一位43歲女性,因頭暈、注意力不集中、步伐不穩和視力模糊前來就診。神經學檢查發現有小腦方面的症狀。磁振造影檢查診斷為第一型Arnold-Chiari異常(Arnold-Chiari malformattion)合併蜘蛛膜囊腫(arachnoid cyst)。病人接受後腦窩減壓術(posterior fossa decompression)之治療。手術後二個月病人做電氣眼震圖(ENG)追蹤檢查發現有垂直性向下眼震(downbeat nystagmus)和方形波反射(square wave jerk)的現象。手術後一年追蹤做電氣眼震圖發現垂直性向下眼震有明顯的改善,病人自覺症狀也是有明顯進步。
A 43-year-old woman with a history of dizziness, inattention, unsteady gait and blurred vision. Clinical neurological findings revealed positive Romberg test, ataxic gait and abnormal Tandem gait. MRI showed Arnold-Chiari malformation, type I and associated with arachnoid cyst in the supracerebellar cistern. She admitted to neurosurgical department and received posterior fossa decompression surgery. Postoperative ENG revealed downbeat nystagmus and square wave jerk which persisted even after eight months follow-up. However, downbeat nystagmus improved and patient felt improvement subjectively one year after operation.