Objective: The aim of this study was to examine the effects of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) on sleep disturbances (SD) in patients with advanced Parkinson Disease (PD) treated at the University Hospital “St. Marina” in Varna, Bulgaria.

Background: PD patients present a variety of non-motor symptoms (NMS) including sleep disturbances which significantly decrease patient’s Quality of Life. STN-DBS is proven highly effective for motor symptoms in advanced PD, but the effects of DBS on the NMS and SD are still uncertain.

Method: Twenty-six individuals (18 male and 8 female) at mean age of 61.6 ± 8.0 were included in this prospective longitudinal study. The participants’ SD were assessed using the Parkinson’s Disease Sleep Scale (PDSS) before the DBS surgery and at 3, 6, 12, 24, 36 and 48 months following the initial bilateral STN neuromodulation.

Results: Compared to the pre-DBS state, the total PDSS score and all subscales showed a significant improvement throughout the short-term follow up during and up to the first year post-DBS (p<0.05). After this period most of the subscales presented with subsequent progressive deterioration suggesting a time-dependent DBS effects and progression of the disease over time (Table 1). The PDSS total score, and nocturia, had a similar pattern over time with initial significant improvement during the first 2 years after surgery, with secondary worsening (Figure 1). Nocturnal restlessness had very prominent improvement during the short-term follow-up (Figure 2). Sleep quality, nocturnal motor symptoms and daytime somnolence subscales were improved in lesser extend and for shorter period- during the first year post-DBS (p<0.05). The nocturnal psychosis subscale presented with high heterogeneity of the self-reported scores. DBS treatment did not lead to an improvement in nocturnal psychosis, while there was a trend for continuous deterioration more pronounced 3 years after DBS (Figure 3).

Conclusion: Bilateral STN-DBS has a significant beneficial effect on SD in the early post-operative stages. Improvement of sleep symptoms might be mediated by improvement of the motor symptoms or due to direct modulation of the basal ganglia-thalamo-cortico loops or spread of current to the surrounding nuclei. The subsequent deterioration after 24 months highlights the need of continues medical observation of these patients and individualized approach.

Table 1. Dynamics in the mean PDSS scores.

Figure 1: PDSS Total Score dynamics.

Figure 2: Nocturnal restlessness score dynamics.

Figure 3: Nocturnal psychosis score dynamics.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/effects-of-deep-brain-stimulation-on-sleep-disturbances-in-parkinsons-disease-a-4-year-follow-up-study/