Dual-task Costs For Gait Research Articles

Lower-Limb Exoskeletons for Gait Training in Parkinson's Disease: The State of the Art and Future Perspectives.

Gait dysfunction (GD) is a common impairment of Parkinson's disease (PD), which negatively impacts patients' quality of life. Among the most recent rehabilitation technologies, a lower-limb powered exoskeleton (LLEXO) arises as a useful instrument for gait training in several neurological conditions, including PD. However, some questions relating to methods of use, achievable results, and usefulness compared to traditional rehabilitation methodologies still require clear answers. Therefore, in this review, we aim to summarise and analyse all the studies that have applied an LLEXO to train gait in PD patients. Literature research on PubMed and Scopus retrieved five articles, comprising 46 PD participants stable on medications (age: 71.7 ± 3.7 years, 24 males, Hoehn and Yahr: 2.1 ± 0.6). Compared to traditional rehabilitation, low-profile lower-limb exoskeleton (lp-LLEXO) training brought major improvements towards walking capacity and gait speed, while there are no clear major benefits regarding the dual-task gait cost index and freezing of gait symptoms. Importantly, the results suggest that lp-LLEXO training is more beneficial for patients with an intermediate-to-severe level of disease severity (Hoehn and Yahr > 2.5). This review could provide a novel framework for implementing LLEXO in clinical practise, highlighting its benefits and limitations towards gait training.

The Effect of Total Knee Replacement on Dual-Task Gait Performance in Older Adults.

Total knee replacement (TKR) is a common solution for patients with advanced knee osteoarthritis (OA). Still, fall rates remain relatively high after surgery. TKR may alter pain and knee function, balance control, and proprioception. However, given the role of complex (dual-task) walking in fall prediction for older adults, it is unknown how TKR alters the attentional demand of walking in older adults. The goal of this study was to examine the effect of TKR on dual-task walking among older adults. Participants were evaluated 1month before surgery and 4.5months after surgery. Participants walked along an instrumented 7-meter path for 1minute with and without a cognitive task (serial-3 subtraction). Pain and knee function, knee proprioception, dynamic balance, and balance confidence, as well as dual-task costs (DTC) were compared before and after the surgery and factors associated with change in gait DTCs were assessed. Thirty-eight participants completed the study (age 72.6years, SD = 4.9; 11 men). A significant decrease in pain was found following TKR, with no change in balance, balance confidence, or proprioception. There were no differences in gait DTCs before and after the surgery. However, change in dynamic balance, specifically reactive postural control and dynamic gait, predicted changes in gait speed and stride time DTCs. The absence of an effect of TKR on gait DTCs can potentially underlie increased fall risk after TKR. Results from this study emphasize the significance of balance as a measure and focal point for rehabilitation after TKR. This study contributes to our understanding of the attentional cost of walking in people before and after TKR, as well as to factors associated with it. Results from this work can assist formulation of rehabilitation programs for people with knee OA.

Association of Dual-Task Gait Cost and White Matter Hyperintensity Burden Poststroke: Results From the ONDRI

Background Acute change in gait speed while performing a mental task [dual-task gait cost (DTC)], and hyperintensity magnetic resonance imaging signals in white matter are both important disability predictors in older individuals with history of stroke (poststroke). It is still unclear, however, whether DTC is associated with overall hyperintensity volume from specific major brain regions in poststroke. Methods This is a cohort study with a total of 123 older (69 ± 7 years of age) participants with history of stroke were included from the Ontario Neurodegenerative Disease Research Initiative. Participants were clinically assessed and had gait performance assessed under single- and dual-task conditions. Structural neuroimaging data were analyzed to measure both, white matter hyperintensity (WMH) and normal appearing volumes. Percentage of WMH volume in frontal, parietal, occipital, and temporal lobes as well as subcortical hyperintensities in basal ganglia + thalamus were the main outcomes. Multivariate models investigated associations between DTC and hyperintensity volumes, adjusted for age, sex, years of education, global cognition, vascular risk factors, APOE4 genotype, residual sensorimotor symptoms from previous stroke and brain volume. Results There was a significant positive global linear association between DTC and hyperintensity burden (adjusted Wilks’ λ = .87, P = .01). Amongst all WMH volumes, hyperintensity burden from basal ganglia + thalamus provided the most significant contribution to the global association (adjusted β = .008, η2 = .03; P = .04), independently of brain atrophy. Conclusions In poststroke, increased DTC may be an indicator of larger white matter damages, specifically in subcortical regions, which can potentially affect the overall cognitive processing and decrease gait automaticity by increasing the cortical control over patients’ locomotion.

