Rehabilitation interventions for oropharyngeal dysphagia in people with Parkinson's disease.

rationaleOropharyngeal dysphagia is a common and disabling symptom in people with Parkinson's disease, affecting the safety and efficiency of swallowing and increasing the risk of malnutrition and aspiration pneumonia. Despite its clinical relevance, the effectiveness of rehabilitation interventions for managing dysphagia in this population remains uncertain.

objectivesTo assess the effectiveness of rehabilitation interventions for oropharyngeal dysphagia in improving swallowing safety and efficiency in people with Parkinson's disease. SEARCH

methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and Speech Pathology Database for Best Interventions and Treatment Efficacy up to 26 September 2025. We also searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform to retrieve ongoing and recently completed trials, and OpenGrey for grey literature. ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) of rehabilitation interventions aimed at improving oropharyngeal dysphagia in people with Parkinson's disease. We included any rehabilitation intervention for oropharyngeal dysphagia, alone or in combination with another rehabilitation intervention, with or without concurrent pharmacological treatments. Comparators included no intervention, usual care, a placebo/sham stimulation or attention control intervention, or any other rehabilitation intervention. OUTCOMES: Critical outcomes: swallowing safety and swallowing efficiency Important outcomes: dysphagia severity, saliva management, quality of life, respiratory outcomes, nutritional and dietary outcomes, and adverse events RISK OF BIAS: We assessed the risk of bias in the included studies using Cochrane's revised risk of bias (RoB 2) tool. SYNTHESIS

methodsWhen two or more studies were pooled, we conducted a random-effects meta-analysis to calculate standardised mean differences (SMDs) and 95% confidence intervals (CIs). When only one study was available, we used a fixed-effect model to estimate the effect, calculating mean differences (MDs) or odds ratios (ORs) with 95% CIs for all outcomes. We used the GRADE approach to assess the certainty of the evidence. INCLUDED STUDIES: We included 18 studies (1216 participants). Five studies were conducted in Europe, four in the USA, and nine in the rest of the world. Generally, studies were heterogeneous and often poorly reported. We included only two studies in the meta-analysis. Ten studies tested behavioural interventions, while eight studies tested one or more stimulation interventions: neuromuscular treatments (three studies), repetitive transcranial magnetic stimulation (two studies), deep brain stimulation (two studies), and transcranial direct current stimulation (one study). SYNTHESIS OF

resultsCompared to sham expiratory muscle strength training (EMST), EMST may improve swallowing safety at the end of four weeks of treatment (SMD -0.66, 95% CI -1.04 to -0.28; I² = 0%; 2 studies; 113 participants; very low-certainty evidence), but the evidence is very uncertain. Similarly, the evidence is very uncertain about the effect of EMST compared to sham EMST on all the following outcomes: swallowing safety after three months of follow-up (MD -0.18, 95% CI -0.69 to 0.33; 1 study, 45 participants); swallowing efficiency at the end of treatment (MD -4.4, 95% CI -7.5 to -1.3; 1 study, 45 participants), and after three months (MD -1.7, 95% CI -4.58 to 1.18; 1 study, 45 participants); dysphagia severity at the end of treatment (MD -2.78, 95% CI -18.04 to 12.48; 1 study; 45 participants) and after three months (MD -2.9, 95% CI -16.94 to 11.14; 1 study; 45 participants); quality of life at the end of treatment (MD 14.69, 95% CI -63.52 to 92.90; 1 study, 45 participants) and after three months (MD 11.4, 95% CI -67.95 to 90.75; 1 study, 45 participants). Lastly, EMST may result in little to no difference in peak expiratory flow after five weeks of treatment (MD -0.5 L/second, 95% CI -1.05 to 0.05; 1 study, 58 participants; low-certainty evidence). The evidence is very uncertain about the effect of video-assisted swallowing therapy (VAST) plus speech-language therapy (SLT) compared to SLT alone on all the following outcomes: quality of life at the end of treatment (MD 1.62, 95% CI 0.33 to 2.91; 1 study, 42 participants), and after six months (MD 1.86, 95% CI 0.82 to 2.9; 1 study, 42 participants); and dysphagia severity at the end of treatment (MD -0.7, 95% CI -5.13 to 3.73; 1 study, 42 participants) and in the long term (MD -4.03, 95% CI -7.85 to -0.21; 1 study, 42 participants). The evidence is very uncertain about the effect of neuromuscular electrical stimulation (NMES) plus SLT compared to sham NMES plus SLT on swallowing safety (MD -1.34, 95% CI -2.32 to -0.36; 1 study, 18 participants; very low-certainty evidence), and swallowing efficiency at the end of four weeks of treatment (MD -2.34, 95% CI -7.16 to 2.48; 1 study, 18 participants; very low-certainty evidence). The evidence is also very uncertain about the effect of tongue strength training plus SLT compared to SLT alone on dysphagia severity after eight weeks of treatment (MD 0.13, 95% CI -0.17 to 0.43; 1 study, 60 participants; very low-certainty evidence). Our certainty in these findings is very low due to imprecision (small sample size), high risk of bias related to deviations from intended interventions, measurement of the outcome, and the randomisation process, and poor reporting. AUTHORS'

conclusionsAlthough the number of RCTs has increased since the publication of a previous Cochrane review on the topic in 2001, uncertainty remains regarding the effectiveness of swallowing rehabilitation in individuals with Parkinson's disease. Behavioural interventions, particularly EMST, may improve swallowing safety by reducing penetration and aspiration, but the evidence is very uncertain. Most included studies were small and methodologically limited, constraining the robustness of conclusions. Large, well-designed, placebo-controlled trials are required to assess the effectiveness of rehabilitation interventions for oropharyngeal dysphagia in people with Parkinson's disease.

fundingNo funding was received for this work. REGISTRATION: Protocol (2024) DOI: 10.1002/14651858.CD015816.