Is pregnancy brain real? Comparison of dual task cost during overground walking in pregnant versus control women

BackgroundMany pregnant women report that their memory is impaired compared to non-pregnancy, but results of studies of cognitive abilities are mixed. The effect of pregnancy on dual tasking, or performance of two tasks simultaneously, has not been studied, however.Research questionWhat is the effect of walking overground at a self-selected speed while also performing a cognitive task on gait and cognitive performance during 3rd trimester of pregnancy compared to non-pregnant controls?MethodsA total of n = 22 3rd trimester pregnant women (mean 33.3 ± 3.3 weeks gestation, age 32.1 ± 4.7 years) and n = 21 non-pregnant controls (age 31.9 ± 3.3 years) were recruited to participate. All participants performed single task walking on a GAITRite gait analysis system and performed three cognitive tests while walking: serial 3 and 7 subtraction tests and a phoneme monitoring test. Participants completed the same assessments while seated and order of the testing was counterbalanced. Dual task cost (DTC) was calculated using the formula (Single task score – Dual task score)/Single task score)*100. Independent t-tests or Mann Whitney U tests were used to compare the two groups depending on normality of data.ResultsThere were no significant differences in cognitive test performance between control and pregnant women while walking or seated (p > 0.05). There were no significant differences between groups for DTC during any cognitive tests, but DTC was significantly greater for walking velocity in pregnant women compared to controls for serial 3 (p < 0.001) and serial 7 (p = 0.005) but not phoneme monitoring (p = 0.061).SignificancePregnant women had elevated cost of dual tasking, though the decrements were not in cognitive tests but in gait, specifically with greater DTC of walking velocity. This suggests that pregnant women modify their walking velocity to preserve cognitive function during activities requiring focus on both cognitive and physical tasks.     

Age-related differences in spatiotemporal markers of gait stability during dual task walking

Increased stride-to-stride variability during walking characterizes gait instability and predicts falling in older adults. Walking while performing cognitive tasks (dual task walking) is also associated with increased risk of falling. The purpose of the study was to examine whether gait velocity and stride-to-stride variability in gait velocity differ in older adults compared with middle-aged and younger adults during normal and dual task walking conditions. Sixty older (n=20, mean age=81 years), middle-aged (n=20, mean age=48 years), and young adults (n=20, mean age=25 years) participated in the study. Gait parameters were quantified with GAITRite instrumentation. In the dual task condition, participants spelled five-letter words in reverse while walking across the walkway. Across groups, gait velocity was slower (p<0.001) and stride-to-stride variability in gait velocity was greater (p=0.001) in dual task walking. Older subjects walked more slowly than did middle-aged and younger subjects and the difference in gait velocity was greatest in the dual task condition (p<0.05). Variability in stride velocity was increased in older subjects compared with middle-aged and younger subjects (p<0.05). Additionally, in older subjects, impaired walking performance was associated with impaired cognitive performance in dual task walking. The gait changes observed in dual task walking characterize decreased gait stability and indicate that cognitively demanding tasks during walking have a destabilizing effect on gait and may place older people at a greater risk of falling.     

A mobile app to transparently distinguish single- from dual-task walking for the ecological monitoring of age-related changes in daily-life gait

