Inspiratory muscle training and the perception of dyspnea in Parkinson's disease.
BACKGROUND: Pulmonary and respiratory muscle function impairment are common in patients with Parkinson's disease (PD). Inspiratory muscle training may improve strength, dyspnea and functional capacity in healthy subjects and in those with chronic obstructive pulmonary disease. This study investigated the effect of specific inspiratory muscle training (SIMT) on pulmonary functions, inspiratory muscle performance, dyspnea and quality of life, in patients with PD. PATIENTS AND METHODS: Twenty patients with PD (stage II and III Hoehn and Yahr scale) were recruited for the study and were divided into two groups: (a) ten patients who received SIMT and (b) ten patients who received sham training, for three months. Pulmonary functions, the respiratory muscle strength and endurance, the perception of dyspnea (POD) and the quality of life were studied before and within one week after the training period. All subjects trained daily, six times a week, each session consisting of 1/2 hour, for 12 weeks. RESULTS: Following the training period, there was a significant improvement, in the training group but not in the control group, in the following parameters: inspiratory muscle strength, (PImax, increased from 62.0 +/- 8.2 to 78.0 +/- 7.5 cm of H2O (p < 0.05), inspiratory muscle endurance (increased from 20.0 +/- 2.8 to 29.0 +/- 3.0 cm of H2O (p < 0.05), and the POD (decreased from 17.9 +/- 3.2 to 14.0 +/- 2.4 units (p < 0.05). There was a close correlation between the increase in the inspiratory muscle performance and the decrease in the POD. CONCLUSIONS: The inspiratory muscle performance may be improved by SIMT in patients with PD. This improvement is associated with a significant decrease in their POD.