Respiratory dysfunction in Parkinson's disease.

Respiratory dysfunction has been associated with Parkinson's disease since it was first described in 1817. The respiratory symptoms observed in Parkinson's disease patients vary greatly. Most patients remain asymptomatic, whereas others present with acute shortness of breath and even stridor. In August 2016, an electronic literature search was conducted using PubMed and Google Scholar. Results were screened and studies reporting on respiratory dysfunction associated with Parkinson's disease were included. Respiratory dysfunction is due to a combination of factors including restrictive changes, upper airway obstruction, abnormal ventilatory drive and response to medications. Much debate surrounds the mechanism underlying respiratory dysfunction in Parkinson's disease, its prevalence and the effect of levodopa on respiration. It is clear from this review that larger studies, comparing patients of similar disease duration and severity using the same pulmonary function parameters, are required to provide a better understanding of the pathophysiology underlying respiratory dysfunction in Parkinson's disease.