A comparison of two walking while talking paradigms in aging

BackgroundOur study aimed to [1] compare dual-task costs in gait and cognitive performance during two dual-task paradigms: walking while reciting alternate letters of the alphabet (WWR) and walking while counting backward by sevens (WWC); [2] examine the relationship between the gait and cognitive interference tasks when performed concurrently.ScopeGait and cognitive performance were tested in 217 non-demented older adults (mean age 76 ± 8.8 years; 56.2% female) under single and dual-task conditions. Velocity (cm/s) was obtained using an instrumented walkway. Cognitive performance was assessed using accuracy ratio: [correct responses]/[total responses]. Linear mixed effects models revealed significant dual-task costs, with slower velocity (p < .01) and decreased accuracy ratio (p < .01) in WWR and WWC compared to their respective single task conditions. Greater dual-task costs in velocity (p < .01) were observed in WWC compared to WWR. Pearson correlations revealed significant and positive relationships between gait and cognitive performance in WWR and WWC (p < .01); increased accuracy ratio was associated with faster velocity.ConclusionsOur findings suggested that dual-task costs in gait increase as the complexity of the cognitive task increases. Furthermore, the positive association between the gait and cognitive tasks suggest that dual-task performance was not influenced by task prioritization strategies in this sample.     

Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking

AimCentral arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT.MethodsGait speed was measured using a motion capture system in 56 women (30–80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7′s. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery.ResultsThe percent change in gait speed was larger for MT than DT (14.1 ± 11.2 vs. 8.7 ± 9.6%, p < 0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85 ± 0.43 vs. 1.47 ± 0.42, p = 0.02) and resistance (0.75 ± 0.07 vs. 0.68 ± 0.07, p = 0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences.ConclusionElevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.     

The effect of a dual task on gait speed in community dwelling older adults: A systematic review and meta-analysis

Background and purposeReduced walking speed in older adults is associated with adverse health outcomes. This review aims to examine the effect of a cognitive dual-task on the gait speed of community-dwelling older adults with no significant pathology affecting gait.Data sources and study selectionElectronic database searches were performed in, Web of Science, PubMed, SCOPUS, Embase and psychINFO. Eligibility and methodological quality was assessed by two independent reviewers. The effect size on gait speed was measured as the raw mean difference (95% confidence interval) between single and dual-task performance. Pooled estimates of the overall effect were computed using a random effects method and forest plots generated.Data extraction and data synthesis22 studies (27 data sets) with a population of 3728 were reviewed and pooled for meta-analysis. The mean walking speed of participants included in all studies was >1.0 m/s and all studies reported the effect of a cognitive dual-task on gait speed. Sub-analysis examined the effect of type of cognitive task (mental-tracking vs. verbal-fluency). Mean single-task gait speed was 1.21 (0.13) m/s, the addition of a dual-task reduced speed by 0.19 m/s to 1.02 (0.16) m/s (p < 0.00001), both mental-tracking and verbal-fluency tasks resulted in significant reduction in gait speed.Limitations and conclusionThe cross-sectional design of the studies made quality assessment difficult. Despite efforts, high heterogeneity remained, possibly due to participant characteristics and testing protocols. This meta-analysis shows that in community-dwelling older adults, the addition of a dual-task significantly reduces gait speed and may indicate the value of including dual-task walking as part of the standard clinical assessment of older people.     

Sleep quality is associated with walking under dual-task,but not single-task performance

ObjectivesThe objective of this study was to assess the relationship between sleep behavior and gait performance under single-task (ST) and dual-task (DT) walking conditions in community- dwelling older adults.MethodsWalking under ST and DT conditions was evaluated in 34 community-dwelling older adults, 64.7% women, mean age 71.5 (SD ± 5.8). Gait-speed and gait-variability data were collected using the OPAL wearable sensors of the Mobility Lab. Sleep behavior (sleep efficiency [SE] and sleep latency [SL]) was assessed using actigraphy, over 5 consecutive nights.ResultsLower SE was associated with decreased gait speed and increased stride-length variability during DT (rs = 0.35; p = 0.04; rs = −0.36; p = 0.03, respectively), whereas longer SL was associated with increased stride-length variability during DT (rs = 0.38; p = .03). After controlling for age and cognition, SE accounted for 24% and 33% of the variability in stride length and stride time. No associations were found between sleep and gait measures under ST walking.ConclusionsLower SE is associated with decreased gait speed and increased gait variability under DT conditions that are indicative of an increased risk for falls in older adults. Our findings support clinical recommendations to incorporate the evaluation of sleep quality in the context of risk assessment for falls.     

