Old adult fallers display reduced flexibility of arm and trunk movements when challenged with different walking speeds

Specific patterns of pelvic and thorax motions are required to maintain stability during walking. This cross-sectional study explored older-adults’ gait kinematics and their kinematic adaptations to different walking speeds, with the purpose of identifying mechanisms that might be related to increased risk for falls. Fifty-eight older adults from self-care residential facilities walked on a treadmill, whose velocity was systematically increased with increments of 0.1 meters/second (m/s) from 0.5 to 0.9 m/s, and then similarly decreased. Thorax, pelvis, trunk, arms, and legs angular total range of motion (tROM), stride time, stride length, and step width were measured. Twenty-one of the subjects reported falling, and 37 didn’t fall. No significant effect of a fall history was found for any of the dependent variables. A marginally significant interaction effect of fall history and walking speed was found for arms’ tROM (p = 0.098). Speed had an effect on many of the measures for both groups. As the treadmill’s velocity increased, the non-fallers increased their arm (15.9 ± 8.6° to 26.6 ± 12.7°) and trunk rotations (4.7 ± 1.9° to 7.2 ± 2.8°) tROM, whereas for the fallers the change of arm (14.7 ± 14.8° to 20.8 ± 13°) and trunk (5.5 ± 2.9° to 7.3 ± 2.3°) rotations tROM were moderate between the different walking speeds. We conclude that walking speed manipulation exposed different flexibility trends. Only non-fallers demonstrated the ability to adapt trunk and arm ROM to treadmill speed i.e., had a more flexible pattern of behavior for arm and trunk motions, supporting the upper-body’s importance for stability while walking.     

Factors influencing short-term outcomes for older patients accessing emergency departments after a fall: The role of fall dynamics

BackgroundWhile the relevance of falls in raising the risk of fractures, hospitalization and disability in older age is well recognized, the factors influencing the onset of fractures and the need for ward admission after a fall have yet to be fully elucidated. We investigated which factors and fall dynamics were mainly associated with fall-related injuries and hospitalization among elderly persons accessing the Emergency Department (ED) following a fall.MethodsThe study involved 2144 older subjects who accessed the ED after a fall. Data on the fall´s nature and related injuries, ward admissions, history of falls, dementia, and medical therapies were examined for all patients. Considering dynamics, we distinguished accidental falls (due to interaction with environmental hazards while in motion) and falls from standing (secondary to syncope, lipothymia, drop attack, or vertigo).ResultsThe overall prevalence of fractures in our population did not differ significantly with advancing age, though hip fractures were more common in the oldest, and upper limb fractures in the youngest patients. Falls from standing were associated with polypharmacy and with higher ward admission rate despite a lower fractures´ prevalence than accidental falls. The chances of fall-related fractures were more than fourfold as high for accidental dynamics (OR = 4.05, 95%CI:3.10–5.29, p < 0.0001). Ward admission was associated with polypharmacy, dementia, anticoagulants´ use and fall-related fractures (OR = 6.84, 95%CI:5.45–8.58, p < 0.0001), while it correlated inversely with accidental fall dynamics.ConclusionsOutcomes of falls in older age depend not only on any fall-related injuries, but also on factors such as polypharmacy, cognitive status and fall dynamics.     

Quantitative trunk sway and prediction of incident falls in older adults

Poor balance and balance impairments are major predictors of falls. The purpose of the current study was to determine the clinical validity of baseline quantitative static trunk sway measurements in predicting incident falls in a cohort of 287 community-dwelling non-demented older Americans (mean age 76.14 ± 6.82 years; 54% female). Trunk sway was measured using the SwayStar™ device, and quantified as angular displacement in degrees in anterior-posterior (pitch) and medio-lateral (roll) planes. Over a one-year follow-up period, 66 elders (23%) reported incident falls. Anterior-posterior angular displacement was a strong predictor of incident falls in older adults in Cox proportional hazards models (hazard ratio adjusted for age, gender, education, RBANS total score, medical comorbidities, geriatric depression scale score, sensory impairments, gait speed, and history of fall in the past 1 year ((aHR) = 1.59; p = 0.033) whereas, angular displacement in the medio-lateral plane was not predictive of falls (aHR = 1.35; p = 0.276). Our results reveal the significance of quantitative trunk sway, specifically anterior-posterior angular displacement, in predicting incident falls in older adults.     

