The influence of concurrent cognitive tasks on motor performance in people with traumatic brain injury: a pilot study.

BACKGROUND: Performing dual-tasks is often required for completing activities of daily living. Limited research investigated the effects of dual-tasking on gait in people with Traumatic Brain Injury (TBI). PURPOSE: To investigate the effects of cognitive tasks on gait in people with TBI Methods: Seven individuals with TBI and nine controls completed walking under three conditions; usual walking, walking with questions and answers, and walking with word generation while 3D motion analysis system captured gait. RESULTS: Significant group x condition interactions were found in which TBI group showed greater changes in speed (p < .01), cadence (p = .07), and ankle kinematics (p = .03) as cognitive task became more complex from usual walking to walking with word generation. TBI group decreased speed (p = .02), stride length (p = .01), and hip kinematics (p = .03) as concurrent task became more complex. The control showed decreases in speed (p = .01), stride length (p = .01), and joint kinematics in the hip (p = .03) and knee (p = .01) as the complexity of concurrent cognitive task increased. CONCLUSION: People with TBI have greater difficulty walking with a cognitive task and show greater compromises in gait performance as the task complexity increases when compared to those without TBI. Clinicians should consider the use of progression in cognitive tasks for dual-task gait training.

Effect of Heart Rate Reserve on Prefrontal Cortical Activation While Dual-Task Walking in Older Adults.

Hypertension is considered a risk factor for cardiovascular health and non-amnestic cognitive impairment in older adults. While heart rate reserve (HRR) has been shown to be a risk factor for hypertension, how impaired HRR in older adults can lead to cognitive impairment is still unclear. The objective of this study was to examine the effects of HRR on prefrontal cortical (PFC) activation under varying dual-task demands in older adults. Twenty-eight older adults (50-82 years of age) were included in this study and divided into higher (n = 14) and lower (n = 14) HRR groups. Participants engaged in the cognitive task which was the Modified Stroop Color Word Test (MSCWT) on a self-paced treadmill while walking. Participants with higher HRR demonstrated increased PFC activation in comparison to lower HRR, even after controlling for covariates in analysis. Furthermore, as cognitive task difficulty increased (from neutral to congruent to incongruent to switching), PFC activation increased. In addition, there was a significant interaction between tasks and HRR group, with older adults with higher HRR demonstrating increases in PFC activation, faster gait speed, and increased accuracy, relative to those with lower HRR, when going from neutral to switching tasks. These results provide evidence of a relationship between HRR and prefrontal cortical activation and cognitive and physical performance, suggesting that HRR may serve as a biomarker for cognitive health of an older adult with or without cardiovascular risk.

BALANCE TRAINING: DOES ANTICIPATED BALANCE CONFIDENCE CORRELATE WITH ACTUAL BALANCE CONFIDENCE FOR DIFFERENT UNSTABLE OBJECTS?

BACKGROUND: Sports rehabilitation professionals often prescribe unstable objects for balance training. Unfortunately, there is a lack of measurement of balance confidence when incorporating these objects. Currently, there is no consensus on the optimal balance confidence measure or proposed progression of unstable objects. Understanding the influence of balance confidence on task performance using unstable objects may help professionals better prescribe a balance training program. PURPOSE: The primary purpose of this investigation was to explore the correlation between anticipated and actual balance confidence on different unstable objects during static double leg and single leg stance. The secondary purpose was to explore the correlation between anticipated and actual unstable object difficulty rankings. STUDY DESIGN: Repeated measure observational, controlled trial. METHODS: Sixty-five active, healthy adults (M = 35, F = 30) (mean age = 24.38 ± 3.56) underwent two testing sessions. During session one, participants took an online survey, rating their anticipated balance confidence after observing images of different unstable objects. During session two, participants stood on each unstable object under two conditions (static double leg stance and single leg stance) and rated their actual balance confidence. The main outcome measure was an ordinal balance confidence score adapted from the activities-specific balance confidence scale. Statistical analysis included subject demographic calculations and appropriate non-parametric tests. RESULTS: For the double leg stance and single leg stance conditions, there was a very strong correlation between anticipated and actual balance confidence scores on the stable surface (ρ = 1.0, p = <.001). There was a weak correlation between scores for foam pad, air-filled discs, Bosu® (dome up), Bosu® (dome down), and wobble board for both conditions. For unstable object rankings, there was a very strong correlation between scores (ρ=1.0, p = <.001). The objects were ranked by perceived difficulty as follows: Level 1 (easy)- ground, Level 2- foam pad, Level 3- air-filled discs, Level 4- Bosu®, and Level 5 (difficult)- wobble board. CONCLUSION: Study findings suggest that actual measures of balance confidence may provide insight into a patient's confidence level and may help with prescribing and progressing their program. The suggested unstable object difficulty rankings may help professionals better match the objects to their patients to produce optimal outcomes. LEVEL OF EVIDENCE: 2c.