Dual-task gait and mild behavioral impairment: The interface between non-cognitive dementia markers.

Mild behavioral impairment (MBI) and dual-task gait cost (DTGC) are two non-cognitive markers of dementia that capture behavioral and motor symptoms. We investigated the relationship between MBI and DTGC in a sample of non-demented older adults. This was a cross-sectional observational study of 193 participants (10 cognitively normal, 48 subjective cognitive decline (SCD), 135 mild cognitive impairment (MCI); 52.8% female) from 13 Canadian sites from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) study. The Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to define MBI severity using a published algorithm. DTGC, the percentage difference between dual-task and preferred walking speeds, was assessed under three cognitive tasks: animal naming, counting backwards, and serial seven subtractions. Associations were tested in the entire cohort and in the MCI subgroup using multivariable linear regression adjusted for age, sex, education, and diagnosis. The role of global cognition, executive function, verbal and working memory in the association were investigated using tests of mediation and moderation. MBI symptoms were present in 46.6% of participants (mean age=72.4years). Greater overall MBI burden was associated with lower gait speed across all conditions. Furthermore, a one-point increase in global MBI symptom severity was associated with a 0.8% increase in DTGC in the animal fluency condition, a 0.9% increase in the counting backwards condition and a 1.1% increase in the serial sevens condition. These associations were strongest in the subgroup of MCI participants. Executive function but not global cognition or verbal and working memory mediated the association between MBI and DTGC in all three conditions. MBI is associated with gait speed and DTGC in this group of non-demented individuals, independent of the presence or absence of MCI. These findings provide evidence of the relationship between these non-cognitive dementia markers of behavior and gait beyond cognitive impairment.

Fear of Falling Does Not Influence Dual-Task Gait Costs in People with Parkinson's Disease: A Cross-Sectional Study.

Cognitive deficits and fear of falling (FOF) can both influence gait patterns in Parkinson’s disease (PD). While cognitive deficits contribute to gait changes under dual-task (DT) conditions, it is unclear if FOF also influences changes to gait while performing a cognitive task. Here, we aimed to explore the association between FOF and DT costs in PD, we additionally describe associations between FOF, cognition, and gait parameters under single-task and DT. In 40 PD patients, motor symptoms (MDS-revised version of the Unified Parkinson’s Disease Rating Scale, Hoehn and Yahr), FOF (Falls Efficacy Scale International), and Montreal Cognitive Assessment (MoCA) were assessed. Spatiotemporal gait parameters were recorded with a validated mobile gait analysis system with inertial measurement units at each foot while patients walked in a 50 m hallway at their preferred speed under single-task and DT conditions. Under single-task conditions, stride length (β = 0.798) and spatial variability (β = 0.202) were associated with FOF (adjusted R2 = 0.19, p < 0.001) while the MoCA was only weakly associated with temporal variability (adjusted R2 = 0.05, p < 0.001). Under DT conditions, speed, stride length, and cadence decreased, while spatial variability, temporal variability, and stride duration increased with the largest effect size for speed. DT costs of stride length (β = 0.42) and age (β = 0.58) explained 18% of the MoCA variance. However, FOF was not associated with the DT costs of gait parameters. Gait difficulties in PD may exacerbate when cognitive tasks are added during walking. However, FOF does not appear to have a relevant effect on dual-task costs of gait.