Cognitive motor interference during dual-task gait in essential tremor

BackgroundFunctional ambulation requires concurrent performance of motor and cognitive tasks, which may create interference (degraded performance) in either or both tasks. People with essential tremor (ET) demonstrate impairments in gait and cognitive function. In this study we examined the extent of interference between gait and cognition in people with ET and controls during dual-task gait.MethodsWe tested 62 controls and 151 ET participants (age range: 72–102). ET participants were divided into two groups based on median score on the modified Mini Mental State Examination. Participants walked at their preferred speed, and performed a verbal fluency task while walking. We analyzed gait velocity, cadence, stride length, double support time, stride time, step width, step time difference, coefficient of variation (CV) of stride time and stride length.ResultsVerbal fluency performance during gait was similar across groups (p = 0.68). Velocity, cadence and stride length were lowest whereas step time difference (p = 0.003), double support time (p = 0.009), stride time (p = 0.002) and stride time CV (p = 0.007) were highest for ET participants with lower cognitive scores (ETp-LCS), compared with ET participants with higher cognitive scores (ETp-HCS) and controls. ETp-LCS demonstrated greatest interference for double support time (p = 0.005), step time difference (p = 0.013) and stride time coefficient of variation (p = 0.03).ConclusionsETp-LCS demonstrated high levels of cognitive motor interference. Gait impairments during complex tasks may increase risk for falls for this subgroup and underscore the importance of clinical assessment of gait under simple and dual-task conditions.     

No differences in tandem gait performance between male and female athletes acutely post-concussion

ObjectivesTo test whether 1) concussed athletes demonstrate slower tandem gait times compared to controls and 2) concussed female athletes display greater post-injury deficits than males.DesignProspective longitudinalMethodFifty concussed collegiate student-athletes (32% female, age = 20.18 ± 1.27 years) completed tandem gait tests during pre-season (Time 1) and acutely (<72 hours) post-concussion (Time 2), and twenty-five controls (52% female, age = 21.08 ± 2.22 years) completed tandem gait at two time points, 1.96 ± 0.46 days apart. Participants completed four single-task (ST) and dual-task (DT) trials. During DT trials, they simultaneously completed a cognitive assessment. The best ST and DT times were recorded, along with cognitive accuracy, and the change score between the two assessments was calculated. A positive change in tandem gait time was indicative of worsening performance. A 2 × 2 (group*sex) ANOVA was used to examine change between pre-injury and post-injury tests for ST/DT tandem gait time and DT cognitive accuracy.ResultsThe change in tandem gait time from Time 1 to Time 2 was significantly higher for the concussion group relative to controls during both ST (Concussion: 1.36 ± 2.6 seconds, Controls: -1.16 ± 0.8 seconds, p < 0.001) and DT (Concussion: 1.70 ± 3.8 seconds, Controls: -0.94 ± 1.7 seconds, p = 0.002) tandem gait. There were no interactions or main effects of sex for tandem gait time or cognitive accuracy.ConclusionsThere were no sex-specific differences in the change in tandem gait performance among concussed collegiate athletes or controls. However, all concussed participants, regardless of sex, performed significantly worse on tandem gait than male and female controls, who both improved between testing time points.     

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age = 15.0 ± 2.1 years, 7.5 ± 3.0 days post-injury) and 51 controls (51% female, mean age = 14.4 ± 2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0 ± 18.0) and males (27.8 ± 18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (−19.7% ± 10.0% vs. −11.3% ± 9.2%, p = 0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13 ± 0.11 m vs. 1.26 ± 0.11 m, p = 0.001; males: 1.14 ± 0.14 m vs. 1.22 ± 0.15 m, p = 0.04) and dual-task gait (females: 0.99 ± 0.10 m vs. 1.10 ± 0.11 m, p = 0.001; males: 1.00 ± 0.13 m vs. 1.08 ± 0.14 m, p = 0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.     

