Examining the Relationship Between Cognition and Driving Performance in Multiple Sclerosis

Schultheis MT, Weisser V, Ang J, Elovic E, Nead R, Sestito N, Fleksher C, Millis SR. Examining the relationship between cognition and driving performance in multiple sclerosis.

Objective

To identify cognitive predictors of driving performance after multiple sclerosis (MS).

Design

Prospective design examining predictive value of cognitive measures on driving performance.

Setting

All data were collected in an outpatient research setting and an outpatient driver rehabilitation program.

Participants

Participants were community-dwelling persons (N=66) with clinically defined MS (86% relapsing-remitting, 14% progressive) with a mean age of 43.47 years. All were active drivers who met vision requirements established by their respective states, and none required adaptive driving equipment.

Intervention

Not applicable.

Main Outcome Measures

Participants were administered a comprehensive neuropsychologic assessment and a clinical behind-the-wheel (BTW) driving evaluation. Additional measures of driving performance included history of traffic violations and collisions (since MS onset).

Results

Logistic regression indicated that information processing speed (Symbol Digit Modality Test [SDMT]) was the strongest predictor of BTW performance. A logistic regression revealed that the strongest predictors of collision and violation frequency were visuospatial learning and recall (7/24 Spatial Recall Test [SPART 7/24]).

Conclusions

These findings indicate that information processing and visuospatial skills are predictive of driving performance among persons with MS. These measures (SDMT and SPART 7/24) may serve as screening methods for identifying the potential impact of cognitive impairment on driving. Furthermore, the findings raise questions regarding the appropriateness of the BTW evaluation to evaluate driving difficulties accurately among individuals with MS.     

Vision and Driving in Multiple Sclerosis

Schultheis MT, Manning K, Weisser V, Blasco A, Ang J, Wilkinson ME. Vision and driving in multiple sclerosis.

Objective

To examine the relationship between measures of visual dysfunction and driving performance in persons with multiple sclerosis (MS).

Design

Between-group comparison.

Setting

All data were collected in an outpatient research setting.

Participants

Persons (N=66) with MS of the relapsing remitting type (26 self-reporting visual difficulties; 40 self-reporting no visual difficulties) and 26 age- and sex-matched healthy controls.

Interventions

Not applicable.

Main Outcome Measures

Measures of vision included visual acuity, depth perception, and color perception. Driving was measured using documented accident/violation rate and self-reported driving behaviors.

Results

Quantitative analysis only revealed that MS persons with self-reported visual difficulties performed significantly worse than healthy controls on color perception (Kruskal-Wallis; χ₂²=8.89, P=.01). There were no group differences on driving behaviors, and correlational analysis revealed a lack of relationship between the selected visual (visual acuity, depth perception, color perception) and driving performance measures (documented accident/violation rate and self-limiting driving behaviors).

Conclusions

Persons with MS who self-reported difficulties with vision had acceptable visual acuity, despite demonstrating impairment in color perception. The fact that visual acuity remains the most common measure for visual fitness to drive remains problematic. There is a need to further define measures of visual dysfunction relevant to driving among this clinical population.     

Improvement of Driving Skills in Persons With Relapsing-Remitting Multiple Sclerosis: A Pilot Study

Objective

To determine the potential to improve driving-related skills using a simulator-based program in persons with relapsing-remitting multiple sclerosis (RRMS).

Design

Pre-post intervention.

Setting

A university driving simulator laboratory.

Participants

Participants (N=50) with RRMS and Expanded Disability Status Scale (EDSS) scores between 1 and 7 were enrolled. Pre- and posttraining data from 36 participants (mean age ± SD, 46±11y; 30 women) who received training and 6 participants (mean age ± SD, 48±13y; 5 women) who did not receive training (control group) were compared.

Interventions

Five hours of driving training in a simulator.

Main Outcome Measures

Performance on a road test at pre- and posttraining. Secondary outcome measures were performance on visual, physical, and cognitive tests.

