecting a functional depression of supratentorial language areas due to reduced input via cerebello-cortical pathways, may represent the neuropathological mechanism responsible for language deficits associated with cerebellar pathology. Although it has been proposed that language is lateralized to the right cerebellar hemisphere, recent clinical and neuroimaging studies suggest that the cerebellum may bilaterally influence the regulation of language, with the left cerebellar hemisphere also contributing to the mediation of language via ipsilateral cerebello-cortical pathways. Aims: The aim of the study was to determine the effect of left primary cerebellar lesions on general as well as higher-level language function. Methods and Procedures: Linguistic profiles of a group of ten individuals with left primary cerebellar lesions were compared with those of a group of non-neurologically impaired controls matched for age, gender and level of education. Outcomes and Results: The findings confirmed that higher-level language deficits may result from left primary cerebellar lesions possibly as a consequence of ipsilateral cerebral diaschisis. Conclusions: The results challenge the notion of a right lateralized cerebellum and support a role for the left as well as the right cerebellar hemisphere in the regulation of language function.