24 Dec Botulinum Injection for Relief from Dystonic Hand Tremor
MedicalResearch.com Interview with:
Dr. Roopa Rajan MD, DM
Post Doctoral Fellowship (Movement Disorders)
Department of Neurology
AIl India Institute of Medical Sciences
MedicalResearch.com: What is the background for this study?
Response: This study was inspired by the need for more effective treatments for patients with disabling hand tremor, particularly dystonic tremor. Dystonic tremor is a movement disorder in which both dystonia (abnormal posturing) and tremor co-exist in the same body part. In general, this common and often disabling disease responds only modestly to oral medications. Surgical treatments such as deep brain stimulation may be offered to persons with severe tremor, however the outcomes are not as robust as seen in other tremor conditions, for instance, essential tremor. Therefore, there is a critical need for more effective treatments for people living with this disease. Botulinum toxin injections are known to be effective for dystonic tremor affecting the head and voice, although these remain off-label indications. Previous studies using botulinum toxin injections for other hand tremors like essential tremor led to limited clinical application, in part due to transient hand weakness that may be a side effect of botulinum toxin injections. Recently, advances in injection delivery such as electromyographically guided botulinum toxin injections with individualized muscle and dose selections were reported to be beneficial in essential tremor. We built upon this existing data to explore the effects of such a treatment in patients with dystonic hand tremor.
MedicalResearch.com: What are the main findings?
Response: Our randomized clinical trial showed that patients who received electromyographically guided, individualized botulinum toxin injections had less severe tremor at 6 and 12 weeks, compared to those who received placebo injections. This difference on a validated rating scale for tremor was statistically significant and clinically meaningful, also accompanied by patient self-reports of benefit in the botulinum toxin injection arm. We used a number of strategies to minimize hand weakness and although subjective hand weakness was reported, the number of patients reporting it was not higher than in the placebo arm.
MedicalResearch.com: What should readers take away from your report?
Response: Botulinum toxin injections are an effective treatment option for patients with dystonic hand tremor and adds to the choice of therapies that we can offer for persons with this disease. Electromyographically guided, individualized botulinum toxin injections into the upper limb are safe and help to minimize unacceptable side effects.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: As with other conditions treated with botulinum toxin, the effect of a single injection lasts for about 12-16 weeks, making repeated injections necessary for continued control of tremor. Future research is required to understand the effect of multiple injection sessions over a longer term and whether it leads to better and sustained outcomes. Also, the effect on overall quality of life over the long term with this strategy needs to be explored in future studies.
MedicalResearch.com: Is there anything else you would like to add?
Response: No relevant disclosures pertaining to this study. This was an investigator-initiated, academic clinical trial funded primarily by an intramural research grant from the All India Institute of Medical Sciences, New Delhi and co-funded by the Department of Science and Technology-Science and Engineering Research Board, India.
Thank you for your interest in our article
Rajan R, Srivastava AK, Anandapadmanabhan R, et al. Assessment of Botulinum Neurotoxin Injection for Dystonic Hand Tremor: A Randomized Clinical Trial. JAMA Neurol. Published online December 21, 2020. doi:10.1001/jamaneurol.2020.4766
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