Blood pressure and cognition in older adults with multiple sclerosis: preliminary examination.

BACKGROUND: Comorbid conditions, particularly vascular comorbidity, are common in MS and may hasten the CNS damage and disease manifestations. We undertook a preliminary examination of the association between blood pressure (BP) and cognitive function in samples of older adults with MS and healthy controls. METHODS: Older adults with MS (n = 29) and healthy controls (n = 29) completed the Brief International Cognitive Assessment for MS (BICAMS) battery and underwent assessment of BP. The data were analyzed using the Baron and Kenny approach for examining blood pressure as an explanatory variable for group differences in cognition. RESULTS: The MS group, as expected, had significantly lower California Verbal Learning Test-II (CVLT-II) z-scores from the BICAMS and higher diastolic BP (DBP) than healthy controls. DBP had statistically significant correlations with CVLT-II z-scores in the overall sample (r = - .42) and MS subsample (r = - .51), but not healthy controls(r = - .29); the correlation was not attenuated when controlling for age and disability status in the MS subsample (pr = - .48). Group initially explained 6% of the variance in z-scores from the CVLT-II (ß = - 0.24). The inclusion of DBP accounted for an additional 14% of the variance in z-scores from the CVLT-II, and DBP(ß = - 0.39), but not group (ß = - 0.13), was a significant correlate of CVLT-II z-scores; the results were unchanged when controlling for anxiety and depression scores. CONCLUSION: Our results provide preliminary, cross-sectional support for future population-based research examining DBP, hypertension, and verbal memory in older adults with MS.

Effect of behavioural practice targeted at the motor action selection network after stroke.

Motor action selection engages a network of frontal and parietal brain regions. After stroke, individuals activate a similar network, however, activation is higher, especially in the contralesional hemisphere. The current study examined the effect of practice on action selection performance and brain activation after stroke. Sixteen individuals with chronic stroke (Upper Extremity Fugl-Meyer motor score range: 18-61) moved a joystick with the more-impaired hand in two conditions: Select (externally cued choice; move right or left based on an abstract rule) and Execute (simple response; move same direction every trial). On Day 1, reaction time (RT) was longer in Select compared to Execute, which corresponded to increased activation primarily in regions in the contralesional action selection network including dorsal premotor, supplementary motor, anterior cingulate and parietal cortices. After 4 days of practice, behavioural performance improved (decreased RT), and only contralesional parietal cortex significantly increased during Select. Higher brain activation on Day 1 in the bilateral action selection network, dorsolateral prefrontal cortex and contralesional sensory cortex predicted better performance on Day 4. Overall, practice led to improved action selection performance and reduced brain activation. Systematic changes in practice conditions may allow the targeting of specific components of the motor network during rehabilitation after stroke.

Examining Multilevel Environmental Correlates of Physical Activity Among Older Adults With Multiple Sclerosis.

Three hundred and sixty-three older adults with multiple sclerosis completed a cross-sectional study examining hierarchical correlates of physical activity using a social cognitive theory perspective within a social ecological model (i.e., built environment, social environment, and individual social cognitive theory variables). Hierarchical linear regression analyses were conducted, wherein significant associations were noted for built environment (i.e., land-use mix diversity and aesthetics) and physical activity in Step 1 (R2 = .09). Social and built environment were significant correlates in Step 2 (R2 = .15). Finally in Step 3, individual social cognitive theory variables (i.e., self-efficacy and outcome expectations) were the only significant correlates of total physical activity (R2 = .38). Results were comparable for health-promoting physical activity; however, self-efficacy was the only significant correlate in Step 3 (R2 = .36). This study provides guidance for researchers and practitioners on relevant targets for tailoring interventions for older adults with multiple sclerosis and supports an emphasis on self-efficacy as a primary predictor of health behavior change.

Test-retest reliability and minimal detectable change of corticospinal tract integrity in chronic stroke.

