晩発性皮質性小脳萎縮症の眼球運動と病理

Abstract

An autopsy case of late cortical cerebellar atrophy (LCCA) is reported. A 58-yearold male without family history developed dysarthria and gait disturbance. Neurological examination revealed scanning speech, bradylaria and gradually progressive cerebellar ataxia of the trunk and all limbs. Clinical test for his eye movement showed both saccadic dysmetria and loss of smoothness in pursuit eye movement, but no nystagmus. His deep tendon reflexes remained normal except for decrease in ankle tendon reflex. There were no mental deterioration, nor dysautonomia. He died of sepsis at the age of 73. The duration of his illness was approximately 15 years. Neuro-otological findings were as follows; 1) On eye tracking test, horizontal pursuit eye movements were disturbed, but the severity of this disturbance was initially very mild and deferiorated slowly. 2) Rapid eye movement system such as saccade was normal. 3) No apparent gaze nor spontaneous nystagmus was revealed. 4) Optokinetic nystagmus were normally evoked in number, and the maximal slow phase velocity was almost normal range.On neuropathological examination, mild cerebellar atrophy of both the vermis and cerebellar hemispheres were shown macroscopically. There was severe deciduation of Purkinje cells in both the cerebellar vermis and hemispheres in microscopic examination. However, neurons of the inferior olivary nuclei were almost normal in number, although, slightly decreased in size. The molecular layer and cerebellar white matter showed no abnormalities. Neurons among the granular layer, the dentate nuclei, pontine nuclei and various nuclei of the brain stem showed a normal appearance.In conclusion, the characteristics of abnormal eye movement in cases that have been pathologically diagnosed as LCCA are disturbance of smooth eye movement system and normally evoked optokinetic nystagmus. We thought the neuropathological findings confirmed these results from a neuro-otological perspective.