Botulinum toxin injections show promise in treating essential head tremor

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Local injections of botulinum toxin type A, administered into specific muscles, have shown significant promise in reducing the severity of essential or isolated head tremors. The study found that patients receiving botulinum toxin experienced a notable improvement compared to those who received a placebo.

Conducted as a multicenter, double-blind, randomized trial, the research involved adult patients diagnosed with essential or isolated head tremor. Participants were randomly assigned to receive either botulinum toxin type A or a placebo, with injections administered under electromyographic guidance into each splenius capitis muscle on the day of randomization and during week 12.

The primary outcome measure was a notable improvement of at least 2 points on the Clinical Global Impression of Change (CGI) scale at week 6 following the second injection (week 18 after randomization). The CGI scale allows patients to assess the degree of improvement or worsening of head tremor since baseline, with scores ranging from 3 (very much improved) to -3 (very much worse).

Of the 120 patients enrolled, 117 were included in the intention-to-treat analysis, with 62 receiving botulinum toxin and 55 receiving placebo. The results found 31% of patients in the botulinum toxin group experienced the desired improvement, compared to only 9% in the placebo group.

Secondary outcomes, measured at 6 and 12 weeks, provided further support for the primary outcome analysis. However, the effects did not persist at the 24-week mark, suggesting a potential waning of the injection’s impact over time.

Approximately half of the patients in the botulinum toxin group experienced side effects, including head and neck pain, posterior cervical weakness, and dysphagia.

Marques A, Pereira B, Simonetta-Moreau M, et al; Btx-HT Study Group. Trial of Botulinum Toxin for Isolated or Essential Head Tremor. N Engl J Med. 2023;389(19):1753-1765. doi: 10.1056/NEJMoa2304192. PMID: 37937777.