RecruitingDevice studyCircadian Adaptive DBS in Essential TremorDeep brain stimulation (DBS) of the thalamus is an effective treatment for medically refractory essential tremor (ET). DBS involves delivering continuous stimulation to the brain through electrodes permanently implanted in the thalamus. Despite proven effectiveness, the long-term benefit of DBS can wane over time (habituation) and side effects, including paresthesia and dysarthria, often limit the amplitude of the stimulation, resulting in suboptimal control of tremor. In clinical practice, many groups advise patients to switch their devices off at night to avoid habituation and reduce side effects. However, manually turning off the device at night can result in uncontrolled tremor when the patient moves at night. This study aims to develop an algorithm that automatically turns off stimulation when a patient is asleep, based on circadian brain signals. Turning off stimulation could potentially improve the therapy by limiting adverse effects, increasing efficacy, reducing the risk of habituation, and prolonging battery life. This study will evaluate the feasibility, safety, and tolerability of circadian adaptive DBS.