Ires Ghielen

83 Longitudinal relationships between anxiety and motor symptoms homes, at the same time of day in the “on” [26] phase, approximately 1 hour after medication intake. Figure 1 represents the RESCUE trial study design in which the T1-T4 measurements represent the time points on which the outcome measures FoG, FoF, and anxiety were assessed. Figure 1. Timeline of the RESCUE trial with cross-over design. T1-T4 represent the moments on which outcome measures have been collected. Outcome measures The Freezing of Gait Questionnaire (FOGQ) is a validated questionnaire which assesses the FoG from a patient’s perspective [27, 28]. The FOGQ consists of six questions which refer to the patient’s experiences, related to FoG, in the previous week. Each question has a 5-point scale, where 0 represents an absence of symptoms and 4 represents the highest prevalence or severity of symptoms. Consequently, the total score on the FOGQ ranges from 0 to 24 points. The higher the score, the more pronounced the FoG. FoF was assessed with the Falls Efficacy Scale (FES) [29]. The FES is a questionnaire to assess an individual’s confidence and its self-efficacy to avoid a fall. The FES consists of 13 questions. Each question has an 11-point scale, where 0 represents an absence of confidence and 10 represents complete confidence during the mentioned activity. The inverse scale of the questionnaire was used, thus the higher the score the more FoF. For measuring anxiety symptoms, we used the Hospital Anxiety and Depression Scale (HADS), a valid and responsive tool for measuring anxiety and depressive symptoms in PD over the past four weeks [13, 30]. The HADS is a self-report questionnaire that consists of seven anxiety and seven mood items. The total score in each subscale ranges from 0 (absence) to 21 (maximum). We used the scores of the anxiety (HADSA) and mood (HADSD) subscales separately. The reliability of the HADSA, for use in PD, is good with a Cronbach’s alpha of 0.82 and an Intraclass Correlation Coefficient of 0.80 [30]. 5