Objective: To characterize response to thalamic deep brain stimulation (DBS) in a patient with medically refractory orthostatic tremor using instrumented measures of tremor and mobility.

Background: Orthostatic tremor (OT) is a disabling disorder characterized by a high frequency tremor in the lower limbs upon standing. Electrophysiologic studies have shown persistence of tremor with ambulation and associated gait abnormalities resembling cerebellar disorders have been described. Treatment options are limited and clinical response to medications is often minimal. Thalamic DBS has been previously reported to improve tremor in OT, but the effect of thalamic DBS on gait/mobility remains poorly characterized.

Method: A 61 year-old woman presented with disabling OT refractory to multiple medications including benzodiazepines. She underwent DBS with bilateral ventral intermediate nucleus (ViM) targets. Tremor and gait metrics were assessed with wireless surface EMG (bilateral tibialis anterior and gastrocnemius medialis) and synchronized body-worn inertial sensors before and 4 months after surgery. Balance self-confidence and quality of life (QOL) were also assessed pre- and post-DBS using the Activities of Balance Confidence (ABC) scale and the Parkinson’s disease questionnaire (PDQ-39) respectively.

Results: Pre-DBS surface EMG recordings of the tibialis anterior demonstrated a 13 Hz tremor that emerged immediately upon standing and persisted with walking in the stance phase of gait. The tremor was present in the legs, trunk, and arms. Post-DBS, the latency to tremor onset was increased to 18 seconds with associated reduction in tremor amplitude. Clinically, this corresponded to the patient being able to stand for 5 minutes without needing to sit or lean compared to 1 minute pre-DBS. Post-DBS assessment with body-worn sensors demonstrated improved gait speed (17% increase), stride length (16% increase), and double support time (12% reduction). The ABC improved from 74% to 84% and QOL improved from 48 to 15. Clinical benefit was sustained at follow-up 7 months after initial DBS programming.

Conclusion: Thalamic ViM DBS clinically improved orthostatic tremor affecting the legs, trunk, and arms as well as spatio-temporal characteristics of gait in a patient with medically-refractory OT.

« Back to MDS Virtual Congress 2020

MDS Abstracts - https://www.mdsabstracts.org/abstract/thalamic-deep-brain-stimulation-improves-tremor-and-spatio-temporal-characteristics-of-gait-in-medically-refractory-orthostatic-tremor/