Botulinum Toxin Treatment of Essential Tremor - A Customized Approach (S27.002)

OBJECTIVE: To evaluate the efficacy and safety of incobotulinumtoxinA (Xeomin) in essential tremor (ET) using a customized approach.BACKGROUND: OnabotulinumtoxinA (Botox) has been reported to alleviate essential tremor, but up to 30[percnt] of the patients in previous studies developed unacceptable hand weakness. A customized treatment approach with incobotulinumtoxinA has been suggested to alleviate this problem (Jankovic 2008), but data has not been reported in a blinded study.DESIGN: 33 adult patients with ET were planned to enroll in this prospective, placebo-controlled, crossover, blinded study design, allowing a minimum inclusion of 30 (10[percnt] drop out). This is a preliminary report on the first 19 patients. Patients were injected under electromyography (EMG) guidance with 100 units of incobotulinumtoxinA (10units/0.1cc). All patients received 15 units into biceps and wrist flexors, but other muscles (finger flexors and extensors, wrist extensors and pronator) were included only if EMG showed significant activity (5-10 units/muscle). Crossover occurred at 4 months. Ratings included NIH Collaborative Genetic Criteria Tremor Severity Scale, patient global impression of change (PGIC), quality of life scale and assessment of hand weakness.RESULTS: 12 of 19 patients receiving incobotulinumtoxinA (63[percnt]) compared to 2 of 19 (11[percnt]) receiving saline demonstrated significant improvement of tremor (two or more grades) by the NIH tremor scale (P= 0.019). 10 of 19 patients receiving incobotulinumtoxinA (53[percnt]) compared to 3 of 19 patients receiving saline (15[percnt]) expressed improvement in PGIC (P=0.031). One patient withdrew from the study due to unacceptable hand weakness (5[percnt]) with complete recovery within 3 months.CONCLUSIONS: This customized, blinded, EMG-guided injection study of incobotulinumtoxinA produced statistically significant improvement of tremor and patient satisfaction. Unacceptable hand weakness occurred in a small percentage of patients. This treatment should be considered for patients with continued bothersome ET despite use of oral medications. Disclosure: Dr. Rostami has nothing to disclose. Dr. Chow has nothing to disclose. Dr. Richardson has nothing to disclose. Dr. Jabbari has received research support from Allergan Inc, Merz Pharmaceuticals, and Ipsen Pharmaceuticals. Dr. Machado has nothing to disclose.