Awake versus asleep deep brain stimulation targeting the caudal zona incerta for essential tremor.

To compare awake and asleep deep brain stimulation (DBS) surgery for Essential Tremor (ET), we conducted this retrospective cohort study of patients consecutively operated with DBS targeting the caudal Zona incerta (cZi). 37 underwent surgery awake and 55 asleep. Tremor before surgery and on/off stimulation one year after surgery were evaluated using the Essential Tremor Rating Scale (ETRS). Procedural time, electrode localization, stimulation parameters and adverse events were noted and compared. ETRS scores were similar at baseline between the groups except for contralateral arm tremor, which was slightly worse in the awake group. Total ETRS, contralateral arm tremor and activities of daily living scores showed no significant difference between the groups on-stimulation at one-year follow-up. Compared to the awake group, the asleep group had shorter procedural time and lower stimulation parameters. There were no intracranial haemorrhages nor surgery site-infections. Both groups showed a good improvement of tremor at one-year follow-up. Image-guided DBS surgery targeting the cZi enables safe and efficient asleep surgery for ET.