Stride Velocity Variability Research Articles

Effects of Hallux Valgus Surgery on Balance and Gait in Middle Aged and Older Adults

Hallux valgus is associated with balance deficits, and has been implicated as an independent risk factor for falls in older adults. However, it is unknown what effect hallux valgus surgery has on static and dynamic (i.e., while walking) balance in older adults. We enrolled 13 middle-aged and older aged adults (mean age 54.3 ± 12.7 years, range 47 to 70) who underwent isolated hallux valgus surgery and followed them for 12 months. Preoperative and postoperative gait and balance performance was assessed using non-invasive body worn sensors with standardized and validated testing protocols. Visual analog scale (VAS) for pain and radiographic angles were also assessed. All subjects reported improvements in pain (VAS mean change -38.3 ± 10.3 mm), and all subjects demonstrated improvements in their hallux valgus angles and first/second intermetatarsal angles (mean change 16.3 ± 8.8°, and 5.5 ± 3.0°, respectively). While standing in full tandem, center of mass (COM) sway was improved upon by 59% at 1 year postoperative (p < .05, paired t-test). While most gait parameters demonstrated little change postoperatively, patients tended to spend less time in double support (p = .08, paired t-test), while gait variability increased by 55% (p = .03, paired t-test) and medial-lateral sway while walking increased by 43% (p = .08, paired t-test) 12 months postoperatively. Balance improved after hallux valgus surgery in our population, particularly when subjects were forced to rely on their operative foot for support (e.g., full tandem). Patients also seemed to walk with greater variability in stride velocity and with greater medial-lateral sway postoperatively, suggesting perhaps increased ambulatory confidence after successful hallux valgus surgery.

REM Sleep Without Atonia and Gait Impairment in People with Mild-to-Moderate Parkinson's Disease.

Subtle gait deficits can be seen in people with idiopathic rapid eye movement (REM) sleep behavior disorder (RBD), a prodromal stage of Parkinson's disease (PD) and related alpha-synucleinopathies. It is unknown if the presence and level of REM sleep without atonia (RSWA, the electromyographic hallmark of RBD) is related to the severity of gait disturbances in people with PD. We hypothesized that gait disturbances in people with mild-to-moderate PD would be greater in participants with RSWA compared to those without RSWA and matched controls, and that gait impairment would correlate with measures of RSWA. Spatiotemporal characteristics of gait were obtained from 41 people with PD and 21 age-matched controls. Overnight sleep studies were used to quantify muscle activity during REM sleep and group participants with PD into those with RSWA (PD-RSWA+, n = 22) and normal REM sleep muscle tone (PD-RSWA-, n = 19). Gait characteristics were compared between groups and correlated to RSWA. The PD-RSWA+ group demonstrated significantly reduced gait speed and step lengths and increased stance and double support times compared to controls, and decreased speed and cadence and increased stride velocity variability compared to PD-RSWA- group. Larger RSWA scores were correlated with worse gait impairment in the PD group. The presence and level of muscle tone during REM sleep is associated with the severity of gait disturbances in PD. Pathophysiological processes contributing to disordered gait may occur earlier and/or progress more rapidly in people with PD and RBD.

The Effects of Dual Task Cognitive Interference and Fast-Paced Walking on Gait, Turns, and Falls in Men and Women with FXTAS.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a genetic neurodegenerative disorder characterized by cerebellar ataxia, tremor, and cognitive dysfunction. We examined the impact of dual-task (DT) cognitive-motor interference and fast-paced (FP) gait on gait and turning in FXTAS. Thirty participants with FXTAS and 35 age-matched controls underwent gait analysis using an inertial sensor-based 2-min walk test under three conditions: (1) self-selected pace (ST), (2) FP, and (3) DT with a concurrent verbal fluency task. Linear regression analyses were performed to assess the association between FXTAS diagnosis and gait and turn outcomes. Correlations between gait variables and fall frequency were also calculated. FXTAS participants had reduced stride length and velocity, swing time, and peak turn velocity and greater double limb support time and number of steps to turn compared to controls under all three conditions. There was greater dual task cost of the verbal fluency task on peak turn velocity in men with FXTAS compared to controls. Additionally, stride length variability was increased and cadence was reduced in FXTAS participants in the FP condition. Stride velocity variability under FP gait was significantly associated with the number of self-reported falls in the last year. Greater motor control requirements for turning likely made men with FXTAS more susceptible to the negative effects of DT cognitive interference. FP gait exacerbated gait deficits in the domains of rhythm and variability, and increased gait variability with FP was associated with increased falls. These data may inform the design of rehabilitation strategies in FXTAS.