BackgroundEarly detection of gait impairments in older adults allows the early uncovering of fall risk and/or cognitive deficits, resulting in timely interventions. Dual-task paradigms have been shown to be more sensitive than single-task conditions for the detection of subtle yet relevant gait impairments.Research questionCan a system - encompassing a pair of instrumented insoles and a customized mobile app - transparently and accurately study ecological walking activities in single- and dual-task conditions, with the aim of detecting early and subtle age-related alterations of gait?MethodsThe system was tested on 19 older adults during outdoor walking (two identical single-task trials and two motor-cognitive dual-task trials with the user engaged in a simple phone call and in a cognitive-demanding phone call). A single-task cognitive trial was included. Relative reliability of the gait parameters provided by the insoles during single-task walking was investigated (Intraclass Correlation Coefficient). The effect of dual tasking on both motor (Friedman test) and cognitive (Wilcoxon signed-rank test) domains was studied.To study usability, the system was tested on 5 older adults in real-life environment over 3 months.ResultsMost of the parameters showed excellent reliability. Independently from the cognitive demand, walking while talking resulted in increased gait cycle and step time, with a prolonged stance phase due to an augmented double-support. Variability of gait cycle and stance phase increased only during the most demanding dual-task. Dual tasking resulted in a reduced cognitive score.Usability feedback were excellent, with users reporting to understand the usefulness of the devised system and to feel at ease when using the system and the insoles.SignificanceThis work paves the way toward fruitful applications of the devised system to achieve accurate and ecological monitoring of daily-life walking activities, with the final aim of detecting early and subtle alterations of gait.     

Interactions between cognitive tasks and gait after stroke: a dual task study

This study investigated the interactions between gait and three different cognitive tasks in people after stroke. Thirteen people post-stroke who were living in the community, were able to walk 10 m without physical assistance, and could respond verbally to auditory stimuli participated. Participants performed a walking task alone, three different cognitive tasks while seated, and each cognitive task in combination with walking. Gait data were acquired continuously for approximately 3 min. Reaction time and accuracy were recorded for two of the cognitive tasks (visuospatial task, working memory task). Speech samples from the spontaneous speech task were analyzed on several dimensions of language. Significant dual task effects were observed for gait speed, stride time, average stride length, and cadence, but not for stride time variability. Speech produced more gait interference than memory and visuospatial tasks. Interference effects on cognition were minimal; only speech was significantly affected by concurrent walking. Narratives in the dual task condition had more pauses, shorter sentences, but more utterances with new information. Even though participants in this study were mobility-impaired, they prioritized the cognitive tasks. Future research should determine whether dual task training can reduce gait decrements in dual task situations in people after stroke.     

Minimal effects of age and prolonged physical and mental exercise on healthy adults’ gait

BackgroundGait adaptability in old age can be examined by responses to various perturbations. Fatigability due to mental or muscle exercises can perturb internal cognitive and muscle resources, necessitating adaptations in gait.Research questionWhat are the effects of age and mental and muscle fatigability on stride outcomes and gait variability?MethodsTwelve older (66–75yrs) and twelve young (20–25 yrs) adults walked at 1.2 m/s before and after two fatigue conditions in two separate sessions. Fatigue conditions were induced by repetitive sit-to-stand task (RSTS) and by 30-min of mental tasks and randomized between days (about a week apart). We calculated the average and coefficient of variation of stride length, width, single support, swing time and cadence, and the detrended fluctuations analysis (DFA) based on 120 strides time intervals. We also calculated multi-scale sample entropy (MSE) and the maximal Lyapunov exponent (λmax) of mediolateral (ML) and anteroposterior (AP) of the Center of Pressure (CoP) trajectories.ResultsIn both age groups, RSTS modestly affected stride length, single support time, cadence, and CV of stride length (p ≤ 0.05), while the mental task did not affect gait. After fatigability, λmax - ML increased (p ≤ 0.05), independent of fatigue condition. All observed effects were small (η²: 0.001 to 0.02).SignificanceMuscle and mental fatigability had minimal effects on gait in young and healthy older adults possibly because treadmill walking makes gait uniform. It is still possible that age-dependent muscle activation underlies the uniform gait on the treadmill. Age- and fatigability effects might be more overt during real life compared with treadmill walking, creating a more effective model for examining gait and age adaptability to fatigability perturbations.     

