Parkinson's disease home diary: further validation and implications for clinical trials

Abstract

We provide further validation of a Parkinson's disease (PD) home diary and explore implications for practical use in clinical trials. We previously developed and published a home PD diary that includes the categories ASLEEP, off, on without dyskinesia, on with nontroublesome dyskinesia, and on with troublesome dyskinesia [Hauser et al., J Clin Neuropharmacol 2000;23:75-81] and demonstrated that patients generally consider off time and on time with troublesome dyskinesia "bad time" and on time without dyskinesia or with nontroublesome dyskinesia "good time". We suggested that that on time without dyskinesia or with nontroublesome dyskinesia would be an appropriate outcome measure in clinical trials of advanced PD patients. In the current study, PD patients with motor fluctuations and dyskinesia (present more than 25% of the awake day and at least moderately disabling) completed daily diaries on 3 consecutive days in each of 2 consecutive weeks. In addition, patients provided responses to five questions regarding dyskinesia and their motor response through the day on visual analog scales (VAS). Three hundred two patients from 10 countries participated. Eighty-three percent (n = 252) completed six diaries without missing or duplicate entries. Seventy-six percent of the missing or duplicate entries occurred after Day 3. Mean percent of the awake day on without dyskinesia or with nontroublesome dyskinesia ("good on", ONG%) was observed to be very stable over time (repeated measure analysis of variance, P = 0.99). Coefficients of reliability as calculated by Cronbach's alpha were as follows: 2 days, r = 0.806; 3 days, r = 0.868; 4 days, r = 0.918; 5 days, r = 0.934; 6 days, r = 0.946. The standard error of measurement (SEM) was calculated to be 10.75%. VAS responses to the question, "How much of the day today did you experience a good response?" more strongly correlated with ONG% (0.41) than ON% (0.24). The diary appears to be sufficiently simple and feasible. Test-retest reliability was good, and reliability increased with increasing number of diary days but compliance diminished beyond 3 days. Good on time (ONG = on time without dyskinesia or with nontroublesome dyskinesia) most strongly correlated with patients' perceived duration of a good response through the day and is an important outcome variable.