Opposite effects of low and high frequency deep brain stimulation of lateral hypothalamus on arousal and temperature in a monkey pilot study.

Deep brain stimulation is a well-established treatment for improving motor symptoms in Parkinson's disease. However, persistent non-motor symptoms, such as excessive daytime sleepiness, remain a significant challenge and necessitate further investigation. In this study, we conducted repeated measurements of daytime sleepiness using a modified multiple sleep latency test in a healthy monkey (macaca fascicularis), which was later rendered parkinsonian through MPTP administration. Deep brain stimulation targeting the lateral hypothalamic area revealed frequency-dependent modulation of both sleepiness level and core body temperature. High-frequency stimulation (80 Hz) increased sleepiness in the healthy state, while low-frequency stimulation (20 Hz) promoted wakefulness in the parkinsonian state. These findings suggest a promising therapeutic approach for addressing sleep/wake disturbances, not only in Parkinson's disease but also in other severe sleep disorders.