Impaired perceived timing of falls in the elderly

Falls are the leading cause of injury-related deaths and hospitalizations, with older adults at an increased risk. As humans age, physical changes and health conditions make falls more likely. While we know how the body reflexively responds to prevent injury during a fall, we know little about how people perceive the fall itself. We previously found that young adults required a fall to precede a comparison sound stimulus by approximately 44 ms to perceive the two events as simultaneous. This may relate to common anecdotal reports suggesting that humans often describe distortions in their perception of time − time seems to slow down during a fall – with very little recollection of how and when the fall began. Here we examine whether fall perception changes with age. Young (19–25y) and older (61–72y) healthy adults made temporal order judgments identifying whether the onset of their fall or the onset of a comparison sound came first to measure the point of subjective simultaneity. Results show that fall perception is nearly twice as slow for older adults, where perturbation onset has to precede sound onset by ∼88 ms to appear coincident, compared to younger adults (∼44 ms). We suggest that such age-related differences in fall perception may relate to increased fall rates in older adults. We conclude that a better understanding of how younger versus older adults perceive falls may identify important factors for innovative fall prevention strategies and rehabilitative training exercises to improve fall awareness.     

Differences in axial segment reorientation during standing turns predict multiple falls in older adults

BackgroundThe assessment of standing turning performance is proposed to predict fall risk in older adults. This study investigated differences in segmental coordination during a 360° standing turn task between older community-dwelling fallers and non-fallers.MethodsThirty-five older adults age mean (SD) of 71 (5.4) years performed 360° standing turns. Head, trunk and pelvis position relative to the laboratory and each other were recorded using a Vicon motion analysis system. Fall incidence was monitored by monthly questionnaire over the following 12 months and used to identify non-faller, single faller and multiple faller groups.ResultsMultiple fallers were found to have significantly different values, when compared to non-fallers, for pelvis onset (p = 0.002); mean angular separation in the transverse plane between the head and trunk (p = 0.018); peak angular separation in the transverse plane between the trunk and pelvis (p = 0.013); and mean angular separation between the trunk and pelvis (p < 0.001).ConclusionsOlder adults who subsequently experience multiple falls show a simplified turning pattern to assist in balance control. This may be a predictor for those at increased risk of falling.     

Dynamic instability during post-stroke hemiparetic walking

Falls and fall-related injuries cause extremely costly and potentially fatal health problems in people post-stroke. However, there is no global indicator of walking instability for detecting which individuals will have increased risk of falls. The purposes of this study were to directly quantify walking stability in stroke survivors and neurologically intact controls and to determine which stability measures would reveal the changes in walking stability following stroke. This study thus provided an initial step to establish objective measures for identifying potential fallers. Nine post-stroke individuals and nine controls walked on a treadmill at four different speeds. We computed short-term local divergence exponent (LDE) and maximum Floquet multiplier (maxFM) of the trunk motion, average and variability of dynamic margins of stability (MOS) and step spatiotemporal measures. Post-stroke individuals demonstrated larger short-term LDE (p = 0.002) and maxFM (p = 0.041) in the mediolateral (ML) direction compared to the controls but remained orbitally stable (maxFM < 1). In addition, post-stroke individuals walked with greater average step width (p = 0.003) but similar average ML MOS (p = 0.154) compared to the controls. Post-stroke individuals also exhibited greater variability in all MOS and step measures (all p < 0.005). Our findings indicate that post-stroke individuals walked with greater local and orbital instability and gait variability than neurologically intact controls. The results suggest that short-term LDE of ML trunk motion and the variability of MOS and step spatiotemporal measures detect the changes in walking stability associated with stroke. These stability measures may have the potential for identifying those post-stroke individuals at increased risk of falls.     

