DEEP BRAIN STIMULATION-DEPENDENT MODULATION OF SLEEP-WAKE BALANCE IN A 6-OHDA RAT MODEL OF PARKINSON’S DISEASE

Sleep disturbances are a prominent non-motor feature of Parkinson’s disease (PD) and the effects of subthalamic nucleus deep brain stimulation (STN-DBS), an established symptomatic treatment, on sleep-wake organisation remain incompletely understood. The aim of this study was to develop an automated pipeline for sleep-wake classification based on limited physiological markers to be used alongside classic motor symptom quantification and to apply this approach to investigate the impact of STN-DBS on sleep-wake patterns and organisation in a unilateral 6-hydroxydopamine (6-OHDA) rat model of PD. Cortical electrophysiological signals alongside inertial movement data from accelerometer and gyroscope were recorded for one hour in 6-OHDA(N=7) and sham animals(N=6) under stimulation ON and OFF conditions during the lights-on phase. Sleep-wake states were extracted for 10-second epochs using spectral features of cortical activity and motion-derived indices. Wake periods were identified using normalised motion, rapid eye movement (REM) sleep was defined by low motion and elevated theta-to-delta power ratios, and non-rapid eye movement (NREM) substages (N1, N2, N3) were classified relative to each animal’s delta activity. 6-OHDA animals exhibited increased wakefulness and reduced total sleep time compared with controls. DBS increased sleep duration and reduced wake time in 6-OHDA animals. In contrast, the relative distribution of sleep stages within total sleep time remained largely preserved across conditions. Visualisation using hypnograms supported these findings by revealing changes in sleep continuity rather than major reorganisation of sleep-stage structure. These results demonstrate that short-term sleep analysis can capture Parkinsonian alterations in sleep-wake balance and their modulation by stimulation.