Background: Parkinson's disease (PD) is a chronic progressive neurodegenerative disease that results in functional loss and disability. People with PD have an increased risk of falling, and most of their falls occur while walking. As yet, there is limited knowledge concerning activity avoidance due to perceived risk of falling in people with PD. In order to quantitatively assess perceived walking difficulties, a psychometrically-sound instrument is necessary. Although the generic Walk-12 scale (the Walk-12G) seems promising, only one prior study has investigated its psychometric properties in people with PD. Moreover, little is known about factors that independently contribute to perceived walking difficulties in people with PD. No study has yet investigated the use and perceived needs of mobility devices (MDs) over a period of time in people with PD.
Aim: The overarching aim of this PhD thesis was to gain increased knowledge regarding activity avoidance due to perceived risk of falling, perceived walking difficulties, and the use and perceived needs of MDs in people with PD.
Methods: The thesis was based on a longitudinal cohort survey of participants with PD with a baseline data collection (n = 255), using self-administered and structured questions/questionnaires, observations and clinical assessments, and an equivalent 3-year follow-up (n = 165). Statistical analyses included bivariate analyses (Study I), psychometric evaluation (Study II), multivariate analyses (Study III), and descriptive- and follow-up analyses (Study IV).
Main results: Study I: Activity avoidance due to perceived risk of falling was reported by 30% of the non-fallers whereas the corresponding rate was 57% in recurrent fallers (i.e. ≥ 2 falls). Twenty-four percent of participants with an early/mild PD stage reported activity avoidance due to the perceived risk of falling which rose to 74% among those in the most severe stages. Moreover, it was reported by 51% of participants with near falls (but no falls). Seventy percent of participants with fear of falling reported that they avoided activities due to the perceived risk of falling. Study II: In the PD sample, the Walk-12G had acceptable missing item responses and floor/ceiling effects, and corrected item-total correlations > 0.60. Based on ordinal alpha and Cronbach’s alpha, values for internal consistency were > 0.95. External construct validity was satisfactory. Study III: The strongest contributing factor to perceived walking difficulties (assessed with the Walk-12G) was freezing of gait, followed by general self-efficacy, fatigue, PD duration, lower extremity function, orthostatic hypotension, bradykinesia and postural instability. Study IV: Over the 3-year period, MD use increased significantly from 22% to 40% for indoor use, and from 48% to 66% for outdoor use. The perceived need of MDs increased from 5% to 21% in people with PD.
Conclusion: Activity avoidance due to perceived risk of falling can be reported even when the person has mild PD. The findings imply that this aspect should not only be considered when the person has a history of falls, since a history of near falls appears also to be of importance. This thesis strengthens the recommendation for using the Walk-12G when assessing perceived walking difficulties in people with PD. It appears that freezing of gait and general self-efficacy should be the primary targets when addressing perceived walking difficulties in people with PD. The knowledge gained on the use and perceived needs of MDs over the 3-year period has implications for improving the provision and follow-ups of MDs, as well as for policy making, planning, and health services. However, the findings need to be replicated in other PD-samples as well as in different national contexts.