Leg spasticity and ambulation in multiple sclerosis.

Background. Spasticity of the legs is common in multiple sclerosis (MS), but there has been limited research examining its association with ambulatory outcomes. Objective. This study examined spasticity of the legs and its association with multiple measures of ambulation in persons with MS. Methods. The sample included 84 patients with MS. Spasticity of the legs was measured using a 5-point rating scale ranging between 0 (normal) and 4 (contracted). Patients completed the 6-minute walk (6 MW), timed 25 foot walk (T25FW), and timed up-and-go (TUG), and O2 cost of walking was measured during the 6 MW. The patients undertook two walking trials on a GAITRite (CIR systems, Inc.) for measuring spatial and temporal parameters of gait. The patients completed the Multiple Sclerosis Walking Scale-12 (MSWS-12) and wore an accelerometer over a seven-day period. Results. 52% (n = 44) of the sample presented with spasticity of the legs. Those with leg spasticity had significantly worse ambulation as measured by 6 MW (P = 0.0001, d = -0.86), T25FW (P = 0.003, d = 0.72), TUG (P = 0.001, d = 0.84), MSWS-12 (P = 0.0001, d = 1.09), O2 cost of walking (P = 0.001, d = 0.75), average steps/day (P < 0.05, d = -0.45), and walking velocity (P < 0.05, d = -0.53) and cadence (P < 0.05, d = -0.46). Conclusion. Leg spasticity was associated with impairments in ambulation, including alterations in spatiotemporal parameters and free-living walking.

Accuracy of StepWatch™ and ActiGraph accelerometers for measuring steps taken among persons with multiple sclerosis.

INTRODUCTION: There has been increased interest in the objective monitoring of free-living walking behavior using accelerometers in clinical research involving persons with multiple sclerosis (MS). The current investigation examined and compared the accuracy of the StepWatch activity monitor and ActiGraph model GT3X+ accelerometer for capturing steps taken during various speeds of prolonged, over-ground ambulation in persons with MS who had mild, moderate, and severe disability. METHODS: Sixty-three persons with MS underwent a neurological examination for generation of an EDSS score and undertook two trials of walking on the GAITRite electronic walkway. Participants were fitted with accelerometers, and undertook three modified six-minute walk (6MW) tests that were interspersed with 10-15 minutes of rest. The first 6MW was undertaken at a comfortable walking speed (CWS), and the two remaining 6MW tests were undertaken above (faster walking speed; FWS) or below (slower walking speed; SWS) the participant's CWS. The actual number of steps taken was counted through direct observation using hand-tally counters. RESULTS: The StepWatch activity monitor (99.8%-99.9%) and ActiGraph model GT3X+ accelerometer (95.6%-97.4%) both demonstrated highly accurate measurement of steps taken under CWS and FWS conditions. The StepWatch had better accuracy (99.0%) than the ActiGraph (95.5%) in the overall sample under the SWS condition, and this was particularly apparent in those with severe disability (StepWatch: 95.7%; ActiGraph: 87.3%). The inaccuracy in measurement for the ActiGraph was associated with alterations of gait (e.g., slower gait velocity, shorter step length, wider base of support). CONCLUSIONS: This research will help inform the choice of accelerometer to be adopted in clinical trials of MS wherein the monitoring of free-living walking behavior is of particular value.

Integrity of the anterior visual pathway and its association with ambulatory performance in multiple sclerosis.

