Effects of focal low energy extracorporeal shock wave treatment on reduction of sialorrhea in Parkinson’s disease

Introduction Sialorrhea is a frequent and disabling non-motor symptom in Parkinson’s disease (PD) and atypical parkinsonian syndromes, often exerting a serious impact on patients’ health and quality of life (QoL). Botulinum toxin injections into the major salivary glands, which reduce salivary secretion, represent an established and effective therapy. However, even with adequate operator training and ultrasound guidance, transient dysphagia may occur. Low-energy extracorporeal shock wave therapy (ESWT) is a noninvasive neuromodulatory technique that has shown anticholinergic-like and antispastic effects in neurological disorders. Aims To evaluate the effects of low-energy ESWT applied to the salivary glands as a potential treatment for sialorrhea in patients with PD or atypical parkinsonian syndromes. Methods In this pilot observational study, 12 patients with advanced PD or atypical parkinsonism and clinically significant sialorrhea (UPDRS-II item 2 ≥ 2) underwent two weekly sessions of bilateral focal ESWT (750 impulses per gland, 0.1–0.3 mJ/mm 2 , 5 Hz) under ultrasound guidance. Clinical assessments were performed at baseline and at 1st, 4th, 8th, and 12th week post-treatment using the Drooling Frequency and Severity Scale (DSFS, primary endpoint), Nocturnal Hypersalivation Rating Scale (NHRS), Sialorrhea Clinical Scale for PD (SCS-PD), Drooling Impact Score (DIS), and both Clinical and Patient Global Impression of Change (CGI-C, PGI-C). Results A statistically significant improvement was observed across all scales at week 4 post-treatment, with more sustained effects on DSFS and SCS-PD. Improvements were evident as early as week 1 and persisted up to week 8 for SCS-PD. DIS scores significantly decreased from baseline to week 4 ( p = 0.005). Subjective improvement was reported by 75% of patients (PGI-C) and confirmed by clinicians in 83.3% (CGI-C). No adverse effects, pain, or dysphagia were reported. Conclusion Focal low-energy ESWT demonstrated efficacy in reducing sialorrhea in patients with advanced PD and atypical parkinsonism. These preliminary findings suggest a novel, well-tolerated, and noninvasive treatment approach that may improve QoL and serve as a potential alternative or adjunct to botulinum toxin therapy.