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.     

Reliability and minimal detectable change of gait variables in community-dwelling and hospitalized older fallers

PurposeGait variables may constitute surrogate outcomes for fall risk. Their reliability in a specific population of older fallers has not been fully established, which limits their research and clinical applications. This study aimed to determine test–retest reliability and minimal detectable change (MDC) values for selected fall-related gait variables in older adults with a recent fall history.MethodsCommunity-dwelling (n = 30) and hospitalized (n = 30) fallers aged ≥ 65 years were assessed twice using an instrumented pressure-sensitive walkway, under single- and dual-task gait conditions. Intraclass correlation coefficient (ICC_(2,1)), standard error of measurement (SEM; SEM%) and MDC at 95% confidence level (MDC₉₅; MDC₉₅%), were used as reliability estimates.ResultsThe ICC_(2,1) for gait velocity was greater than 0.84 across all gait conditions and groups; SEM% and MDC₉₅% did not exceed 6.5% and 18.1%, respectively. Gait variability measures returned lower ICC_(2,1) (range 0.18–0.79), and markedly higher SEM% (16.3–31.9%) and MDC₉₅% (45.3–88.3%). Overall, hospitalized fallers exhibited larger SEM and MDC₉₅ values for variability measures compared to community-dwellers in all gait conditions, while larger values were found for all variables while dual-tasking compared to single-tasking in both groups.ConclusionsGait velocity was found to be highly reliable and likely to be sensitive to change over repeated sessions in community-dwelling and hospitalized older fallers, both under single- and dual-task conditions. Gait variability measures showed lower reliability, irrespective of gait condition or group, displaying consistently larger measurement error, particularly under dual-task conditions. Clinicians should consider MDC₉₅ values before using gait variability variables as evaluative outcome measures at patient level.     

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.     

Dynamic stability of superior vs. inferior segments during walking in young and older adults

Active control of trunk motion is believed to enable humans to maintain stability during walking, suggesting that stability of the trunk is prioritized over other segments by the nervous system. We investigated if superior segments are more stable than inferior segments during walking and if age-related differences are more prominent in any particular body segments. Eighteen healthy older adults and 17 healthy young adults walked on a treadmill for two trials of 5 min each at their preferred speed. 3D kinematics of the trunk, pelvis, and left thigh, shank, and foot were recorded. Local divergence exponents and maximum Floquet multipliers (FM) were calculated to quantify each segment's responses to small inherent perturbations during walking. Both older and younger adults walked with similar preferred walking speeds (p = 0.86). Local divergence exponents were larger in inferior segments (p < 0.001), and larger in older adults (p < 0.001). FM was larger in the superior segments (p < 0.001), and larger in older adults (p < 0.001). The age-associated difference in local divergence exponents was larger for trunk motion (interaction p = 0.02). Thus, superior segments exhibited less local instability but greater orbital instability. Trunk motion was more sensitive to age-associated differences in dynamic stability during gait. Trunk motion should be considered in studying age-related deterioration of gait.     

Trunk sway reductions in young and older adults using multi-modal biofeedback

This study investigated whether real-time biofeedback of angular trunk displacement could alter balance performance among healthy older and young adults. Healthy community-dwelling older adults (n = 32) and healthy young adults (n = 32) were included in the randomized control trial study. The intervention group received combined vibrotactile, auditory and visual biofeedback of angular trunk displacement in real-time during training on a battery of static and dynamic balance tasks and during the subsequent post-training balance re-assessment. The control group received balance training and were re-assessed in the absence of real-time biofeedback of their trunk displacement. The 90% range of angular trunk displacement was calculated for each balance task pre- and post-training. Significant age-related differences were observed independent of the intervention. Biofeedback intervention significantly changed the angular displacement of the trunk for both young and older participants on a number of balance tasks compared to control treatment (40–60% reduction in angular displacement). In some cases, biofeedback influenced balance in older adults, but not younger adults.     

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.     

