94 Chapter 6 observed differences in stability measures at comfortable gait speed cannot merely be explained by speed differences, but (at least partly) reflect true differences in gait stability. Interestingly, our data show that balance confidence (as measured with the ABC6), had the best potential to discriminate between fallers and non-fallers with HSP. Previous studies also reported that ABC or ABC-6 is able to differentiate fallers from non-fallers in people with multiple sclerosis (AUC: 0.92) 5, Parkinson’s disease (AUC: 0.73) 39, stroke (AUC: 0.78) 40, and dystonia (AUC: 0.72) 41. Our data additionally show that balance capacity as assessed with the Mini-BEST may be a good objective clinical test for fall risk assessment in people with HSP. It’s ability to discriminate fallers from non-fallers has previously been reported in people with Parkinson’s disease (AUC: 0.75-0.86) 6, 42, 43, myotonic dystrophy (AUC: 0.83) 44, and in the elderly (AUC: 0.72-0.80). 45, 46 In contrast to the discriminatory ability of the ABC-6 and the MiniBEST, we did not find similar evidence for any of the gait capacity or biomechanical measures. This is in contrast to recent studies that reported increased LDEs when comparing fallers and non-fallers in the elderly47, 48 and in people with multiple sclerosis. 10, 11 The question remains why the biomechanical measures were unable to discriminate between fallers and non-fallers in HSP. In order not to fall, people have to be able to recover from both small perturbations that occur during every step (e.g. resulting from heel strike), and larger perturbations (e.g. when tripping over an obstacle). 8 In the current study, the biomechanical measures were derived from unperturbed treadmill walking. Therefore, the biomechanical measures primarily reflect the ability to recover from small perturbations. 8 In contrast, the Mini-BEST includes tasks that impose greater challenges to both proactive and reactive balance control. These perturbations are more representative of those encountered in daily life, and as such, more representative of those resulting in falls. This difference may partly explain the higher discriminatory ability of the Mini-BEST compared to the treadmill-based biomechanical measures of gait stability in this study. Therefore, future studies could explore whether biomechanical measures have the ability to capture individual deficits contributing to falls when derived from daily life walking. Apart from the biomechanical considerations above, our study has some methodological limitations. Participants with HSP logged their falls using a fall diary prior to the assessment. 16 As a result, fallers answered the questions of the ABC-6 after they had experienced a fall, which may have affected their confidence. Future research could evaluate the predictive validity of ABC-6 for fall risk assessment in people who have not yet experienced a fall. Furthermore, previous studies have shown that a fall in the preceding year is a strong predictor for future falls. 49, 50 Unfortunately, we were unable to collect fall data of the year preceding our assessment, as this timespan partly coincided with the fifteen-week fall diary. Moreover, we were unable to maintain a fall diary following the assessment in
RkJQdWJsaXNoZXIy MjY0ODMw