Clinical and Electrophysiological Analysis of Chronic Eyelid Twitching.

PURPOSE: Nearly everyone had experience of eyelid twitching (ET) and most physicians think it is benign and self limited. Most neurologists consider it is a symptom rather a disease. However, sometimes ET persists longer and becomes bothersome in some cases, i.e. chronic ET (CET). CET was seldom discussed seriously and studied extensively. Few studies concerning of CET especially its electrophysiological features had been reported. The purposes of this study are to delineate its clinical features and electrophysiological characters of CET. In consequence by knowing its pathophysiology we can prove CET is a disease entity as minor form of facial nerve neuropathy.

METHODS: A retrospective study by reviewing medical charts of patients with facial twitching and have been received examinations of facial nerve latency and blink response. We defined CET as persisting of ET more than 2 weeks. We collected 142 patients, age from 12 to 73 years-old, 34 men and 108 women. The onset month and season, sex, abnormal side, and abnormal index (AI=abnormal side minus normal side/normal side) of several variables from electrophysiological study were compared between men and women of CET.

RESULTS: There was significant gender difference on CET. Women were more vulnerable than men (female to male: 3 to 1). CET tended to develop more in cold weather (61.27%). Half of CET cases demonstrated delayed or absent R2 response in blink reflex. And 45.8% cases had prolonged facial nerve latency (>5% side to side difference), with the rate higher in women (48.5% vs 38.2%). These two findings indicating conduction defect of facial nerve pathway in CET cases.

CONCLUSION: Although CET has been considered as a benign, transient, somewhat physiological phenomenon, our study may suggest it can be a disease entity with minor facial nerve neuropathy.