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Background: The six-minute walk (6MW) test has been identified as a valid, reliable, and reproducible measure of endurance walking performance that differentiates persons with multiple sclerosis (MS) and controls and correlates with disability and walking impairment., Aim: This study examined symptoms of fatigue, pain, and depression as correlates of 6MW performance and the possibility that such symptoms would account for the difference in 6MW distance between persons with MS and controls., Design: Observational., Setting: Research laboratory., Population: Sixty-six persons, 33 with MS and 33 controls matched on age, sex, height, and weight. METHODS. Participants completed the fatigue severity scale (FSS), short-form of the McGill pain questionnaire (SF-MPQ), and depression items of the hospital anxiety and depression scale (HADS-D) and then performed the six-minute walk (6MW) in a rectangular corridor., Results: There were statistically significant differences between groups in 6MW distance (p = 0.0001) and FSS (P=0.0001) and SF-MPQ (P=0.025), but not HADS-D (P>0.05), scores. 6MW distance was significantly correlated with FSS (P=-0.66), SF-MPQ (P=-0.38), and HADS-D (P=-0.33) scores in the overall sample, but 6MW distance was significantly correlated with only FSS scores in the separate samples of those with MS (P=-0.46) and controls (P=-0.46). Only group (β=0.32) and FSS scores (β=-0.53) explained variance in overall 6MW distance in a hierarchical, linear regression analysis., Conclusion: This study provides new insight into the symptomatic correlates of 6MW performance and identifies fatigue as a possible target of interventions designed to improve walking endurance in MS., Clinical Rehabilitation Impact: Clinicians and practitioners might consider targeting fatigue as a method of managing compromised endurance walking in persons with MS.

Single motherhood has been associated with negative health consequences, such as increased risk for cardiovascular disease and depression, which might be accompanied by reduced levels of physical activity. This pilot study aimed to compare the magnitude of differences in physical activity between unmarried mothers, married mothers, and non-mothers. Participants (N = 66) in three equal-sized groups (n = 22) completed a battery of physical activity questions and wore an accelerometer for one week in March to May of 2012. Analyses of covariance controlling for group differences in demographic characteristics and Bonferroni post-hoc comparisons were conducted to detect differences in physical activity between groups. Compared to unmarried mothers, married mothers and non-mothers had significantly greater leisure time activity as measured by the Godin leisure-time exercise questionnaire (F(2,61) = 6.11, p = .004), overall activity in the previous year measured by the modifiable activity questionnaire scores (F(2, 61) = 8.65, p = .001), and minutes spent in moderate-to-vigorous physical activity from the accelerometer (F(2,58) = 4.39, p = .02). No statistically significant differences were observed among groups for international physical activity questionnaire scores or accelerometer activity and step counts. Overall, unmarried mothers were less physically active when compared to married mothers and non-mothers. Future studies should explore the correlates and health outcomes associated with physical activity among unmarried mothers.

