Evaluation of a novel biomechanics-informed walking frame, developed through a Knowledge Transfer Partnership between biomechanists and design engineers.

BACKGROUND: Walking aids such as walking frames offer support during walking, yet paradoxically, people who self-report using them remain more likely to fall than people who do not. Lifting of walking frames when crossing door thresholds or when turning has shown to reduce stability, and certain design features drive the need to lift (e.g. small, non-swivelling wheels at the front). To overcome shortfalls in design and provide better stability, biomechanists and industrial engineers engaged in a Knowledge Transfer Partnership to develop a novel walking frame that reduces the need for lifting during everyday tasks. This paper presents the results for the final prototype regarding stability, safety and other aspects of usability. METHODS: Four studies were conducted that explored the prototype in relation to the current standard frame: a detailed gait lab study of 9 healthy older adults performing repeated trials for a range of everyday tasks provided mechanical measures of stability, a real-world study that involved 9 users of walking frames provided measures of body weight transfer and lifting events, two interview studies (5 healthcare professionals and 7 users of walking frames) elicited stakeholder perceptions regarding stability, safety and usability. RESULTS: Analysis of healthy older adults using a standard walking frame and the prototype frame demonstrated that the prototype increases stability during performance of complex everyday tasks (p < 0.05). Similarly, gait assessments of walking frame users in their home environment showed that the prototype facilitated safer usage patterns and provided greater and more continuous body weight support. Interviews with healthcare professionals and users showed that the prototype was perceived to be safe and effective and hence more usable. CONCLUSIONS: The outcomes of the separate studies all support the same conclusion: the prototype is an improvement on the status quo, the typical front-wheeled Zimmer frame for indoor use which has not changed in design for decades. The significance of this work lies in the success of the Knowledge Transfer Partnership and in biomechanics-informed design leading to improvements, which in future may be applied to other walking aids, to benefit walking aid users by promoting safer, more stable use of their aid.

Are older people putting themselves at risk when using their walking frames?

BACKGROUND: Walking aids are issued to older adults to prevent falls, however, paradoxically their use has been identified as a risk factor for falling. To prevent falls, walking aids must be used in a stable manner, but it remains unknown to what extent associated clinical guidance is adhered to at home, and whether following guidance facilitates a stable walking pattern. It was the aim of this study to investigate adherence to guidance on walking frame use, and to quantify user stability whilst using walking frames. Additionally, we explored the views of users and healthcare professionals on walking aid use, and regarding the instrumented walking frames ('Smart Walkers') utilized in this study. METHODS: This observational study used Smart Walkers and pressure-sensing insoles to investigate usage patterns of 17 older people in their home environment; corresponding video captured contextual information. Additionally, stability when following, or not, clinical guidance was quantified for a subset of users during walking in an Activities of Daily Living Flat and in a gait laboratory. Two focus groups (users, healthcare professionals) shared their experiences with walking aids and provided feedback on the Smart Walkers. RESULTS: Incorrect use was observed for 16% of single support periods and for 29% of dual support periods, and was associated with environmental constraints and a specific frame design feature. Incorrect use was associated with reduced stability. Participants and healthcare professionals perceived the Smart Walker technology positively. CONCLUSIONS: Clinical guidance cannot easily be adhered to and self-selected strategies reduce stability, hence are placing the user at risk. Current guidance needs to be improved to address environmental constraints whilst facilitating stable walking. The research is highly relevant considering the rising number of walking aid users, their increased falls-risk, and the costs of falls.

Methods for the Real-World Evaluation of Fall Detection Technology: A Scoping Review.

Falls in older adults present a major growing healthcare challenge and reliable detection of falls is crucial to minimise their consequences. The majority of development and testing has used laboratory simulations. As simulations do not cover the wide range of real-world scenarios performance is poor when retested using real-world data. There has been a move from the use of simulated falls towards the use of real-world data. This review aims to assess the current methods for real-world evaluation of fall detection systems, identify their limitations and propose improved robust methods of evaluation. Twenty-two articles met the inclusion criteria and were assessed with regard to the composition of the datasets, data processing methods and the measures of performance. Real-world tests of fall detection technology are inherently challenging and it is clear the field is in its infancy. Most studies used small datasets and studies differed on how to quantify the ability to avoid false alarms and how to identify non-falls, a concept which is virtually impossible to define and standardise. To increase robustness and make results comparable, larger standardised datasets are needed containing data from a range of participant groups. Measures that depend on the definition and identification of non-falls should be avoided. Sensitivity, precision and F-measure emerged as the most suitable robust measures for evaluating the real-world performance of fall detection systems.

Feasibility study of a take-home array-based functional electrical stimulation system with automated setup for current functional electrical stimulation users with foot-drop.

