Weak detrusor contractility correlates with motor disorders in Parkinson's disease

Limited attention has been paid to the relationship between urinary symptoms or urodynamic findings and motor disorders in Parkinson's disease (PD). We aimed to correlate pressure-flow urodynamic parameters with video-gait analysis parameters in PD. We recruited 41 patients with PD (25 men and 16 women; age, 70.6 ± 8.5 years; H & Y motor grading: 2 [range, 1-3]; disease duration: 4 years [range, 1-7]; taking levodopa 300 mg/day [range, 100-400]). All patients underwent pressure-flow urodynamics (parameters: first sensation, bladder capacity, detrusor overactivity [noted in 24 patients], and Watts factor [WF]) and video-gait analysis (parameters: time and number of strides for 5-m gait [simple task] and time for timed up and go [complex task]). Statistical analysis was made by Mann-Whitney's U-test for analyzing the relation between detrusor overactivity and gait as well as Spearman's rank-correlation coefficient test for analyzing the relation between the remaining parameters and gait. We found no relation between filling-phase urodynamics (detrusor overactivity, first sensation, and bladder capacity) and video-gait analysis parameters. By contrast, we found a significant relation between voiding-phase urodynamics (WF, reflecting detrusor power) and all three video-gait analysis parameters (reflecting lower-half bradykinesia and loss of postural reflex) in our PD patients (P < 0.01). The close relation between the WF and motor disorders in the present study suggests that, though clinically mild, a weak detrusor in PD might have a central origin. We should follow postvoid residual volume carefully in PD patients with advanced gait disorder, because postvoid residual volume might increase in such patients.