Focused ultrasound thalamotomy has potential clinical use to improve medication-refractory tremor in patients with tremor-dominant Parkinson disease (TDPD), according to study findings published in JAMA Neurology.
Patients with TDPD enrolled in the clinical trial (ClinicalTrials.gov identifier NCT01772693) were randomly assigned to undergo either focused ultrasound thalamotomy (n=20) or sham procedure (n=7). Researchers sought to determine the efficacy and safety of focused ultrasound thalamotomy for medication-refractory tremor. All motor assessments were performed in the on-medication state.
Following focused ultrasound thalamotomy, hand tremor improved 62% (interquartile range [IQR], 22%-79%) compared with baseline (IQR, 10.5-27.5).
Participants receiving the sham procedure experienced a 22% improvement (IQR, -11% to 29%) from their baseline values. Scores of the Unified Parkinson’s Disease Rating Scale improved by 8 points (IQR, 0.5-11.0) from baseline in the group receiving focused ultrasound thalamotomy vs a 1-point improvement (IQR, -5.0 to 9.0) among those receiving the sham procedure.
Quality of life, as assessed by the 39-item Parkinson’s Disease Questionnaire, improved by 5.4 (−2.4 to 11.9) points in the intervention group vs 7.6 (0.9 to 13.0) in the sham group.
The small patient population represented one of the primary study limitations. Additionally, the failure to achieve a fixed medication dose may have contributed to potential confounders. The investigators also suggest that the study might have achieved more clinical relevance if it had compared focused ultrasound thalamotomy with gamma knife radiosurgery, deep-brain stimulation, or other interventions.
Overall, these findings suggest that focused ultrasound thalamotomy is useful in subsets of patients for whom unilateral tremor reduction will likely improve quality of life.
Bond AE, Shah BB, Huss DS, et al. Safety and efficacy of focused ultrasound thalamotomy for patients with medication-refractory, tremor-dominant Parkinson disease: a randomized clinical trial [published online October 30, 2017]. JAMA Neurol. doi:10.1001/jamaneurol.2017.3098