An exploratory study of the consistency of balance control and the mobility of people with Parkinson's disease (PD) between medication doses

Abstract

Objective: To evaluate the consistency of balance control, mobility and perceived difficulties with functional tasks by people on carefully controlled anti-parkinsonian medication programmes, between doses on a single day and across days using standard clinical measures. Design: Small group prospective study. Setting: A hospital outpatient physiotherapy department. Subjects: Subjects, recruited from a specialist Parkinson's disease (PD) clinic, had to be independently mobile, diagnosed with PD at least five years previously and on a stable drug regime. Method: Assessments (timed up and go, functional reach and a tap test) were completed 30 minutes prior to medication and hourly for 4 hours. They were repeated on a second day within a seven-day period. The self- assessment of functional disability was completed during the worst and best periods of the drug cycle. A general linear model (repeated measures analysis of variance) was used to analyse the data. Results: Nine subjects (8 males) with PD (grade III Hoehn and Yahr, average duration of symptoms eight years), average age 72 years, were recruited to the study. Four subjects had worse Hoehn and Yahr scores (grade 4) during the worst phase of the L-dopa cycle. Balance and mobility data did not change significantly over the medication cycle. Tests on day 2 were similar to day 1 with only the tap test showing a significant mean difference ( p = 0.02) (2.6, 95% confidence interval (CI) 0.5–4.8). Individuals perceived significantly greater difficulty (mean difference = 7.9, 95% CI 3.6–12.2) ( p < 0.001) in achieving functional tasks at the end of dose than peak dose of the medication cycle. Conclusion: Measures of balance and mobility remained stable over the cycle. Fluctuations in the perception of difficulties with daily functional tasks were not accompanied by observed fluctuations in performance. The improvement in the mean of the tap test over the days could reflect a learning effect.