Background. Retinal nerve fiber layer thickness (RNFLT) and total macular volume (TMV) represent markers of neuroaxonal degeneration within the anterior visual pathway that might correlate with ambulation in persons with multiple sclerosis (MS). Objective. This study examined the associations between RNFLT and TMV with ambulatory parameters in MS. Methods. Fifty-eight MS patients underwent a neurological examination for generation of an expanded disability status scale (EDSS) score and measurement of RNFLT and TMV using optical coherence tomography (OCT). Participants completed the 6-minute walk (6MW) and the timed 25-foot walk (T25FW). The associations were examined using generalized estimating equation models that accounted for within-patient, inter-eye correlations, and controlled for disease duration, EDSS score, and age. Results. RNFLT was not significantly associated with 6MW (P = 0.99) or T25FW (P = 0.57). TMV was significantly associated with 6MW (P = 0.023) and T25FW (P = 0.005). The coefficients indicated that unit differences in 6MW (100 feet) and T25FW (1 second) were associated with 0.040 and -0.048 unit differences in TMV (mm(3)), respectively. Conclusion. Integrity of the anterior visual pathway, particularly TMV, might represent a noninvasive measure of neuroaxonal degeneration that is correlated with ambulatory function in MS.

Rationale and design of a randomized controlled, clinical trial investigating a comprehensive exercise stimulus for improving mobility disability outcomes in persons with multiple sclerosis.

This randomized controlled trial (RCT) examines the effect of a comprehensive exercise training stimulus on physiological function and mobility disability (i.e., problems walking) in individuals with multiple sclerosis (MS) who have walking impairment. This trial will recruit 30 persons with MS across central Illinois who have an Expanded Disability Status Scale score between 4.0 and 6.0, and those persons will be randomized into either the intervention or control arm of the study; the participants will not be blinded regarding group assignment. The intervention will incorporate equal amounts of aerobic, resistance, and balance modes of training delivered 3 times/week with a gradual progression of duration and intensity across a 6-month period. The control will involve stretching along with minimal muscle strengthening stimuli and will be delivered on the same frequency and duration. The primary outcomes will be clinical, kinematic, patient-rated, and physiological measures of mobility disability. The secondary outcomes will be measures of physiological function including aerobic capacity, muscle strength, and balance. This study will lay the foundation for the design of a subsequent Phase II or Phase III RCT by (a) providing effect sizes that can be included in a power analysis for sample size estimation and (b) investigating whether aerobic capacity, muscle strength, and balance are possible factors associated with the beneficial effect of exercise training on walking outcomes. Taken as a whole, the proposed study and our subsequent research agenda has the potential for advancing the management of mobility disability using exercise training in the 2nd stage of MS.

Steps per day among persons with multiple sclerosis: variation by demographic, clinical, and device characteristics.

OBJECTIVES: To identify steps per day in a large sample of persons with multiple sclerosis (MS) and to describe variation by demographic and clinical characteristics and device type. DESIGN: Cross-sectional design. SETTING: General community. PARTICIPANTS: Convenience sample of persons with multiple sclerosis (N=645) recruited from the general community who were ambulatory and relapse free for 30 days. Mean age ± SD of the participants was 46.3 ± 10.6 years old. Participants were mostly women (85%), white (93%), and employed (64%). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Step counts measured by a motion sensor during a 7-day period. RESULTS: The average value for the entire sample was 5,903 ± 3,185 steps per day. This value varied by demographic and clinical characteristics, but not device type, and indicated that men, participants who were unemployed, had a high school education or less, progressive MS, a longer disease duration, and higher disability were less physically active based on the metric of steps per day. CONCLUSIONS: This study provides an expected value for average steps per day among persons with MS. Such an expected value for this population is an important first step to help researchers and clinicians interested in improving the overall health of persons with MS through physical activity promotion.

Cognitive processing speed is related to fall frequency in older adults with multiple sclerosis.

OBJECTIVE: To examine mobility, balance, fall risk, and cognition in older adults with multiple sclerosis (MS) as a function of fall frequency. DESIGN: Retrospective, cross-sectional design. SETTING: University research laboratory. PARTICIPANTS: Community-dwelling persons with MS (N=27) aged between 50 and 75 years were divided into 2 groups-single-time (n=11) and recurrent (n=16; >2 falls/12 mo) fallers-on the basis of fall history. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Mobility was assessed using a variety of measures including Multiple Sclerosis Walking Scale-12, walking speed (Timed 25-Foot Walk test), endurance (6-Minute Walk test), and functional mobility (Timed Up and Go test). Balance was assessed with the Berg Balance Scale, posturography, and self-reported balance confidence. Fall risk was assessed with the Physiological Profile Assessment. Cognitive processing speed was quantified with the Symbol Digit Modalities Test and the Paced Auditory Serial Addition Test. RESULTS: Recurrent fallers had slower cognitive processing speed than single-time fallers (P ≤.01). There was no difference in mobility, balance, or fall risk between recurrent and single-time fallers (P>.05). CONCLUSIONS: Results indicated that cognitive processing speed is associated with fall frequency and may have implications for fall prevention strategies targeting recurrent fallers with MS.

