Treatment of essential tremor: a systematic review of evidence and recommendations from the Italian Movement Disorders Association

Essential tremor (ET) is one of the most common movement disorders of adults, characterized by postural and kinetic tremor. It often causes embarrassment andmore rarely serious disability, requiring treatment. Toassess the current state of knowledge on ET therapy andproduce recommendations based on the analysis of evidence the authors reviewed the literature regarding pharmacologic and surgical therapies, providing a qualityassessment of the studies and the strength of recommendations for each treatment. A committee of experts selectedclinical-based questions to guide the search. A systematicliterature review was performed to identify all the studiesconducted on patients with ET published until September2010. Articles were classified according to GRADE evidence profile, a system for grading the quality of evidenceand the strength of recommendation based on the quality ofthe studies. The quality of evidence was often rated as‘‘low’’ or ‘‘very low’’ for the studies analyzed. Propranolol,long-acting propranolol, primidone, and topiramate arerecommended as first-line therapy, with restrictions fortheir side effects. Arotinolol, sotalol, ICI 118.551 and LI32.468 (experimental drugs), zonisamide, gabapentin,alprazolam, clozapine, and olanzapine are recommended asa second-line treatment. Botulinum toxin type A and thalamic deep-brain stimulation are recommended for refractory ET. The results highlight the need of well-designeddirect comparison trials aimed at evaluating relativeeffectiveness and safety of the drugs currently used inclinical practice. Furthermore, additional controlled clinical trials are required to define other possible treatmentstrategies for ameliorating the management of ET.