Improved oxygen saturation after deep brain stimulation in Parkinson's disease

Respiratory dysfunction is an underrecognized non-motor symptom in Parkinson's disease (PD), contributing significantly to morbidity and mortality. Prior studies have described restrictive ventilatory patterns, impaired cough, and reduced respiratory muscle strength in PD. While dopaminergic therapies have shown variable effects, the impact of deep brain stimulation (DBS) on oxygenation remains unclear. This study aimed to evaluate the long-term effects of bilateral subthalamic nucleus (STN)-DBS on peripheral oxygen saturation (SpO₂) in PD patients. In this retrospective, single-center study, 66 patients with idiopathic PD who underwent bilateral STN-DBS implantation were analyzed. Patients with pulmonary disease, cardiac failure, or active infection were excluded. SpO₂ was measured at rest in room air during pre-anesthesia evaluation before DBS surgery and again at the time of internal pulse generator (IPG) replacement after a mean follow-up of 4.3 ± 0.9 years. Paired-sample t-tests were used to compare pre- and postoperative values, and subgroup analyses were conducted by motor phenotype. Mean preoperative SpO₂ was 92.7 ± 1.2% (range: 90-95), and postoperative values at IPG replacement were higher (98.4 ± 0.9%, range: 96-100; p < 0.001), indicating an association between STN-DBS and long-term improvement in SpO₂. Resting SpO₂ increased by an average of + 5.6% (95% CI 5.1-6.0; p < 0.001) following STN-DBS compared with the preoperative off-medication state. Bilateral STN-DBS was associated with a significant long-term improvement in resting oxygen saturation in PD patients, suggesting a potential beneficial effect on respiratory function beyond established motor outcomes. These findings support the hypothesis that neuromodulation may positively influence non-motor manifestations such as subclinical respiratory dysfunction. Prospective studies with comprehensive pulmonary function testing are warranted to confirm these results and explore underlying mechanisms.