Diffusion tensor imaging (DTI) can be used to index white matter integrity of the corticospinal tract (CST) after stroke; however, the psychometric properties of DTI-based measures of white matter integrity are unknown. The purpose of this study was to examine test-retest reliability as determined by intraclass correlation coefficients (ICC) and calculate minimal detectable change (MDC) of DTI-based measures of CST integrity using three different approaches: a Cerebral Peduncle approach, a Probabilistic Tract approach, and a Tract Template approach. Eighteen participants with chronic stroke underwent DTI on the same magnetic resonance imaging scanner 4 days apart. For the Cerebral Peduncle approach, a researcher hand drew masks at the cerebral peduncle. For the Probabilistic Tract approach, tractography was seeded in motor areas of the cortex to the cerebral peduncle. For the Tract Template approach, a standard CST template was transformed into native space. For all approaches, the researcher performing analyses was blind to participant number and day of data collection. All three approaches had good to excellent test-retest reliability for fractional anisotropy (FA; ICCs >0.786). Mean diffusivity, axial diffusivity, and radial diffusivity were less reliable than FA. The ICC values were highest and MDC values were the smallest for the most automated approach (Tract Template), followed by the combined manual/automated approach (Probabilistic Tract) then the manual approach (Cerebral Peduncle). The results of this study may have implications for how DTI-based measures of CST integrity are used to define impairment, predict outcomes, and interpret change after stroke.

Targeted Engagement of the Action Selection Network during Task-Oriented Arm Training after Stroke.

Action selection (AS), or selection of an action from a set of alternatives, is an important movement preparation process that engages a frontal-parietal network. The addition of AS demands to arm training after stroke could be used to engage this motor planning process and the neural network that supports it. The purpose of this case series is to describe the feasibility and outcomes associated with task-oriented arm training aimed at engaging the AS behavioral process and the related neural network in three individuals with chronic stroke. Three participants with mild to moderate motor deficits completed 13 to 15 sessions of task-oriented arm training that included AS cues for each movement repetition; cues dictated movement direction, height, or distance. Before and after training, individuals completed an AS brain-behavior probe during functional MRI. AS behavioral performance improved after training (increased accuracy, decreased reaction time) in all participants while brain activation in the AS network (dorsal premotor, parietal, dorsolateral prefrontal cortices) decreased in two participants. Gains in motor function were also found in all three participants, especially on patient-reported measures of perceived difficulty and confidence to complete upper extremity functional tasks. It was feasible to target the AS behavioral process and the related neural network through the addition of AS demands to functional, task-oriented arm training in three individuals with mild to moderate motor dysfunction poststroke.

Response heterogeneity in fitness, mobility and cognition with exercise-training in MS.

BACKGROUND: Exercise-training is a beneficial approach for improving function in persons with multiple sclerosis (MS). However, it is unlikely that every participant who engages in an exercise-training intervention will demonstrate similar benefits. Identifying factors that may influence the accrual of specific exercise-training benefits can aid in the development of optimized rehabilitation interventions for improving specific outcomes in MS. OBJECTIVE: This study described possible response heterogeneity in physical fitness, mobility and cognitive outcomes with exercise-training and identified baseline performance, compliance and demographic/clinical outcomes as possible predictors of exercise-related changes in those outcomes. METHODS: Thirty-two persons with MS-related mobility disability completed 6-months of multimodal exercise-training. Physical fitness, mobility and cognitive processing speed (CPS) were measured before and after the 6 months. RESULTS: There was response heterogeneity in fitness, mobility and cognitive outcomes with multimodal exercise-training. Low baseline aerobic fitness, slow walking speed and slow CPS were associated with greater exercise-related improvements in those respective outcomes. CONCLUSIONS: Those with MS-related mobility disability who have the lowest aerobic fitness, walking speed and CPS might benefit the most from multimodal exercise-training. This provides critical evidence for informing the development of a precision medicine framework for improving targeted outcomes with exercise-training in MS.

Changes in Cognitive Performance With Age in Adults With Multiple Sclerosis.