Bracing the trunk and neck in young adults leads to a more aged-like gait

Older individuals typically walk at slower speeds, with shorter step lengths, greater step widths and spend a larger proportion of the gait cycle in double stance. Changes in neck and trunk mobility may underlie some of the changes in walking seen with increasing age. Consequently, this study was designed to assess whether externally increasing trunk/neck stiffness in young adults leads to similar changes in gait pattern observed with aging. Twelve young adults (20–29 years), sixteen old adults (60–69 years) and fifteen older adults (70–79 years) walked across a 20′ pressure sensitive GAITRite© instrumented walkway at their preferred speed. The young adults also walked under three bracing conditions: (1) Neck braced, (2) Trunk braced, and (3) Neck and Trunk braced. The results revealed that the old and older age groups walked significantly slower, with a shorter step length and with a narrower base of support (p’s < 0.05) compared to the young adults. In young adults, combined neck and trunk bracing led to reduced walking speed, shorter step length, wider base of support and a larger proportion of the gait cycle spent in double stance (p’s < 0.05). The walking speed and step length of older adults remained less than fully braced young adults (p’s < 0.05). Overall these results indicate that artificially stiffening the trunk and neck of young individuals leads to systematic gait changes similar to aging. Consequently, age-related changes in mobility of the neck and torso may in part contribute to the decrements in walking seen for older adults.     

Dual tasking affects lateral trunk control in healthy younger and older adults

Assessing the effects of attention-demanding tasks on trunk movement provides useful insights into postural control while walking in an attention-split situation, such as occurs in daily life. The coefficient of attenuation of acceleration (CoA) at the trunk is a useful gait index to assess whole trunk movements. We investigated the effect of attention-demanding tasks on CoA to assess the role of attention on trunk control during walking. Thirty healthy, community-dwelling older adults (70.1 ± 5.6 years) and 38 younger adults (22.1 ± 3.4 years) participated in this study. Participants walked 20 m at a self-selected speed (slow, normal, fast) and while performing an attention-demanding cognitive task. Trunk acceleration was measured using triaxial accelerometers attached to the lower (L3 spinous process) and upper (C7 spinous process) trunk and used to compute CoA (the reduction in acceleration from the lower to upper trunk). Results showed that an attention-demanding task significantly decreased CoA in the medio-lateral (ML) direction in both age groups (p < 0.001), whereas it did not affect CoA in the vertical (VT) and anterior–posterior (AP) directions. Our findings suggest that the priority of whole trunk control in the ML direction may be higher than in other directions and be strongly associated with attention, whereas whole trunk control in the VT and AP directions may be passively regulated and require minimal attentional control.     

Biomechanical balance response during induced falls under dual task conditions in people with knee osteoarthritis

ObjectivePeople with knee osteoarthritis (OA) are at twice the risk of falling compared to older people without knee OA, however the mechanism for this is poorly understood. This study investigated the biomechanical response of the trunk and lower limb joints during a forward induced fall under different task conditions in people with and without knee OA.MethodTwenty-four participants with OA (68.6 ± 6.2 years) and 15 asymptomatic controls (72.4 ± 4.8 years) participated in the study. Forward fall was induced by releasing participants from a static forward leaning position. Participants were required to recover balance during three conditions: normal, physical (obstacle clearance) and cognitive dual tasks (counting backwards). Spatiotemporal parameters, lower limb joint kinematics and kinetics of the recovery limb were compared between the two groups and across the three task conditions.ResultsThe OA group demonstrated slower spatio-temporal characteristics and reduced hip and knee flexion angles, joint moments/powers and reduced muscle negative work at the knee and ankle (p < 0.05). Cognitive dual task resulted in reduced centre of mass velocity and step length (p = 0.03) compared to the physical dual task condition. Reduced knee (p = 0.02) and hip joint powers (p = 0.03) were demonstrated in the OA group in the physical task condition.ConclusionWhen simulating a forward fall, participants with OA demonstrated difficulty in absorbing the impact and slowing down the forward momentum of the body during a recovery step. Moreover, poor dynamic postural control was demonstrated as task complexity increased.     