Dual‐task gait and mild behavioral impairment: Findings on the interface between non‐cognitive dementia markers in the COMPASS‐ND study

AbstractBackgroundMild behavioral impairment (MBI) and poor dual‐task gait performance are non‐cognitive markers for dementia. Both MBI and dual‐task gait performance have been associated with an increased risk of cognitive decline, but to our knowledge the relationship between them has yet to be investigated.MethodCross‐sectional data from 193 non‐demented participants (10 cognitively normal, 48 subjective cognitive decline, 135 mild cognitive impairment; MCI) in the COMPASS‐ND study (February 2020 release) were analyzed. MBI was approximated using the Neuropsychiatric Inventory Questionnaire (NPI‐Q) using a published algorithm. Dual‐task gait cost (DTGC), operationalized as the percentage difference between dual‐task and preferred walking speeds, was assessed under three cognitive tasks: animal naming, counting backwards by one, and serial seven subtractions. Multivariable linear regression was used to determine the association between global MBI burden and DTGC, adjusting for age, sex, years of education, and Montreal Cognitive Assessment (MoCA) score, or diagnosis. Models were additionally fitted for the subgroup of participants with MCI alone. Mediation analyses were conducted using bootstrapping to determine if the association between MBI and DTGC was mediated by global cognition (MoCA), executive function (Trail Making B), verbal (Rey Auditory Verbal Learning Test) or working (Digit Span) memory.ResultParticipants on average were 72.4 years old (52.8% female) and had completed 15.8 years of education. MBI symptoms were observed in 46.6% of participants. Greater overall MBI burden was associated with reduced gait speed and higher DTGC for all three gait conditions in MCI, and in all participants without dementia when controlling for diagnosis or MoCA (Table 1), except for DTGC under animal naming conditions when controlling for MoCA. The associations between MBI and DTGC were mediated by executive function but not global cognition, verbal or working memory (Table 2).ConclusionIn this group of older adults at risk but without dementia (SCD and MCI spectrum), MBI is associated with DTGC, which in itself is a dementia risk marker. Our findings support the role of these non‐cognitive dementia markers in the detection of at‐risk individuals. Identification of older adults at risk of incident dementia may be enhanced by considering MBI and DTGC in conjunction.

Dual-Task Gait Cost and Frontal Lobe Integrity in Poststroke: Results From ONDRI

Dual-task gait performance is a marker of motor-cognitive interactions modulated by the frontal lobes. After a stroke, gait disturbances are more evident, particularly when concurrently completing a mental task and walking, an effect called high dual-task cost (DTC). Following a stroke, the potential association of high-DTC, integrity of the frontal lobes and cognitive functioning is unclear. This study screened 161 participants with stroke history from the Ontario Neurodegenerative Disease Research Initiative (ONDRI)-cerebrovascular disease cohort (69.2±7.41 years of age; 31.7% women). Individuals scoring zero in the National Institute of Health Stroke Scale were analyzed (n=102). DTC was the percentage change in gait speed from the single to dual-task condition. Standardized normal-appearing white matter (NAWM) and grey matter (NAGM) volumes from superior, middle and inferior frontal lobe were compared between DTC quartiles (adjusted for age, sex, and education) using a multivariate model (MANOVA), with total frontal lobe volume as a covariate. Another model compared group performance across 5 adjusted cognitive domains (attention, memory, language, visuospatial performance, and executive functioning). Univariate tests revealed that NAWM volume in the superior frontal lobe (F=4.50; p=0.005; partial eta-squared=0.122) was significantly different across DTC quartiles. Contrast tests suggested that the first quartile had larger NAWM than the second and fourth. DTC quartiles also showed differences in attention (F=2.93; p=0.03; partial eta-squared=0.083) and contrast tests indicated that the first quartile performed significantly better than second and fourth. DTC poststroke may be a proxy for structural integrity of superior frontal lobe regions and attention.

