Gait and balance in Parkinson's disease : psychometric properties and effects of training

Abstract

Aim: The overarching aims of this thesis were to: evaluate the psychometric properties of a new clinical balance tool in People with Parkinson’s disease (PwPD) with mild to moderate disease severity; as well as to investigate the effects of a new gait and balance training regime, developed to target specific symptoms commonly observed in this population.

Methods: Paper one entailed the evaluation of a balance tool’s (the Mini-BESTest) reproducibility in a clinical context, when used in PwPD. In order to investigate how the reproducibility was affected by different administrators, 27 PwPD performed the Mini- BESTest with two physiotherapists who administered the test separately. In order to evaluate how the reproducibility was affected between test occasions, the participants returned 7 days later to be reassessed by one of the physiotherapists. Paper two entailed the evaluation of the Mini-BESTest’s validity by means of hypotheses testing, which included, for example, the test’s ability to distinguish between PwPD and healthy controls; and between PwPD with mild and moderate severity. A total of 105 PwPD and 47 healthy controls participated in this evaluation. Papers III & IV evaluated, in form of a randomised controlled trial (RCT), if participation in 10-weeks of symptom-specific and challenging training affected gait and balance abilities, fall related concerns, physical activity and activities of daily living (ADL). In addition, the training effects on the abilities to walk while simultaneously performing an added task were also specifically addressed. One-hundred PwPD were recruited to this study and were randomised to either the training or control group (care as usual).

Results: The reliability of the Mini-BESTest was found to be good. However the measurement error on individual level was considered high, reflecting more than 10 percent of the total score. When the agreement is related to a group level (in this case, 91 individuals), the measurement error only reflected 2 percent of the total score. Moreover, the Mini- BESTest was able to adequately distinguish between PwPD and healthy controls, as well as between PwPD with mild and moderate disease severity, respectively. The findings from the RCT showed that the participants in the training group, when compared to the control group, improved balance, gait, ADL and showed tendencies towards increased physical activity, whereas fall related concerns were unaffected. During gait with an added task, the performance of the added task was improved while the gait remained unaffected.

Conclusions: The psychometric properties of the Mini-BESTest make it appropriate for research purposes. Although the measurement error on individual level is considered large, the clinical value of the test is considered to exceed its flaws. Specific and challenging training can improve gait and balance abilities amongst PwPD, effects that might influence improved physical activity. Future research should investigate the importance of the added cognitive task when performed during gait.