Background: Disability progression is a hallmark feature of multiple sclerosis (MS) that has been predicted by a variety of demographic and clinical variables and treatment with disease modifying therapies. This study examined premorbid physical activity as a predictor of change in disability over 24 months in persons with relapsing-remitting MS (RRMS)., Methods: 269 persons with RRMS completed baseline measures of demographic and clinical variables, premorbid and current physical activity, and disability status. The measure of disability was further completed every six months over the subsequent 24-month period. The data were analyzed with unconditional and conditional latent growth curve modeling (LGCM)., Results: The unconditional LGCM indicated that there was a significant, linear increase in disability scores over time (p=.0015). The conditional LGCM indicated that premorbid physical activity significantly predicted the linear change in disability scores (standardized β=-.23, p<.005); current physical activity (standardized β=-.02, p=.81), gender (standardized β=-.06, p=.54), age (standardized β=.05, p=.56), duration of MS (standardized β=.11, p=.15), and treatment with disease modifying therapies (standardized β=-.03, p=.77) did not predict change in disability scores., Conclusions: The current research highlights the possible role of premorbid physical activity for lessening disability progression over time in persons with RRMS. Additional research is necessary on physical activity initiated after the diagnosis of RRMS as a lifestyle approach for bolstering physiological reserve and preventing disability progression., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Accelerometers are seemingly a criterion standard of real-life walking mobility and this is supported by assumptions and empirical data. This application would be strengthened by including objective measures of walking mobility along with a matched control sample for verifying specificity versus generality in accelerometer output. We compared associations among accelerometer output, walking mobility, and physical activity between persons with multiple sclerosis (MS) and controls without a neurological disorder. Sixty-six persons (33 MS, 33 matched controls) completed a battery of questionnaires, performed the six-minute walk (6MW) and timed-up-and-go (TUG), and wore an accelerometer for a 7-day period. After this period, participants completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ) and International Physical Activity Questionnaire (IPAQ). Accelerometer output was significantly correlated with only mobility measures (6MW, ρ=.78; TUG, ρ=-.68) in MS, whereas it correlated with both mobility (6MW, ρ=.58; TUG, ρ=-.49) and physical activity (GLTEQ, ρ=.56; IPAQ, ρ=.53) measures in controls. Regression analysis indicated that only 6MW explained variance in accelerometer output in MS (β=.65, R(2)=.43). These findings support the possibility that accelerometers primarily and specifically measure real-life walking mobility, not physical activity, in persons with MS., (Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.)

Objective: This brief report describes the possibility of reactivity in the baseline assessment of physical activity using accelerometry from two separate randomized controlled trials of a behavior intervention for increasing physical activity in persons with multiple sclerosis (MS)., Method: The samples included 18 persons with multiple sclerosis (MS) from Study 1 and 20 from Study 2 who were randomized into treatment arms of the intervention. The participants initially wore an accelerometer over a 7-day period for collection of baseline data, and one week later wore a pedometer over a 7-day period for collection of data for self-monitoring and goal setting in week 1 of the 12-week intervention. The accelerometer and pedometer data were both expressed in average steps per day over a 7-day period., Results: There was a moderate (d = .56), statistically significant (p = .03) difference of 1,822 steps per day between baseline and week 1 of the intervention in Study 1. There was a large (d = 1.36), statistically significant (p = .0001) difference of 2,338 steps per day in Study 2., Conclusion: We are unaware of other research describing a significant change in physical activity between baseline and the first week of a behavioral intervention and believe that this change reflects reactivity in the baseline assessment using accelerometry.

Background and Purpose: The disabling consequences of multiple sclerosis (MS) emphasize the significance of developing physiologically relevant strategies for rehabilitation of function. This pilot study examined changes in walking function associated with combined exercise training consisting of aerobic, resistance, and balance activities in persons with MS who had recent onset of gait impairment., Methods: Thirteen participants with significant disability due to MS (Expanded Disability Status Scale range = 4.0-6.0) completed the Multiple Sclerosis Walking Scale-12, 2 trials of the Timed 25-Foot Walk, the Timed Up & Go, and functional ambulation profile score derived from 4 walking trials on an instrumented walkway (GaitRite) before and after an 8-week training period. The training program was designed by a physical therapist and was performed 3 days per week under the supervision of an exercise specialist. In week 1, the session was 15 minutes in duration (ie, 5 minutes of each mode of exercise), session durations were increased by approximately 5 minutes per week up to a maximum of 60 minutes in week 8 (ie, 20 minutes of each mode of exercise)., Results: There were significant improvements in Multiple Sclerosis Walking Scale-12 scores (Mpre = 56.0, Mpost = 46.7, P = 0.03, d = 0.56), Timed 25-Foot Walk (Mpre = 11.7, Mpost = 9.8, P = 0.004, d = 0.90) and Timed Up & Go (Mpre = 16.0, Mpost = 13.0, P = 0.01, d = 0.72) performance, and functional ambulation profile score (Mpre = 72.8, Mpost = 77.6, P = 0.02, d = 0.65)., Discussion and Conclusion: These results suggest that a moderately intense, comprehensive, combined exercise training program represents a rehabilitation strategy that is associated with improved walking mobility in a small sample of persons with MS who have recent onset of gait impairment.