Results

Overall, no significant differences were observed between the training and control groups before and after training. However, 4 of the 7 participants in the training group who failed the road test at pretraining passed posttraining, while the only participant in the control group who failed at pretraining still failed at posttraining. The training group also improved on perception of red and colored numbers, the Paced Auditory Serial Addition Test, and the dot cancellation test of the Stroke Driver Screening Assessment battery and reported less fatigue. These improvements were most pronounced among those with an EDSS score between 3 and 7.

Conclusions

This pilot study demonstrates the potential of using a simulator to improve driving-related visual, cognitive, and on-road skills in individuals with RRMS, particularly those with an EDSS score >3. Future randomized controlled trials with adequate power are needed to expand this field of study.     

The contribution of cognition and spasticity to driving performance in multiple sclerosis

Marcotte TD, Rosenthal TJ, Roberts E, Lampinen S, Scott JC, Allen RW, Corey-Bloom J. The contribution of cognition and spasticity to driving performance in multiple sclerosis.

Objective

To examine the independent and combined impact of cognitive dysfunction and spasticity on driving tasks involving high cognitive workload and lower-limb mobility in persons with multiple sclerosis (MS).

Design

Single-visit cohort study.

Setting

Clinical research center.

Participants

Participants included 17 drivers with MS and 14 referent controls. The group with MS exhibited a broad range of cognitive functioning and disability. Of the 17 patients with MS, 8 had significant spasticity in the knee used to manipulate the accelerator and brake pedals (based on the Modified Ashworth Scale).

Interventions

Not applicable.

Main Outcome Measures

A brief neuropsychologic test battery and 2 driving simulations. Simulation 1 required participants to maintain a constant speed and lane position while attending to a secondary task. Simulation 2 required participants to adjust their speed to accelerations and decelerations of a lead car in front of them.

Results

Patients with MS showed greater variability in lane position (effect size, g=1.30), greater difficulty in maintaining a constant speed (g=1.25), and less ability to respond to lead car speed changes (g=1.85) compared with controls. Within the MS group, in a multivariate model that included neuropsychologic and spasticity measures, cognitive functioning was the strongest predictor of difficulty in maintaining lane position during the divided attention task and poor response time to lead car speed changes, whereas spasticity was associated with reductions in accuracy of tracking the lead car movements and speed maintenance.

Conclusions

In this preliminary study, cognitive and physical impairments associated with MS were related to deficits in specific components of simulated driving. Assessment of these factors may help guide the clinician regarding the types of driving behaviors that would put patients with MS at an increased risk for an automobile crash.     

Alcohol Misuse and Multiple Sclerosis

Turner AP, Hawkins EJ, Haselkorn JK, Kivlahan DR. Alcohol misuse and multiple sclerosis.

Objective

To describe the prevalence of alcohol misuse and medical advice to reduce drinking in a national sample of veterans with multiple sclerosis (MS).

Design

Cross-sectional cohort study linking computerized medical record information to mailed survey data from 2004 through 2006.

Setting

Veterans Health Administration (VHA).

Participants

Two thousand six hundred fifty-five of 4929 veterans with MS who received services in VHA between 2004 and 2006 and also a survey questionnaire (53.9% response rate).

Interventions

Not applicable.

Main Outcome Measures

Demographic information, Short-Form 12-Item Health Survey Mental Component Summary and Physical Component Summary, Alcohol Use Disorders Identification Test Consumption questions, and questions assessing depressive symptoms and the receipt of alcohol-related advice from a medical professional.