Gait and cognition: the relationship between gait stability and variability with executive function in persons with and without dementia

Besides cognitive decline, dementia is characterized by gait changes and increased fall risk, also in early stages of the disease. The aim of this study was to investigate differences in the relationship between executive function and gait variability and stability during single task and dual task walking in persons with and without dementia. The study sample consisted of three groups: fifteen dementia patients (aged 75-87), fourteen healthy elderly (aged 75-85), and twelve relatively younger elderly (aged 55-70). Participants underwent neuropsychological testing and tests of single and dual task walking while wearing an accelerometer. Outcome measures include stride related measures such as mean and coefficient of variation of stride time, and dynamic measures regarding the magnitude, smoothness, predictability and local stability of trunk accelerations. Patients with dementia exhibited a significantly (p<.05) less variable, but more irregular trunk acceleration pattern than cognitively intact elderly on single and dual task walking. The walking pattern during dual tasking for the whole group became increasingly unstable, even though participants modified their gait pattern by slowing their walking speed, and decreasing the magnitude of trunk accelerations. Moderate to high correlations (r>.51) were found between executive tasks and gait parameters. In conclusion, these findings indicate that decreased executive function plays an important role in increased gait variability in dementia patients; a fact that should be considered when designing fall risk interventions for this population. Furthermore, results indicate that measures of gait variability and stability should be deemed worthwhile in the diagnosis of dementia.     

Does cognitive loading interfere with walking control?

BackgroundCognitive-motor interference is a common method used to investigate the cognitive demands of human walking. Using this methodology, consistent effects emerge: under cognitive load, walking velocity decreases, while spatio-temporal variability of walking increases. These effects are often interpreted as indicative of an interference in the ability to control gait. However, walking velocity is highly correlated with most gait parameters; thus, the increase in variability does not necessarily reflect reduced control, but rather a constant signal-to-noise ratio.MethodsTo investigate the effect of cognitive loading on gait variability, we retrospectively analysed 3721 records of healthy young adults, walking with and without a concurrent cognitive task, on a treadmill.ResultsStride duration and length increased under cognitive load, while the variability of these parameters decreased. Further, these effects were different between participants starting to walk without cognitive loading and those starting to walk with cognitive loading.ConclusionsDual tasking is more likely to divert the focus of attention away from the walking task, causing a shift of balance between automatic and conscious control, as opposed to interference per-se.     

Cognitive and visual demands,but not gross motor demand,of concurrent smartphone use affect laboratory and free-living gait among young and older adults

BackgroundAs smartphones are an integral part of daily activities, understanding the underlying mechanism associated with concurrent cell phone use while walking may help reduce the risks of injury.Research questionThis study examined the effect of cognitive, visual, and gross motor demands while using a phone during gait among young and older adults in the laboratory and free-living environments.MethodsTwelve young and twelve older adults walked along a 10-m walkway under five conditions: single-task walking (Walk), walking and bi-manually holding a phone (Walk-Hold), walking while looking at a phone held in front of the participants (Walk-Look), walking while answering questions (Walk-Answer), and walking while texting (Walk-Text). All conditions were performed in laboratory and free-living environments. Gait velocity, step time, step length, and cadence were obtained using a smartphone with a built-in accelerometer attached to the body. The dual-task cost (DTC) was also assessed. A three-way ANOVA was utilized for all parameters.ResultsWhile no three-way interactions were found for any parameter, group × condition interactions were significant for gait velocity, step time, step length, cadence and their corresponding DTC. Decreased gait velocity, step length and cadence, with increased step time was demonstrated during Walk-Look, Walk-Answer, and Walk-Text, compared to Walk and Walk-Hold. While older adults markedly changed their gait during Walk-Answer and Walk-Text, these changes were less pronounced among young adults.SignificanceVisual and cognitive demand while concurrently using a phone influenced gait, especially among the elderly. Environment did not accentuate gait alterations during concurrent phone use. Therefore, smartphone technology should be developed to detect dual-task walking and temporarily modify functionality to reduce risk of injury from divided attention.     

