Breathing and locomotion in patients with Parkinson's disease

The phase relationship between respiration and locomotion was examined in ten patients with Parkinson's disease (PD, mean age 65, range 51-79 years) and in six healthy subjects (mean age 63, range 58-68 years). Locomotion was measured by means of pressure sensors attached below the subjects' feet. Respiration was measured using respiratory inductive plethysmography. The data were recorded with a battery-driven portable device. We determined the coordination degree as the portion of steps which occurred within 12/50 bins of the respiratory cycle. The mean degree of coordination of PD patients was 45.0%+/-11.9%, for the healthy subjects 85.1%+/-10.8% (P<0.001). Three healthy subjects showed a 2:1 ratio between step and breathing rate, three a 3:2 ratio. Two PD patients showed a coordination of 4:1 and 3:1, respectively, with a larger scatter than in controls. In the other eight patients steps were almost equally distributed over the entire respiratory cycle. We conclude that in patients with PD the coordination between locomotion and breathing is reduced.