[Cerebello-cerebral functional relationship in spinocerebellar degeneration using positron emission tomography].

In order to investigate the laterality of cerebellar ataxia and its influence for the cerebral cortex in spinocerebellar degeneration (SCD), regional cerebral blood flow (r CBF) was measured using positron emission tomography (PET) in 10 patients with sporadic olivopontocerebellar atrophy (sOPCA), 7 patients with hereditary SCD (h SCD), and 10 age matched control subjects. The laterality of cerebellar ataxia was evaluated by the total score of the difference between left and right limbs of three limb-coordination tests. The lateralities of rCBF were calculated by asymmetry indices (AIs) of each region of interest in the cerebellum, thalamus, caudate, putamen, cerebral cortices. The laterality of cerebellar ataxia was significantly correlated with AI in the cerebellum in patients with sOPCA. Furthermore, significant negative correlations were observed between AI in the cerebellum and each AI in the thalamus, frontal cortex in patients with sOPCA. However, no correlations were observed between AI in the cerebellum and the other AIs in controls and patients with h SCD. Duration of illness in patients with sOPCA with laterality is shorter than that in patients without laterality. These results suggest that the existence of crossed cerebello-cerebral diaschisis (CCCD) resulting from transneuronal deactivation through cerebello-thalamo-cerebral pathway in patients with the early stage of sOPCA with laterality.