BACKGROUND: Cognitive impairment is one of the most common consequences of multiple sclerosis (MS), yet there is a shortage of data regarding how cognition changes during the life span of individuals with MS. This information is of increasing importance given the growing proportion of older adults with MS. OBJECTIVE: To study possible changes in cognitive function in correlation with increasing age in individuals with MS. METHODS: Participants (N=129) were recruited and a priori allocated into one of three age groups (young, middle-aged, and older). All participants completed the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) during a single laboratory testing session. The BICAMS measures cognitive processing speed as well as verbal and visuospatial learning and memory. RESULTS: A multivariate analysis of variance indicated that cognitive function significantly differed by age group, and these differences were not explained by amount of physical activity, years of education, years since diagnosis, or race. Older adults displayed significantly worse cognitive processing speed than young and middle-aged adults. The older and middle-aged adults also demonstrated significantly worse visuospatial learning and memory than the younger adults. Effect sizes indicated that cognitive processing speed and verbal learning and memory were more affected in late adulthood than early adulthood, whereas visuospatial learning and memory was affected similarly in early and late adulthood. CONCLUSIONS: Older adults with MS demonstrated significant impairments in cognitive function compared to young and middle-aged adults with MS. Future studies should determine the predictors of cognitive decline in this age cohort.

The effect of energy-matched exercise intensity on brain-derived neurotrophic factor and motor learning.

BACKGROUND: Pairing a bout of high-intensity exercise with motor task practice can enhance motor learning beyond task practice alone, which is thought, in part, to be facilitated by an exercise-related increase in brain-derived neurotrophic factor (BDNF). The purpose of the current study was to examine the effect of different exercise intensities on BDNF levels and motor learning while controlling for exercise-related energy expenditure. METHODS: Forty-eight young, healthy participants were assigned to one of three groups: high-intensity exercise [High], low-intensity exercise [Low], or quiet rest [Rest]. The duration of the exercise bouts were individually adjusted so that each participant expended 200 kcals regardless of exercise intensity. BDNF was measured before and after exercise or rest. After exercise or rest, all participants practiced a 3-dimensional motor learning task, which involved reach movements made to sequentially presented targets. Retention was tested after 24-h. BDNF genotype was determined for each participant to explore its effects on BDNF and motor learning. RESULTS: All participants equally improved performance, indicated by a reduction in time to complete the task. However, the kinematic profile used to control the reach movement differed by group. The Rest group travelled the shortest distance between the targets, the High group had higher reach speed (peak velocity), and the Low group had earlier peak velocities. The rise in BDNF post-exercise was not significant, regardless of exercise intensity, and the change in BDNF was not associated with motor learning. The BDNF response to exercise did not differ by genotype. However, performance differed between those with the polymorphism (Met carriers) and those without (Val/Val). Compared to the Val/Val genotype, Met carriers had faster response times throughout task practice, which was supported by higher reach speeds and earlier peak velocities. CONCLUSION: Results indicated that both low and high-intensity exercise can alter the kinematic approach used to complete a reach task, and these changes appear unrelated to a change in BDNF. In addition, the BDNF genotype did not influence BDNF concentration, but it did have an effect on motor performance of a sequential target reach task.

Within-Session Practice Effects in the Jebsen Hand Function Test (JHFT).

The Jebsen Hand Function Test (JHFT) is a standardized assessment that has been used as a clinical outcome measure. To appropriately interpret the effects of an intervention on hand function (as measured by the JHFT), the extent to which this instrument shows significant practice effects must be quantified. The purpose of this study was to determine whether the JHFT is susceptible to within-session practice effects. The results showed that the dominant and nondominant hands significantly improved on the JHFT and many of its subtests over six consecutive trials. Although practice effects might complicate the interpretation of change due to intervention, we briefly relate our findings to emerging neuropsychological evidence that practice effects may indicate a person's motor learning potential or treatment responsiveness.

Health-Related Quality of Life and Physical Activity in Older Adults With Multiple Sclerosis.

BACKGROUND: People with multiple sclerosis (MS) are living longer but not necessarily better lives, and this portends reduced health-related quality of life (HRQOL). Physical activity (PA) may be a correlate of HRQOL for people with MS. We examined differences in HRQOL and PA between older adults with and without MS to determine whether PA is associated with HRQOL and whether it accounts for group differences in HRQOL. METHODS: Thirty-one older adults with MS and 30 age- and sex-matched controls without MS completed the 36-Item Short Form Health Survey (SF-36) and the Godin Leisure-Time Exercise Questionnaire (GLTEQ). Data were analyzed using the Baron and Kenny approach for examining PA via the GLTEQ as a mediator of group differences in HRQOL. RESULTS: The MS group had significantly lower component scores on the SF-36 and the GLTEQ than the control group. The GLTEQ scores were correlated with SF-36 physical component scores (r = 0.52), whereas the correlation with mental component scores (r = 0.23) was small and nonsignificant. Group assignment initially explained 31% of the variance in physical component scores (ß = 0.55) and adding GLTEQ to the model accounted for an additional 12% of the variance in physical component scores. Thus, group (ß = 0.42) and GLTEQ (ß = 0.37) were both significant correlates of physical component scores. The group effect was modestly attenuated with the addition of GLTEQ in step 2 (step 1 ß = 0.55; step 2 ß = 0.42) and indicated partial rather than full mediation. CONCLUSIONS: These results provide cross-sectional support for future research examining approaches to increase PA to possibly improve the physical component of HRQOL in older adults with MS.

