Treatment Of Holmes Tremor By Deep Brain Stimulation Of The Prelemniscal Radiations

Objective: Present a case of Holmes Tremor that was treated successfully by Deep Brain Stimulation (DBS) in a novel target region. Background: Holmes tremor is a post-traumatic, low-frequency tremor that can include resting, kinetic and postural components. Dopaminergic-nigrostriatal and cerebello-thalamic circuits are thought to be involved. Pharmacological treatment is ineffective in the majority of cases. DBS has proven to be an alternative therapy for medically refractory Holmes tremor. Typical targets include ventralis intermedius (VIM), subthalamic nucleus, and/or globus pallidus pars interna. Stimulation parameters are typically higher than in Parkinson’s or Essential Tremor, and can require additional electrodes. This requires higher power consumption, shorter battery life, and more frequent battery replacement. Design/Methods: Case report, which includes surgical history, imaging and outcome data. Stereotactic CT scan and pre-operative MR images were co-registered via a standard linear registration algorithm. Volume of Tissue Activated computed programmatically from imaging data and stimulation parameters. Results: A 34-year-old man developed right-predominate tremor, seizures, speech and gait disturbances after falling from a roof in 2003. MRI demonstrated bilateral thalamic lesions. His tremor did not improve with baclofen or levodopa. He underwent left-sided DBS electrode placement. Recording microelectrodes targeted VIM. Localization confirmed with neurophysiological recording. DBS electrode 3387 replaced the recording electrodes. Intraoperative imaging revealed that the target electrode was not within VIM, but rather in prelemniscal radiations (RAPRL) or the posterior subthalamic area. Nevertheless, his intraoperative and subsequent clinical response was excellent. His optimized setting was monopolar stimulation with contact 1, amplitude 1 Volt, pulse-width 90 microseconds, and frequency 130 Hz. Postoperatively he has had clinically significant improvement in tremor, gait and speech, and reports improved quality of life. Conclusions: Prelemniscal radiations present an alternative target for DBS in Holmes Tremor. Lower voltage threshold than expected was found. Benefit could be lower power consumption, longer battery life, and less frequent battery replacement. Disclosure: Dr. Foutz has nothing to disclose. Dr. Martinez has nothing to disclose. Dr. Hu has nothing to disclose. Dr. Ko has nothing to disclose.