Respiratory muscle training and sleep-disordered breathing among individuals with spinal cord injury: A scoping review

CONTEXT: Scoping review. OBJECTIVE: To map the empirical literature evaluating respiratory muscle training (RMT) on objectively measured sleep-disordered breathing (SDB) outcomes in individuals with spinal cord injury (SCI). METHODS: Seven databases were searched for original empirical studies evaluating RMT and objective SDB outcomes among individuals with SCI. Additional searches were performed in Google Scholar and PEDro. Studies were independently double-screened at two consecutive levels, and relevant data from the included studies were extracted. A narrative synthesis of results was performed. RESULTS: Six studies met the inclusion criteria. Interventions included standalone inspiratory training, combined inspiratory and expiratory training, and "triple-combined" protocols involving additional oropharyngeal exercises. While case-based reports demonstrated clinically significant reductions in global SDB indices, larger experimental trials, such as exploratory and feasibility-oriented designs, found no significant between-group differences in objective SDB severity or nocturnal oxygenation. However, a randomized pilot trial suggested that combined RMT and oropharyngeal exercises could significantly reduce upper airway collapsibility. Equally, a prospective cohort study found that participants achieving gains in maximal inspiratory pressure showed modest improvements in nocturnal gas exchange. CONCLUSION: The assembled research suggests that RMT is insufficient as a standalone intervention for treating objective SDB outcomes in heterogeneous SCI cohorts. Given the sparse and methodologically heterogeneous evidence base, further standardized, high-quality longitudinal studies are required to determine the potential role of RMT in managing and treating SDB following SCI.