Comparison of temporal and stride characteristics in myotonic dystrophies type 1 and 2 during dual-task walking

ObjectiveWe analyzed temporal and stride characteristics in patients with myotonic dystrophy type 1 (DM1) and type 2 (DM2) while performing dual mental and motor tasks, and investigated correlations between gait parameters and cognitive impairments.MethodDual-task walking was performed by 37 patients (20 DM1 and 17 DM2) and 48 healthy subjects divided into two groups, age- and gender-matched control group for DM1 (HC1) and age- and gender-matched control group for DM2 (HC2). The subjects performed a basic walking task, dual-motor task, dual-mental task, and combined motor and mental task.ResultsDM1 and DM2 patients differed significantly in temporal and stride characteristics compared to HC. Main differences in DM1 were slower gait and shorter stride length, while both DM1 and DM2 patients had a higher degree of variation of the swing time during dual-task gait, a parameter that reflects posture and balance. Impact of the cognitive dual task on gait pattern changes was also observed. Visuospatial ability correlated with gait changes in DM1, while executive functions had stronger influence in DM2 (p < 0.01). Both patient groups had leg muscle weakness.ConclusionGait pattern was impaired in both patient groups concerning temporal and stride characteristics. Dual-task walking paradigm may discover mild initial gait changes and could provide early identification of fall risks and predict possible falls in DM patients.     

Medication improves balance and complex gait performance in Parkinson disease

Gait and balance impairments in people with Parkinson disease (PD) may lead to falls and serious injuries. Therefore, it is critical to improve our understanding of the nature of these impairments, including how they respond to prescribed anti-Parkinson medication. This is particularly important for complex balance and gait tasks that may be associated with falls. We evaluated motor function, functional balance, and gait performance during various gait tasks in 22 people with PD OFF and ON medication (PD OFF, PD ON) and 20 healthy older adults. Although MDS-UPDRS-III score, Berg Balance Scale, Mini-Balance Evaluations Systems test, and Timed-Up-and-Go improved in PD with medication, impairments persisted in all measures on medication, compared to controls. Dual task Timed-Up-and-Go did not improve with medication, and PD ON required more time than controls. Gait velocity and stride length improved similarly with medication in PD across forward, fast, backward, dual task forward, and dual task backward gait tasks. Cadence did not change with medication, nor did it differ between PD ON and controls. Velocity and stride length were reduced in PD ON compared to controls. Velocity reductions in PD ON during fast gait were cadence-mediated, while velocity reductions in backward gait were stride length-mediated. Our results suggest functional balance improves with medication in PD and gait performance improves with medication, regardless of task complexity. Remaining impairments on medication highlight the need to examine additional therapeutic options for individuals with PD to reduce the risk of falls.     

Effects of barefoot vs. shod walking during indoor and outdoor conditions in younger and older adults

BackgroundGait stability and variability measures in barefoot and shod locomotion are frequently investigated in younger but rarely in older adults. Moreover, most studies examine gait measures in laboratory settings instead of real-life settings.Research questionsHow are gait stability and variability parameters affected by footwear compared to barefoot walking in younger and older adults as well as under indoor vs. outdoor conditions?MethodsHealthy younger (<35 years) and older adults (>65 years) participated in the randomised within-subject study design. Participants conducted consecutive 25 m walking trials barefoot and with standardised footwear inside and outside. Inertial measurement units were mounted on the participant’s foot and used to calculate local dynamic stability (LDS), velocity and minimal toe clearance (MTC), stride length and stride time, including variabilities for these parameters. Linear mixed models were calculated.ResultsData of 32 younger (17 female, 15 male, age: 30 ± 4 years) and 42 older participants (24 female, 18 male, age: 71 ± 4 years) were analysed. MTC variability was higher in shod conditions compared to barefoot (p = 0.048) and in outdoor conditions (p < 0.001). LDS was different between age groups (p < 0.001). Gait velocity and MTC were higher in shod and outdoor conditions (both p < 0.001). Stride length and time were higher in shod conditions (both p < 0.001) and different between outdoor vs. indoor (longer stride length and shorter stride time outdoor, both (p < 0.001) as well as age groups (shorter stride length (p < 0.021) and stride time in older adults (p < 0.001).SignificanceResults suggest that gait stability and variability in older and younger adults are acutely affected by footwear vs. barefoot and indoor vs. outdoor walking conditions, indicating a high adaptiveness of these parameters to different experimental conditions. Consequently, future studies should be careful with generalising results obtained under certain conditions. Findings stress the clinical potential of barefoot walking.     

