Bilateral thalamic stimulation induces insomnia in patients treated for intractable tremor.

STUDY OBJECTIVES: To explore the influence of acute bilateral ventral intermediate thalamic nucleus (VIM) stimulation on sleep. DESIGN: Three consecutive full-night polysomnography recordings were made in the laboratory. After the habituation night, a random order for night ON-stim and OFF-stim was applied for the second and third nights. SETTING: Sleep disorders unit of a university hospital. PATIENTS: Eleven patients with bilateral stimulation of the ventral intermediate nucleus of the thalamus (VIM) for drug-resistant tremor. MEASUREMENTS: Sleep measures on polysomnography. RESULTS: Total sleep time was reduced during night ON-stim compared to OFF- stim, as well as rapid eye movement sleep percentage while the percentage of N2 increased. Wakefulness after sleep onset time was increased. CONCLUSION: Our results show that bilateral stimulation of the VIM nuclei reduces sleep and could be associated with insomnia.