Evidence for the different physiological significance of the 6- and 2-minute walk tests in multiple sclerosis.

BACKGROUND: Researchers have recently advocated for the 2-minute walk (2MW) as an alternative for the 6-minute walk (6MW) to assess long distance ambulation in persons with multiple sclerosis (MS). This recommendation has not been based on physiological considerations such as the rate of oxygen consumption (V·O2) over the 6MW range. OBJECTIVE: This study examined the pattern of change in V·O2 over the range of the 6MW in a large sample of persons with MS who varied as a function of disability status. METHOD: Ninety-five persons with clinically-definite MS underwent a neurological examination for generating an Expanded Disability Status Scale (EDSS) score, and then completion of the 6MW protocol while wearing a portable metabolic unit and an accelerometer. RESULTS: There was a time main effect on V·O2 during the 6MW (p=.0001) such that V·O2 increased significantly every 30 seconds over the first 3 minutes of the 6MW, and then remained stable over the second 3 minutes of the 6MW. This occurred despite no change in cadence across the 6MW (p=.84). CONCLUSIONS: The pattern of change in V·O2 indicates that there are different metabolic systems providing energy for ambulation during the 6MW in MS subjects and steady state aerobic metabolism is reached during the last 3 minutes of the 6MW. By extension, the first 3 minutes would represent a test of mixed aerobic and anaerobic work, whereas the second 3 minutes would represent a test of aerobic work during walking.

Perceived impact of spasticity is associated with spatial and temporal parameters of gait in multiple sclerosis.

Background. Spasticity is prevalent and disabling in persons with multiple sclerosis (MS), and the development of the Multiple Sclerosis Spasticity Scale-88 (MSSS-88) provides an opportunity for examining the perceived impact of spasticity and its association with gait in this population. Purpose. This study examined the association between the perceived impact of spasticity and spatio-temporal parameters of gait in persons with MS. Methods. The sample included 44 adults with MS who completed the MSSS-88 and 4 walking trials on a 26-foot GAITRite(TM) electronic walkway for measurement of spatio-temporal components of gait including velocity, cadence, base of support, step time, single support, double support, and swing phase. Results. The overall MSSS-88 score was significantly associated with velocity (r = -0.371), cadence (r = -0.306), base of support (r = 0.357), step time (r = 0.305), single leg support (r = -0.388), double leg support (r = 0.379), and swing phase (r = -0.386). Conclusions. The perceived impact of spasticity coincides with alterations of the spatio-temporal parameters of gait in MS. This indicates that subsequent interventions might target a decrease in spasticity or its perceived impact as an approach for improving mobility in MS.

Fatigue, depression, and physical activity in relapsing-remitting multiple sclerosis: Results from a prospective, 18-month study.

BACKGROUND: Fatigue, depression, and physical inactivity are common in multiple sclerosis (MS), but there is limited information on the bi-directional associations among those variables over a long period of time. OBJECTIVE: This study examined the hypothesis that fatigue and depression would predict change in physical activity and that physical activity would predict changes in fatigue and depression over an 18-month period of time in persons with MS, even after controlling for disability status, disease duration, sex, and age. METHODS: This longitudinal study collected data on fatigue, depression, physical activity, and confounding variables from the same sample of persons with relapsing-remitting MS on two occasions that were separated by 18 months. RESULTS: The cross-lagged path coefficient between baseline fatigue and follow-up physical activity was statistically significant (path coefficient=-.26, p<.0001) as was the cross-lagged path coefficient between baseline physical activity and follow-up fatigue (path coefficient=-.11, p<.05). Those bi-directional associations were independent of depression, disability status, disease duration, sex, and age. There were no statistically significant cross-lagged path coefficients between depression and physical activity. CONCLUSIONS: This study identified bi-directional associations between fatigue and physical activity over an 18-month period of time. The nature of such associations opens the door for research on fatigue management as an approach for sustaining or promoting physical activity over time.

