Examining the Relationship Between Reactive Stepping Outcomes and Falls in People With Multiple Sclerosis

Generalization of In-Place Balance Perturbation Training in People With Parkinson Disease

BACKGROUND AND PURPOSE

Reactive balance training improves reactive postural control in people with Parkinson disease (PwPD). However, the extent to which reactive balance training generalizes to a novel, unpracticed reactive balance task is unknown. This study aimed to determine whether reactive training stepping through support surface translations can be generalized to an unpracticed, instrumented tether-release task.

METHODS

Twenty-five PwPD (70.52 years ± 7.15; Hoehn and Yahr range 1-3) completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Stepping was trained through a 2-week (6-session) intervention with repeated support surface translations. Performance on an untrained tether-release task (generalization task) was measured at 2 baseline assessments (B1 and B2, 2 weeks apart), immediately after the intervention (P1), and 2 months after training (P2). The tether-release task outcomes were the anterior-posterior margin of stability (MOS), step length, and step latency during backward and forward steps.

RESULTS

After support surface translation practice, tether-release stepping performance improved in MOS, step length, and step latency for both backward and forward steps compared to baseline ( P < 0.05). Improvements in MOS and step length during backward and forward steps in the tether-release task, respectively, were related to stepping changes in the practiced task. However, the improvements in the generalization task were not retained for 2 months.

DISCUSSION AND CONCLUSIONS

These findings support short-term generalization from trained balance tasks to novel, untrained tasks. These findings contribute to our understanding of the effects and generalization of reactive step training in PwPD.

VIDEO ABSTRACT AVAILABLE

for more insights from the authors (see the Video, Supplemental Digital Content available at http://links.lww.com/JNPT/A465 ).

A custom-built step exergame training programme to prevent falls in people with multiple sclerosis: A multicentre randomised controlled trial

BACKGROUND

Cognitive-motor step training can improve stepping, balance and mobility in people with multiple sclerosis (MS), but effectiveness in preventing falls has not been demonstrated.

OBJECTIVES

This multisite randomised controlled trial aimed to determine whether 6 months of home-based step exergame training could reduce falls and improve associated risk factors compared with usual care in people with MS.

METHODS

In total, 461 people with MS aged 22-81 years were randomly allocated to usual care (control) or unsupervised home-based step exergame training (120 minutes/week) for 6 months. The primary outcome was rate of falls over 6 months from randomisation. Secondary outcomes included physical, cognitive and psychosocial function at 6 months and falls over 12 months.

RESULTS

Mean (standard deviation (SD)) weekly training duration was 70 (51) minutes over 6 months. Fall rates did not differ between intervention and control groups (incidence rates (95% confidence interval (CI)): 2.13 (1.57-2.69) versus 2.24 (1.35-3.13), respectively, incidence rate ratio: 0.96 (95% CI: 0.69-1.34, p = 0.816)). Intervention participants performed faster in tests of choice-stepping reaction time at 6 months. No serious training-related adverse events were reported.

CONCLUSION

The step exergame training programme did not reduce falls among people with MS. However, it significantly improved choice-stepping reaction time which is critical to ambulate safely in daily life environment.

Associating white matter microstructural integrity and improvements in reactive stepping in people with Parkinson's Disease

Reactive steps are rapid responses after balance challenges. People with Parkinson's Disease (PwPD) demonstrate impaired reactive stepping, increasing fall-risk. Although PwPD can improve steps through practice, the neural mechanisms contributing to improved reactive stepping are poorly understood. This study investigated white-matter correlates of responsiveness to reactive step training in PwPD. In an eighteen-week multiple-baseline study, participants (n = 22) underwent baseline assessments (B1 and B2 two-weeks apart), a two-week training protocol, and post-training assessments immediately (P1) and two-months (P2) post-training. Assessments involved three backward reactive step trials, measuring anterior-posterior margin of stability (AP MOS), step length, and step latency. Tract-Based Spatial Statistics correlated white-matter integrity (fractional anisotropy (FA) and radial diffusivity (RD)) with retained (P2-B2) and immediate improvements (P1-B2) in stepping. Significant and sustained improvements in step length and AP MOS were observed. Greater retention of step length improvement correlated with increased FA in the left anterior thalamic radiation (ATR), left posterior thalamic radiation (PTR), left superior longitudinal fasciculus (SLF), and right inferior longitudinal fasciculus (ILF). Step latency retention was associated with lower RD in the left posterior corona radiata and left PTR. Immediate improvements in AP MOS correlated with increased FA of the right ILF, right SLF, and right corticospinal tract. Immediate step length improvements were associated with increased FA in right and left ATR and right SLF. These findings highlight the importance of white-matter microstructural integrity in motor learning and retention processes in PD and could aid in identifying individuals with PD who would benefit most from balance rehabilitation.