Effects of dichotic listening on gait domains of healthy older adults during dual-tasking: An exploratory observational study

Identification of the cognitive mechanisms behind gait changes in aging is a prime endeavor in gerontology and geriatrics. For this reason, we have implemented a new dual-task paradigm where an auditory attentional task is performed during over-ground walking. Dichotic listening assesses spontaneous attention and voluntary attention directed to right and left-ear. The uniqueness of dichotic listening relies on its requirements that vary in difficulty and recruitment of resources from whole brain to one brain hemisphere. When used in dual-tasking, asymmetric effects on certain gait parameters have been reported. The present study aims to acquire a more global understanding on how dichotic listening affects gait domains. Specifically, we aimed to understand how spontaneous vs lateralized auditory attention altered the Principal Component Analysis (PCA) structure of gait in healthy older adults. Seventy-eight healthy older adults (mean age: 71.1years; 44 women and 34 men) underwent the Bergen dichotic listening test while walking. As this study only focuses on the effects of the cognitive task on gait, only dual-task costs for gait were calculated and entered into the PCA analyses. We explored the PCA structure for the effects on bilateral gait parameters (i.e., both limbs together) as well as on lateralized gait parameters (i.e, separate parameters by limb). We first established gait domains during single-task walking. Then, dual-task cost scores for gait were entered in a series of PCAs. Results from the PCAs for bilateral gait parameters showed limited alterations on gait structure. In contrast, PCAs for lateralized data demonstrated modifications of the gait structure during dichotic listening. The PCAs corresponding for all dichotic listening conditions showed different factor solutions ranging between 4 and 6 factors that explained between 73.8% to 80% of the total variance. As a whole, all conditions had an impact on "pace", "pace variability" and "base of support variability" domains. In the spontaneous attention condition, a six-factor solution explaining 78.3% of the variance showed asymmetrical disruptions on the PCA structure. When attention was focused to right-ear, a five-factor solution explaining 89% of the variance and similar to baseline was found. When attention was directed to left-ear, a four-factor solution explaining 73.8% of the variance was found with symmetrical impact on all factors. These findings demonstrate for the first time that specific facets of attentional control affects gait domains both symmetrically and asymmetrically in healthy older adults.

Relating Self-Reported Balance Problems to Sensory Organization and Dual-Tasking in Chronic Traumatic Brain Injury.

Individuals who have experienced a traumatic brain injury (TBI) often have residual balance problems. It remains unclear whether these balance problems are driven by vestibular dysfunction or gait automaticity deficits, particularly in the chronic stages of TBI recovery, because most studies include only acute/subacute cases. Compare performance on the Sensory Organization Test vestibular score and Dual-Task test in individuals with and without subjective balance problems at least 1 year after a TBI. Investigate the ability of each test to predict perceived balance problems. Prospective cohort study. Rehabilitation department within a single institution. Fifty adults (21-71 years) with a history of mild, moderate, or severe TBI 1 to 5 years following nonpenetrating TBI. N/A. Measures included the Dual-Task test, Sensory Organization Test, Neurobehavioral Symptom Inventory, Dizziness Handicap Inventory, and assessments of four cognitive domains and depression. Participants who endorsed "feeling dizzy" and "loss of balance" on the Neurobehavioral Symptom Inventory were classified as symptomatic (n = 26) and others as asymptomatic (n = 24). T-tests, chi-square, and regression analyses predicting the Dizziness Handicap Inventory total score were performed. Dual-task gait cost was negatively associated with the Dizziness Handicap Inventory (P = .044), controlling for depression and gender, whereas vestibular scores failed to predict balance-related disability. Symptomatic individuals endorsed more balance problems (P < .001) and depression symptoms (P = .007), had poorer dual-task cognitive output (P = .036), and slower dual-task gait velocity (P = .036) than asymptomatic participants. Groups did not differ on Sensory Organization Test scores. The nature of balance problems in chronic TBI may be related to automaticity of gait. These findings suggest that patients in the chronic stages of TBI may benefit from dual-task assessments and interventions. Balance rehabilitation should be tailored to patient needs and assess cognition and affect.