Outcome-dependent effects of walking speed and age on quantitative and qualitative gait measures

BackgroundWalking speed predicts many clinical outcomes in old age. However, a comprehensive assessment of how walking speed affects accelerometer based quantitative and qualitative gait measures in younger and older adults is lacking.Research questionWhat is the relationship between walking speed and quantitative and qualitative gait outcomes in younger and older adults?MethodsYounger (n = 27, age: 21.6) and older participants (n = 27, age: 69.5) completed 340 steps on a treadmill at speeds of 0.70 to a maximum of 1.75 m·s^-1. We used generalized additive mixed models to determine the relationship between walking speed and quantitative (stride length, stride time, stride frequency and their variability) and qualitative (stride regularity, stability, smoothness, symmetry, synchronization, predictability) gait measures extracted from trunk accelerations.ResultsThe type of relationship between walking speed and the majority of gait measures (quantitative and qualitative) was characterized as logarithmic, with more prominent speed-effects at speeds below 1.20 m·s⁻¹. Changes in quantitative measures included shorter strides, longer stride times, and a lower stride frequency, with more variability at lower speeds independent of age. For qualitative measures, we found a decrease in gait symmetry, stability and regularity in all directions with decreasing speeds, a decrease in gait predictability (Vertical, V, anterior-posterior, AP) and stronger gait synchronization (AP-mediolateral, ML, AP-V), and direction dependent effects of gait smoothness, which decreased in V direction, but increased in AP and ML directions with decreasing speeds. We found outcome-dependent effects of age on the quantitative and qualitative gait measures, with either no differences between age-groups, age-related differences that existed regardless of speed, and age-related differences in the type of relationship with walking speed.SignificanceThe relationship between walking speed and quantitative and qualitative gait measures, and the effects of age on this relationship, depends on the type of gait measure studied.     

Dual-task prioritization during overground and treadmill walking in healthy adults

BackgroundThe dual-task effect on walking performance is different during treadmill and overground walking, though the cause of this difference is unknown. This study examined the effects of task prioritization on overground and treadmill dual-task walking.MethodTwenty-two adults walked overground and on a treadmill under three dual-task conditions: prioritization of walking performance, prioritization of cognitive performance (serial subtraction in sevens), or no prioritization.ResultsCompared to single-task walking, stride velocity was reduced and stride time variability was increased during dual-task overground walking. During treadmill walking, there was no dual-task effect on walking performance, but cognitive task performance was improved. Prioritization of the cognitive task reduced the dual-task effect on stride velocity during overground walking only, whilst prioritization of the walking task reduced cognitive task performance in both walking modalities.SignificanceThese results corroborate recent findings that the dual-task effects on treadmill walking are not equivalent to those on overground walking. Healthy adults appear to prioritize cognitive task performance during treadmill dual-task walking without detrimental effects to gait. During overground walking however, allocation of attention to the secondary task reduces gait performance. These results indicate that treadmill based dual-task paradigms should not be used to infer factors which influence the cognitive control of overground walking.     

