In a groundbreaking study published in The New England Journal of Medicine, researchers have affirmed the safety and efficacy of using botulinum toxin to treat isolated and essential head tremors. The study, led by Dr. Ana Marques and her colleagues at the Centre Hospitalier Universitaire de Clermont-Ferrand in France, addresses a common movement disorder that previously lacked a clearly demonstrated treatment.Â
Dr. Marques emphasized the impact of their findings on the therapeutic approach, stating, “Our findings confirm that botulinum toxin injections in splenius capitis muscles are an effective and safe treatment for isolated and essential head tremor, and this will impact the therapeutic attitude of clinicians who can now propose more confident treatment options.”Â
The multicenter, double-blind, randomized trial involved 117 adults with essential or isolated head tremors. Participants were randomly assigned to receive either injections of botulinum toxin type A or a placebo. The injections, administered under electromyographic guidance into splenius capitis muscles, were given on the day of randomization and again during week 12 of the trial.Â
The primary outcome measured was a 2-point or more improvement in the Clinical Global Impression of Change (CGI) scale at week 18. The CGI scale evaluates changes from “very much improved” to “very much worse.” The results revealed a significant difference, with 31% of patients in the botulinum toxin group meeting the primary outcome compared to 9% in the placebo group.Â
Interestingly, the study also found that increasing the dose of botulinum toxin above 75 IU in each splenius did not seem to improve efficacy, providing valuable insights for clinical practice. Despite the positive outcomes, the researchers noted that the association between botulinum toxin and improvement diminished by week 24, suggesting that the effects of the injection might wane over time.Â
Adverse events were reported in approximately half of the patients in the botulinum toxin group, including head and neck pain, posterior cervical weakness, and dysphagia. In comparison, only 16% of patients in the placebo group experienced adverse events. Most adverse events in the botulinum toxin group were mild, but two patients experienced severe events leading to hospitalization.Â
Dr. Marques outlined the next steps of their research, focusing on identifying the clinical characteristics of patients insufficiently improved with botulinum toxin injections. This information will guide the development of treatment options for this specific subgroup.Â
In conclusion, this study represents a significant advancement in the treatment of isolated and essential head tremors, providing clinicians with a well-supported and confident therapeutic option in the form of botulinum toxin injections. Â
Journal Reference Â
Marques, A., Pereira, B., Simonetta-Moreau, M., Castelnovo, G., De Verdal, M., Fluchère, F., … Rieu, I. (2023). New England Journal of Medicine, 389(19), 1753–1765. doi:10.1056/nejmoa2304192Â