Home-based interventions improve trained,but not novel,dual-task balance performance in older adults: A randomized controlled trial

The purpose of this study was to compare the efficacy of four different home-based interventions on dual-task balance performance and to determine the generalizability of the four trainings to untrained tasks. Sixty older adults, aged 65 and older, were randomly assigned to one of four home-based interventions: single-task motor training, single-task cognitive training, dual-task motor-cognitive training, and dual-task cognitive–cognitive training. Participants received 60-min individualized training sessions, 3 times a week for 4 weeks. Prior to and following the training program, participants were asked to walk under two single-task conditions (i.e. narrow walking and obstacle crossing) and two dual-task conditions (i.e. a trained narrow walking while performing verbal fluency task and an untrained obstacle crossing while counting backward by 3 s task). A nine-camera motion capture system was used to collect the trajectories of 32 reflective markers placed on bony landmarks of participants. Three-dimensional kinematics of the whole body center of mass and base of support were computed. Results from the extrapolated center of mass displacement indicated that motor-cognitive training was more effective than the single-task motor training to improve dual-task balance performance (p = 0.04, ES = 0.11). Interestingly, balance performance under both single-task and dual-task conditions can also be improved through a non-motor, single-task cognitive training program (p = 0.01, ES = 0.13, and p = 0.01, ES = 0.11, respectively). However, improved dual-task processing skills during training were not transferred to the novel dual task (p = 0.15, ES = 0.09). This is the first study demonstrating that home-based dual-task training can be effectively implemented to improve balance performance during gait in older adults.     

Intra-individual gait speed variability in healthy children aged 1–15 years

IntroductionGait speed is one of the most commonly and frequently used parameters to evaluate gait development. It is characterized by high variability when comparing different steps in children. The objective of this study was to determine intra-individual gait speed variability in children.MethodsGait speed measurements (6–10 trials across a 3 m walkway) were performed and analyzed in 8263 children, aged 1–15 years. The coefficient of variation (CV) served as a measure for intra-individual gait speed variability measured in 6.6 ± 1.0 trials per child. Multiple linear regression analysis was conducted to evaluate the influence of age and body height on changes in variability. Additionally, a subgroup analysis for height within the group of 6-year-old children was applied.ResultsA successive reduction in gait speed variability (CV) was observed for age groups (age: 1–15 years) and body height groups (height: 0.70–1.90 m). The CV in the oldest subjects was only one third of the CV (CV 6.25 ± 3.52%) in the youngest subjects (CV 16.58 ± 10.01%). Up to the age of 8 years (or 1.40 m height) there was a significant reduction in CV over time, compared to a leveling off for the older (taller) children.DiscussionThe straightforward approach measuring gait speed variability in repeated trials might serve as a fundamental indicator for gait development in children. Walking velocity seems to increase to age 8. Enhanced gait speed consistency of repeated trials develops up to age 15.     

Consistency and cost of dual-task gait balance measure in healthy adolescents and young adults

Matched control data are commonly used to examine recovery from concussion. Limited data exist, however, examining dual-task gait data consistency collected over time in healthy individuals. The study purposes were to: 1) assess the consistency of single-task and dual-task gait balance control measures, 2) determine the minimal detectable change (MDC) of gait balance control measures, and 3) examine the extent to which age and task complexity affect dual-task walking costs in healthy adolescents and young adults. Twenty-four adolescent (mean age = 15.5 ± 1.1 years) and 21 young adult (mean age = 21.2 ± 4.5 years) healthy participants completed 5 testing sessions across a two-month period, which involved analyses of gait balance control and temporal-distance variables during single-task and dual-task walking conditions in a motion analysis laboratory. Cronbach’s α and MDCs were used to determine the consistency of the gait balance control variables and the smallest amount of change required to distinguish true performance from change due to the performance/measurement variability, respectively. Dual-task costs were evaluated to determine the effect of task complexity and age across time using 3-way ANOVAs. Good to excellent test-retest consistency was found for all single-task and dual-task walking (Cronbach’s α range: 0.764–0.970), with a center-of-mass medial-lateral displacement MDC range of 0.835–0.948 cm. Greater frontal plane dual-task costs were observed during more complex secondary tasks (p < 0.001). The results revealed good-excellent consistency across testing sessions for all variables and indicated dual-task costs are affected by task complexity. Thus, healthy controls can be effective comparators when assessing injured subjects.     

