ｏｐｓｏｃｌｏｎｕｓならびにｏｐｓｏｃｌｏｎｕｓ類似の異常眼球運動について

Abstract

We described three patients with abnormal eye movements and acute cerebellar ataxia.The first patient, a 57-year-old man, had irregular paroxysmal ocular oscillations in the horizontal and vertical direction. These ocular movements lasted 0.2-5 seconds at a frequency of 4-5 Hz and an amplitude of 10°-20°. Two months after the onset of his illness, these ocular movements disappeared. His abnormal eye movements were considered to be opsoclonus.The second patient, a 50-year-old man, had paroxysmal horizontal ocular oscillations lasting 0.2 seconds at a frequency of 10 Hz and amplitude of 10°. Three weeks after the onset of his illness, his abnormal eye movements disappeared.The third pal:ient, a 37-year-old man showed bursts of horizontal saccadic oscillations at a frequency of 4-10 Hz. A single burst of oscillations lasted for 0.2-0.9 seconds. Their amplitude was 10-20. They were still present, but had diminished, one month after the onset. The abnormal eye movements observed in the latter two cases were considered to be flutter-like oscillations.Opsoclonus is a distinct clinical entity, a bizarre oculomotor disturbance with chaotic conjugate accadic eye oscillations in all directions. The term “ocular myoclonus” has also been used to describe opsoclonus. The pendular ocular oscillations associated with regular palatal myoclonus have also been called ocular myoclonus. The term “acquired pendular nystagmus” is much more appropriate to describe the ocular oscillations associated with palatal myoclonus.Flutter-like oscillations are intermittent horizontal oscillations of the eyes lasting not more than a few seconds. They are sometimes observed in patients with opsoclonus, either simultaneously or in sequence. However, the characteristics of opsoclonus are quite different from those of flutter-like oscillations. Therefore, they should be classified as two different entities.