Background: Persons with multiple sclerosis (MS) have consistently reported lower levels of self-esteem compared with the general population. Despite this, very little is known about the antecedents and consequences of self-esteem in persons with MS., Objectives: To examine (1) physical activity and social support as potentially modifiable correlates (i.e., antecedents) of self-esteem and (2) physical and psychological health-related quality of life as possible consequences of self-esteem in persons with MS., Methods: Participants (N = 46) wore an Actigraph accelerometer for 7 days and then completed a battery of questionnaires, including the Rosenberg Self-Esteem Scale (RSES), Multiple Sclerosis Impact Scale (MSIS-29), and Social Provisions Scale (SPS). The data were analyzed using PASW Statistics 18., Results: Bivariate correlation analysis indicated that average daily step counts (r = .298, p = .026) and social support (r = .366, p = .007) were significantly correlated with self-esteem. Multiple linear regression analysis indicated that only social support was a significant predictor of self-esteem scores (β = .411, p = .004); pedometer steps approached significance as a predictor of self-esteem (β = .178, p = .112). Bivariate correlation analysis further indicated significant negative associations between self-esteem and physical (r = -.391, p = .004) and psychological (r = -.540, p = .0001) domains of health-related quality of life (HRQOL), indicating that higher self-esteem was associated with more positive HRQOL., Conclusions: Social support is a potentially modifiable variable that may be important to target when designing interventions to improve self-esteem and this might have implications for improving physical and psychological HRQOL in persons with MS.

The present study examined the pattern of associations among physical activity, social support, mobility disability, perceived stress, and depressive symptoms in relapsing-remitting MS (RRMS). Persons (N = 218) with RRMS completed a battery of questionnaires that was sent and returned through the United States Postal Service (USPS). Bivariate correlation analysis indicated that physical activity and social support were both inversely associated with depressive symptoms (r's = -0.288 and -0.386, p ≤ 0.05, respectively). Multiple linear regression analysis indicated that physical activity (β = -0.21, p = 0.002) and social support (β = -0.37, p = 0.0001) were independently associated with depressive symptoms. Path analysis confirmed that the associations between physical activity and social support with depressive symptoms were indirect via mobility disability and perceived stress. Collectively, the evidence indicates that physical activity and social support are independently and indirectly associated with depression via mobility disability and perceived stress in relapsing-remitting MS. This supports the design of interventions and programs that target physical activity and social support for reducing depressive symptoms among persons with MS.

Purpose: The aim of the current study was to better understand the adoption and maintenance of physical activity from the perspective of women with multiple sclerosis (MS)., Methods: Participants (N = 11) were women with MS who had low levels of disability and who engaged in varying levels of physical activity. Participants completed two semi-structured, audio taped interviews focusing on their beliefs, motivators, and experiences of physical activity., Results: Across all activity levels participants reported similar beliefs and motivations related to being physically active including the desire to be "normal", savoring current health, enjoyment of the activity, "feeling good" after activity, weight control, and maintenance of physical function. Active and inactive participants differed in the practical strategies they reportedly used to adopt and maintain physical activity, such as prioritizing and scheduling physical activity, managing disease-specific barriers, and building social support networks., Conclusions: A consideration of these beliefs, motivations, and strategies may be useful for designing behavioral interventions to increase physical activity that are sensitive to the needs and preferences of women with MS.

Physical activity is associated with many benefits, but persons with multiple sclerosis (MS) are less physically active than the general population. There is a critical need for research on methods of increasing and sustaining the physical activity levels of this population. This randomized controlled trial examined the efficacy of an Internet-delivered and theory-based behavioral intervention that was supplemented with video coaching for increasing and sustaining physical activity over time in persons with MS. Physically inactive, ambulatory persons with MS (N = 45) were randomly assigned to intervention (n = 22) or control (n = 23) conditions and completed a battery of questionnaires before, after, and three months after a 12-week intervention period. Data analyses were conducted in PASW 18.0. Partial eta squared ([Formula: see text]) effect size indicated that there was a large, statistically significant condition-by-time interaction on physical activity ([Formula: see text]). Cohen's d effect sizes indicated that the intervention group had a large increase in physical activity after the 12-week trial (d = .98) that was sustained over a three-month follow-up (d = .79). The current study supports the efficacy of a behavioral intervention for increasing and sustaining physical activity in a sample of persons with MS.

