본태성 진전에서 시각의 영향

Visual Cues in Essential Tremor

Purpose : The pathophysiology of essential tremor(ET) remains unknown. PET studies of ET showed some conflicting data. One study reported significant glucose hypermetabolism of the medulla and thalami, but other studies reported abnormal bilateral overactivity of cerebellar and red nuclear connections. The previous experimental studies suggested that each PET finding reflects a part of neural circuit which is responsible for ET. So it can be imagined that olivocerebellar oscillation may be transmitted by the way of cerebellar projections to the thalamus in ET. It has been reported that the cerebellar dentate nucleus neurons are involved in the generation and/or guidance of movement based on visual cues. The purpose of this study is to clarify the role of dentato-thalamic tract in ET. Methods : Tremor amplitudes were recorded as each patient perform two kinds of task, one involving sensory-guided movement and the other involving memory-guided movement. Each patient was asked to move his/her index finger following a smoothly moving target. He/She also was asked to perform the same movements with his/her eyes closed ET. Results : The results showed that average amplitudes of tremor were significantly higer during visually guided task than during memory guided task in ET patients. Conclusions : Our results led us to conclude that dentato-thalamic tract might be related to the control of tremor in ET.