Influence of the environment on cognitive-motor interaction during walking in people living with and without multiple sclerosis

BackgroundMotor and cognitive impairments are highly prevalent in people with multiple sclerosis (pwMS). The current theoretical frameworks of cognitive-motor interaction (CMI) suggest that the environment can influence both motor and cognitive performance during walking. However, the relationship between increasing environmental demands and CMI in pwMS remains to be elucidated. Research questionWhat is the impact of increased environmental demands on CMI during walking in people living with and without MS? MethodsTwenty pwMS and 20 age-matched healthy adults (HA) participated in this cross-sectional study. Participants (age = 57.6 ± 7.8 years) performed four walks (baseline walking (BW), obstacle walking (OW), narrow walking (NW), and narrow with obstacles (NO)) in single-task and dual-task (serial-7 subtraction test) conditions. The dual-task costs (DTC) of gait (% change in walking time) and cognition (% change in correctly verbalized utterances) were calculated to quantify CMI. Secondary outcomes included physiological profile assessment (PPA), measures of cognition and falls efficacy scale international (FES-I). ResultsMixed-factor ANOVAs revealed no main effect of task (F = 1.71, p = 0.196) and group (F = 0.71, p = 0.406) on DTC of gait, while there were significant main effects of both task (F = 23.75, p < 0.001) and group (F = 6.53, p = 0.015) on DTC of cognition. Simple main effects revealed that pwMS had a significantly higher DTC of cognition during BW (+37.6 %, p=0.013), NW (+34.2 %, p=0.014) and NO (+49 %, p=0.016) compared to HA. Additionally, DTC of cognition increased during the more environmentally demanding conditions compared to BW (range: +28.4 % to +54.2 %, all p-values<0.01) in both pwMS and HA. Only DTCs of cognition were significantly correlated with PPA and FES-I. SignificanceThe study findings suggest that CMI may be influenced by the individual/environment at levels above those described by the more mechanistic theories of attention.

Quantifying Physical Activity After Concussion: The Relationship Between Sleep Quality, Symptoms, And Steps.

BACKGROUND: Concussion management guidelines have evolved over recent years to include earlier introduction of physical activity. Determining optimal post-concussion physical activity levels with objective methods will further aid clinicians in counseling patients on the role of physical activity in concussion recovery. PURPOSE: Our aim was to investigate the relationship of physical activity, as measured by daily step count, with post-injury sleep quality, symptom rating, and dual-task gait measures among youth athletes with concussion. METHODS: We conducted a longitudinal investigation of youth athletes who sustained a concussion and were evaluated at 2 time points: within 2 weeks of injury and at clearance for return-to-play. Following the initial visit, athletes wore an activity tracking device (Fitbit Charge 3). Dual-task gait, Post-Concussion Symptom Inventory, and Pittsburgh Sleep Quality Index values were collected at both visits. We compared outcomes between those who recorded an average of ≥10,000 steps/day (high physical activity) and <10,000 steps day (low physical activity) between initial and return-to-play clearance visits. RESULTS: Six concussed athletes were classified as having high physical activity (33% female; 14.9±2.0 years of age; 13,900±3,390 steps/day), and five were classified as having low physical activity (40% female; 15.8±1.7 years of age; 8,415±1,775 steps/day). There were no significant differences found at initial visit for total symptom severity (44.3±30.8 vs. 58.2±28.4; p=0.46), sleep quality (6.8±4.4 vs. 8.8±2.0; p=0.38), or dual-task gait cost (-22.4±7.9% vs. -20.1±13.5%; p=0.73) between the high and low physical activity groups. At the time of return-to-play clearance, however, the high physical activity group reported significantly better sleep quality (1.3 ±1.9 vs. 6.7±1.5; p=0.009) and lower symptom severity (0.3±0.8 vs. 3.0±2.0; p=0.02) than the low physical activity group. CONCLUSIONS: Adolescents with a concussion who participated in more physical activity after their initial clinical visit reported better sleep quality and lower symptom severity at return-to-play clearance than the low physical activity group. These preliminary results further support the utility of physical activity in concussion management.