The accumulation of excess body weight may have important health and disease consequences for persons with multiple sclerosis (MS). This study examined the effect of weight status on mobility using a comprehensive set of mobility outcomes including ambulatory performance (timed 25-foot walk, T25FW; 6-minute walk, 6MW; oxygen cost of walking, C(w); spatiotemporal parameters of gait; self-reported walking impairment, Multiple Sclerosis Walking Scale-12 (MSWS-12); and free-living activity, accelerometry) in 168 ambulatory persons with MS. Mean (SD) BMI was 27.7 (5.1) kg/m(2). Of the 168 participants, 31.0% were classified as normal weight (BMI = 18.5-24.9 kg/m(2)), 36.3% were classified as overweight (BMI = 25.0-29.9 kg/m(2)), and 32.7% were classified as obese, classes I and II (BMI = 30-39.9 kg/m(2)). There were no significant differences among BMI groups on T25FW and 6MW, C(w), spatiotemporal gait parameters, MSWS-12, or daily step and movement counts. The prevalence of overweight and obesity in this sample was almost 70%, but there was not a consistent nor significant impact of BMI on outcomes of mobility. The lack of an effect of weight status on mobility emphasizes the need to focus on and identify other factors which may be important targets of ambulatory performance in persons with MS.

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., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Accelerometer activity counts have been correlated with energy expenditure during treadmill walking among ambulatory adults with multiple sclerosis (MS). This study examined the effects of gait disability on 1) the association between rates of energy expenditure and accelerometer output in overground walking and 2) the calibration of accelerometer output for quantifying time spent in moderate-to-vigorous physical activity (MVPA) in people with MS. The sample consisted of 24 individuals with MS, of whom 10 reported gait disability based on Patient-Determined Disease Steps (PDDS) scores. The participants undertook three 6-minute periods of overground walking while wearing an accelerometer and a portable metabolic unit (K4b2, Cosmed, Rome, Italy). In the first period of walking, the participants walked at a self-selected, comfortable speed. In the two subsequent walking periods, participants walked at speeds above and below (±0.5 mph) the comfortable walking speed, respectively. Strong linear relationships were observed between rates of accelerometer activity counts and energy expenditure during walking in the overall sample (R(2) = 0.90) and subsamples with (R(2) = 0.88) and without gait disability (R(2) = 0.91). The slope of the relationship was significantly steeper in the subsample with gait disability (β= 0.0049) than in the subsample without gait disability (β= 0.0026). The difference in slopes resulted in a significantly lower cut-point for MVPA (1886 vs. 2717 counts/min) in those with gait disability. These findings provide a metabolic cut-point for quantifying time spent in MVPA in people with MS, both with and without gait disability.

The present study adopted an interrupted time-series design for identifying the possibility of behavioral reactivity and examining the effect of an Internet-delivered behavioral intervention for increasing self-reported and objectively-measured physical activity among persons with multiple sclerosis (MS). Participants (n = 18) wore an accelerometer for 7 days and completed a battery of questionnaires to measure physical activity at 3 time points (before and after a 3-month period of no treatment and again after a 3-month period of treatment). There was a small change in objectively-measured, but not self-reported, physical activity in the period of no treatment, whereas there was a large increase in self-reported and objectively-measured physical activity in the period of treatment. These findings both complement and extend previous research and further support the efficacy of the current Internet behavioral intervention for increasing physical activity in persons with MS.