Whole-Brain Metabolic Abnormalities Are Associated With Mobility in Older Adults With Multiple Sclerosis.

BACKGROUND: Older adults with multiple sclerosis (MS) experience mobility impairments, but conventional brain imaging is a poor predictor of walking abilities in this population. OBJECTIVE: To test whether brain metabolites measured with Magnetic Resonance Spectroscopy (MRS) are associated with walking performance in older adults with MS. METHODS: Fifteen older adults with MS (mean age: 60.9, SD: 5.1) and 22 age-matched healthy controls (mean age: 64.2, SD: 5.7) underwent whole-brain MRS and mobility testing. Levels of N-acetylaspartate (NAA), myo-inositol (MI), choline (CHO), and temperature in 47 brain regions were compared between groups and correlated with walking speed (Timed 25 Foot Walk) and walking endurance (Six-Minute Walk). RESULTS: Older adults with MS had higher MI in 23 areas, including the bilateral frontal (right: t (21.449) = -2.605, P = .016; left: t (35) = -2.434, P = .020), temporal (right: t (35) = -3.063, P = .004; left: t (35) = -3.026, P = .005), and parietal lobes (right: t (21.100) = -2.886, P = .009; left: t (35) = -2.507, P = .017), and right thalamus (t (35) = -2.840, P = .007). MI in eleven regions correlated with walking speed, and MI in twelve regions correlated with walking endurance. NAA was lower in MS in the bilateral thalami (right: t (35) = 3.449, P < .001; left: t (35) = 2.061, P = .047), caudate nuclei (right: t (33) = 2.828, P = .008; left: t (32) = 2.132, P = .041), and posterior cingulum (right: t (35) = 3.077, P = .004; left: t (35) = 2.972, P = .005). NAA in four regions correlated with walking speed and endurance. Brain temperature was higher in MS patients in four regions, but did not correlate with mobility measures. There were no group differences in CHO. CONCLUSION: MI and NAA may be useful imaging end-points for walking ability as a clinical outcome in older adults with MS.

Do physical activity, cardiorespiratory fitness, and subcortical brain structures explain reduced walking performance in older adults with multiple sclerosis?

BACKGROUND: As adults with multiple sclerosis (MS) age, walking speed and endurance progressively decline, yet there is limited understanding of factors that explain such age-related declines. The current study examined subcortical brain structures, cardiorespiratory fitness, and moderate-to-vigorous physical activity (MVPA) as explanations for reduced walking performance in older adults with MS. METHODS: Older adults with MS (n = 29, 62.8 ± 5.8 years) and age-and-sex matched controls (n = 28, 63.8 ± 5.5 years) completed measures of walking speed (Timed-25 ft Walk) and walking endurance (Six-minute Walk), cardiorespiratory fitness, device-measured MVPA, and underwent an MRI to provide composite volumes of the thalamus, caudate, putamen, and pallidum. We used a mediator variable framework to describe group differences, determine correlations in the overall sample, and identify variables that explain reduced walking performance. RESULTS: Compared to controls, older adults with MS had worse walking speed (p<0.001) and endurance (p<0.001), lower fitness (p = 0.04), lower levels of MVPA (p = 0.001), and smaller composite volumes of the thalamus (p=<0.001), putamen (p = 0.04), and pallidum (p = 0.007). In the overall sample, both measures of walking performance were significantly correlated with fitness, MVPA, and volumes of the thalamus and putamen (r range 0.34-0.65). Regression analyses indicated that MVPA (ß=0.007094) partially explained the group differences in walking speed, and fitness (ß=7.7640) and MVPA (ß=17.5797) partially explained the group differences in walking endurance. CONCLUSIONS: Collectively, these results suggest that cardiorespiratory fitness and MVPA, but not subcortical brain structures, may be modifiable targets of future interventions for improving walking in older adults with MS.