Age-related differences in gait adaptations during overground walking with and without visual perturbations using a virtual reality headset

Older adults have difficulty adapting to new visual information, posing a challenge to maintain balance during walking. Virtual reality can be used to study gait adaptability in response to discordant sensorimotor stimulations. This study aimed to investigate age-related modifications and propensity for visuomotor adaptations due to continuous visual perturbations during overground walking in a virtual reality headset. Twenty old and twelve young subjects walked on an instrumented walkway in real and virtual environments while reacting to antero-posterior and medio-lateral oscillations of the visual field. Mean and variability of spatiotemporal gait parameters were calculated during the first and fifth minutes of walking. A 3-way mixed-design ANOVA was performed to determine the main and interaction effects of group, condition and time. Both groups modified gait similarly, but older adults walked with shorter and slower strides and did not reduce stride velocity or increase stride width variability during medio-lateral perturbations. This may be related to a more conservative and anticipatory strategy as well as a reduced perception of the optic flow. Over time, participants adapted similarly to the perturbations but only younger participants reduced their stride velocity variability. Results provide novel evidence of age- and context-dependent visuomotor adaptations in response to visual perturbations during overground walking and may help to establish new methods for early identification and remediation of gait deficits.

Short Bouts of Gait Data and Body-Worn Inertial Sensors Can Provide Reliable Measures of Spatiotemporal Gait Parameters from Bilateral Gait Data for Persons with Multiple Sclerosis.

Wearable devices equipped with inertial sensors enable objective gait assessment for persons with multiple sclerosis (MS), with potential use in ambulatory care or home and community-based assessments. However, gait data collected in non-controlled settings are often fragmented and may not provide enough information for reliable measures. This paper evaluates a novel approach to (1) determine the effects of the length of the walking task on the reliability of calculated measures and (2) identify digital biomarkers for gait assessments from fragmented data. Thirty-seven participants (37) diagnosed with relapsing-remitting MS (EDSS range 0 to 4.5) executed two trials, walking 20 m each, with inertial sensors attached to their right and left shanks. Gait events were identified from the medio-lateral angular velocity, and short bouts of gait data were extracted from each trial, with lengths varying from 3 to 9 gait cycles. Intraclass correlation coefficients (ICCs) evaluate the degree of agreement between the two trials of each participant, according to the number of gait cycles included in the analysis. Results show that short bouts of gait data, including at least six gait cycles of bilateral data, can provide reliable gait measurements for persons with MS, opening new perspectives for gait assessment using fragmented data (e.g., wearable devices, community assessments). Stride time variability and asymmetry, as well as stride velocity variability and asymmetry, should be further explored as digital biomarkers to support the monitoring of symptoms of persons with neurological diseases.

Relations between gait characteristics and subjective visual vertical results in young adults.

