[Skip to Navigation]
Comment & Response
May 2018

Assessing Tremor and Adverse Events in Patients With Tremor-Dominant Parkinson Disease Undergoing Focused Ultrasound Thalamotomy

Author Affiliations
  • 1Department of Neurology, Rambam Health Care Campus, Haifa, Israel
  • 2Department of Neurosurgery, Rambam Health Care Campus, Haifa, Israel
JAMA Neurol. 2018;75(5):632-633. doi:10.1001/jamaneurol.2018.0263

To the Editor We read with interest the article of Bond et al1 regarding focused ultrasonographic thalamotomy for the treatment of patients with Parkinson disease.1 In our experience,2-4 which was not referenced in this article, Unified Parkinson Disease Rating Scale scores and Parkinson Disease Questionnaire–39 scores are significantly improved with this procedure as compared with the baseline.2,3 In all of the procedures we performed there was improvement in arm tremor as well as in coexisting tremors of the head, chin, and leg. The results of Bond et al1 seem to emanate from either not having enough power to reveal the association or having a not rigorous enough patient selection; the authors state that they recruited patients with tremor-dominant Parkinson disease that were “medication refractory, severe and disabling.” It is not clear from this statement or from the supplement material that the disability was due to the tremor and not to “on” and “off” phenomenon. This might have adversely biased their results. Furthermore, because the levodopa dosage was not kept constant throughout the study, changes in the levodopa dosage may have affected the study results. In addition, because the Clinical Rating Scale for Tremor score was the primary end point of the study, the authors should have explained how reemergent tremor was rated, as the Clinical Rating Scale for Tremor score was developed for assessing essential tremor and does not take this kind of tremor into account. We were surprised by the high rate of adverse events in these 2 treatment centers, probably due to inexact lesion localization, including lesioning of the internal capsule, which we have not seen in the patients in our treatment center. In our experience, sensory and gait disturbances were, at most, transient, and none of the patients had any adverse event that lasted for more than 3 months. We submit that specialization and experience are critical for optimization of focused ultrasonographic thalamotomy results.

Add or change institution