Social Cognitive Theory variables as correlates of physical activity in fatigued persons with multiple sclerosis.

BACKGROUND: There is interest in the application of behavioral interventions based on theory for increasing physical activity among adults with multiple sclerosis (MS). To date, researchers have applied theory such as Social Cognitive Theory (SCT) for identifying correlates of physical activity that can then inform the design and delivery of behavioral interventions. Such research often has been conducted in heterogeneous samples of persons with MS without a focus on those with a specific symptom, such as fatigue, that may be targeted by physical activity behavioral interventions. To that end, this study examined SCT variables (i.e., self-efficacy, barriers, outcome expectations, goal-setting, planning, social support, and functional limitations) as correlates of physical activity in persons with MS who self-reported elevated fatigue. METHODS: Persons with MS (N=210; aged 49.6[13.2] years) who ambulated with or without assistance participated in the study. Participants completed self-report measures of fatigue, physical activity, and SCT variables and wore an ActiGraph GT3X+ accelerometer on a belt around the waist for 7 days. The accelerometer data were processed and delineated into time spent in light and moderate-to-vigorous physical activity (MVPA) based on MS-specific cut-points. We generated groups of fatigued (n=134) and non-fatigued (n=76) persons with MS based on the cut-off score of 4 for the Fatigue Severity Scale. RESULTS: There were differences in physical activity and SCT variables between fatigued and non-fatigued persons with MS. Among those with fatigue, functional limitations (ρ=0.52), self-efficacy (ρ=0.31), and goal-setting (ρ=0.25) were associated with device-measured MVPA, and all SCT variables except outcome expectations were associated with self-reported physical activity. The regression analyses indicated self-efficacy, functional limitations, and goal-setting as significant correlates of MVPA in those with fatigue. CONCLUSION: Self-efficacy, goal-setting, and social support may be important targets of SCT-based behavioral interventions for increasing physical activity among persons with MS who have fatigue.

Cardiorespiratory fitness and moderate-to-vigorous physical activity in older adults with multiple sclerosis.

BACKGROUND: Cardiorespiratory fitness (VO2peak) may be a modifiable indicator of health status and well-being in older adults with multiple sclerosis. PURPOSE: We examined differences in VO2peak and moderate-to-vigorous physical activity between older adults with multiple sclerosis and healthy controls, and whether moderate-to-vigorous physical activity accounted for group differences in VO2peak. METHODS: Older adults with multiple sclerosis (n = 31) and healthy controls (n = 29) completed a cardiopulmonary exercise test and wore an accelerometer for measuring moderate-to-vigorous physical activity. The data were analyzed using the Baron and Kenny approach for examining moderate-to-vigorous physical activity as a mediator of group differences in VO2peak. RESULTS: The multiple sclerosis group had significantly lower VO2peak and moderate-to-vigorous physical activity than healthy controls. VO2peak had a large correlation with moderate-to-vigorous physical activity (r = .59). Group initially explained 8% of the variance in VO2peak (ß = -0.29). The inclusion of moderate-to-vigorous physical activity accounted for an additional 27% of the variance in VO2peak, but only moderate-to-vigorous physical activity (ß = 0.57) was a statistically significant correlate of VO2peak. The effect of Group was attenuated and non-significant with the addition of moderate-to-vigorous physical activity in Step 2 (Group ß Step 1 = -0.29, Group ß Step 2 = -0.05). CONCLUSIONS: Our results provide initial support for targeting moderate-to-vigorous physical activity as an approach for improving VO2peak in older adults with multiple sclerosis.

Cognitive Function and Whole-Brain MRI Metrics Are Not Associated with Mobility in Older Adults with Multiple Sclerosis.