Subjective visual vertical (SVV) deviation can indicate impairments of motion perception and spatial orientation in individuals with vestibular disorders. This study investigated the influence of SVV on tandem gait ability by assessing differences between temporal, spatial, and kinematic characteristics in young adults. We recruited sixteen young adults with increased SVV and 17 age-matched control subjects. All subjects recruited for this study were with no history of neurological or musculoskeletal diseases. Knee and hip-joint kinematic data, spatio-temporal parameters, and gait variability were measured during tandem gait. Stride time variability and stride velocity variability were significantly greater in the experimental group than the control group (p < 0.05). In addition, a significant correlation was observed between stride time variability and SVV results (r = 0.345, p < 0.05). However, hip and knee joint angles were non-significantly different in the experimental and control groups (p > 0.05) and spatio-temporal parameters were similar between the two groups (p > 0.05). Stride time variability and stride velocity variability during tandem gait were significantly different in the experimental and control groups. We presume that increased SVV deviation is related to greater gait variability during tandem gait.

Gait characteristics and clinical relevance of hereditary spinocerebellar ataxia on deep learning.

Deep learning has always been at the forefront of scientific research. It has also been applied to medical research. Hereditary spinocerebellar ataxia (SCA) is characterized by gait abnormalities and is usually evaluated semi-quantitatively by scales. However, more detailed gait characteristics of SCA and related objective methods have not yet been established. Therefore, the purpose of this study was to evaluate the gait characteristics of SCA patients, as well as to analyze the correlation between gait parameters, clinical scales, and imaging on deep learning. Twenty SCA patients diagnosed by genetic detection were included in the study. Ten patients who were tested via functional magnetic resonance imaging (fMRI) were included in the SCA imaging subgroup. All SCA patients were evaluated with the International Cooperative Ataxia Rating Scale (ICARS) and Scale for the Assessment and Rating of Ataxia (SARA) clinical scales. The gait control group included 16 healthy subjects, and the imaging control group included seven healthy subjects. Gait data consisting of 10 m of free walking of each individual in the SCA group and the gait control group were detected by wearable gait-detection equipment. Stride length, stride time, velocity, supporting-phase percentage, and swinging-phase percentage were extracted as gait parameters. Cerebellar volume and the midsagittal cerebellar proportion in the posterior fossa (MRVD) were calculated according to MR. There were significant differences in stride length, velocity, supporting-phase percentage, and swinging-phase percentage between the SCA group and the gait control group. The stride length and stride velocity of SCA groups were lower while supporting phase was longer than those of the gait control group. SCA group's velocity was negatively correlated with both the ICARS and SARA scores. The cerebellar volume and MRVD of the SCA imaging subgroup were significantly smaller than those of the imaging control group. MRVD was significantly correlated with ICARS and SARA scores, as well as stride velocity variability. SCA gait parameters were characterized by a reduced stride length, slower walking velocity, and longer supporting phase. Additionally, a smaller cerebellar volume correlated with an increased irregularity in gait. Gait characteristics exhibited considerable clinical relevance to hereditary SCA. We conclude that a combination of gait parameters, ataxia scales, and MRVD may represent more objective markers for clinical evaluations of SCA.

Gait in Very Preterm School-Aged Children in Dual-Task Paradigms.

ObjectiveThe control of gait requires executive and attentional functions. As preterm children show executive and attentional deficits compared to full-term children, performing concurrent tasks that impose additional cognitive load may lead to poorer walking performance in preterm compared to full-term children. Knowledge regarding gait in preterm children after early childhood is scarce. We examined straight walking and if it is more affected in very preterm than in full-term children in dual-task paradigms.Study designTwenty preterm children with very low birth-weight (≤ 1500 g), 24 preterm children with birth-weight > 1500 g, and 44 full-term children, born between 2001 and 2006, were investigated. Gait was assessed using an electronic walkway system (GAITRite) while walking without a concurrent task (single-task) and while performing one concurrent (dual-task) or two concurrent (triple-task) tasks. Spatio-temporal gait parameters (gait velocity, cadence, stride length, single support time, double support time), normalized gait parameters (normalized velocity, normalized cadence, normalized stride length) and gait variability parameters (stride velocity variability, stride length variability) were analyzed.ResultsIn dual- and triple-task conditions children showed decreased gait velocity, cadence, stride length, as well as increased single support time, double support time and gait variability compared to single-task walking. Further, results showed systematic decreases in stride velocity variability from preterm children with very low birth weight (≤ 1500 g) to preterm children with birth weight > 1500 g to full-term children. There were no significant interactions between walking conditions and prematurity status.ConclusionsDual and triple tasking affects gait of preterm and full-term children, confirming previous results that walking requires executive and attentional functions. Birth-weight dependent systematic changes in stride velocity variability indicate poorer walking performance in preterm children who were less mature at birth.

