Pulmonary functions in Parkinson's disease.

Background: Parkinson's disease (PD) is a common disabling and progressive neuro-degenerative disorder. Morbidity and mortality are frequently associated with pulmonary dysfunction in patients with PD.
Aim: To investigate characteristics of pulmonary function test (PFT) abnormalities in patients with PD and to study the effect of levodopa on the PFT findings.
Methods: Pulmonary function testing was performed in 35 patients with PD during 'off' and 'on' state while on levodopa; and 35 matched healthy controls.
Results: The forced vital capacity (FVC) (P < 0.001), maximum voluntary ventilation (MVV) (p < 0.001), maximum expiratory pressure (MEP) (p < 0.001), and maximum inspiratory pressure (MIP) (p < 0.001) were significantly reduced in patients with PD compared to controls. There was significant improvement in the PFT values in 'on' state compared to 'off' state.
Conclusions: A restrictive pattern of pulmonary dysfunction is present in patients with PD, which improves significantly with levodopa. The evaluation and rehabilitation of respiratory disturbances should be routinely included in the management of patients with Parkinson's disease.