Clinical and electromyographic assessment of essential tremor treatment

It is a matter of debate whether beta-blockers or primidone have a better influence on essential tremor. It is also controversial whether essential tremor with synchronous electromyographic activity is influenced by the administration beta-blockers, while tremor with alternating electromyographic activity is influenced by primidone. The aim of this study was to reevaluate the effects of beta-blockers and primidone on essential tremor. We also aimed to evaluate the differential effects of beta-blockers and primidone on tremor with synchronous or alternating electromyographic activity and on tremor in different limb positions. One hundred patients (57 female, 43 male) with essential tremor were included in this study. According to the electromyographic pattern recorded from the antagonistic muscles, the patients were subdivided into group with synchronous (SYN) and group with alternating (ALT) activity. After the initial clinical and electromyographic examinations the patients were randomly assigned first to treatment with propranolol (180 mg daily), or to treatment with primidone (500 mg daily) for 30 days. After a washout period of 20 days the patients were assigned to the other treatment. Our results revealed that the effects of propranolol and primidone on essential tremor and on SYN or ALT tremor were similar. Differences between both drugs existed as regards to better primidone influence on the kinetic and intention tremors and to tremor localized outside the limbs. In conclusion it is better to treat patients with kinetic and intention essential tremor and tremor localized outside the limbs with primidone.