Gait variability in Parkinson’s disease: influence of walking speed and dopaminergic treatment

Objectives: To study the effects of levodopa and walking speed on gait variability in individuals with Parkinson’s disease (PD).Methods: Thirty-three individuals with PD were studied. Their mean age was 70·61±9·23 year. The average time since diagnosis was 9·65±5·80 year. Gait variability was studied while ‘OFF’ and ‘ON’ dopaminergic medication when the subjects walked at their usual and fastest speeds.Results: Variability of step time, double support time, stride length and stride velocity decreased significantly (P=0·037; P=0·037; P=0·022; P=0·043, respectively) after dopaminergic treatment. When subjects increased walking speed, the variability of stride length and stride velocity decreased significantly (P=0·038 and P=0·004, respectively) both while ‘OFF’ and ‘ON’ levodopa. Increasing walking speed did not change the variability of step time and double support time regardless of medication status.Conclusions: Levodopa decreased gait variability in persons with PD. Stride length and stride velocity variability appeared to be speed dependent parameters, whereas, the variability of step time and double support time appeared to be speed independent measures. Levodopa had positive effects on gait stability in PD.

Number of strides required for reliable measurements of pace, rhythm and variability parameters of gait during normal and dual task walking in older individuals

The reliability with which spatiotemporal gait parameters are measured has neither been well-established for variability parameters nor during dual task walking. The purpose of this study was to examine test–retest reliability of three gait parameters representing pace, rhythm and variability in healthy older persons during normal and dual task walking and to determine the number of strides necessary to measure the parameters reliably. Twenty-four healthy adults aged 65 or older participated in the study. Subjects walked during normal and dual task (backward spelling) walking conditions at self-selected speeds and then repeated the tests. Velocity, cadence and variability in stride velocity were measured with GAITRite ® instrumentation. Intraclass correlation coefficients (ICCs) were calculated and the numbers of strides required to meet desired magnitudes of reliability were estimated with the Spearman–Brown prophecy formula. ICCs for velocity and cadence were high (>0.841) during normal and dual task walking, indicating strong test–retest reliability. Test–retest reliability for variability in stride velocity was moderate (ICC = 0.656) in normal walking and poor (ICC = 0.226) in dual task walking. While data collected from fewer than 10 to 20 strides may reliably measure velocity and cadence in either normal or dual task walking, measuring variability in stride velocity reliably may require that data be collected from hundreds of strides, particularly in dual task walking.

Altered vision destabilizes gait in older persons

This study assessed the effects of dim light and four experimentally induced changes in vision on gait speed and footfall and trunk parameters in older persons walking on level ground. Using a quasi-experimental design, gait characteristics were assessed in full light, dim light, and in dim light combined with manipulations resulting in reduced depth vision, double vision, blurred vision, and tunnel vision, respectively. A convenience sample of 24 home-dwelling older women and men (mean age 78.5 years, SD 3.4) with normal vision for their age and able to walk at least 10 m without assistance participated. Outcome measures were gait speed and spatial and temporal parameters of footfall and trunk acceleration, derived from an electronic gait mat and accelerometers. Dim light alone had no effect. Vision manipulations combined with dim light had effect on most footfall parameters but few trunk parameters. The largest effects were found regarding double and tunnel vision. Men increased and women decreased gait speed following manipulations ( p = 0.017), with gender differences also in stride velocity variability ( p = 0.017) and inter-stride medio-lateral trunk acceleration variability ( p = 0.014). Gender effects were related to differences in body height and physical functioning. Results indicate that visual problems lead to a more cautious and unstable gait pattern even under relatively simple conditions. This points to the importance of assessing vision in older persons and correcting visual impairments where possible.

