Utility of center of pressure measures during obstacle crossing in prediction of fall risk in people with Parkinson’s disease

INTRODUCTION

Postural instability during walking and tripping over obstacles are the main causes of falls in people with Parkinson's disease (PD). Preliminary limited evidence suggests that the length of the prospective follow-up period affects falls prediction in PD, with shorter periods leading to more accurate prediction. Thus, the primary aim of the present study was to test the performance of center of pressure (CoP) variables during obstacle crossing to predict fall risk in people with PD during subsequent periods of four, six, and 12 months. We also compared CoP variables during obstacle crossing between fallers and non-fallers.

METHODS

Forty-two individuals with PD, in mild to moderate stages, completed the baseline obstacle crossing assessment and reported falls for 12 months. Participants walked at their self-selected pace and were instructed to cross an obstacle (half knee height) positioned in the middle of an 8-m long pathway. A force platform was used to analyze CoP parameters of the stance phase of the trailing limb (most affected limb). The ability of each outcome measure to predict fall risk at four, six, and 12 months was assessed using receiver operating characteristic curve analyses.

RESULTS

Ten individuals (23.8%) were considered fallers at four months, twelve individuals (28.5%) at six months, and twenty-one individuals (50%) at 12 months. CoP amplitude and CoP velocity in the mediolateral direction significantly predicted fall risk at four, six, and 12 months. As judged by the area under the curve, mediolateral CoP velocity showed the best performance at four months, while mediolateral CoP amplitude showed the best performance at six months. Fallers presented greater values of mediolateral CoP velocity and amplitude than non-fallers.

CONCLUSION

These findings suggest that mediolateral CoP velocity and amplitude during obstacle crossing might be useful to predict fall risk in people with PD. Therefore, larger studies are encouraged.

The effects of habitual footwear in gait outcomes in people with Parkinson's disease

BACKGROUND

Gait is impaired in individuals with Parkinson's disease (PD). Although the effect of habitual footwear on gait spatiotemporal parameters has already been established in neurologically healthy individuals, its effects on people with PD is unknown.

RESEARCH QUESTION

This study aimed to investigate the impact of habitual footwear on the step spatiotemporal parameters in people with PD.

METHODS

Sixteen individuals with PD (G-PD) and 15 neurologically healthy individuals (G-HC) were assessed. Participants walked on an 8 m long pressure sensitive walkway at their preferred speed with and without their habitual footwear (3 trials per condition). Footwear included flip-flops, shoes, sneakers and sandals. The average, variability and asymmetry for step length, width, duration, and velocity and the percentage time in the swing and stance phases were calculated.

RESULTS

The results showed in both groups a reduced percentage time in the swing phase and an increased step width, duration and length with footwear (F(1,29)>5.64; p<0.02). Additionally, habitual footwear increased step width variability in G-PD and G-HC (F(1,29)=3.97; p=0.06). Interestingly, only G-HC showed a higher step length asymmetry in the footwear condition than in the barefoot condition (p=0.02). Finally, only when habitual footwear was used, G-HC showed a higher step velocity asymmetry than G-PD (p=0.04).

SIGNIFICANCE

These results indicate a negative influence of footwear on gait spatiotemporal parameters in both groups. Furthermore, footwear induced differences between groups. These findings indicate that footwear use is an influencing factor in studies comparing people with PD and healthy elderly. Further data are needed before definitive recommendations are made.