Trunk sway during walking among older adults: Norms and correlation with gait velocity

The aim of this study was to establish quantitative norms for trunk sway during walking for older male and female ambulatory adults at different age groups (65–70, 71–75, 76–80, ≥81). We also assessed the relationship between dynamic trunk sway and gait velocity in older individuals with clinically normal or abnormal gaits. Trunk sway in medio-lateral (roll) and antero-posterior (pitch) planes was measured using a body-mounted gyroscope (SwayStar) during walking on a 4.5 m long instrumented walkway. Of the 284 older adults (mean age 76.8, 54.6% women) in this sample, the mean ± SD value of roll and pitch angles were 6.0 ± 2.0° and 6.7 ± 2.2° respectively. Older women showed significantly greater trunk sway in both roll and pitch angles than older men (p < 0.01). In both men and women, there was no significant association of roll angle with age although gait velocity decreased with increasing age. The relationship between roll angle and gait velocity was U-shaped for the overall sample. Among the subgroup with clinically normal gait, increased roll angle was associated with increased gait velocity (p < 0.001). However, there was no significant relationship between roll angle and gait velocity among the subgroup with abnormal gait. Therefore, the relationship between medio-lateral trunk sway and gait velocity differs depending on whether gait is clinically normal.We conclude that trunk sway during walking should be interpreted with consideration of both gait velocity and presence of gait abnormality in older adults.     

Trunk sway during walking among older adults: Norms and correlation with gait velocity

The aim of this study was to establish quantitative norms for trunk sway during walking for older male and female ambulatory adults at different age groups (65–70, 71–75, 76–80, ≥81). We also assessed the relationship between dynamic trunk sway and gait velocity in older individuals with clinically normal or abnormal gaits. Trunk sway in medio-lateral (roll) and antero-posterior (pitch) planes was measured using a body-mounted gyroscope (SwayStar) during walking on a 4.5 m long instrumented walkway. Of the 284 older adults (mean age 76.8, 54.6% women) in this sample, the mean ± SD value of roll and pitch angles were 6.0 ± 2.0° and 6.7 ± 2.2° respectively. Older women showed significantly greater trunk sway in both roll and pitch angles than older men (p < 0.01). In both men and women, there was no significant association of roll angle with age although gait velocity decreased with increasing age. The relationship between roll angle and gait velocity was U-shaped for the overall sample. Among the subgroup with clinically normal gait, increased roll angle was associated with increased gait velocity (p < 0.001). However, there was no significant relationship between roll angle and gait velocity among the subgroup with abnormal gait. Therefore, the relationship between medio-lateral trunk sway and gait velocity differs depending on whether gait is clinically normal.We conclude that trunk sway during walking should be interpreted with consideration of both gait velocity and presence of gait abnormality in older adults.     

Attentional requirements of walking according to the gait phase and onset of auditory stimuli

A dual-task paradigm was used to examine the influence of an attention demanding cognitive task on each phase of gait. Twenty-three participants (aged 18–27) walked on a treadmill at a 20% increase of their self-selected speed, either alone or while performing a cognitive task. Muscle activity was measured with electromyography (iEMG) for eight muscles of the dominant leg. The cognitive task consisted of subtracting one (EASY) or seven (HARD) from aurally presented numbers. Reaction time (RT) and accuracy were recorded. iEMG events were selected according to stimulus onset (0–150 ms, 150–300 ms and 300–450 ms) prior to phases of gait (double-leg stance, single-leg stance and swing). There was a decrease in iEMG amplitude of fibularis longus (p = .013) and a trend in the same direction for vastus lateralis (p = .065) while walking and performing the cognitive task. When stimulus onset was considered, iEMG of medial gastrocnemius (p = .021) and lateral gastrocnemius (p = .004) were reduced during single-leg stance, when stimuli occurred between 300 and 450 ms prior to this phase. Cognitive performance was affected by task difficulty (RT, accuracy) and by dual-task load (RT). Dual-task costs were observed in both the motor and the cognitive tasks, suggesting that walking requires attention. There was a specific moment (300 ms after stimulus onset) during single-leg stance when dual-task costs were most pronounced, corroborating supraspinal involvement in the control of normal walking. Time-based approaches should be considered when analyzing attentional demands of a dynamic task such as gait.     

Using a dual-task protocol to investigate motor and cognitive performance in healthy children and youth

ObjectivesMild traumatic brain injury (or concussion) is a prevalent yet understudied health concern in children and youth. This injury can cause dysfunction in both motor and cognitive domains; however, most literature focuses on single-task neuropsychological tests which only assess cognition. Although dual-task research on concussed children and youth is needed as many daily activities require both motor and cognitive domains, we must first investigate whether performing simultaneous motor and cognitive tasks of varied complexity impact these domains in healthy children and youth.Participants and designData collected from 106 healthy children and youth (5–18 years) created a normative dataset. Participants performed motor (postural stability) and cognitive (visual attention) tasks under single- and dual-task conditions. The cognitive task difficulty remained constant while the motor task had four conditions of increasing difficulty. The relationship between the number of correct responses (cognitive performance) and sway index (motor performance) was determined using two repeated measures ANOVAs (p < 0.05).ResultsDual-task conditions resulted in reduced postural stability, with greater differences on the foam surface (F_2,206 = 16.070, p < 0.0005). No statistically significant differences were observed in attention (F_4,101 = 0.713, p = 0.584).ConclusionsPostural stability decreased under dual-task conditions, but attention was maintained or improved. Consequently, attention took precedence over postural control when performing tasks concurrently, demonstrating the ability for dual-task methodology to isolate specific processes. This study provides a normative dataset to be used during clinical management to identify functional deficits following concussion and acts as a starting point to explore dual-task protocols in children and youth following concussion.     

