UCSF

Background

Orthostatic tremor (OT) is characterized by high-frequency leg tremor when standing still, resulting in a sense of imbalance, with limited treatment options. Ventral intermediate (Vim) nucleus thalamic deep brain stimulation (DBS) has been reported as beneficial in a few cases.

Objective

To report clinical outcomes, lead locations, and stimulation parameters in 2 patients with severe medication-refractory OT treated with Vim DBS.

Methods

The patients underwent surface electromyography (EMG) to confirm the OT diagnosis. Outcomes were measured as change in tolerated standing time at the last follow-up. Lead locations were quantified using postoperative MRI.

Results

Vim DBS was well tolerated and resulted in improvement in standing time (patient 1: 50 s at baseline to 15 min 16 months after surgery; patient 2: 34 s at baseline to 4.2 min 7 months after surgery). Postoperative surface EMG for patient 1 demonstrated a delayed onset of tremor, lower-amplitude tremor, and periods of quiescence, but an unchanged tremor frequency.

Conclusion

These cases provide further support for Vim DBS to improve standing time in severe medication-refractory OT. The location of the effective thalamic target for OT does not differ from the effective target for essential tremor.