Stability Changes in Fall-Prone Individuals With Parkinson Disease Following Reactive Step Training

BACKGROUND AND PURPOSE

Poor reactive steps may lead to falls in people with Parkinson disease (PwPD). However, whether reactive steps can be improved in PwPD at risk for falls or whether step training reduces falls remains unclear. This study aimed to determine whether 2 weeks of reactive step training result in (1) immediate and retained improvements in stepping and (2) fewer prospective falls in PwPD at fall risk.

METHODS

Twenty-five PwPD (70.52 years ± 7.15; Hoehn & Yahr range 1-3) at risk for falls completed a multiple baseline, open-label, uncontrolled pre-/postintervention study. Stepping performance was assessed at 2 baseline assessments (B1 and B2) followed by a 2-week, 6-session training protocol. Stepping was assessed immediately (P1) and 2 months after training (P2). Primary outcomes were anterior-posterior margin of stability (MOS), step length, and step latency during backward stepping. Fall frequency was measured for 2 months before and after training.

RESULTS

MOS during backward steps was significantly larger (better) after training ( P < 0.001, d = 0.83), and improvements were retained for 2 months ( P = 0.04, d = 0.66). Step length was not statistically significant different after training ( P = 0.13, d = 0.46) or at follow-up ( P = 0.08, d = 0.62), although effect sizes were medium and large, respectively. Step latency improved after initial exposure ( P = 0.01, d = 0.60) but not following training ( P = 0.43, d = 0.35). Twelve participants experienced fewer falls after training than before (10 = no change, 5 = increase; P = 0.12). Greater improvements in MOS were related to fewer falls ( P = 0.04).

DISCUSSION AND CONCLUSIONS

Two weeks of reactive step training resulted in immediate and retained improvements in some reactive stepping outcomes in PwPD at risk for falls and may reduce fall risk. Reactive step training may be a viable approach to reduce falls in PwPD.

Cognitive Predictors of Responsiveness to Reactive Step Training in People with Parkinson's Disease at Fall-Risk

Reactive stepping can be improved in people with Parkinson's Disease (PwPD). However, there is variability in the responsiveness to such training. This study examined if cognition could predict the responsiveness of PwPD to a two-week reactive step training intervention. 25 PwPD (70.52 years ± 7.15; Hoehn & Yahr range 1-3) at risk for falls completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Reactive stepping was trained through a two-week (six-session) intervention with repeated support surface translations. Stepping performance was measured at two baseline assessments (B1 and B2), immediately after the intervention (P1), and two months after training (P2). Primary stepping outcomes were anterior-posterior margin of stability (MOS), step length, and step latency during backward steps. The primary aim assessed whether global cognition (Scales for Outcomes in Parkinson's Disease-Cognition - SCOPA-COG, & Montreal Cognitive Assessment - MoCA) was related to two-month retention of improvements in reactive stepping after practice. The secondary aim explored whether specific cognitive domains predicted retained stepping improvements, including attention/working memory, executive function, language, memory, and visuospatial function. Greater baseline global cognition was related to better two-month retention of step length improvements (SCOPA-COG: p = 0.002, f2 = 0.31; MoCA: p = 0.002, f2 = 0.38). However, only SCOPA-COG retained statistical significance after p-value adjustment for multiple comparisons (p = 0.04). Optimal cut-point analysis revealed that a SCOPA-COG threshold of 31 or higher was optimal for identifying individuals likely to retain improvement. Specific cognitive domains did not predict changes in reactive stepping outcomes. Participants with greater baseline global cognition, particularly as measured by SCOPA-COG, demonstrated greater retention of improvements in reactive stepping. In this cohort, a SCOPA-COG threshold of 31 could predict individuals likely to benefit from the intervention. These findings highlight the potential of cognitive screening to identify people more or less likely to benefit from reactive balance training.