Age-related differences in dual task walking: a cross sectional study

BackgroundVariability in stride velocity during walking characterizes gait instability and predicts falling in older individuals. Walking while executing a cognitive task is also associated with increased risk of falling, particularly in older adults. Variability in stride velocity, particularly during dual task walking conditions, may differ between younger and older individuals. The purpose of this study was to examine whether gait velocity and variability in stride velocity differ between older community-dwelling women and younger women during dual task walking.MethodsTwenty-three older (80 ± 9 years) and 19 younger (23 ± 2 years) women walked under each of two conditions: (1) walking at a self-selected velocity and (2) walking at a self-selected velocity while incrementally counting backwards. Gait velocity and variability in stride velocity were measured with GAITRite® instrumentation.ResultsGait velocity decreased and variability in stride variability increased, in both groups, during dual task walking. The relative reduction in gait velocity and the magnitude of variability in stride velocity were greater in the older subjects than younger subjects.ConclusionThe gait changes observed in dual task walking characterize reduced gait stability and indicate that cognitively demanding tasks during walking have a destabilizing effect on gait that may place older persons at greater risk of falls.

The effects of age on medio-lateral stability during normal and narrow base walking

We examined age-related differences in frontal plane stability during performance of narrow base (NB) walking relative to usual gait. A cross-sectional analysis of participants from the Baltimore Longitudinal Study of Aging (BLSA) was performed on data from the BLSA Motion Analysis Laboratory. Participants were 34 adults aged 54–92 without history of falls. We measured step error rates during NB gait and spatial–temporal parameters, frontal plane stability, and gait variability during usual and NB gait. There was a non-significant age-associated linear increase in step error rate ( P = 0.12) during NB gait. With increasing age, step width increased ( P = 0.002) and step length and stride velocity decreased ( P < 0.001), especially during NB gait. Age-associated increases in medio-lateral (M-L) center of mass (COM) peak velocity ( P < 0.001) and displacement ( P = 0.005) were also greater during NB compared to usual gait. With increasing age there was greater variability in stride velocity ( P = 0.001) and step length ( P < 0.001) under both conditions. Age-associated differences related to M-L COM stability suggest that the quantification of COM control during NB gait may improve identification of older persons at increased falls risk.

AGE-RELATED DIFFERENCES IN SPATIOTEMPORAL MARKERS OF GAIT STABILITY DURING DUAL TASK WALKING.

Purpose/Hypothesis: 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 variability in stride velocity differ in older adults compared with middle-aged and younger adults during normal and dual task walking conditions. Subjects: Sixty healthy 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. All subjects were independent ambulators classified as non-fallers. Materials/Methods: Subjects walked across an instrumented GAITRite® walkway under each of two conditions. In normal walking, subjects walked at self-selected speeds across the walkway. In dual task walking, subjects walked across the walkway while they verbally spelled 5-letter words backward. Three trials were completed in both conditions. Variability in stride velocity was quantified with the coefficient of variation (%CV). Errors in the cognitive task were quantified in the dual task condition. Results: Older subjects walked more slowly (p<.05) than did middle-aged and younger subjects in normal walking (122 ± 23, 148 ± 15 and 146 ± 18 cm/s, respectively) and in dual task walking (97 ± 22, 136 ± 16 and 135 ± 22 cm/s, respectively). Similarly, older subjects walked with greater variability in stride velocity (p<.05) than did middle-aged and younger subjects both in normal walking (6.1 ± 2.0, 3.6 ± 1.5 and 3.9 ± 2.3 %CV, respectively) and in dual task walking (9.0 ± 6.5, 5.1 ± 1.6 and 5.2 ± 3.0 %CV, respectively). Across groups, gait velocity decreased (p<.001) and variability in stride velocity increased (p=.001) in dual task walking. Additionally, in older subjects only, an increase in the number of errors in the cognitive task was associated with reduced gait velocity (r=-.487; p<.05) and increased variability in stride velocity (r=.534; p<.05) during dual task walking. Conclusions: The gait changes observed in dual task walking characterize decreased gait stability and indicate that performing cognitively demanding tasks during walking has a destabilizing effect on gait that is most apparent in older people. Performing cognitively demanding tasks during walking may place older people at greater risk of falling. Clinical Relevance: It is important to recognize that attention-demanding tasks have a destabilizing effect on gait and that attentional processes are involved in walking. Recognizing the potential role of attention-demanding tasks on fall risk, one might instruct older individuals who are at risk of falls to avoid performing cognitive tasks while they are walking. In contrast, one may also recognize the utility of dual tasking and choose to engage the individual in cognitive activities while walking in an effort to improve the person's ability to perform dual tasks in a safe and functional manner.