Dual-Task Costs of Quantitative Gait Parameters While Walking and Turning in People with Parkinson's Disease: Beyond Gait Speed.

There is a lack of recommendations for selecting the most appropriate gait measures of Parkinson's disease (PD)-specific dual-task costs to use in clinical practice and research. We aimed to identify measures of dual-task costs of gait and turning that best discriminate performance in people with PD from healthy individuals. We also investigated the relationship between the most discriminative measures of dual-task costs of gait and turning with disease severity and disease duration. People with mild-to-moderate PD (n = 144) and age-matched healthy individuals (n = 79) wore 8 inertial sensors while walking under single and dual-task (reciting every other letter of the alphabet) conditions. Outcome measures included 26 objective measures within four gait domains (upper/lower body, turning and variability). The area under the curve (AUC) from the receiver-operator characteristic plot was calculated to compare discriminative ability of dual-task costs on gait across outcome measures. PD-specific, dual-task interference was identified for arm range of motion, foot strike angle, turn velocity and turn duration. Arm range of motion (AUC = 0.73) and foot strike angle (AUC = 0.68) had the largest AUCs across dual-task costs measures and they were associated with disease severity and/or disease duration. In contrast, the most commonly used dual-task gait measure, gait speed, showed an AUC of only 0.54. Findings suggest that people with PD rely more than healthy individuals on executive-attentional resources to control arm swing, foot strike, and turning, but not gait speed. The dual-task costs of arm range of motion best discriminated people with PD from healthy individuals.

Less noise during dual-task walking in healthy young adults: an analysis of different gait variability components.

Dual-task costs of gait (variability) parameters are frequently used to probe the grade of automaticity of walking. However, recent studies reported contradicting dual-task costs for different gait variability measures within the same cohorts. The effects of a dual-task on the gait pattern are, thus, not fully understood. The aim of the current study was to analyze the different gait variability components ('Tolerance', 'Noise', and 'Covariation') during dual-task walking compared to single-task walking. In an experimental study, 21 young and healthy adults (11 males, 10 females, age: 24 ± 3years) were included. The participants completed three experimental conditions: (a) single-task walking, (b) dual-task walking (serial-seven subtractions), and (c) cognitive single task in sitting position. To analyze different gait variability components, we applied a method which distinguishes the three components: 'Tolerance', 'Noise', and 'Covariation' (TNC). To test for differences, we used the statistical parametric mapping method. Compared to single-task walking, the results depict lower gait variability of the result parameters during the dual-task condition at 0-15% (p = 0.010) and 94-100% (p = 0.040) of the stance phase and 0-63% (p < 0.001) during the swing phase. The decreased result parameter variability was due to less (sensorimotor) 'Noise' (stance: 2-100%, p < 0.001; swing: 2-59%, p < 0.001) during the dual-task walking condition. In further studies, the sources of the reduced unstructured (sensorimotor) noise in the dual-task condition should be analyzed to better understand the effect of a cognitive dual task on the gait pattern.

Donepezil for gait and falls in mild cognitive impairment: a randomized controlled trial.

Cognitive enhancers are commonly prescribed to people with Alzheimer's disease and related dementias to improve cognition and function. However, their effectiveness for individuals in the pre-stages of dementia, particularly in functional motor outcomes, remains unknown. We aimed to determine the efficacy of donepezil, a cognitive enhancer that improves cholinergic neurotransmission, on gait performance in mild cognitive impairment (MCI). This was a double-blind, placebo-controlled trial including 60 older adults with MCI, randomized to receive donepezil (10 mg/daily, maximal dose) or placebo. Primary outcome was gait speed (cm/s) under single and three dual-task conditions (counting backwards by 1 or 7 and naming animals) measured using an electronic walkway. Dual-task gait cost (DTC), a valid measure of motor-cognitive interaction, was calculated as the percentage change between single (S) and dual-task (D) gait speeds: [(S - D)/S] × 100. Secondary outcomes included attention, executive function, balance and falls. After 6 months, the donepezil group experienced an improvement in dual-task gait speed (range 4-11 cm/s), although this was not statistically significant. The donepezil group showed a significant reduction in DTC (improvement) by counting backwards by 1 and 7 compared with placebo (10.25% vs. 1.75%, P = 0.048; 21.38% vs. 14.64%, P = 0.037, intention-to-treat analysis). Per-protocol analyses showed that all three DTCs improved in the donepezil group, along with a non-significant reduction of rate of falls. Donepezil treatment improved dual-task gait speed and DTC in elderly patients with MCI. Our results support the concept of reducing falls in MCI by targeting the motor-cognitive interface.