Mobility, balance and falls in persons with multiple sclerosis.

BACKGROUND: There is a lack of information concerning the relation between objective measures of gait and balance and fall history in persons with MS (PwMS). This investigation assessed the relation between demographic, clinical, mobility and balance metrics and falls history in persons with multiple sclerosis (MS). METHODS: 52 ambulatory persons with MS (PwMS) participated in the investigation. All persons provided demographic information including fall history over the last 12 months. Disease status was assessed with Expanded Disability Status Scale (EDSS). Walking speed, coordination, endurance and postural control were quantified with a multidimensional mobility battery. RESULTS: Over 51% of the participants fell in the previous year with 79% of these people being suffering recurrent falls. Overall, fallers were older, had a greater prevalence of assistive devices use, worse disability, decreased walking endurance, and greater postural sway velocity with eyes closed compared to non-fallers. Additionally, fallers had greater impairment in cerebellar, sensory, pyramidal, and bladder/bowel subscales of the EDSS. CONCLUSIONS: The current observations suggest that PwMS who are older, more disabled, utilize an assistive device, have decreased walking coordination and endurance and have diminished balance have fallen in the previous year. This suggests that individuals who meet these criteria need to be carefully monitored for future falls. Future research is needed to determine a prospective model of falls specific to PwMS. Additionally, the utility of interventions aimed at reducing falls and fall risk in PwMS needs to be established.

Social cognitive variables as correlates of physical activity in persons with multiple sclerosis: findings from a longitudinal, observational study.

There is a lack of data regarding the associations among changes in social cognitive variables and physical activity over time in persons with multiple sclerosis (MS). To that end, the current study adopted a panel design and analysis for examining hypothesized relationships among changes in social cognitive variables and physical activity over time in persons with MS, and this is necessary for designing effective behavioral interventions. On two occasions separated by an 18-month period, persons (N = 218) with relapsing-remitting MS (RRMS), who were initially recruited by telephone for a cross-sectional study, completed a battery of questionnaires that assessed social cognitive variables and physical activity. Those study materials were delivered and returned via the United State Postal Service. The 18-month changes in self-efficacy (path coefficient = .25, p < .01) and goal setting (path coefficient = .26, p < .01) had direct effects on residual change in physical activity. The change in self-efficacy further had an indirect effect on residual change in physical activity that was accounted for by change in goal setting (path coefficient = .05, p < .05). This longitudinal study suggests that self-efficacy and goal setting represent plausible targets for changing physical activity behavior in persons with RRMS.

Most common types of physical activity self-selected by people with multiple sclerosis.

The promotion of physical activity for people with multiple sclerosis (MS) would benefit from information about the common types of physical activity self-selected by this population. This study examined the most frequent types of physical activity self-reported by a large sample of people with MS. The data were collected as part of the baseline assessment of a longitudinal investigation of physical activity in relapsing-remitting MS (RRMS). The participants (N = 272) were sent a battery of questionnaires through the US Postal Service that included the Modifiable Activity Questionnaire for assessing types of physical activity performed during the previous year. Walking was ranked number 1 for both the first and second most common types of physical activity self-selected by people with MS, and it was ranked number 4 as the third most common type of self-selected physical activity. Collectively, 79% of the sample reported walking as a frequent form of self-selected physical activity in the previous year. Other notable types of physical activities self-selected by people with MS were gardening (44%), weight training (34%), bicycling (30%), and calisthenics (20%). This information may assist clinicians and practitioners in the development of physical activity programs and recommendations for people with MS.