Effects of Neuromuscular Electrical Stimulation in Patients with Post-Stroke Related Dysarthria: A Double-Blinded, Phase-II Randomized Sham-Controlled Trial Protocol - ULYSSES Trial

Introduction: Post-stroke individuals with dysarthria experience difficulties in producing speech due to muscle dysfunction. Neuromuscular electrical stimulation (NMES) can stimulate motor units and enhance their functionality. The objective of this study is to investigate the effects of NMES on speech intelligibility in patients with persistent dysarthria 3-6 months post-ischemic stroke. Methods: This study will be designed as a phase II, double-blinded, randomized, two-arm, parallel-group, superiority trial conducted at a single center. The target population will consist of post-stroke individuals with dysarthria, who will undergo randomization to receive either neuromuscular electrical stimulation (NMES) or sham-NMES. Both intervention groups will receive treatment sessions 5 days a week over a 4-week period. The sample size for this study will be 154 patients, recruited exclusively from a Rehabilitation Unit located in the United States. The primary outcome measure will focus on determining the mean difference in the FDA-2 intelligibility score between the two treatment groups. Secondary outcomes will involve evaluating the mean difference in the full FDA-2 score, as well as various subsets of the score, alongside an assessment of the participants’ health-related quality of life, utilizing the Stroke Impact Scale (SIS). Conclusion: To the best of our knowledge, this will be a comprehensive assessment of the potential benefits of NMES for post- stroke patients with dysarthria. Considering the positive impact of NMES on enhancing muscle functionality, it is plausible to anticipate its potential benefits in improving speech outcomes as well. Despite early studies indicating the safety and tolerability of NMES for various motor muscle conditions, there is limited data on its use in patients with dysarthria.