The effects of respiratory muscle training on peak cough flow in patients with Parkinson's disease: a randomized controlled study.

OBJECTIVE

To compare the effects of an inspiratory versus and expiratory muscle-training program on voluntary and reflex peak cough flow in patients with Parkinson disease.

DESIGN

A randomized controlled study.

SETTING

Home-based training program.

PARTICIPANTS

In all, 40 participants with diagnosis of Parkinson's disease were initially recruited in the study and randomly allocated to three study groups. Of them, 31 participants completed the study protocol (control group, n = 10; inspiratory training group, n = 11; and expiratory training group, n = 10) Intervention: The inspiratory and expiratory group performed a home-based inspiratory and expiratory muscle-training program, respectively (five sets of five repetitions). Both groups trained six times a week for two months using a progressively increased resistance. The control group performed expiratory muscle training using the same protocol and a fixed resistance.

MAIN MEASURES

Spirometric indices, maximum inspiratory pressure, maximum expiratory pressure, and peak cough flow during voluntary and reflex cough were assessed before and at two months after training.

RESULTS

The magnitude of increase in maximum expiratory pressure ( d = 1.40) and voluntary peak cough flow ( d = 0.89) was greater for the expiratory muscle-training group in comparison to the control group. Reflex peak cough flow had a moderate effect ( d = 0.27) in the expiratory group in comparison to the control group. Slow vital capacity ( d = 0.13) and forced vital capacity ( d = 0.02) had trivial effects in the expiratory versus the control group.

CONCLUSIONS

Two months of expiratory muscle-training program was more beneficial than inspiratory muscle-training program for improving maximum expiratory pressure and voluntary peak cough flow in patients with Parkinson's disease.