Two-year changes in gait variability in community-living older adults

BackgroundIncreases in stride-to-stride fluctuations (gait variability) are common among older adults, but little is known about the natural progression of gait variability with increasing age.Research questionDoes gait variability change with increasing age in a group of community-living older adults?MethodsThe participants were community-living volunteers between 70–81 years, who were tested with a two-year interval between tests. They walked 6.5 m under four different conditions: At preferred speed, at fast speed, during a dual task condition and on an uneven surface. Trunk accelerations in the anteroposterior (AP), mediolateral (ML) and vertical (V) direction were captured using a body-worn sensor worn at the lower back. Gait variability was estimated using an autocorrelation procedure, where coefficients tending towards 1.0 indicated low variability and 0.0 as high variability. To estimate change, we used an ANOVA-procedure with baseline gait speed as a covariate.ResultsAt baseline, 85 older adults were tested, and data for 56 of these were available for analysis over a two-year period of time. The average age at inclusion was 75.8 years (SD 3.43) and 60% were women. During preferred speed walking, variability increased in the AP direction (mean difference 0.05, p = .038), during fast speed walking it increased in the V direction (mean difference 0.04, p = .037) and during dual task-walking, it increased in the ML and V directions (mean differences 0.03, p = .032 and 0.09, p = .020 respectively).SignificanceThe findings from this study could be helpful for discriminating between normal and pathological progression of gait variability in older adults.     

Reliability of spatial–temporal gait parameters during dual-task interference in people with multiple sclerosis. A cross-sectional study

PurposeTo evaluate the reliability and minimum detectable change (MDC) of spatial–temporal gait parameters in subjects with multiple sclerosis (MS) during dual tasking.MethodThis cross-sectional study involved 25 healthy subjects (mean age 49.9 ± 15.8 years) and 25 people with MS (mean age 49.2 ± 11.5 years). Gait under motor-cognitive and motor–motor dual tasking conditions was evaluated in two sessions separated by a one-day interval using the GAITRite^® Walkway System. Test–retest reliability was assessed using intraclass correlation coefficients (ICCs), standard errors of measurement (SEM), and coefficients of variation (CV). MDC scores were computed for the velocity, cadence, step and stride length, step and stride time, double support time, the % of gait cycle for single support and stance phase, and base of support.ResultsAll of the gait parameters reported good to excellent ICCs under both conditions, with healthy subject values of >0.69 and MS subject values of >0.84. SEM values were always below 18% for both groups of subjects. The gait patterns of the people with MS were slightly more variable than those of the normal controls (CVs: 5.88–41.53% vs 2.84–30.48%).ConclusionsThe assessment of quantitative gait parameters in healthy subjects and people with MS is highly reliable under both of the investigated dual tasking conditions.     

Reliability of spatial–temporal gait parameters during dual-task interference in people with multiple sclerosis. A cross-sectional study

PurposeTo evaluate the reliability and minimum detectable change (MDC) of spatial–temporal gait parameters in subjects with multiple sclerosis (MS) during dual tasking.MethodThis cross-sectional study involved 25 healthy subjects (mean age 49.9 ± 15.8 years) and 25 people with MS (mean age 49.2 ± 11.5 years). Gait under motor-cognitive and motor–motor dual tasking conditions was evaluated in two sessions separated by a one-day interval using the GAITRite^® Walkway System. Test–retest reliability was assessed using intraclass correlation coefficients (ICCs), standard errors of measurement (SEM), and coefficients of variation (CV). MDC scores were computed for the velocity, cadence, step and stride length, step and stride time, double support time, the % of gait cycle for single support and stance phase, and base of support.ResultsAll of the gait parameters reported good to excellent ICCs under both conditions, with healthy subject values of >0.69 and MS subject values of >0.84. SEM values were always below 18% for both groups of subjects. The gait patterns of the people with MS were slightly more variable than those of the normal controls (CVs: 5.88–41.53% vs 2.84–30.48%).ConclusionsThe assessment of quantitative gait parameters in healthy subjects and people with MS is highly reliable under both of the investigated dual tasking conditions.     

Multiple gait parameters derived from iPod accelerometry predict age-related gait changes