Results

Among all survey respondents with MS, the prevalence of alcohol misuse for the sample was 13.9% (confidence interval [CI], 12.5-15.2), with 11.9% (CI, 10.6-13.2) and 2.0% (CI, 1.4-2.5) of participants scoring in the mild/moderate and severe range of alcohol misuse, respectively. In contrast to community samples there was no difference in prevalence by sex. In multivariate logistic regression, age younger than 60 years (<50y; adjusted odds ratio [AOR]=1.66; CI, 1.17-2.37, and 50-59; AOR=1.64; CI, 1.19-2.27), employment (AOR=1.54; CI, 1.06-2.24) and better physical health (AOR=1.02; CI, 1.01-1.04) were associated with a higher likelihood of alcohol misuse. Among persons who screened positive for alcohol misuse, only 26.2% (CI, 21.5-30.9) reported they had received advice from a medical provider in the past year to decrease or abstain from drinking. Self-report of advice was more likely among those endorsing severe misuse (AOR=3.65; CI, 1.85-7.17) and less likely among those with better mental health (AOR=0.97; CI, 0.94-1.00).

Conclusions

Despite the numerous health and social consequences of alcohol misuse, routine screening and intervention for people with MS remain uncommon. Brief screening and advice to reduce or refrain from alcohol use can be accomplished in as little as 5 minutes and can be incorporated into the regular course of medical care.     

Balance-Based Torso-Weighting May Enhance Balance in Persons With Multiple Sclerosis: Preliminary Evidence

Widener GL, Allen DD, Gibson-Horn C. Balance-based torso-weighting may enhance balance in persons with multiple sclerosis: preliminary evidence.

Objective

To determine whether weight placed on the trunk in response to directional balance loss would enhance function and stability in people with multiple sclerosis (MS).

Design

Quasi-experimental study in which subjects served as their own controls.

Setting

Research laboratory.

Participants

Subjects (N=16) age 20 to 65 years with MS recruited through the Northern California Chapter of the National Multiple Sclerosis Society.

Interventions

Balance-based torso-weighting where up to 1.5% body weight was placed in a garment on the trunk. Subjects were tested at baseline and then in randomly ordered balance-based torso-weighting and nonweighted garment conditions.

Main Outcome Measures

Sharpened Romberg, eyes open (SREO) and Sharpened Romberg, eyes closed, computerized dynamic platform posturography (CDPP), Timed Up & Go (TUG), and 25-foot timed walk.

Results

Significant improvement (P<.014) was found with SREO in the balance-based torso-weighting compared with nonweighted conditions. CDPP eyes open and TUG showed improvements (P<.03) from baseline to balance-based torso-weighting and nonweighted conditions.

Conclusions

Improved performance in a group of adults with MS was seen when light weights were placed on the torso to counteract balance loss. Placement of weights may have the potential to produce immediate improvements in balance in this population.     

Neuropsychological,Balance, and Mobility Risk Factors for Falls in People With Multiple Sclerosis: A Prospective Cohort Study

Objectives

To determine whether impaired performance in a range of vision, proprioception, neuropsychological, balance, and mobility tests and pain and fatigue are associated with falls in people with multiple sclerosis (PwMS).

Design

Prospective cohort study with 6-month follow-up.

Setting

A multiple sclerosis (MS) physiotherapy clinic.

Participants

Community-dwelling people (N=210; age range, 21–74y) with MS (Disease Steps 0–5).

Interventions

Not applicable.

Main Outcome Measures

Incidence of falls during 6 months' follow-up.

Results

In the 6-month follow-up period, 83 participants (39.7%) experienced no falls, 57 (27.3%) fell once or twice, and 69 (33.0%) fell 3 or more times. Frequent falling (≥3) was associated with increased postural sway (eyes open and closed), poor leaning balance (as assessed with the coordinated stability task), slow choice stepping reaction time, reduced walking speed, reduced executive functioning (as assessed with the difference between Trail Making Test Part B and Trail Making Test Part A), reduced fine motor control (performance on the 9-Hole Peg Test [9-HPT]), and reported leg pain. Increased sway with the eyes closed, poor coordinated stability, and reduced performance in the 9-HPT were identified as variables that significantly and independently discriminated between frequent fallers and nonfrequent fallers (model χ²₃=30.1, P<.001). The area under the receiver operating characteristic curve for this model was .712 (95% confidence interval, .638–.785).