Changes in performance markers and wellbeing in elite senior professional rugby union players during a pre-season period: Analysis of the differences across training phases

ObjectivesTo assess the magnitude of change and association with variation in training load of two performance markers and wellbeing, over three pre-season training blocks, in elite rugby union athletes.DesignObservational.MethodsTwenty-two professional players (age 25 ± 5 years; training age 6 ± 5 years; body mass, 99 ± 13 kg; stature 186 ± 6 cm) participated in this study, with changes in lower (CMJ height) and upper body (bench press mean speed) neuromuscular function and self-reported wellbeing (WB) assessed during an 11-week period.ResultsThere was a small increase in CMJ height (0.27, ±0.17 – likely substantial; standardised effect size, ±95% confidence limits – magnitude-based inference) (p = 0.003), bench press speed (0.26, ±0.15 – likely substantial) (p = 0.001) and WB (0.26, ±0.12 – possibly substantial) (p < 0.0001) across the pre-season period. There was a substantial interaction in the effect of training load on these three variables across the three training phases. A two-standard deviation (2SD) change in training load was associated with: a small decrease in CMJ height during the power phase (−0.32, ±0.19 – likely substantial) (p = 0.001); a small reduction in bench press speed during the hypertrophy phase (−0.40, ±0.32 – likely substantial) (p = 0.02); and a small reduction in WB during the strength phase (−0.40, ±0.24 – very likely substantial) (p < 0.0001). The effects of changes in training load across other phases were either likely trivial, only possibly substantial, or unclear.ConclusionsThe effect of training load on performance can vary both according to the type of training stimulus being administered and based on whether upper- or lower-body outcomes are being measured.     

Differentiation of young and older adult stair climbing gait using principal component analysis

IntroductionPrincipal component analysis (PCA) has been used to reduce the volume of gait data and can also be used to identify the differences between populations. This approach has not been used on stair climbing gait data. Our objective was to use PCA to compare the gait patterns between young and older adults during stair climbing.MethodsThe knee joint mechanics of 30 healthy young adults (23.9 ± 2.6 years) and 32 healthy older adults (65.5 ± 5.2 years) were analyzed while they ascended a custom 4-step staircase. The three-dimensional net knee joint forces, moments, and angles were calculated using typical inverse dynamics. PCA models were created for the knee joint forces, moments and angles about the three axes. The principal component scores (PC scores) generated from the model were analyzed for group differences using independent samples t-tests. A stepwise discriminant procedure determined which principal components (PCs) were most successful in differentiating the two groups.ResultsThe number of PCs retained for analysis was chosen using a 90% trace criterion. Of the scores generated from the PCA models nine were statistically different (p < .0019) between the two groups, four of the nine PC scores could be used to correctly classify 95% of the original group.ConclusionsThe PCA and discriminant function analysis applied in this investigation identified gait pattern differences between young and older adults. Identification of stair gait pattern differences between young and older adults could help in understanding age-related changes associated with the performance of the locomotor task of stair climbing.     

Gait Profile Score in multiple sclerosis patients with low disability

BackgroundGait abnormalities are subtle in multiple sclerosis (MS) patients with low disability and need to be better determined. As a biomechanical approach, the Gait Profile Score (GPS) is used to assess gait quality by combining nine gait kinematic variables in one single value. This study aims i) to establish if the GPS can detect gait impairments and ii) to compare GPS with discrete spatiotemporal and kinematic parameters in low-disabled MS patients.MethodThirty-four relapsing-remitting MS patients with an Expanded Disability Status Scale (EDSS) score ≤2 (mean age 36.32 ± 8.72 years; 12 men, 22 women; mean EDSS 1.19 ± 0.8) and twenty-two healthy controls (mean age 36.85 ± 7.87 years; 6 men, 16 women) matched for age, weight, height, body mass index and gender underwent an instrumented gait analysis.ResultsNo significant difference in GPS values and in spatiotemporal parameters was found between patients and controls. However patients showed a significant alteration at the ankle and pelvis level.ConclusionGPS fails to identify gait abnormalities in low-disabled MS patients, although kinematic analysis revealed subtle gait alterations. Future studies should investigate other methods to assess gait impairments with a gait score in low-disabled MS patients.     