Entorhinal Cortex Volume Is Associated With Dual-Task Gait Cost Among Older Adults With MCI: Results From the Gait and Brain Study

BackgroundLow dual-task gait performance (the slowing of gait speed while performing a demanding cognitive task) is associated with low cognitive performance and an increased risk of progression to dementia in older adults with mild cognitive impairment. However, the reason for this remains unclear. This study aimed to examine the relationship between dual-task cost and regional brain volume, focusing on the hippocampus, parahippocampal gyrus, entorhinal cortex, and motor and lateral frontal cortices in older adults with mild cognitive impairment.MethodsForty older adults with mild cognitive impairment from the “Gait and Brain Study” were included in this study. Gait velocity was measured during single-task (ie, walking alone) and dual-task (ie, counting backwards, subtracting serial sevens, and naming animals, in addition to walking) conditions, using an electronic walkway. Regional brain volumes were derived by automated segmentation, using 3T magnetic resonance imaging.ResultsPartial rank correlation analyses demonstrated that a smaller volume of the left entorhinal cortex was associated with higher dual-task costs in counting backwards and subtracting serial sevens conditions. Subsequent logistic regression analyses demonstrated that a smaller volume of the left entorhinal cortex was independently associated with higher dual-task cost (slowing down >20% when performing cognitive task) in these two conditions. There were no other significant associations.ConclusionsOur results show that lower dual-task gait performance is associated with volume reduction in the entorhinal cortex. Cognitive and motor dysfunction in older adults with mild cognitive impairment may reflect a shared pathogenic mechanism, and dual-task-related gait changes might be a surrogate motor marker for Alzheimer’s disease pathology.

Worsening Dual-Task Gait Costs after Concussion and their Association with Subsequent Sport-Related Injury.

Prior studies suggest that concussion may lead to an increased risk of a subsequent time-loss sport-related injury, but the mechanisms responsible are unknown. We measured the symptom and dual-task gait outcomes for athletes initially post-concussion and after clinical recovery. Participants then self-reported any additional injuries incurred in the year after their concussion. Forty-two athletes (52% female, mean age = 16.8 ± 3.2 years) completed the study. They underwent a dual-task gait evaluation and symptom inventory within 21 days post-concussion, and again after they were deemed clinically recovered. Approximately one year later, participants documented if they had sustained any subsequent sport-related injuries. The repeated measures analysis of variance (ANOVA) was used to evaluate changes in dual-task gait and symptoms across time and between groups. A significant group*time interaction (p = 0.02) indicated that the group that went on to sustain a subsequent time-loss injury after returning to sports (n = 15) demonstrated significant average walking speed dual-task cost worsening across time (-17.9 ± 9.1% vs. -25.1 ± 12.5%; p = 0.007). In contrast, the group that did not sustain an additional injury walked with consistent dual-task cost values across time (-25.2 ± 9.2% vs. -24.6 ± 8.4%; p = 0.76). Symptoms improved for all participants (main effect of time, p < 0.001; Post-Concussion Symptom Scale [PCSS] = 25.0 ± 16.9 vs. 2.8 ± 7.5; p < 0.001), but did not differ between groups (p = 0.77). Significant dual-task gait cost worsening throughout concussion recovery was associated with time-loss injuries during sports in the year after a concussion. These findings indicate that worsening ability to execute a concurrent gait and cognitive task may relate to the risk of incurring an injury during sports after clinical concussion recovery.