Perturbation-based Balance Training to improve postural responses and falls in people with multiple sclerosis: a randomized controlled trial

PURPOSE

To determine the effects of Perturbation-based Balance Training (PBT) on postural responses and falls in people with multiple sclerosis (PwMS) and compare the results with conventional balance training (CBT).

MATERIALS AND METHODS

Thirty-four PwMS were randomized to receive 4 weeks of PBT or CBT. Latency of postural responses to external perturbations, Timed-Up-and-Go (TUG), 10-meter-walk (10MW), Berg Balance Scale (BBS), and Activities-specific Balance Confidence Scale (ABC) were measured at baseline and post-training. Also, the proportion of fallers and fall rate were assessed at a 3-month follow-up.

RESULTS

The latency of postural responses significantly decreased in PBT compared to CBT. TUG, 10MW, BBS, and ABC, at post-training, and relative risk of falls and fall rate at 3-month follow-up had no statistically significant between-group differences.

CONCLUSIONS

The results show that PBT is at least as effective as CBT in improving balance and decreasing falls, while it has superiority over CBT whenever the clinicians mainly aim to improve reactive balance strategies. Future studies with a larger sample size are warranted to complement the results of this study.Implication for rehabilitationPerturbation-based Balance Training is at least as effective as conventional balance training (CBT) in improving proactive postural control in people with multiple sclerosis (PwMS).Perturbation-based Balance Training has superiority over CBT in improving reactive postural control in PwMS.Perturbation-based Balance Training has no superiority over CBT in improving fall-related outcomes.

Preliminary race-ethnicity-based analyses of fall risk among people with multiple sclerosis

BACKGROUND

Mounting evidence suggests differences in the disease characteristics of multiple sclerosis (MS) across ethnic and racial groups. Although it is widely recognized that falls are a significant concern for people with MS (PwMS), no study has explored if the fall risk is related to race/ethnicity in PwMS. The primary purpose of this pilot study was to examine whether the risk of falls is different between age-matched White, Black, and Latinx PwMS.

METHODS

Fifteen White, 16 Black, and 22 Latinx, age-matched ambulatory PwMS were selected from previous studies. Demographic and disease information, the fall risk (annual fall prevalence, proportion of recurrent fallers, and the number of falls) in the preceding year, and a battery of fall risk factors (including the disability level, gait speed, and cognition) were compared between race/ethnicity groups. The fall history was gathered using the valid fall questionnaire. The disability level was assessed by the Patient Determined Disease Steps score. Gait speed was measured using the Timed 25-Foot Walk test. The short Blessed Orientation-Memory-Concentration test evaluates participants' cognitive function. SPSS 28.0 was used for all statistical analyses and a significance level of 0.05 was applied.

RESULTS

Among the demographic measurements, age (p = 0.052), sex (p = 0.17), body mass (p = 0.338), age at diagnosis (p = 0.623), and disease duration (p = 0.280) were comparable across groups while the body height was significantly different between racial groups (p < 0.001). Binary logistic regression analysis did not detect a significant relationship between the faller status and racial/ethnic group (p = 0.571) after controlling the body height and age. Similarly, the recurrent faller status was not associated with our participants' race/ethnicity (p = 0.519). There was no difference in the number of falls in the past year between racial groups (p = 0.477). The fall risk factors of disability level (p = 0.931) and gait speed (p = 0.252) were similar among the groups. However, the White group had a significantly better Blessed Orientation-Memory-Concentration score than the Black (p = 0.037) and Latinx (p = 0.036) groups. No significant difference in the Blessed Orientation-Memory-Concentration score was observed between the Black and Latinx groups (p = 0.857).

