CEREBELLAR INDUCED APHASIA - CASE-REPORT OF CEREBELLAR INDUCED PREFRONTAL APHASIC LANGUAGE PHENOMENA SUPPORTED BY SPECT FINDINGS

A 73-year-old right-handed man with ischemic infarction in the vascula r territory of the right arteria cerebellaris superior is described. I n the acute phase he presented with cerebellar and brainstem symptoms, followed within a few days by a paresis of the right arm and unexpect ed language disturbances of aphasic origin. The core features of the a phasic syndrome corresponded to a diagnosis of Luria's dynamic aphasia , complicated by expressive and receptive agrammatism During one year follow-up the ataxia and paretic symptoms disappeared but the slightly ameliorated aphasic syndrome and the sensory disturbances in the left hemicorpus persisted. In the absence of any neuroradiological evidenc e for a structural lesion in the left frontal language areas, the hypo thetical causative role of the right cerebellar lesion on the contrala teral prefrontal aphasic symptomatology is advocated and supported by positive Tc-99m-hexamethylpropyleneamine oxime single-photon emission- computed tomography findings, revealing a focal hypoperfusion in the c linically suspected areas. In our case, this phenomenon of so-called ' crossed cerebello-cerebral diaschisis', reflecting the distant functio nal impact of the right cerebellum on the contralateral prefrontal cor tical areas, is for the first time associated with an aphasiologic sub strate. The co-occurrence of a right cerebellar lesion and an aphasic syndrome forms the first clinical illustration of the pathophysiologic al hypothesis of a deactivation of prefrontal left hemisphere language functions due to the loss of excitatory impulses through cerebello-po nto-thalamo-cortical pathways.