IntroductionNormative data of how natural aging affects gait can serve as a frame of reference for changes in gait dynamics due to pathologies. Therefore, the present study aims (1) to identify gait variables sensitive to age-related changes in gait over the adult life span using the iPod and (2) to assess if these variables accurately distinguish young (aged 18–45) from healthy older (aged 46–75) adults.MethodsTrunk accelerations were recorded with an iPod Touch in 59 healthy adults during three minutes of overground walking. Gait variables included gait speed and accelerometry-based gait variables (stride, amplitude, frequency, and trajectory-related variables) in the anterior-posterior (AP) and medio-lateral (ML) directions. Multivariate partial least square analysis (PLS) identified variables sensitive to age-related differences in gait. To classify young and old adults, a PLS-discriminant analysis (PLS-DA) was used to test the accuracy of these variables.ResultsThe PLS model explained 42% of variation in age. Influential variables were: mean stride time, phase variability index, root mean square, stride variability, AP sample entropy and ML maximal Lyaponov exponent. PLS-DA classified 83% of the participants correctly with a sensitivity of 83% and specificity of 71%.DiscussionContrary to the frequently reported high gait variability observed in old adults with frailty and fall history, the present study showed that younger compared with older healthy adults had a more variable, less predictable and more symmetrical gait pattern. A model based on a combination of variables reflecting gait dynamics, could distinguish healthy younger adults from older adults.     

Walking indoors,outdoors, and on a treadmill: Gait differences in healthy young and older adults

BackgroundAlthough human gait is typically studied in a laboratory environment, the findings of laboratory-based gait assessments are often applied to daily life scenarios. Assessing gait in varied conditions may offer a better understanding of the influence of environment on gait performance.Research questionsHow do spatiotemporal gait measures differ between indoor overground walking, outdoor walking, and treadmill walking in healthy adults? Do different walking environments exaggerate age-related alterations in gait performance in older compared to young adults?Methods30 young (18−30yrs) and 28 older adults (60−80yrs) completed four randomized conditions at their typical, comfortable walking pace: 1) 8 m of indoor walking, 2) continuous indoor walking, 3) treadmill walking, and 4) outdoor walking on a sidewalk. Wearable inertial sensors recorded gait data and the magnitudes and variability (in standard deviations) of the following gait measures were computed: cadence, percent double support, stride length (with sample entropy), and gait velocity.ResultsDespite the lack of significant univariate interactions between group and walking condition, significant main effects for condition and group were observed in both the magnitude and variability analyses. Treadmill walking resulted in a slower gait with shorter, less variable strides (p < .001), while walking outdoors resulted in faster gait with longer strides (p < .001) compared to other walking conditions. Stride length regularity was reduced when walking outdoors compared to treadmill walking (p = .019).SignificanceThe results showed that the effects of walking condition on gait measures were more dramatic than participant age, and gait performance differs between walking environments in both older and younger adults. Since daily life gait encompasses both tightly controlled and unconstrained, free-living walking, researchers and clinicians should use caution when generalizing gait performance across walking conditions. Measures of gait performance typically used in laboratory gait analyses may not adequately characterize daily life gait in indoor and outdoor environments.     

Cognitive load of walking in people who are blind: Subjective and objective measures for assessment

BackgroundAlthough walking without vision seems to carry a high cognitive cost, few studies have measured the cognitive load involved in this activity in blind people. The aim of this study was to assess the cognitive load of walking in blind people, using gait analysis, a dual task paradigm and a subjective assessment of cognitive load.MethodsIn a quantitative quasi-experimental design, 25 blind adults walked 40 meters. In one trial, participants walked normally (control condition). In another, they walked while performing an auditory simple reaction time task, and in the third trial they walked, performed the simple reaction time task and avoided obstacles. In addition to the simple reaction time task performance, walking speed was recorded, and participants provided a subjective assessment of cognitive load after each trial. Performance of participants aged less than 60 years were compared with those aged over than 60 years.ResultsWalking significantly reduced performance of the simple reaction time task; carrying out the simple reaction time task while walking significantly reduced walking performance and increased the subjective assessment of cognitive load; and simple reaction time task performance decreased and subjective assessment increased when obstacles were present. Few significant age effects were found.SignificanceWalking without vision involves a cognitive load that increases when the environment becomes complex. Each of the three methods used is relevant when assessing the cognitive load involved in walking in blind people, and could be useful in rehabilitation intervention. The results obtained allowed recommendations to be suggested for the design of technological mobility devices.