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.

Stride-to-stride variability while backward counting among healthy young adults

BackgroundLittle information exists about the involvement of attention in the control of gait rhythmicity. Variability of both stride time and stride length is closely related to the control of the rhythmic stepping mechanism. We sought 1) to determine whether backward counting while walking could provoke significant gait changes in mean values and coefficients of variation of stride velocity, stride time and stride length among healthy young adults; and 2) to establish whether change in stride-to-stride variability could be related to dual-task related stride velocity change, attention, or both.MethodsMean values and coefficients of variation of stride velocity, stride time and stride length were recorded using the Physilog®-system, at a self-selected walking speed in 49 healthy young adults (mean age 24.1 ± 2.8 years, women 49%) while walking alone and walking with simultaneous backward counting. Performance on backward counting was evaluated by recording the number of figures counted while sitting alone and while walking.ResultsCompared with walking alone, a significant dual-task-related decrease was found for the mean values of stride velocity (p < 0.001), along with a small but significant increase for the mean values and coefficients of variation of stride time (p < 0.001 and p = 0.015, respectively). Stride length parameters did not change significantly between both walking conditions. Dual-task-related increase of coefficient of variation of stride time was explained by changing stride velocity and variability between subjects but not by backward counting. The number of figures counted while walking decreased significantly compared to backward counting alone. Further, the dual-task related decrease of the number of enumerated figures was significantly higher than the dual-task related decrease of stride velocity (p = 0.013).ConclusionThe observed performance-changes in gait and backward counting while dual tasking confirm that certain aspects of walking are attention-demanding in young adults. In the tested group of 49 young volunteers, dual tasking caused a small decrease in stride velocity and a slight increase in the stride-to-stride variability of stride time, while stride velocity variability was not affected by the attention-demanding task. The increase in stride time variability was apparently the result of a change in gait speed, but not a result of dual tasking. This suggests that young adults require minimal attention for the control of the rhythmic stepping mechanism while walking.

Spatiotemporal gait deviations in a virtual reality environment

Previous research suggests that postural sway in standing increases in virtual reality (VR) environments. This study was conducted to examine whether gait instability is prevalent when people walk in a VR environment. Ten healthy adults participated in the study. Subjects walked on a treadmill in a VR environment and a non-VR environment at each of three walking speeds: 0.9, 1.1, and 1.3 m/s. In the VR environment, an endless corridor with colored vertical stripes comprising the walls was projected onto a hemispherical screen placed in front of the treadmill. The speed of the moving corridor image was matched to the speed of the treadmill to create the illusion that subjects were walking through the endless corridor. Spatiotemporal data during gait were collected with an instrumented treadmill housing two piezoelectric force platforms. Gait parameters reflective of gait instability (stride length, step width, variability in stride velocity, and variability in step width) were compared between the VR and non-VR environments. Subjects walked in the VR environment with reduced stride lengths (p = 0.001), increased step widths (p = 0.001), and with increased variability in stride velocity (p < 0.001) and step width (p = 0.002). The gait deviations suggest that walking in a VR environment may induce gait instability in healthy subjects.