Pilot Trial of a Social Cognitive Theory-Based Physical Activity Intervention Delivered by Nonsupervised Technology in Persons With Multiple Sclerosis.

BACKGROUND: Physical inactivity is prevalent in people with multiple sclerosis (MS) and this highlights the importance of developing behavioral interventions for increasing physical activity (PA) in MS. This pilot trial examined the efficacy of a 6-week, behavioral intervention based on social cognitive theory (SCT) delivered by newsletters and phone calls for increasing PA in persons with MS who were physically inactive and had middle levels of self-efficacy. METHODS: The sample included 68 persons with relapsing-remitting MS who were randomly assigned into intervention and control groups. The intervention group received SCT-based information by newsletters and phone calls, whereas the controls received information regarding topics such as stress management over 6 weeks. Participants completed self-report of PA and social cognitive variables. RESULTS: The intervention group had a significant increase in self-reported PA (d = 0.56, P = .02) over the 6 weeks, but the controls had a nonsignificant change (d = -0.13, P = .45). Goal setting was changed in the intervention group (d = 0.68, P ≤ .01) and identified as a significant mediator of change in self-reported PA. CONCLUSIONS: This study provides initial evidence for the benefit of a theory-based behavioral intervention for increasing PA in MS.

Social cognitive predictors of physical activity in relapsing-remitting multiple sclerosis.

BACKGROUND: Persons with relapsing-remitting multiple sclerosis (RRMS) are often sedentary, despite the benefits of the regular physical activity. This has motivated the search for variables that act as determinants of physical activity. Such variables are derived from theory and presumably represent targets of behavioral interventions for increasing physical activity. PURPOSE: This prospective, observational study examined variables from social cognitive theory as determinants of physical activity 6 weeks later in persons with RRMS. METHODS: Persons (N = 68) with RRMS initially completed a questionnaire battery that included measures of self-efficacy, physical, social, and self-evaluative outcome expectations, functional limitations as an impediment, social support as a facilitator, and goal setting for physical activity. The participants wore an accelerometer and completed a self-reported physical activity measure 6 weeks later. Data were analyzed using path analysis in Mplus 3.0. RESULTS: Self-efficacy (path coefficient = 0.19, p < 0.05), functional limitations (path coefficient = -0.33, p < 0.0001), and goal setting (path coefficient = 0.26, p < 0.01) had statistically significant direct effects on physical activity. Self-efficacy further had a statistically significant indirect effect on physical activity by way of functional limitations (path coefficient = 0.12, p < 0.05), but not by goal setting (path coefficient = 0.02, p = 0.66). This model explained 28 % of the variance in physical activity. CONCLUSIONS: This prospective study suggests that self-efficacy, functional limitations, and goal setting might represent modifiable targets of behavioral interventions for increasing physical activity among persons with RRMS.

Does physical activity change over 24 months in persons with relapsing-remitting multiple sclerosis?

OBJECTIVE: There is strong evidence for prevalent physical inactivity among persons with multiple sclerosis (MS). By comparison, very little is known about natural occurring change in physical activity over time. Such inquiry is important for identifying the rate, patterns, and predictors of change for the design and delivery of behavioral interventions in this population. The present study conducted latent growth modeling (LGM) and latent class growth analysis (LCGA) for understanding the rate, patterns, and predictors of change in physical activity over a 24-month period among persons with MS. METHODS: On three occasions each separated by 12 months, persons (n = 269) with relapsing-remitting MS (RRMS) completed a battery of questionnaires that included assessment of physical activity behavior. Data were analyzed using Mplus 3.0. RESULTS: The LGM indicated that a linear model provided a good fit to the data (χ2 = 3.94, p = .05, CFI = .987, SRMR = .025), but the slope (Ms = 0.8) was nonsignificant (p > .05) and indicated no change in physical activity over time. LCGA identified a 2-class solution, and, based on the Lo-Mendell-Rubin likelihood ratio test, this model fit the data better than the 1-class solution. The 2-class solution consisted of low-active (∼80%) and high-active (∼20%) persons, but there was no change in physical activity over time per group. Sex and disability, but not age and disease duration, were predictors of being in the low active class. CONCLUSIONS: There was prevalent physical inactivity, but little interindividual and intraindividual change over 24 months in this cohort of persons with RRMS. Such results identify the importance of behavior interventions, perhaps early in the disease process wherein physical inactivity originates.

Gait and six-minute walk performance in persons with multiple sclerosis.