Due to advances in disease-modifying medications and earlier management of comorbidities, adults with multiple sclerosis (MS) are living longer, and this coincides with the aging of the general population. One major problem among older adults with and without MS is limited mobility, a consequence of aging that often negatively affects quality of life. Identifying factors that contribute to mobility disability is needed to develop targeted rehabilitation approaches. This study examined cognitive processing speed and global brain atrophy as factors that may contribute to mobility disability in older adults with and without MS. Older adults (≥55 years) with MS (n = 31) and age- and sex-matched controls (n = 22) completed measures of mobility (Short Physical Performance Battery) and cognitive processing speed (Symbol Digit Modalities Test) and underwent an MRI to obtain whole-brain metrics (gray matter volume, white matter volume, ventricular volume) as markers of atrophy. Mobility was significantly worse in the MS group than in the control group (p = 0.004). Spearman correlations indicated that neither cognitive processing speed (MS: rs = 0.26; Control: rs = 0.08) nor markers of global brain atrophy (MS: rs range = -0.30 to -0.06; Control: rs range = -0.40 to 0.16) were significantly associated with mobility in either group. Other factors such as subcortical gray matter structures, functional connectivity, exercise/physical activity, and cardiovascular fitness should be examined as factors that may influence mobility in aging adults with and without MS.

Social Cognitive Theory and Physical Activity in Older Adults with Multiple Sclerosis.

BACKGROUND: The expanding population of older adults with multiple sclerosis (MS) likely experiences many of the same benefits of physical activity (PA) as younger and middle-aged adults with MS. However, participation in PA is exceedingly low in this segment of the MS population. This study examined variables from social cognitive theory (SCT) as correlates of PA in older adults with MS to inform the subsequent development of behavioral interventions. METHODS: Older adults with MS (≥60 years of age, N = 180) completed an online survey including demographic and clinical characteristics, SCT variables (exercise self-efficacy, exercise goal setting, social support, and outcome expectations), and PA (total PA [TPA] and moderate-to-vigorous PA [MVPA]). RESULTS: Bivariate correlation analyses indicated that all SCT variables were significantly associated with TPA and MVPA (all P ≤ .001). Hierarchical linear regression analyses indicated that disability status was a significant correlate of TPA (ß = -0.48, R2 = 0.23) and MVPA (ß = -0.44, R2 = 0.19) in step 1; disability and self-efficacy were significant correlates of TPA (disability ß = -0.20, self-efficacy ß = 0.59, R2 = 0.50) and MVPA (disability ß = -0.16, self-efficacy ß = 0.60, R2 = 0.47) in step 2; and disability, self-efficacy, and exercise goal setting were significant correlates of TPA (disability ß = -0.21, self-efficacy ß = 0.50, exercise goal setting ß = 0.14, R2 = 0.55) and MVPA (disability ß = -0.17, self-efficacy ß = 0.51, exercise goal setting ß = 0.15, R2 = 0.51) in step 3. CONCLUSIONS: These results suggest that behavioral interventions focusing on self-efficacy and exercise goal setting as targets from SCT may be appropriate for increasing PA in older adults with MS.

Rates, patterns, and correlates of fitness tracker use among older adults with multiple sclerosis.

BACKGROUND: Older adults with multiple sclerosis (MS) engage in alarmingly low levels of physical activity. Fitness trackers may be a promising approach for promoting and monitoring physical activity among older adults with MS. OBJECTIVE/HYPOTHESIS: This study reports on the rates, patterns of fitness tracker use in adults with MS who are over 60 years of age. We hypothesized that older adults with MS who use fitness trackers "users" would report significantly more physical activity than those who don't "non-users." METHODS: Participants across the United States completed an online survey that included self-reported demographic and clinical characteristics, fitness tracker use questionnaire, and Godin Leisure-Time Exercise Questionnaire (GLTEQ) for measuring total and health-promoting physical activity (GLTEQ-HCS). RESULTS: Of the 440 participants who completed the full survey, 112 (28%) identified as fitness tracker users. The most common activity monitors were Fitbit®, Smartphone app, Apple® watch, and Garmin®. Fitness tracker users mostly reported having relapsing-remitting MS, less disability (i.e., lower Patient Determined Disability Steps), higher income, and higher rates of employment. There was a statistically significant difference in GLTEQ Total (t(438) = -3.8, p = .001) and GLTEQ-HCS (t(438) = -2.8, p = .006) scores between fitness tracker users and non-users. Self-reported step counts were strongly correlated with both GLTEQ Total (ρ = .50) and GLTEQ-HCS (ρ = 0.54) scores in fitness tracker users. CONCLUSIONS: Further research is warranted investigating fitness tracker use and interests among older adults with MS and how technology may be applied as a behavioral tool to increase physical activity among this growing portion of the MS population.