Conclusions

The study reveals important balance, coordination, and cognitive determinants of falls in PwMS. These should assist the development of effective strategies for prevention of falls in this high-risk group.     

Cognitive Motor Interference During Walking in Multiple Sclerosis Using an Alternate-Letter Alphabet Task

Objective

To examine cognitive motor interference (CMI) during walking using a simple, standardized, and well-refined alphabet dual-task (DT) paradigm in individuals with multiple sclerosis (MS) in whom cognitive and walking impairment often co-occur.

Design

A single time point, cross-sectional study.

Setting

A university clinical laboratory.

Participants

Individuals with MS (N=61; mean age ± SD, 50.8±9.3y) performed 4 walking trials over a 4.6-m walkway to determine gait parameters.

Interventions

Not applicable.

Main Outcome Measures

Gait parameters were assessed over 4 walking trials. The first 2 walks involved the single task (ST) of walking only; the second 2 walks involved participants performing the DT of reciting alternate letters of the alphabet while walking. The gait parameters recorded during the ST and DT walks were used to compute a dual-task cost (DTC) of walking (% change in gait parameter between ST and DT walks) as a metric of CMI.

Results

Our multivariate analysis with univariate follow-ups indicated CMI during walking based on slower velocity (η_p²=.59; F=84.6; P<.001) and cadence (η_p²=.46; F=51.6; P<.001), shorter step length (η_p²=.38; F=36; P<.001), and increased step time (η_p²=.34; F=31; P<.001) and double-support time (η_p²=.31; F=27.3; P<.001) in DT versus ST conditions. The DTC of walking for the gait parameters was not correlated with clinical (disability, disease duration) and demographic (eg, education, age) factors (all |r|≤.240).

Conclusions

The alphabet DT paradigm is easily administered and well refined. We highlight its ability and acceptability to determine CMI during walking in people with MS, independent of disease status.     

Objectively Quantified Physical Activity in Persons With Multiple Sclerosis

Objectives

To investigate levels of moderate-to-vigorous physical activity (MVPA) in a large sample of persons with multiple sclerosis (MS) and controls using accelerometry as a measure of physical activity, and to compare the rates of meeting public health guidelines for MVPA (ie, 30min/d) between persons with MS and controls.

Design

Secondary analysis of a combined data set of persons with MS and healthy controls from 13 previous investigations of physical activity over a 8-year period (2005–2013).

Setting

University.

Participants

Participants with MS (n=800) were recruited primarily within Illinois through multiple sources, including print and e-mail flyers and an online advertisement on the National Multiple Sclerosis Society website. Healthy controls (n=137) were recruited via public e-mail postings delivered across the university community.

Interventions

Not applicable.

Main Outcome Measures

Levels of MVPA and meeting public health guidelines for MVPA between persons with MS and controls.

Results

After controlling for covariates (ie, age, sex, education, race, income), there was a moderate (d=.68) and statistically significant (F=47.2, P<.001) difference of 13.1 minutes of MVPA per day (95% confidence interval, 9.4–16.8) between MS and controls. There was a difference in the rates of meeting public health guidelines for MVPA (χ²=50.7, P<.001) between MS patients (20%) and controls (47%). Among those with MS, minutes of MVPA significantly differed as a function of education, employment status, clinical course, disease duration, and disability status.

Conclusions

We provide data using an objective physical activity measure and a large sample to indicate that only a small proportion of persons with MS are achieving adequate amounts of daily MVPA.     

Predicting Exercise Capacity Through Submaximal Fitness Tests in Persons With Multiple Sclerosis

Kuspinar A, Andersen RE, Teng SY, Asano M, Mayo NE. Predicting exercise capacity through submaximal fitness tests in persons with multiple sclerosis.

