Variability in spatiotemporal gait characteristics over the course of the L-dopa cycle in people with advanced Parkinson disease .
OBJECTIVE
Understanding the nature and extent of fluctuations in spatial and temporal variables of gait (eg, speed, stride length [SL], stride time [ST]) over the course of the levodopa (L-dopa) cycle of individuals with advanced Parkinson disease (PD) is important in order to assess patients and examine the effectiveness of interventions. The purpose of this study was to determine whether gait variables are sufficiently stable to be used as outcome measures in a clinical trial involving patients with advanced PD.


METHODS
Five volunteers (3 male, 2 female; mean age=67.8 years; Hoehn and Yahr stages 3-4) with idiopathic PD of a mean duration of 15.0 years participated.


METHODS
Gait speed, SL, and ST were measured as the subjects walked 7.2 m at self-selected speeds. To evaluate the full "on-off" sequence of the L-dopa response, this analysis was repeated 11 times, at intervals of 10% of the L-dopa cycle. Each subject was analyzed on 3 separate days, with approximately 1 month between tests. Two-way repeated-measures analyses of covariance, with 2 within-subject factors (percentage of L-dopa cycle and day) and 1 covariate (height), were applied, and coefficients of variation were calculated to determine the extent of change in speed, SL, and ST over the L-dopa cycle and over the 3 days.


RESULTS
The subjects' overall mean gait speed was 70.39 cm/s, representing 55.4% of the age-related normative values. There were no effects of percentage of the L-dopa cycle or day or of the interaction of percentage of the L-dopa cycle and day on speed, SL, and ST. The coefficients of variation for speed and SL were consistently higher than the normative values, ranging from 13.5% to 23.8% and from 13.9% to 23.3% at 20% of the L-dopa cycle, respectively.


CONCLUSIONS
When interpreting spatiotemporal measurements of gait of patients with advanced PD, fluctuations can be extensive and may not follow a predictable pattern.
School of Physiotherapy, Dalhousie University, Halifax, Nova Scotia, Canada. mmackay@is.dal.ca
M
M
MacKay-Lyons
D000368:Aged; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D005684:Gait / Q000187:drug effects*; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology*; D015203:Reproducibility of Results; D013037:Spatial Behavior / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome
D000978:Antiparkinson Agents; D007980:Levodopa