The six-minute walk (6 MW) has been established as a clinic-based, performance measure of walking endurance that reflects community ambulation in multiple sclerosis (MS). Consequently, identifying the contribution of variables to 6 MW performance may provide targets for improving real-life walking in MS, and these variables may differ as a function of disability. This study examined cadence and stride length as gait variables that explain differences in 6 MW performance between persons with MS and controls, and by level of disability. 256 community-residing persons with MS and 49 non-MS controls performed a standard 6 MW test and completed 2 trials of comfortable walking on an electronic walkway for quantifying gait. Regression analyses indicated that cadence and stride length explain differences in 6 MW performance between MS and controls, and by level of disability in MS. The contribution of cadence and stride length to walking endurance differed as a function of disability, such that cadence and to a greater extent stride length explained variance in 6 MW performance in mild MS, whereas cadence and stride length explained approximately an equivalent amount of variance in 6 MW performance in moderate-to-severe MS. We provide evidence for intervention strategies that are specific to disability level to improve walking endurance in 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.

Physical activity, self-efficacy, and health-related quality of life in persons with multiple sclerosis: analysis of associations between individual-level changes over one year.

BACKGROUND: Physical activity and self-efficacy represent behavioral and psychological factors, respectively, that are compromised in persons with multiple sclerosis (MS), but might be modifiable through intervention and result in better health-related quality of life (HRQOL). PURPOSE: The present study adopted a panel research design and examined the associations between individual-level changes in physical activity, self-efficacy, and HRQOL over a one-year period in persons with MS. METHOD: The sample consisted of 269 persons with relapsing-remitting MS who completed the Godin Leisure-Time Questionnaire (GLTEQ), Multiple Sclerosis Self-Efficacy (MSSE) Scale, and Multiple Sclerosis Quality of Life-29 (MSIS-29) Scale on two occasions that were separated by 1 year. The data were analyzed using panel analysis in Mplus 3.0. RESULTS: The initial panel analysis indicated that individual-level change in physical activity was associated with individual-level change in both physical and psychological HRQOL. The subsequent panel analysis indicated that (a) individual-level change in self-efficacy for functioning with MS was associated with individual-level change in physical HRQOL, whereas individual-level change in self-efficacy for control was associated with individual-level change in psychological HRQOL; (b) individual-level change in self-efficacy for functioning with MS, but not self-efficacy for control, mediated the association between individual-level change in physical activity and physical HRQOL; and (c) individual-level change in self-efficacy for controlling MS was the strongest predictor of individual-level change in HRQOL. CONCLUSION: Physical activity and self-efficacy both might be important targets of subsequent behavioral and self-management interventions for improving the HRQOL of persons with MS, although self-efficacy is seemingly more important than physical activity.

Body composition and physical function in women with multiple sclerosis.

Persons with multiple sclerosis (MS) have reduced physical activity (PA) and lower-limb physical function and potentially disordered body composition compared with their peers without MS. The aim of this study was to determine whether PA and body composition were differentially associated with lower-limb physical function in persons with MS compared with controls. Females with MS and age- and body mass index-matched female controls (n = 51; average age 48.1 +/- 9.7 yr) were measured for PA with daily step counts, relative fat mass (%Fat), and leg lean mass (LM-LEG) via dual energy X-ray absorptiometry and for lower-limb physical function with objective performance tests. Persons with MS had 12.5% to 53% poorer lower-limb physical function than controls (all p < 0.05). PA, %Fat, and LM-LEG to body mass ratio (LM-LEG/BM) were associated with lower-limb physical function in both persons with MS and controls (all p < 0.05). Based on median splits, higher %Fat, lower LM-LEG/BM, and MS conferred poorer lower-limb physical function (all p < 0.05). PA, %Fat, and LM-LEG/BM were associated with lower-limb physical function, suggesting that body composition, specifically reducing adiposity and increasing lean mass and/or increasing PA levels, may be a potential target for MS interventions.

Further validation of multiple sclerosis walking scale-12 scores based on spatiotemporal gait parameters.

OBJECTIVE: To examine the association between Multiple Sclerosis Walking Scale-12 (MSWS-12) scores and spatiotemporal parameters of gait as indicators of gait quality among ambulatory persons with multiple sclerosis (MS). DESIGN: Cross-sectional study. SETTING: University research laboratory. PARTICIPANTS: Community-residing persons with MS (N=268). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Main outcome measures included the MSWS-12 and spatial and temporal gait parameters (walking speed, cadence, step length, step time, base of support [ie, the distance between 1 footfall and the line of progression of the opposing foot], and percentage of gait cycle spent in double support). Secondary outcomes included the timed 25-foot walk (T25FW), 6-minute walk (6MW), and Patient-Determined Disease Steps scale. RESULTS: MSWS-12 scores were significantly correlated with walking speed (r=-.59), cadence (r=-.50), step length (r=-.53), step time (r=.46), base of support (r=.29), and percentage of the gait cycle spent in double support (r=.54). MSWS-12 scores further were significantly correlated with T25FW (r=.57) and 6MW (r=-.75) scores. CONCLUSIONS: Such findings suggest that the MSWS-12 captures aspects of walking quality, assessed as spatiotemporal parameters of gait, in addition to walking speed and endurance in persons with MS.

Accelerometer output and its association with energy expenditure in persons with multiple sclerosis.

