Clinical characteristics of essential tremor in Taiwan: An exploratory-comparative study

Background: There are few large-scale clinical analyses of essential tremor (ET) in Asia. We studied the detailed clinical profile with emphasizing the age of onset, tremor location, specific tremor patterns, and rate of progression (ROP) to delineate the characteristics of Taiwanese ET patients and found the difference between the Taiwanese and the Caucasians ET patients. Methods: All ET patients fulfilled the Movement Disorders Society diagnosis criteria were investigated with a standardized assessment protocol, which including clinical evaluation, uniform severity scoring, self-reported questionnaires, accelerometry, surface electromyography, and videotaped tremor examination. Results: Of 219 patients recruited from July 2008 to October 2009, 153 completed the study protocol. Their mean age was 58.9years and 47% were women, and 33.3% had family history (FH). There was bimodal distribution in age of tremor onset in patients without but not in those with FH. Head tremor (HT) was present in 48 of 153 (31%) patients. Patients with HT showed slower tremor frequency and less ROP than those without HT. Sixty-seven (44%) patients presented with intention tremor (IT). Male gender and voice tremor were predictive factors of IT occurrence. Conclusions: Comparing with the Caucasians, Taiwanese ET patients have different patterns of onset-age distribution and lack of female predominance in ET with HT. However, patients with IT and without HT also progressed more rapid as found in the Caucasian.