Background: Among neurodegenerative diseases, multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) have a high rate of respiratory disability.

Objective: To analyze the effects of respiratory muscle training (RMT) on ventilatory function, muscle strength and functional capacity in patients with MS or ALS.

Methods: A systematic review and meta-analysis of randomized controlled trials (RCTs) was performed. The sources were MEDLINE, PEDro, Cochrane CENTRAL, EMBASE, and LILACS, from inception to January 2015. The following were included: RCTs of patients with neurodegenerative diseases (MS or lateral ALS) who used the intervention as RMT (inspiratory/expiratory), comparison with controls who had not received RMT full time or were receiving training without load, and evaluations of ventilatory function (forced vital capacity - FVC, forced expiratory volume in one second - FEV1, maximum voluntary ventilation - MVV), respiratory muscle strength (maximal expiratory pressure/maximum inspiratory pressure - MEP/MIP) and functional capacity (6-minute walk test - 6MWT).

Results: The review included nine papers, and a total of 194 patients. It was observed that RMT significantly increased at MIP (23.50cmH2O; 95% CI: 7.82 to 39.19), MEP (12.03cmH2O; 95% CI: 5.50 to 18.57) and FEV1 (0.27L; 95% CI: 0.12 to 0.42) compared to the control group, but did not differ in FVC (0.48L; 95% CI: -0.15 to 1.10) and distance in 6MWT (17.95m; 95% CI: -4.54 to 40.44).

Conclusions: RMT can be an adjunctive therapy in the rehabilitation of neurodegenerative diseases improving ventilatory function and respiratory strength.