Backwards walking speed reserve in persons with multiple sclerosis

BACKGROUND

Decreased gait speed is common in persons with Multiple Sclerosis (PwMS) and has been associated with elevated fall risk. The walking speed reserve (WSR) indicates the ability to increase gait speed on demand and has previously been examined in PwMS. Backward walking is a sensitive measure of fall risk in PwMS; however, no studies have reported on the utility of backward walking speed reserve (BW-WSR) as a clinical assessment tool of functional mobility or fall risk in PwMS, nor have they associated this measure with cognition.

METHODS

23 PwMS completed walking trials at their preferred walking speed (PWS) and maximal walking speed (MWS). Participants performed these walking trials in both the forward (FW) and backward direction (BW). The forward walking speed reserve (FW-WSR) was calculated as the difference between MWS and PWS in the forward direction, while the backward walking speed reserve (BW-WSR) was calculated as the difference between MWS and PWS in the back backward direction. Correlation analyses examined the relationship between the FW- and BW-WSR with clinical assessments of functional mobility (the timed up-and-go) as well as cognitive functioning (the Symbol Digit Modalities Test, the Brief Visuospatial Memory Test-Revised, the California Verbal Learning Test, and the Trail Making Test A and B). Correlations also examined the relationship between FW- and BW-WSR with prospective falls.

RESULTS

A lower BW-WSR was associated with disease severity and poorer performance on clinical walking and balance assessment, as well as with decreased information processing speed and attentional performance. Interestingly, FW-WSR showed similar relations. Neither FW- or BW-WSR were associated with prospective risk in this small sample of PwMS.

CONCLUSION

The BW-WSR did not offer a distinct advantage over other measures, such as the FW-WSR, PWS, or MWS, in the forward or backward direction. The selection of the most sensitive clinical measures of functional mobility and fall risk is crucial; our study holds valuable clinical implications for PwMS by providing novel insights into functional mobility assessments in PwMS.

Establishing the Reliability of The Step Test Evaluation of Performance on Stairs (STEPS) in Multiple Sclerosis

OBJECTIVE

To establish the inter- and intra-rater reliability of The Step Test Evaluation of Performance on Stairs (STEPS) for people with multiple sclerosis (PwMS) and examine its relation to clinical mobility measures, cognition, and activity levels.

DESIGN AND SETTING

STEPS performance was rated by 3 raters at the initial visit. Two raters observed the STEPS performance via videotape at the initial visit and then 1 week later. Participants also completed in lab clinical mobility tests and cognitive assessments at their initial visit. Activity levels were tracked for the subsequent 6 months.

PARTICIPANTS

In total, 23 people with relapsing-remitting MS (N=23).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Intraclass correlation coefficients (ICCs) were used to assess intra-rater and inter-rater reliability, while correlation analyses compared STEPS performance with cognition, clinical mobility assessments, and activity levels. The inter-rater reliability analysis among the 3 raters included scoring from only the initial evaluation. For the intra-rater reliability, 2 raters viewed and rated the videotaped session for each of the participants and then repeated the same process 1 week later.

RESULTS

Total STEPS scores demonstrated excellent agreement by ICC for inter- (ICC=0.97) and intra-rater reliability (ICC>0.95) and significant correlations with established clinical mobility assessments in PwMS. Better performance on STEPS was associated with information processing speed and prospective activity levels in PwMS.

CONCLUSIONS

Stair ambulation is a challenging task, integral for mobility and independence, therefore, having a sensitive and valid reliable assessment of stair performance is critical for PwMS. The STEPS assessment is a quick, easily administered, reliable, and valid tool for assessing stair ambulation in PwMS.

Evaluating Postural Transition Movement Performance in Individuals with Essential Tremor via the Instrumented Timed Up and Go

Flexibility in performing various movements like standing, walking, and turning is crucial for navigating dynamic environments in daily life. Individuals with essential tremor often experience movement difficulties that can affect these postural transitions, limiting mobility and independence. Yet, little research has examined the performance of postural transitions in people with essential tremor. Therefore, we assessed postural transition performance using two versions of the timed up and go test: the standard version and a more complex water-carry version. We examined the total duration of the standard and water-carry timed up and go in 15 people with and 15 people without essential tremor. We also compared the time taken for each phase (sit-to-stand phase, straight-line walk phase, stand-to-sit phase) and the turning velocity between groups. Our findings revealed decreased performance across all phases of standard and water-carry timed up and go assessments. Further, both ET and non-ET groups exhibited reduced performance during the water-carry timed up and go compared to the standard timed up and go. Evaluating specific phases of the timed up and go offers valuable insights into functional movement performance in essential tremor, permitting more tailored therapeutic interventions to improve functional performance during activities of daily living.

