OKAN検査を用いた異常眼球運動の鑑別—正常，病的意義の鑑別

Differential Diagnosis of Spontancous Abnormal Eye Movements Using Optokinetic after Nystag-mus Test

I．はじめに

　われわれ神経耳科医が日常臨床において眼振検査中に，一見観察では眼球が「キョロ，キョロ」と動いたとしか思われないような非眼振性自発性異常眼球運動にしばしば遭遇することがある。

　これら眼球が「キョロ，キョロ」と動いたとしか思えないような，正常，病的の判断の比較的困難な異常眼球運動のうち，①Zickzackbewegung^1），②Fixationsrucke^2），③Lightning eye movement^3）について新たに視運動後眼振検査（optokineticafter nystagmus test（OKAN））^4）を行うことにより，これら異常眼球運動のOKAN検査における態度によって，臨床診断学的にその正常か，病的かの判断について検討を加えた。

　Spontaneous abnormal eye movements such as shifty eye movement in normal subjects are very difficult to be evaluated as whether they are normal or abnormal.

　For differential diagnosis of these abnormal eye movements, several methods in which frequency, velocity or amplitude of the eye movement wereinvestigated have been reported.

　In the present study we investigated the abnormal eye movement by means of optokinetic after nystagmus test. This method was thought to be valuable to differentiate abnormal eye movements from normal eye movements, and it was found that when an eye movement is abnormal, nystagmus has to be enhanced on optokinetic after nystagmus test while when it is normal there must be no enhancement of nystagmus test while when it is normal there must be no enhancement of nystagmus on this test.