Effects of aerobic fitness on cognitive motor interference during self-paced treadmill walking in older adults.

BACKGROUND: Older adults experience greater cognitive motor interference (CMI) due to declines in cognitive and physical function. Although aerobic fitness has beneficial effects on cognition, its association with CMI is not clear. AIMS: This study aims to investigate the effects of aerobic fitness on CMI during self-paced treadmill walking in older adults. METHODS: Thirty participants (67.6 ± 10.34 years, 21 females) were included in a 2-day cross-sectional design study. Aerobic fitness was assessed with the Rockport 1-mile test. The dual-task paradigm consisted of walking only, and dual-task standing and dual-task walking (i.e., standing/walking while performing the Modified Stroop color word test) on a treadmill. To assess CMI, gait speed and accuracy rate were measured to later calculate the dual-task cost for each parameter. RESULTS: Individuals with low aerobic fitness exhibited significantly greater gait speed dual-task cost than individuals with high aerobic fitness (p < 0.05). There were no significant findings for accuracy rate dual-task cost. DISCUSSION: These study findings are the first to demonstrate increases in CMI in relation to low aerobic fitness. Results can be attributed to the relationship between aerobic fitness and cognition as well as theories related to attentional capacity. CONCLUSION: Older adults with low aerobic fitness possess greater CMI when compared to older adults with high aerobic fitness. This provides a foundation of knowledge on how aerobic fitness in older adults may affect CMI which can lead researchers to examine the causal relationships between an aerobic exercise intervention program and CMI in older adults.

Brain Activation Changes During Balance- and Attention-Demanding Tasks in Middle- and Older-Aged Adults With Multiple Sclerosis.

Functional near-infrared spectroscopy was used to evaluate prefrontal cortex activation differences between older adults with multiple sclerosis (MS) and healthy older adults (HOA) during the performance of a balance- and attention-demanding motor task. Ten older adults with MS and 12 HOA underwent functional near-infrared spectroscopy recording while talking, virtual beam walking, or virtual beam walking while talking on a self-paced treadmill. The MS group demonstrated smaller increases in prefrontal cortex oxygenation levels than HOA during virtual beam walking while talking than talking tasks. These findings indicate a decreased ability to allocate additional attentional resources in challenging walking conditions among MS compared with HOA. This study is the first to investigate brain activation dynamics during the performance of balance- and attention-demanding motor tasks in persons with MS.

Effects of aerobic fitness on cognitive performance as a function of dual-task demands in older adults.

The objective of this study was to examine the effects of aerobic fitness on cognitive performance under varying dual-task demands in older adults. Thirty-four participants (mean ±â€¯SD age: 68.6 ±â€¯10.1 years, 24 females) were included in this study. VO2 max was assessed with the Rockport 1-mile walk test (range = 6.68-45.57). Participants engaged in a cognitive task, the Modified Stroop Color Word Test (MSCWT) on a self-paced treadmill while simultaneously standing or walking. Performance on the Stroop Test was measured as interference of the accuracy score. Participants demonstrated over a 4-fold increase in SI when going from Incongruent to Switching MSCWT blocks across both standing and walking tasks. Furthermore, there was a significant interaction between the MSCWT block and VO2 max in Stroop interference, such that Switching Stroop interference demonstrated greater changes due to VO2 max, in comparison to Incongruent SI, even after controlling for age, gender, body mass index, and years of education as covariates in analyses. These results provide evidence of a relationship between aerobic fitness and cognition, suggesting that dual-task interference may provide a sensitive indicator of effects of an aerobic intervention program on the cognitive performance among older adults.

Physical Function in Older Adults With Multiple Sclerosis: An Application of the Short Physical Performance Battery.

BACKGROUND AND PURPOSE: There is a growing prevalence of older persons living with multiple sclerosis (MS), and this cohort likely undergoes changes in physical function associated with MS and its progression as well as those associated with normal aging. This cross-sectional study examined physical function in a community-dwelling sample of older adults with MS compared with matched controls using the Short Physical Performance Battery (SPPB). METHODS: The sample (N = 40) included 20 older adults with MS and 20 older adults without MS who were matched on sex and age. All participants completed the SPPB. RESULTS: Statistically significant differences were observed between groups for the overall SPPB score (P = .013; d = 0.45) and the balance (P = .002; d = 0.46) and gait speed (P = .009; d = 0.30) component scores. The difference between groups in the lower extremity strength component approached significance (P = .056; d = 0.34). Of note, only 2 older adults without MS had SPPB scores below 10 (ie, 10%), whereas 8 older adults with MS had SPPB scores below 10 (ie, 40%); this represented a statistically significant difference in future risk for disability (P = .028). DISCUSSION/CONCLUSIONS: We provide preliminary evidence for reduced physical function based on the SPPB as a valid, objective measure of lower extremity functional performance among older adults with MS.

