Development and Validation of a Fall Questionnaire for Patients with Parkinson's Disease

Background In Parkinson's disease, postural instability and falls are of particular socioeconomic relevance. Although effective fall prevention and the prophylaxis of fall-related injuries depend on low-threshold symptom monitoring, validated instruments are lacking. Objectives To develop a self-report questionnaire for the assessment of falls, near falls, fear of falling, fall-related injuries, and causes of falls for patients with Parkinson's disease (PwPD). Methods A pool of potential items was generated from a literature review and by discussion in an expert panel. The first version of the Dresden Fall Questionnaire (DREFAQ) was tested in a group of German-speaking movement disorder specialists as well as PwPD. The resulting 5-item questionnaire was assessed in a validation cohort of 36 PwPD who documented fall events and near-fall events in a calendar for 3 months and completed the DREFAQ at the end of the study. The questionnaire was subsequently used in a separate cohort of 46 PwPD to determine test-retest reliability and confirm the factor structure. Results The DREFAQ showed good internal consistency (Cronbach's alpha = 0.84) and good test-retest reliability (intraclass correlation coefficient, 0.76; 95% confidence interval, 0.60-0.86). The total DREFAQ score showed good concurrent validity with fall events (Spearman's rho = 0.82) and near-fall events (Spearman's rho = 0.78) as determined by fall and near-fall diaries. Factor analysis revealed a 2-factor structure composed of near falls with fear of falling and severe falls with injuries. Conclusions The DREFAQ is a reliable and valid 5-item questionnaire for determining the incidence of falls, near falls, fear of falling, fall-related injuries, and causes of falls in PwPD.