左右逆転プリズム装置下の前庭動眼反射における適応現象の臨床的応用

スポンサーリンク

概要

• 論文の詳細を見る

• The vestibulo-ocular reflex (VOR) helps to hold a stable retinal image by compensatory eye movements against head rotation. Recent experiments using reversing prism have cleary demonstrated that the VOR is not only plastic but also adaptive. Robinson reported that the adaptive gain control of VOR was abolished after removal of the vestibulocerebellum in the cats. From the fundamental experiments mentioned above, the clinical observation of adaptive changes in the VOR by prism-reversal of vision expected to be an useful diagnostic tool for detecting the cerebellar dysfunction.Prior to the clinical application for detecting cerebellar dysfunction, twenty-six normal adults, ranging in age from 19 to 34 years, without any vestibular and oculomotor disorders, were tested. The subjects sit on the pendular rotation chair and the eye movements (E), eye velocities (E) and head movements (H) were recorded during the pendular rotation (0.25Hz, 30° amplitude)under the condition of the eyes covered in the dark. After initial recording of E, E and H, subjects wore the reversing prism and the rotation continued up to one hour. During the test period, subjects were asked to watch the fixed small spot light in 2m distance at the center of the rotation angle. Every 15 minutes, subjects wore dark goagle over the reversing prism and E, E and H were recorded. The results showed clear reduction of the gain of the VOR (apploximately 50% decrease relative to control value), but no phase shift was observed.Thirteen patients with cerebellar lesions were examined using the same test. The adaptation of the VOR was cleary reduced in comparison to normal subjects, (the gain was approximately 20%), but no remarkable changes of the phase were observed. The degree of the gain reduction was related to the extents of the cerebellar lesions.The analysis of the data of the thirteen cases with cerebellar lesions, revealed the clinical application of the adaptive changes in the VOR by prism-reversal of vision was an useful tool for detecting the cerebellar disorders.

• 社団法人 日本耳鼻咽喉科学会の論文

著者

• 清水 元博

  日本医科大学耳鼻咽喉科学教室

関連論文

• 第34回 日本平衡神経科学会
• 左右逆転プリズム装置下の前庭動眼反射における適応現象の臨床的応用
• 左右逆転視プリズムを用いた新しい神経耳科学検査法
• 前庭動眼反射における適応現象とVisual Suppression Test
• ENG検査日の違いによる眼振の変化について-1-眼振出現率からの検討

スポンサーリンク