Functional Lower Extremity Strength Influences Stepping Strategy in Community-Dwelling Older Adults During Single and Dual-Task Walking

As age increases, a decline in lower extremity strength leads to reduced mobility and increased fall risks. This decline outpaces the age-related reduction in muscle mass, resulting in mobility limitations. Older adults with varying degrees of mobility-disability use different stepping strategies. However, the link between functional lower extremity strength and stepping strategy is unknown. Therefore, understanding how age-related reductions in functional lower extremity strength influence stepping strategy is vital to unraveling mobility limitations. Participants were recruited and tested at a local community event, where they were outfitted with IMUs and walked across a pressurized walkway. Our study reveals that older adults with normal strength prefer adjusting their step time during walking tasks, while those with reduced strength do not exhibit a preferred stepping strategy. This study provides valuable insights into the influence of functional lower extremity strength on stepping strategy in community-dwelling older adults during simple and complex walking tasks. These findings could aid in diagnosing gait deviations and developing appropriate treatment or management plans for mobility disability in older adults.

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.

Characterization of initial ankle-foot prosthesis prescription patterns in U.S. Service members following unilateral transtibial amputation

Introduction

The purpose of this study was to explore relationships between patient-specific characteristics and initial ankle-foot prosthesis prescription patterns among U.S. Service members with unilateral transtibial limb loss.

Methods

A retrospective review of health records identified 174 individuals with unilateral transtibial limb loss who received care at Walter Reed National Military Medical Center between 2001 and 2019. We examined patient-specific factors such as demographics, participant duty status at injury and amputation, amputation etiology, and timing between injury, amputation, and initial prescription. The type of first prescribed ankle-foot prosthesis was categorized as energy storing and return - nonarticulating, energy storing and return - articulating, or computer controlled.

Results

Sex, amputation etiology, time from injury to initial prescription, and time from amputation to initial prescription differed by type of initial ankle-foot prosthesis prescription. Service members with shorter intervals between injury-initial prescription and amputation-initial prescription, and those injured by combat blast, were more likely to receive a non-articulating device. Incorporating sex, time from injury-initial prescription, time from amputation-initial prescription, and amputation etiology as predictors of prosthesis type, we were able to correctly classify 72% of all first prostheses prescribed.

Discussion

Patient-specific characteristics such as sex, the time between injury-initial prescription, time from amputation-initial prescription and amputation etiology are essential characteristics that influence initial ankle-foot prosthesis prescription patterns in U.S. Service members.

Physical activity does not impact mediolateral margin of stability across a range of postural-perturbing conditions in young adults

BACKGROUND

The maintenance of stability during walking is critical for successful locomotion. While targeted balance training can improve stability, it is unclear how simply meeting recommended physical activity guidelines may impact dynamic stability in healthy young adults.

RESEARCH QUESTION

Examining the differences in the mediolateral margin of stability (ML-MOS) and the variability of the ML-MOS in physically active and inactive young adults across a range of stability-challenging walking tasks METHOD: Twenty-one physically active and twenty inactive young adults completed four experimental walking conditions: (1) Overground Walking, (2) Tandem Walking, (3) Beam Walking, and (4) Stepping-Stones. The ML-MOS and coefficient of variation of the ML-MOS were calculated at each heel strike while participants walked at their preferred walking speed. A two-way mixed-effects ANOVA was conducted to examine the effects of group and condition and their interaction on ML-MOS and ML-MOS variability RESULTS: Neither the ML-MOS nor the variability of the ML-MOS was significantly different between physically active and physically inactive young adults during any experimental walking conditions. A significant main effect of the experimental walking condition was observed, with the ML-MOS decreasing from overground walking to the tandem and beam walking conditions. The ML-MOS also became more variable in the tandem, beam, and stepping-stones conditions than in overground gait.

SIGNIFICANCE

Physical activity status did not influence frontal plane dynamic balance in healthy young adults, even in stability-challenging environments. Conditions that constrain step width, such as tandem and beam walking, are adequate for challenging frontal plane dynamic balance and indicate that trunk kinematics may be adjusted when step width is constrained.

The effect of shoe cushioning on gait and balance in females with multiple sclerosis

Gait and balance deficits are significant concerns for people with multiple sclerosis (MS). Shoe cushioning can influence mobility and balance, but its effect on walking and balance remains unknown in MS. This study aimed to determine how shoe cushioning affects gait and balance in females with MS (FwMS). We hypothesized that extra cushioning would improve gait but reduce balance performance. FwMS performed gait (n = 18) and balance (n = 17) assessments instrumented using inertial sensors in two different shoe conditions: a standard-cushioned and an extra-cushioned shoe. Care was taken to ensure minimal differences between shoe types other than midsole cushioning, but shoe construction was not identical between conditions. Spatiotemporal gait parameters were assessed during a 2-min walk test, while postural sway measures were evaluated using the modified Clinical Test of Sensory Interaction and Balance. In the extra-cushioned shoe, FwMS spent less time in the double support and stance phase with more time in the single support and swing phase. No differences in stride length, gait speed, or elevation at midswing were observed between shoe conditions. Decreased path length, RMS sway, and sway velocity were observed in the extra-cushioned shoe. No differences were observed in the gait cycle's spatial composition between shoe conditions, but FwMS demonstrated improvements in the gait cycle's temporal parameters and postural sway in the extra-cushioned shoe. This may suggest a less cautious walking strategy and improved balance when wearing a shoe with extra cushioning.