The interacting effect of cognitive and motor task demands on performance of gait,balance and cognition in young adults

Mobility limitations and cognitive impairments, each common with aging, reduce levels of physical and mental activity, are prognostic of future adverse health events, and are associated with an increased fall risk. The purpose of this study was to examine whether divided attention during walking at a constant speed would decrease locomotor rhythm, stability, and cognitive performance. Young healthy participants (n = 20) performed a visuo-spatial cognitive task in sitting and while treadmill walking at 2 speeds (0.7 and 1.0 m/s).Treadmill speed had a significant effect on temporal gait variables and ML-COP excursion. Cognitive load did not have a significant effect on average temporal gait variables or COP excursion, but variation of gait variables increased during dual-task walking. ML and AP trunk motion was found to decrease during dual-task walking. There was a significant decrease in cognitive performance (success rate, response time and movement time) while walking, but no effect due to treadmill speed. In conclusion walking speed is an important variable to be controlled in studies that are designed to examine effects of concurrent cognitive tasks on locomotor rhythm, pacing and stability. Divided attention during walking at a constant speed did result in decreased performance of a visuo-spatial cognitive task and an increased variability in locomotor rhythm.     

The use of the dual-task paradigm in detecting gait performance deficits following a sports-related concussion: A systematic review and meta-analysis

ObjectivesThe purpose of this systematic review was to determine the viability of the dual-task paradigm in the evaluation of a sports-related concussion.DesignSystematic review and meta-analysis.MethodsEight electronic databases were searched from their inception until the 11^th of April 2011. Studies were grouped according to their reported gait performance variables and their time(s) of assessment(s). Raw mean differences (MD) and 95% confidence intervals (CI) were calculated based on raw means and standard deviations for gait performance measures in both single- and dual-task conditions. Dual-task deficits were pooled using a random effects model and heterogeneity (I²) between studies was assessed.ResultsTen studies representing a total sample of 168 concussed and 167 matched (age and gender) non-concussed participants met the inclusion criteria. Meta-analysis demonstrated that dual-task performance deficits were detected (p < 0.05) in the concussed group for gait velocity (GV) (MD = ?0.133; 95% CI ?0.197, ?0.069) and range of motion of the centre of mass in the coronal plane (ML-ROM) (MD = 0.007; 95% CI 0.002, 0.011), but not in the non-concussed group; GV (MD = ?0.048; 95% CI ?0.101, 0.006), ML-ROM (MD = 0.002; 95% CI ?0.001, 0.005).ConclusionsThe results of this study indicate that GV and ML-ROM are sensitive measures of dual-task related changes in concussed patients and should be considered as part of a comprehensive assessment for a sports-related concussion.     

Gait initiation time is associated with the risk of multiple falls—A population-based study

AimsIn a population-based study of older people to examine whether 1) overall gait initiation (GI) time or its components are associated with falls and 2) GI under dual-task is a stronger predictor of falls risk than under single-task.MethodsParticipants aged 60–85 years were randomly selected from the electoral roll. GI was obtained with a force platform under both single and dual-task conditions. Falls were ascertained prospectively over a 12-month period. Log multinomial regression was used to examine the association between GI time (total and its components) and risk of single and multiple falls. Age, sex and physiological and cognitive falls risk factors were considered as confounders.ResultsThe mean age of the sample (n = 124) was 71.0 (SD 6.8) years and 58.9% (n = 73) were male. Over 12 months 21.8% (n = 27) of participants reported a single fall and 16.1% (n = 20) reported multiple falls. Slower overall GI time under both single (RR all per 100 ms 1.28, 95%CI 1.03, 1.58) and dual-task (RR 1.14, 95%CI 1.02, 1.27) was associated with increased risk of multiple, but not single falls (p < 0.05). Multiple falls were also associated with slower time to first lateral movement under single-task (RR 1.90 95%CI 0.59, 1.51) and swing time under dual-task condition (RR 1.44 95%CI 1.08, 1.94).ConclusionSlower GI time is associated with the risk of multiple falls independent of other risk factors, suggesting it could be used as part of a comprehensive falls assessment. Time to the first lateral movement under single-task may be the best measures of this risk.