Preliminary Evidence For The Effects Of Aging And Multiple Sclerosis On Cognitive Performance: An Analysis Based On Effect Size Estimates.

Background/Study Context: Although cognitive impairment is common in persons with multiple sclerosis (MS), there are limited data on older adults with MS. The current pilot study involved a preliminary examination of cognitive impairments across a comprehensive neuropsychological assessment in older adults with MS compared with older adults without MS. METHODS: Twenty older adults with MS and 20 older adults without MS (≥60 years of age) underwent cognitive assessments, including the Trail Making Test (TMT) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The primary analytical model involved independent-samples t tests on the TMT and RBANS scores. The analysis focused on ½ SD (i.e., Cohen's d of 0.5) for judging the differences as meaningful. RESULTS: Overall, the study hypotheses were supported such that older adults with MS demonstrated decreased cognitive performance that exceeded ½ SD compared with the older adults without MS. CONCLUSION: This preliminary study demonstrated moderate and meaningful differences in cognitive performance in older adults with MS compared with older adults without MS. This suggests a clear need for identifying strategies for alleviating cognitive impairment in older adults with MS.

Frontal brain activation changes due to dual-tasking under partial body weight support conditions in older adults with multiple sclerosis.

BACKGROUND: Gait impairments present while dual-tasking in older adults with multiple sclerosis (MS) have been associated with an increased risk of falls. Prior studies have examined prefrontal cortex (PFC) activity using functional near infrared spectroscopy (fNIRS) while dual-tasking in older adults with and without cognitive impairment. While the benefits of partial body weight support (PBWS) on gait have been clearly outlined in the literature, the potential use of PBWS to improve the ability to dual task in older adults with and without MS has not been examined. The aim of this study was to examine the effects of PBWS on the PFC activation while dual-tasking in older adults with and without MS. METHODS: Ten individuals with MS (mean 56.2 ± 5.1 yrs., 8 females) and 12 healthy older adults (HOA) (mean 63.1 ± 4.4 yrs., 9 females) participated in this study. PFC activation (i.e., oxygenated hemoglobin-HbO2) was measured using fNIRS. Assessments were done under two treadmill walking conditions: no body weight support (NBWS) and PBWS. Under each condition, participants were asked to walk at a comfortable speed (W) or walk and talk (WT). Linear mixed models were used to test for differences between cohorts, conditions, and tasks. RESULTS: HbO2 levels differed significantly between task (p < .001), cohort (p < .001), and BWS (p = .02). HbO2 levels increased under higher cognitive demands (i.e., W vs WT), in individuals with MS, and under different conditions (i.e., NBWS vs PBWS). Post-hoc analysis demonstrated a significant difference between cohorts during the WT and NBWS condition (p = .05). When examining the relative change in HbO2 levels during each task, a significant interaction between task, BWS, and cohort across time was observed (p < 0.01). While HOA increased PFC activation across time, MS exhibited a maintenance of PFC activation patterns during the WT under PBWS condition. CONCLUSIONS: This study establishes the potential impact of PBWS on PFC activation patterns under dual-tasking conditions and sheds light on the ability for PBWS to be used as a therapeutic tool in individuals with neurological conditions to decrease cognitive demands while dual-tasking and thus decrease the risk of falls.

Brain activation changes during locomotion in middle-aged to older adults with multiple sclerosis.

Mobility and cognitive impairments are common in persons with multiple sclerosis (MS), and are expected to worsen with increasing age. However, no studies, to date, in part due to limitations of conventional neuroimaging methods, have examined changes in brain activation patterns during active locomotion in older patients with MS. This study used functional Near Infrared Spectroscopy (fNIRS) to evaluate real-time neural activation differences in the pre-frontal cortex (PFC) between middle-aged to older adults with MS and healthy controls during single (Normal Walk; NW) and dual-task (Walking While Talking; WWT) locomotion tasks. Eight middle-aged to older adults with MS and eight healthy controls underwent fNIRS recording while performing the NW and WWT tasks with an fNIRS cap consisting of 16 optodes positioned over the forehead. The MS group had greater elevations in PFC oxygenation levels during WWT compared to NW than healthy controls. There was no walking performance difference between groups during locomotion. These findings suggest that middle-aged to older individuals with MS might be able to achieve similar levels of performance through the use of increased brain activation. This study is the first to investigate brain activation changes during the performance of simple and divided-attention locomotion tasks in MS using fNIRS.