Reversibility of upper airway obstruction after levodopa therapy in Parkinson's disease.

Serial flow-volume loops obtained in a 66-year-old patient with Parkinson's disease and recurrent episodes of dyspnea revealed a pattern consistent with upper airway obstruction, reversible after oral intake of levodopa. This observation shows that extrapyramidal involvement of the striated upper airway musculature may limit airflow and cause respiratory symptoms. Persistence of flow oscillations on the flow-volume loop contour after reversal of upper airway obstruction and dyspnea should be considered to reflect upper airway dysfunction with possibly serious consequences.