Background: Persons with multiple sclerosis (MS) are often physically inactive and sedentary. This observation has prompted the search for modifiable variables derived from established theories that act as correlates of physical activity. Such variables would presumably represent targets for interventions designed to promote change in physical activity behavior among persons with MS. The current study examined social cognitive variables as correlates of physical activity in persons with MS., Methods: Persons (N = 218) with relapsing-remitting MS completed a questionnaire battery that assessed physical activity behavior; self-efficacy for physical activity; physical, social, and self-evaluative outcome expectations for exercise, functional limitations as an impediment for physical activity, and exercise goal-setting. The battery was delivered and returned through the US postal service. Data were analyzed using covariance modeling in Mplus 3.0., Results: Self-efficacy had indirect effects on physical activity via impediments (path coefficient = .10, P < .005), self-evaluative outcome expectations (path coefficient = .07, P < .025), and goal-setting (path coefficient = .09, P < .01). The model explained 40% of variance in self-reported physical activity., Conclusions: This cross-sectional study suggests that self-efficacy is indirectly associated with physical activity by way of goals, self-evaluative outcome expectations, and impediments in persons with relapsing-remitting MS.

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.

Persons with multiple sclerosis (MS) are often physically inactive. This observation has prompted the search for modifiable constructs derived from established theories that act as correlates of physical activity. This study investigated self efficacy, outcome expectations, impediments, and goal setting as correlates of physical activity in inactive persons with MS. Participants (n=54) completed a battery of measures as part of baseline data collection from an ongoing Internet intervention for increasing physical activity in inactive persons with MS. Bivariate correlation analysis indicated that physical activity was significantly correlated with outcome expectations (r=0.29), functional limitations (r=0.28), and goal setting (r=0.31), but not self efficacy (r=0.13). Multiple linear regression analysis indicated that only goal setting was significantly associated with physical activity (β=0.31). Such results suggest that goal setting may be a primary correlate of physical activity in inactive persons with MS.

Walking impairment is a ubiquitous feature of multiple sclerosis (MS) and the O(2) cost of walking might quantify this dysfunction in mild MS. This paper examined the difference in O(2) cost of walking between persons with MS who have mild disability and healthy controls and the correlation between the O(2) cost of walking and disability. Study 1 included 18 persons with mild MS and 18 controls and indicated that the O(2) cost of walking was significantly higher in MS than controls and that disability was significantly associated with the O(2) cost of slow, moderate, and fast treadmill walking. Study 2 included 24 persons with mild MS and indicated that disability was significantly correlated with O(2) cost of comfortable, fast, and slow over-ground walking. We provide evidence that the O(2) cost of walking is an indicator of walking dysfunction in mildly disabled persons with MS and should be considered in clinical research and practice.

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.

Background: Physical activity has been associated with improvements in walking mobility and quality of life in persons with multiple sclerosis (MS), and yet this population is largely sedentary and inactive compared with the general population., Objectives: We conducted a pilot, randomized controlled trial (RCT) for examining the effect of an Internet intervention based on social cognitive theory (SCT) for favorably increasing physical activity among persons with MS. We further examined variables from SCT as possible mediators of the Internet intervention., Methods: We randomly allocated 54 persons with MS into either an Internet intervention condition or a waitlist control condition. The participants completed measures of physical activity, self-efficacy, outcome expectations, functional limitations, and goal setting before and after the 12-week period., Results: The intervention group reported a statistically significant (p = 0.01) and large increase in physical activity over time (d = 0.72), whereas the control group had a small (d = 0.04) and non-significant change in physical activity (p = 0.71). The intervention group further reported a statistically significant (p = 0.001) and large increase in goal setting over time (d = 0.97), whereas the control group had a small (d = -0.13) and non-significant change (p = 0.17). The change in goal setting over time mediated the effect of the Internet intervention on physical activity behavior., Conclusions: This pilot study sets the stage for a subsequent RCT that includes a larger sample of persons with MS, longer intervention period along with a follow-up, objective measure of physical activity, and secondary outcomes of walking mobility and QOL.

Our previous research indicated that an Internet intervention was effective in increasing self-reported physical activity in persons with multiple sclerosis (MS). The present study examined the efficacy of the same Internet intervention in persons with MS by using both objective and self-report measures of physical activity. Participants (N = 21) wore an accelerometer around the waist for 7 days and then completed the International Physical Activity Questionnaire (IPAQ) and Godin Leisure-Time Exercise Questionnaire (GLTEQ) before and after receiving the 12-week Internet intervention. The Internet intervention resulted in moderate increases in accelerometer activity counts (d = 0.68) and steps counts (d = 0.60), and this was paralleled by small increases in IPAQ (d = 0.43) and GLTEQ (d = 0.34) scores. The number of weeks that persons logged on was correlated with change in accelerometer activity counts (r = 0.42) and step counts (r = 0.37) but not change in IPAQ (r = 0.10) or GLTEQ (r = 0.08) scores. The novel contribution of this study was the observation that an Internet intervention was efficacious for increasing physical activity in persons with MS by using both objective and self-report measures.