Cognitive Processing Speed Impairment Does Not Influence the Construct Validity of Six-Spot Step Test Performance in People With Multiple Sclerosis.

OBJECTIVE: There is evidence supporting the construct validity of Six-Spot Step Test (SSST) performance as a functional mobility measure in people with multiple sclerosis (MS); however, it is unknown if cognitive processing speed impairment confounds the construct validity of SSST performance in MS, as this test seemingly requires intact cognitive processing. The objective of this study was to examine the influence of cognitive processing speed impairment on the construct validity and precision of SSST performance as a functional mobility measure in MS. METHODS: Participants (N = 213) completed the SSST, timed 25-foot walk, 6-Minute Walk Test, Timed "Up and Go" Test, Multiple Sclerosis Walking Scale-12, device-measured steps per day, and Late-Life Function and Disability Inventory, Patient-Determined Disease Steps, and the Symbol-Digit Modalities Test as a cognitive processing speed measure. The overall sample was divided into subsamples with (n = 75) and without (n = 138) cognitive processing speed impairment based on normative Symbol-Digit Modalities Test data. Correlations between SSST performance with other mobility outcomes in the overall sample and cognitive processing speed impairment subsamples were examined and compared. SSST performance was compared relative to other mobility measures for differentiating MS walking function levels in people with and without cognitive processing speed impairment. RESULTS: SSST performance was significantly and strongly correlated with most mobility outcomes in the overall sample and cognitive processing speed impairment subsamples. The magnitudes of correlations between SSST performance with most mobility outcomes were not statistically different among subsamples. Cognitive processing speed impairment did not diminish the relative precision of SSST performance for differentiating walking function levels. CONCLUSION: The presence of cognitive processing speed impairment is not a source of invalidity or imprecision when interpreting SSST performance as a functional mobility measure among people with MS. IMPACT: The SSST is a high-quality endpoint for inclusion in interventions targeting mobility in MS, regardless of cognitive processing speed status. This information is critical for rehabilitation research and clinical practice given that mobility and cognitive impairment are highly prevalent, co-occurring, and disabling in MS.

Do internet resources align with exercise training and physical activity guidelines for people with multiple sclerosis?

BACKGROUND: Exercise training and lifestyle physical activity have been identified as evidence-based approaches for improving symptoms and quality of life among persons with multiple sclerosis (MS). Such evidence supported the development of physical activity guidelines (PAGs) for people with MS. The goal of such guidelines involved broad dissemination and uptake, as there is substantial evidence for low rates of participation in exercise training and physical activity in this population. OBJECTIVE: The current study evaluated the quality and consistency of information on webpages for physical activity against the established PAGs for people with MS. METHOD: The search was conducted in September 2020 using the Google search engine for webpages containing physical activity information for people with MS. We evaluated the webpages with a list of 18 guidelines for adults with MS based on recommendations from three resources. RESULTS: The search yielded 157 webpages, of which 27 met the inclusion criteria. On average, webpages accurately addressed only 5 of the 18 guidelines. The most commonly addressed guidelines involved MS-specific symptom identification (n = 26), and example modalities for aerobic (n = 20) and strength (n = 16) training. CONCLUSION: Many online recourses regarding physical activity and exercise training for MS were either inconsistent with the established PAGs or did not address the guidelines.

Effect of Standing on a Standardized Measure of Upper Extremity Function.

Although many daily activities that require the upper extremity are performed in standing, arm motor function is generally measured in sitting. The purpose of this study was to examine the effect of standing on a measure of upper extremity function, the Jebsen Hand Function Test (JHFT). Twelve nondisabled adults (26.3 ± 3.1 years) completed the JHFT with the right and left arms under two conditions: sitting and standing. Total time to complete the JHFT increased when performed in standing compared with sitting in both arms (p = .005); mean increase was 4.4% and 5.6% for the right and left arms, respectively. Checker stacking was the only subtest that showed a significant increase in completion time in standing for both arms (p = .001); card turning showed an increase for the left arm only (p = .002). Measurement of upper extremity function in standing may provide insight into arm motor capacity within the context of standing postural control demands.