Changes in Training, Lifestyle, Psychological and Demographic Factors, and Associations With Running-Related Injuries During COVID-19

The primary purpose of this study was to examine how the type and magnitude of changes in running behavior, as a consequence of COVID-19 pandemic restrictions, influence running-related injuries. Secondarily, we aimed to examine how lifestyle and psychosocial well-being measures may influence running behavior change. An online survey was advertised to individuals over the age of 18 that currently run or have previously participated in running for exercise. The survey questions examined injury history and new injuries sustained during COVID-19 restrictions, as well as changes related to training behavior changes, training environment changes, social behaviors, and psychosocial well-being. Changes reflected differences in running behaviors prior to COVID-19 restrictions (1 month prior to COVID-19 restrictions being imposed) and during COVID-19 restrictions (May 5 to June 10, 2020). A total of 1,035 runners were included in the analysis. Current injuries sustained during COVID-19 occurred in 9.5% of the runners. Injured runners made a greater number of total changes (p = 0.031) as well as training-related (p = 0.042) and environment-related (p = 0.017) changes compared with uninjured runners. A significant relationship was found between injury and those that reported less time to exercise to changes in work environment (p = 0017). This study highlights the multi-dimensional nature of running-related injuries and the need to consider the interaction of multiple changes in running behavior, rather than isolating single factors. Greater understanding of the underlying causes of running-related injuries can help reduce the risk of future injury.

Adapting gait with asymmetric visual feedback affects deadaptation but not adaptation in healthy young adults

Split-belt treadmill walking allows researchers to understand how new gait patterns are acquired. Initially, the belts move at two different speeds, inducing asymmetric step lengths. As people adapt their gait on a split-belt treadmill, left and right step lengths become more symmetric over time. Upon returning to normal walking, step lengths become asymmetric in the opposite direction, indicating deadaptation. Then, upon re-exposure to the split belts, step length asymmetry is less than the asymmetry at the start of the initial exposure, indicating readaptation. Changes in step length symmetry are driven by changes in step timing and step position asymmetry. It is critical to understand what factors can promote step timing and position adaptation and therefore influence step length asymmetry. There is limited research regarding the role of visual feedback to improve gait adaptation. Using visual feedback to promote the adaptation of step timing or position may be useful of understanding temporal or spatial gait impairments. We measured gait adaptation, deadaptation, and readaptation in twenty-nine healthy young adults while they walked on a split-belt treadmill. One group received no feedback while adapting; one group received asymmetric real-time feedback about step timing while adapting; and the last group received asymmetric real-time feedback about step position while adapting. We measured step length difference (non-normalized asymmetry), step timing asymmetry, and step position asymmetry during adaptation, deadaptation, and readaptation on a split-belt treadmill. Regardless of feedback, participants adapted step length difference, indicating that walking with temporal or spatial visual feedback does not interfere with gait adaptation. Compared to the group that received no feedback, the group that received temporal feedback exhibited smaller early deadaptation step position asymmetry (p = 0.005). There was no effect of temporal or spatial feedback on step timing. The feedback groups adapted step timing and position similarly to walking without feedback. Future work should investigate whether asymmetric visual feedback also results in typical gait adaptation in populations with altered step timing or position control.

All eyes on you: how researcher presence changes the way you walk

Most human movement research takes place within controlled laboratories where researchers observe participant movement. Because a majority of daily activity is performed without observation, we hypothesized movement within a laboratory would vary when there was a small, large or absence of research group. We also hypothesized that personality type would influence movement during observation. Participants completed a personality questionnaire, then walked in a laboratory during three different conditions: no research group (no researchers), small research group (2 researchers), and large research group (6-10 researchers). Results revealed spatiotemporal parameters were altered between conditions, however personality type did not influence changes in movement. As the number of researchers increased, gait speed, cadence, and stride length increased, and step duration decreased. Gait speed increased by .03 m/s from the no research group to the small research group, by .06 m/s from the no research group to the large research group, and by .03 m/s from the small to large research group (all p values < .001). Understanding how researcher observation modifies movement is important and affects the replicability of results, as well as the interpretation of laboratory-based movement studies to activities of daily living in real world settings.