Sleep microstructure and neurodegeneration as measured by [123I]β-CIT SPECT in treated patients with Parkinson's disease

Objectives Along with spindles, K-complexes are well known hallmarks of stage 2 (S2) sleep. However, little is known about their quantity in S2 sleep of patients with Parkinson's disease (PD). Setting Sleep laboratory, Department of Neurology, University of Vienna, Austria. Patients and methods Whole-night polysomnography (PSG) was performed in twelve treated PD patients and ten healthy controls without history of sleep complaints. The quantity of spontaneous K-complexes, K-alpha-complexes, and sleep spindles in one hour S2 sleep, distributed in four epochs of 15 minutes all through the night, were visually selected and analysed. The quantity and the temporal course of these phasic events were compared with the quantity in age-matched healthy controls. Nine of the twelve PD patients underwent [I-123]beta-CIT SPECT for calculating dopamine transporter binding in the striatum and serotonin transporter density in the thalamus-hypothalamus region. Results There was no difference between the quantity of K-complexes, K-alpha-complexes, and sleep spindles in PD patients and in the healthy control group. K-complexes but not sleep spindles decreased over the night in both groups. The number of sleep spindles did not correlate with the dopamine transporter binding in the striatum or the serotonin binding in the thalamic/hypothalamic region. Conclusion K-complexes and sleep spindles are not reduced and do not seem to be related to the degree of dopaminergic degeneration in treated PD patients.