Dual-Task Gait Testing Identifies MCI Patients Likely to Develop Dementia

Easy to administer, noninvasive, and low-cost, dual-task gait testing may capture some subtleties missed by global cognitive methods.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment

Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. To determine whether a dual-task gait test is associated with incident dementia in MCI. The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity - dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (<0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P = .05)while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Dual-task gait is associated with progression to dementia in patients with MCI. Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI. clinicaltrials.gov: NCT03020381.

A randomized controlled pilot study assessing the feasibility of combined motor–cognitive training and its effect on gait characteristics in the elderly

Objective: (1) To develop a motor–cognition training programme; (2) to evaluate the ability to recruit and retain elderly people; (3) to assess the effects of the interventions. Design: Pilot randomized controlled trial. Setting: Assisted living facility. Participants: Sixteen subjects (11 female) living in an assisted living facility were randomized to a motor or motor–cognition group. Interventions: Both groups received machine-driven strength training and balance exercises for 45 minutes, twice weekly, for 12 weeks. In addition, the motor–cognition group received computerized training for attention 3–5 times per week for 10 weeks. Main outcome measures: Baseline and post-intervention (12 weeks) assessments focused on recruitment, attrition and adherence. Secondary outcome measures assessed dual-task costs of gait (velocity, cadence, step time, step length), expanded timed get-up-and-go, falls efficacy and reaction time. Results: Of 35 subjects initially approached, 16 started and 14 completed the study, resulting in 46% recruitment, 19% attrition and >80% adherence rates. There is more evidence of altered levels in the motor–cognitive treatment group with significant differences in average change for fear of falling (P = 0.017) and foot reaction time (P = 0.046). No statistical significance was reached for gait parameters. Conclusions: Motor–cognition training is feasible and shows trends to stronger improvement in walking and reaction time. The application in a main study is deemed feasible. A minimum of ±55 subjects per group are required to achieve a power of 80% at the 5% level of significance based on step length and considering the expectable attrition rate in a required larger scale study.

Cognitive and Motor Mechanisms Underlying Older Adults' Ability to Divide Attention While Walking

An impaired ability to allocate attention to gait during dual-task situations is a powerful predictor of falls. The primary purpose of this study was to examine the relative contributions of participant characteristics and motor and cognitive factors to the ability to walk while performing cognitive tasks. The impact of cognitive task complexity on walking also was examined. A cross-sectional, exploratory study design was used. Seventy-seven community-dwelling older adults with a mean (SD) age of 75.5 (5.8) years completed comprehensive testing. Participant characteristics were assessed via questionnaires. The motor test battery included measures of strength (force-generating capacity), gait speed, and static and dynamic balance. The cognitive abilities test battery assessed psychomotor and perceptual speed, recall and working memory, verbal and spatial ability, and attention (sustained, selective, and divided). Time to walk while performing 4 cognitive tasks was measured. In addition, dual-task costs (DTCs) were calculated. Multiple hierarchical regressions explored walking under dual-task conditions. The ability to walk and perform a simple cognitive task was explained by participant characteristics and motor factors alone, whereas walking and performing a complex cognitive task was explained by cognitive factors in addition to participant and motor factors. Regardless of the cognitive task, participants walked slower under dual-task conditions than under single-task conditions. Increased cognitive task complexity resulted in greater slowing of gait: gait DTCs were least for the simplest conditions and greatest for the complex conditions. Limitations Walking performance was characterized by a single parameter (time), whereas other spatiotemporal parameters have been related to dual-task performance. However, this type of measurement (timed performance) will be easy to implement in the clinic. Two factors-participant characteristics and motor abilities-explained the majority of variance of walking under dual-task conditions; however, cognitive abilities also contributed significantly to the regression models. Rehabilitation focused on improving underlying balance and gait deficits, as well as specific cognitive impairments, may significantly improve walking under dual-task conditions.