Limited data support the strong association between rates of accelerometer activity counts and energy expenditure during dynamic activity in persons with multiple sclerosis (MS). This study examined the association between rates of activity counts and energy expenditure during walking by using two models of accelerometers and generated cut-points representing moderate-to-vigorous physical activity (MVPA) in persons with MS. Participants were 43 persons with MS and 43 controls who undertook 5 min of seated rest and up to five 6 min periods of walking at five different speeds on a treadmill. While walking, participants wore two models of accelerometers and a mouthpiece in-line with an open-circuit spirometry system for measuring energy expenditure (rate of oxygen consumption). Strong linear associations were found between accelerometer activity counts and energy expenditure, and the magnitude did not differ between MS and controls for both accelerometer models. The mean slopes of the linear relationships were steeper in persons with MS than controls and resulted in distinct cut-points for MVPA based on accelerometer counts for persons with MS and controls. The strong linear relationship between activity counts and energy expenditure and cut-points for quantifying time spent in MVPA should allow for better understanding of physical activity and examination of its predictors and consequences when using accelerometers in MS.

Energy cost of walking and its association with gait parameters, daily activity, and fatigue in persons with mild multiple sclerosis.

BACKGROUND: Energy cost of walking (C(w)) is elevated in persons with multiple sclerosis (MS), perhaps because of gait impairment, and may impact daily activity and fatigue. OBJECTIVE: The authors examined for associations between C(w), spatiotemporal gait parameters, daily activity, and perceived fatigue in persons with mild MS. METHODS: Forty-four participants completed 4 trials of walking on a GAITRite mat and one 6-minute trial of walking on a treadmill at a constant, controlled speed of 54 m min(-1) while expired gases were analyzed for oxygen consumption. Participants also completed the Fatigue Severity Scale (FSS) and wore a waist-mounted accelerometer for 7 days. RESULTS: C (w) was significantly and inversely associated with gait speed (r = -.25) and stride length (r = -.32) and positively associated with double limb support (r = .27). C (w) was significantly and inversely associated with daily accelerometer activity counts (r = -.35) and positively associated with FSS scores (ρ = .31). CONCLUSION: The results support the development and application of rehabilitation strategies to address impaired gait parameters as an approach to improve C(w), daily activities, and fatigue.

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.

Accelerometry is associated with walking mobility, not physical activity, in persons with multiple sclerosis.

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 (ß=.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.

Accuracy of the actibelt(®) accelerometer for measuring walking speed in a controlled environment among persons with multiple sclerosis.

BACKGROUND: Advances in portable sensor technology have opened an era for objective, real-life monitoring of walking speed in persons with multiple sclerosis (MS). PURPOSE: The present study examined the accuracy of the actibelt(®) accelerometer for measuring walking speed during a standard 6-min walk (6MW) and the possibility that disability status influenced the degree of accuracy among persons with MS. METHODS: On a single testing session, 51 persons with MS and Expanded Disability Status Scale scores between 2.0 and 6.5 performed a 6MW while wearing an actibelt(®) in the body's sagittal symmetry plane and close to the body's centre of mass. RESULTS: All 51 participants completed the 6MW without stopping, falling, or any adverse events, and the actibelt(®) provided walking speed data for each of the participants. The actibelt(®) significantly overestimated walking speed (actual minus actibelt(®)) by a mean±standard deviation of -0.12±0.17 m/s for the overall sample (p<0.0001). There was no significant overestimation in the sample with mild disability (-0.02±0.11 m/s), but there was in the samples with moderate (-0.10±0.16 m/s) and severe (-0.26±0.12 m/s) disability. CONCLUSION: The actibelt(®) is ready for real-life monitoring of walking speed in persons with mild MS, but caution is necessary when interpreting the accuracy of the walking speed data for those with MS who have moderate and severe disability.

Physical activity, social support, and depression: possible independent and indirect associations in persons with multiple sclerosis.

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 (ß = -0.21, p = 0.002) and social support (ß = -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.

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.

Social cognitive correlates of physical activity: findings from a cross-sectional study of adults with relapsing-remitting multiple sclerosis.

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.

Effects of change in fatigue and depression on physical activity over time in relapsing-remitting multiple sclerosis.

This prospective, observational study examined the effects of change in the symptoms of fatigue and depression on physical activity over time in persons with relapsing-remitting multiple sclerosis (RRMS). Adults with a confirmed diagnosis of RRMS completed a battery of questionnaires at baseline (n = 269) and six-month follow-up (n = 263). The data were analyzed using linear panel analysis and covariance modeling in Mplus 3.0. The panel model fit the data (χ(2) = 24.00, df = 15, p = 0.07, SRMR = 0.04, CFI = 0.98) and demonstrated that changes in both fatigue (path coefficient = -0.09) and depressive symptoms (path coefficient = -0.12) were significantly associated with residual change in physical activity. Such findings support the importance of fatigue and depression for predicting longitudinal changes in physical activity in adults with RRMS.

Oxygen cost of treadmill and over-ground walking in mildly disabled persons with multiple sclerosis.

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.