Postural sway in low back pain: Effects of dual tasks

Recurrence quantification analysis (RQA), a nonlinear method of postural analysis, was used to explore the effects of dual-tasking on postural performance in people with nonspecific low back pain (LBP) compared with healthy participants. Postural performance was quantified by RQA % recurrence, % determinism, entropy and trend. People with nonspecific LBP (n = 22) and unimpaired individuals (n = 22) randomly performed quiet standing tasks with three levels of difficulty (rigid-surface eyes open, rigid-surface eyes closed and foam-surface eyes closed). These tasks were performed in isolation or concurrently with an easy or difficult cognitive task. Increasing postural difficulty was associated with higher % determinism, higher entropy and lower trend in anteroposterior (AP) and mediolateral (ML) directions in people with LBP and healthy participants. All RQA variables in the ML direction decreased as cognitive conditions became more difficult. Significant interactions between group and cognitive difficulty were shown for % recurrence, % determinism and trend in the AP direction. While healthy participants decreased % recurrence and trend by increasing the level of cognitive difficulty, the LBP patients did not. This preliminary study suggests that LBP may be one factor that modulates the posture–cognition interaction.     

Vibrotactile tilt feedback improves dynamic gait index: A fall risk indicator in older adults

The purpose of this study was to determine the effectiveness of vibrotactile feedback of body tilt in improving dynamic gait index (DGI) a fall risk indicator in community dwelling older adults. Twelve healthy elderly subjects (three males and nine females, age 79.7 ± 5.4 yrs) were tested in an institutional balance rehabilitation laboratory to investigate changes between the feedback off and on conditions. Subjects were acutely exposed to a vibrotactile display that indicated the magnitude and direction of their body tilt from the vertical. DGI and mediolateral (ML) sway were determined during locomotion with, and without, vibrotactile tilt feedback (VTTF). All subjects were at risk for falls based on their initial DGI Score (range: 15–19, mean 17.4 ± 1.56), which was taken with the vibratory stimulus turned off. Subjects learned to use the trunk tilt information from the vibrotactile feedback vest through 20–30 min of gait and balance training consisting of activities that challenged their balance. Subjects were then retested on the DGI. Statistically significant changes were demonstrated for the DGI total score while using the vibrotactile tilt feedback. DGI total scores improved from 17.1 ± 0.4 to 20.8 ± 0.3 (p < 0.05). We conclude that vibrotactile tilt feedback improves both control of mediolateral sway during gait and dynamic gait index. Both are fall risk indicators for this population.     

Test–retest reliability of sensor-based sit-to-stand measures in young and older adults

This study investigated test–retest reliability of sensor-based sit-to-stand (STS) peak power and other STS measures in young and older adults. In addition, test–retest reliability of the sensor method was compared to test–retest reliability of the Timed Up and Go Test (TUGT) and Five-Times-Sit-to-Stand Test (FTSST) in older adults. Ten healthy young female adults (20–23 years) and 31 older adults (21 females; 73–94 years) participated in two assessment sessions separated by 3–8 days. Vertical peak power was assessed during three (young adults) and five (older adults) normal and fast STS trials with a hybrid motion sensor worn on the hip. Older adults also performed the FTSST and TUGT. The average sensor-based STS peak power of the normal STS trials and the average sensor-based STS peak power of the fast STS trials showed excellent test–retest reliability in young adults (intra-class correlation (ICC) ≥ 0.90; zero in 95% confidence interval of mean difference between test and retest (95%CI of D); standard error of measurement (SEM) ≤ 6.7% of mean peak power) and older adults (ICC ≥ 0.91; zero in 95%CI of D; SEM ≤ 9.9%). Test–retest reliability of sensor-based STS peak power and TUGT (ICC = 0.98; zero in 95%CI of D; SEM = 8.5%) was comparable in older adults, test–retest reliability of the FTSST was lower (ICC = 0.73; zero outside 95%CI of D; SEM = 14.4%). Sensor-based STS peak power demonstrated excellent test–retest reliability and may therefore be useful for clinical assessment of functional status and fall risk.