The valid application of accelerometry and interpretation of its output (i.e., counts per unit time) for the measurement of walking behavior in persons with multiple sclerosis (MS) rests upon multiple untested assumptions. This study tested the assumption that a waist-worn accelerometer should capture the intra- and inter-person variation in walking behavior. Twenty-four participants with a neurologist-confirmed diagnosis of MS and who were ambulatory with minimal assistance undertook three 6-min periods of over-ground walking that involved comfortable (CWS) and then slower (SWS) and faster (FWS) walking speeds while wearing ActiGraph, model 7164, accelerometers around the waist and ankle. The experimental manipulation of walking was successful such that the CWS was 76.7±13.0m/min (range=55.6-105.14), whereas the SWS and FWS were 64.3±12.3m/min (range=44.5-90.1) and 89.1±13.8m/min (range=60.9-116.4), respectively. Movement counts from the waist and ankle-worn accelerometer were strongly associated with the manipulation of speed, but the association was stronger for the waist than ankle based on both eta-squared estimates (η(2) values=.78 and .46) and the average squared multiple correlations from individual regression analyses (R(2) values=.97±.04 and .88±.21). The bivariate correlation between movement counts from the waist-worn accelerometer and speed of walking (r=.823, p=.001) was large in magnitude and significantly different (z=3.22, p=.001) from that between movement counts from the ankle-worn unit and walking speed (r=.549, p=.001). This study provides novel evidence that an accelerometer worn around the waist captures intra- and inter-person variation in over-ground walking behavior in those with MS., (Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.)

Objective: To validate accelerometry based on its correlations with 6-minute walk distance (6MWD) and oxygen cost of walking as objective markers of walking limitations in multiple sclerosis (MS)., Design: Cross-sectional., Setting: Laboratory and general community., Participants: Ambulatory participants with MS (N=26) who resided in the local community., Interventions: Not applicable., Main Outcome Measures: Patient Determined Disease Steps (PDDS) scale and Multiple Sclerosis Walking Scale-12 (MSWS-12); 6-minute walk test while wearing a portable metabolic unit for measuring the 6MWD and oxygen cost of walking; accelerometer during the waking hours of a 7-day period., Results: The average of total daily movement counts from the accelerometer correlated significantly and strongly with MSWS-12 scores (ρ=-.681, P=.001), PDDS scores (ρ=-.609, P=.001), 6MWD (ρ=.519, P=.003), and oxygen cost of walking (ρ=-.541, P=.002)., Conclusions: We provide evidence that further supports the validity of accelerometry as a measure of walking limitations in ambulatory persons with MS., (Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Background: The 12-item multiple sclerosis walking scale (MSWS-12) has been validated against self-report and clinical markers, but has not been validated with a physiological marker of locomotor impairment., Objective: This study further validates the MSWS-12 based on its correlation with the oxygen cost (O(2) cost) of walking as a physiological marker of locomotor impairment in persons with multiple sclerosis (MS)., Methods: Participants (N=24) with MS completed the MSWS-12 and then wore a portable metabolic unit for measuring the O(2) cost of walking during three 6-min walk (6MW) tests. The first 6MW test involved the participant's comfortable walking speed (CWS), whereas the second and third 6MW tests were undertaken above (faster walking speed, FWS) and below (slower walking speed, SWS) the participant's CWS (i.e., +/-5mph CWS)., Results: MSWS-12 scores correlated strongly with O(2) cost of walking during the 6MW tests undertaken at CWS (r=.641, p=.001), FWS (r=.616, p=.001), and SWS (r=.639, p=.001)., Interpretation: We provide evidence that further confirms the validity of the MSWS-12 as a measure of the impact of MS on walking., (Copyright 2010 Elsevier B.V. All rights reserved.)