CONCLUSION

As the initial attempt, our preliminary study suggests that the annual risk of being a faller or recurrent faller may not be affected by PwMS' race/ethnicity. Similarly, the physical functions (quantified by the Patient Determined Disease Steps and the gait speed) are comparable between racial/ethnic groups. However, the cognitive function may differ among age-matched racial groups of PwMS. Given the small sample size, caution is warranted when interpreting our findings. Despite the limitations, our study provides pilot knowledge about how race/ethnicity affects the fall risk in PwMS. Due to the limited sample size, it is too soon to definitively conclude that race/ethnicity has ignorable impacts on fall risk in PwMS. Further studies with larger sample sizes and more fall risk metrics are needed to clarify the effects of race/ethnicity on fall risk in this population.

Using the Instrumented Sway System (ISway) to Identify and Compare Balance Domain Deficits in People With Multiple Sclerosis

OBJECTIVE

To develop a multiple sclerosis (MS)-specific model of balance and examine differences between (1) MS and neurotypical controls and (2) people with MS (PwMS) with (MS-F) and without a fall history (MS-NF).

DESIGN AND SETTING

A cross-sectional study was conducted at the Gait and Balance Laboratory at the University of Kansas Medical Center. Balance was measured from the instrumented sway system (ISway) assessment.

PARTICIPANTS

In total, 118 people with relapsing-remitting MS (MS-F=39; MS-NF=79) and 46 age-matched neurotypical controls.

INTERVENTION

Not applicable.

OUTCOME MEASURES

A total of 22 sway measures obtained from the ISway were entered into an exploratory factor analysis to identify underlying balance domains. The model-derived balance domains were compared between (1) PwMS and age-matched, neurotypical controls and (2) MS-F and MS-NF.

RESULTS

Three distinct balance domains were identified: (1) sway amplitude and velocity, (2) sway frequency and jerk mediolateral, and (3) sway frequency and jerk anteroposterior, explaining 81.66% of balance variance. PwMS exhibited worse performance (ie, greater amplitude and velocity of sway) in the sway velocity and amplitude domain compared to age-matched neurotypical controls (P=.003). MS-F also exhibited worse performance in the sway velocity and amplitude domain compared to MS-NF (P=.046). The anteroposterior and mediolateral sway frequency and jerk domains were not different between PwMS and neurotypical controls nor between MS-F and MS-NF.

CONCLUSIONS

This study identified a 3-factor, MS-specific balance model, demonstrating that PwMS, particularly those with a fall history, exhibit disproportionate impairments in sway amplitude and velocity. Identifying postural stability outcomes and domains that are altered in PwMS and clinically relevant (eg, related to falls) would help isolate potential treatment targets.

Comparison of physical performance, gait, balance, falls efficacy, and step reaction time in individuals with multiple sclerosis

OBJECTIVE

The study aimed to investigate the physical performance, gait, balance, falls efficacy, and step reaction time in individuals with MS.

METHODS

A total of 60 individuals (30 individuals with MS and 30 age and sex-matched healthy controls) were enrolled. Individuals' physical performance was evaluated with the Timed Up and Go Test (TUG) and Five-Times-Sit-to-Stand Test (FTSTS). Activities-specific Balance Confidence (ABC) Scale, 12-item Multiple Sclerosis Walking Scale (MSWS-12v2) and Falls Efficacy Scale International (FES-I) were used to assess the balance, gait and fall efficacy of the participants. Individuals' step reaction time (SRT) was calculated with video-based software. The time between the step command and the first contact of the foot with the ground in the first step was recorded.

RESULTS

The mean age of the individuals with MS and the control group was 38.5 ± 9.4 years and 33.9 ± 11.7 years, respectively. Significant differences existed between the groups in SRT, FES-I, ABC, and FTSTS (p < 0.05). There was no significant correlation between SRT with any other parameter (p > 0.05). TUG was moderately correlated with MSWS-12 and FES-I (r1 =0.426, r2 =0.495, p < 0.05). Besides, there was a moderate correlation between ABC with TUG and FTSTS (r1 =-0.605, r2 =-0.468, p < 0.05). A high degree correlation was found between MSWS-12 with FES-I and ABC (r1 =0.843, r2 =-0.834, p < 0.05).

CONCLUSION

Individuals with MS have decreased SRTs. However, this condition was not found to be related to physical performance. Further studies should focus on the association of SRT with cognitive and psychosocial parameters.