Objective

To estimate, for persons with multiple sclerosis (MS), the extent to which peak oxygen consumption (Vo₂peak) can be predicted by the results on submaximal tests.

Design

Cross-sectional study.

Setting

Three MS clinics in the Greater Montreal region, Canada.

Participants

A center-stratified random sample of 135 women and 48 men was drawn (N=183). A subgroup of 59 subjects with MS, who were able to perform the step test, was selected from this sample to complete the maximal exercise test.

Interventions

Not applicable.

Main Outcome Measure

Vo₂peak.

Results

In this sample (mean age ± SD, 39 ± 9y; median Expanded Disability Status Scale=1.5), the mean Vo₂peak ± SD was 27.6 ± 7.3mL·kg⁻¹·min⁻¹. This value is considerably low when compared with healthy persons, ranking below the 25th percentile for both men and women. In a multivariate regression analysis, the step test and grip strength were identified as the only significant predictors of Vo₂peak. When combined with body weight, grip strength and the step test explained 74% of the variance in Vo₂peak.

Conclusions

Patients with MS with a mild degree of disability exhibit marked reductions in exercise capacity. Also, in persons with MS, submaximal tests are good predictors of exercise capacity. These measures may be used in clinical settings to help assess and monitor maximum oxygen consumption and in research to evaluate the effect of exercise-related interventions. Furthermore, they will allow people with MS to self-monitor their exercise capacity and be more actively engaged in taking charge of their fitness level.     

Neuroprosthetic Effect of Peroneal Nerve Stimulation in Multiple Sclerosis: A Preliminary Study

Sheffler LR, Hennessey MT, Knutson JS, Chae J. Neuroprosthetic effect of peroneal nerve stimulation in multiple sclerosis: a preliminary study.

Objective

To determine the neuroprosthetic effect of a peroneal nerve stimulator on tasks of functional ambulation in multiple sclerosis (MS).

Design

A single point-in-time assessment of functional ambulation tasks under the conditions of no device and peroneal nerve stimulator.

Setting

Outpatient academic medical center.

Participants

Participants (N=11) with diagnosis of MS (>6mo), dorsiflexion weakness, and prior usage of an ankle-foot orthosis.

Intervention

Surface peroneal nerve stimulator for ambulation.

Main Outcome Measures

Timed 25-foot Walk portion of the MS Functional Composite; Floor, Carpet, Up and Go, Obstacle, and Stair components of the Modified Emory Functional Ambulation Profile.

Results

Peroneal nerve stimulator-Stair performance was significantly enhanced (P=.05) versus no device, and statistical significance was approached for peroneal nerve stimulator-Obstacles (P=.09) versus no device. There were no significant differences between peroneal nerve stimulator and no device conditions in the remaining outcome measures.

Conclusions

The neuroprosthetic effect of the peroneal nerve stimulator is modest relative to no device in the performance of specific functional tasks of ambulation in MS gait. A longitudinal, controlled trial is needed to show effectiveness.     

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 5903±3185 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.     

Improved Physical Fitness Correlates With Improved Cognition in Multiple Sclerosis

Objective

To determine whether there is an association between improvements in objective measures of physical fitness and performance on cognitive tests in people with multiple sclerosis (MS).

Design

Post hoc correlational analysis in which people demonstrating physical improvement were compared with those not demonstrating physical improvement.

Setting

Individuals with MS residing in the community.

Participants

Adults with clinically confirmed MS (N=88) who participated in a controlled trial of a telephone-based health promotion intervention, chose to work on exercise, and completed the pre- and postintervention assessments.

Interventions

Participants were measured for strength (isokinetic dynamometer), aerobic fitness (bicycle ergometer), and cognition (Paced Auditory Serial Addition Test [PASAT], Trail Making Test [TMT]) at baseline and 12 weeks later. Change in fitness was calculated by subtracting each participant's baseline score from the outcome score, and then transforming the difference to a z score. Individuals with a z score ≥1 on any fitness measure were placed in the physically improved group (n=25). All others were in the physically not improved group (n=57).

