Effect of Neuromuscular Electrical Stimulation of Rectus Abdominis and Transversus Abdominis on the Respiratory Parameters in Stroke Survivors: A Randomised Controlled Trial

Introduction: Stroke is a major cause of long-term disability and is frequently associated with respiratory muscle weakness, leading to reduced pulmonary function and functional dependence. Weakness of abdominal muscles such as the rectus abdominis and transversus abdominis contributes significantly to impaired ventilation and ineffective coughing. Neuromuscular Electrical Stimulation (NMES) has been proposed as an adjunct intervention to enhance muscle activation and respiratory performance; however, evidence targeting abdominal muscles in stroke survivors remains limited. Aim: To evaluate the effectiveness of NMES applied to the rectus abdominis and transversus abdominis muscles on chest expansion, respiratory parameters, and functional independence in individuals recovering from stroke. Materials and Methods: The present single-blinded, parallelgroup, Randomised Controlled Trial (RCT) was conducted at the Department of Medicine in KS Hegde Charitable Hospital, NITTE (Deemed to be university), Mangaluru, Karnataka, India, from October 2024 to February 2025 on 34 post-stroke participants who were randomly allocated into a control group (Group A) (conventional physiotherapy) and an experimental group (Group B) (NMES combined with conventional physiotherapy). NMES was administered for 20 minutes per day for five consecutive days. Outcome measures included upper and lower chest expansion, chest symmetry using the Palpation Meter (PALM) device, pulmonary function parameters {Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1)/FVC ratio, and Peak Expiratory Flow (PEF)}, and functional independence assessed using the Barthel Index (BI). Data were analysed using descriptive statistics, paired and independent sample t-tests, and the Chi-square test, with the level of significance set at p<0.05. Results: Both groups demonstrated significant within-group improvements in chest expansion, pulmonary function, and functional independence (p<0.05). Between-group analysis revealed a statistically significant improvement in functional independence favouring the NMES group (p=0.022). Although improvements in chest expansion and spirometric parameters were greater in the NMES group, these differences were not statistically significant. Conclusion: NMES applied to the rectus abdominis and transversus abdominis muscles serves as an effective adjunct to conventional physiotherapy in improving respiratory function and functional independence in stroke survivors. However, no significant changes were observed in FVC and the FEV1 /FVC ratio.