Main Outcome Measures

TMT, PASAT.

Results

After controlling for covariates (age, sex, ethnicity, education, disease activity, MS type), there was a significant group-by-time interaction, suggesting that cognitive functioning changed over time based on level of fitness. Participants in the physically improved group demonstrated improved performance on measures of executive functioning after 12 weeks of exercise.

Conclusions

The results of this study lend support to the hypothesis that change in fitness is associated with improved executive functioning in people with MS.     

Frequency,Characteristics, and Consequences of Falls in Multiple Sclerosis: Findings From a Cohort Study

Objective

To evaluate falls rate and the characteristics of falls (including fall-related injuries) in a multiple sclerosis (MS) cohort.

Design

As part of a study evaluating falls risk, a cohort of 150 participants prospectively recorded actual and near fall events using a daily diary over 3 months, as well as the circumstances of each fall including related injuries.

Setting

Community setting.

Participants

A population-based sample of people (N=150) with a confirmed diagnosis of MS (Expanded Disability Status Scale, 3.5–6.5) was recruited via a patient-centered longitudinal study database of disease course in people with MS.

Interventions

Not applicable.

Main Outcome Measures

Rate of actual and near falls, circumstances and consequences of falls (including rates and type of injury plus follow-up care).

Results

The response rate for the falls diary was 92.7%. A total of 672 actual falls and 3785 near falls were recorded, with a moderate correlation between the numbers of actual and near falls per person (ρ=.474; 95% confidence interval, .34–.59). Men recorded significantly more falls than women. Falls were associated with a range of activities, although 27.6% occurred during general mobility activities such as walking, turning, and moving between positions. Injuries occurred in 11.1% of falls, with 6 individuals requiring medical attention.

Conclusions

People with MS experience high numbers of falls, with associated injuries. Falls occur during a wide range of activities, reflecting their potential impact on daily life. Evaluating the characteristics of individuals who experience frequent near falls but few actual falls may be valuable for research and clinical practice.     

Prevalence and Impact of Pain in Multiple Sclerosis: Physical and Psychologic Contributors

Hirsh AT, Turner AP, Ehde DM, Haselkorn JK. Prevalence and impact of pain in multiple sclerosis: physical and psychologic contributors.

Objective

To characterize the prevalence and impact of pain in veterans with multiple sclerosis (MS) and to assess their association with demographic, biologic, and psychologic variables.

Design

Cross-sectional cohort study linking computerized medical record information to mailed survey data.

Setting

Veterans Health Administration (VHA).

Participants

Sixty-four percent (2994/4685) of veterans with MS who received services in VHA and also returned survey questionnaires.

Interventions

Not applicable.

Main Outcome Measures

Items assessing pain intensity, pain interference, and physical and mental health functioning.

Results

Ninety-two percent of participants reported bodily pain within the prior 4 weeks, with 69% of the total sample indicating pain of moderate or higher intensity. Eighty-five percent indicated that pain caused functional interference during the past 4 weeks, with 71% of the total sample reporting pain-related interference that was moderate or greater. No significant sex or race differences emerged for the pain indices. A significant but modest relationship between increasing age and pain interference emerged (r=.05, P<.01); however, age was not significantly related to pain intensity. Multivariate regression analyses identified pain intensity (β=.73), physical health functioning (β=-.07), and mental health functioning (β=-.13) variables as significant, unique contributors to the prediction of pain interference. The interaction of pain intensity and physical functioning was also significant but of minimal effect size (β=-.03).

Conclusions

Pain is highly prevalent and causes substantial interference in the lives of veterans with MS. The functional impact of pain in veterans with MS is influenced by pain intensity, physical health, and emotional functioning. Clinical practice should take each of these domains into consideration and reflect a biopsychosocial conceptualization.