OBJECTIVE: To investigate the feasibility of unsupervised community use of an array-based automated setup functional electrical stimulator for current foot-drop functional electrical stimulation (FES) users. DESIGN: Feasibility study. SETTING: Gait laboratory and community use. PARTICIPANTS: Participants (N=7) with diagnosis of unilateral foot-drop of central neurologic origin (>6mo) who were regular users of a foot-drop FES system (>3mo). INTERVENTION: Array-based automated setup FES system for foot-drop (ShefStim). MAIN OUTCOME MEASURES: Logged usage, logged automated setup times for the array-based automated setup FES system and diary recording of problems experienced, all collected in the community environment. Walking speed, ankle angles at initial contact, foot clearance during swing, and the Quebec User Evaluation of Satisfaction with Assistive Technology version 2.0 (QUEST version 2.0) questionnaire, all collected in the gait laboratory. RESULTS: All participants were able to use the array-based automated setup FES system. Total setup time took longer than participants' own FES systems, and automated setup time was longer than in a previous study of a similar system. Some problems were experienced, but overall, participants were as satisfied with this system as their own FES system. The increase in walking speed (N=7) relative to no stimulation was comparable between both systems, and appropriate ankle angles at initial contact (N=7) and foot clearance during swing (n=5) were greater with the array-based automated setup FES system. CONCLUSIONS: This study demonstrates that an array-based automated setup FES system for foot-drop can be successfully used unsupervised. Despite setup's taking longer and some problems, users are satisfied with the system and it would appear as effective, if not better, at addressing the foot-drop impairment. Further product development of this unique system, followed by a larger-scale and longer-term study, is required before firm conclusions about its efficacy can be reached.

Visuomotor behaviours when using a myoelectric prosthesis.

BACKGROUND: A recent study showed that the gaze patterns of amputee users of myoelectric prostheses differ markedly from those seen in anatomically intact subjects. Gaze behaviour is a promising outcome measures for prosthesis designers, as it appears to reflect the strategies adopted by amputees to compensate for the absence of proprioceptive feedback and uncertainty/delays in the control system, factors believed to be central to the difficulty in using prostheses. The primary aim of our study was to characterise visuomotor behaviours over learning to use a trans-radial myoelectric prosthesis. Secondly, as there are logistical advantages to using anatomically intact subjects in prosthesis evaluation studies, we investigated similarities in visuomotor behaviours between anatomically intact users of a trans-radial prosthesis simulator and experienced trans-radial myoelectric prosthesis users. METHODS: In part 1 of the study, we investigated visuomotor behaviours during performance of a functional task (reaching, grasping and manipulating a carton) in a group of seven anatomically intact subjects over learning to use a trans-radial myoelectric prosthesis simulator (Dataset 1). Secondly, we compared their patterns of visuomotor behaviour with those of four experienced trans-radial myoelectric prosthesis users (Dataset 2). We recorded task movement time, performance on the SHAP test of hand function and gaze behaviour. RESULTS: Dataset 1 showed that while reaching and grasping the object, anatomically intact subjects using the prosthesis simulator devoted around 90% of their visual attention to either the hand or the area of the object to be grasped. This pattern of behaviour did not change with training, and similar patterns were seen in Dataset 2. Anatomically intact subjects exhibited significant increases in task duration at their first attempts to use the prosthesis simulator. At the end of training, the values had decreased and were similar to those seen in Dataset 2. CONCLUSIONS: The study provides the first functional description of the gaze behaviours seen during use of a myoelectric prosthesis. Gaze behaviours were found to be relatively insensitive to practice. In addition, encouraging similarities were seen between the amputee group and the prosthesis simulator group.

An investigation of the effects of walking frame height and width on walking stability.

BACKGROUND: Walking aids are designed for structural support during walking, however, surprisingly self-reported use of a walking aid ("Yes, I use one.") has been identified as a risk factor for falling. Adjustment and design of walking aids may affect their usefulness in facilitating a stable walking pattern. We previously identified that increased body weight transfer onto a walking frame ('device loading') is associated with increased user stability. RESEARCH QUESTION: We asked: "Could adjustment of walking frame height to a lower height than clinically recommended serve as a mechanism to facilitate device loading and thereby increase stability? And: "Do ultra-narrow frames have an adverse effect on stability as compared to standard-width frames? METHODS: Ten older adults that were users of front-wheeled walking frames walked with walking frames of 1) 'standard width, standard height', 2)'standard width, low height', 3)'narrow width, standard height'. Smart Walker technology was used to record forces acting on the walking frame and inside the user's shoes, and cameras recorded relative position of the user's feet in relation to the frame's feet. Stability of the user-frame system and device loading (percent body weight transferred onto the frame) were calculated. A general linear mixed effects model was used for statistical analysis. RESULTS: A lower height setting did not increase device loading and stability, therefore adjusting the height to a lower setting proved to be an unsuccessful mechanism to increase stability. However, device loading was positively correlated with stability for all frame conditions (p < 0.05). Finally, stability was reduced when walking with the ultra-narrow, as compared to standard-width, frame (p = 0.002). SIGNIFICANCE: To increase stability in fall-prone users, active encouragement to transfer body weight onto the walking frame is needed. Considering the adverse effects of ultra-narrow frames on stability, such frames should be prescribed and used with caution.

Movement variability in stroke patients and controls performing two upper limb functional tasks: a new assessment methodology.

BACKGROUND: In the evaluation of upper limb impairment post stroke there remains a gap between detailed kinematic analyses with expensive motion capturing systems and common clinical assessment tests. In particular, although many clinical tests evaluate the performance of functional tasks, metrics to characterise upper limb kinematics are generally not applicable to such tasks and very limited in scope. This paper reports on a novel, user-friendly methodology that allows for the assessment of both signal magnitude and timing variability in upper limb movement trajectories during functional task performance. In order to demonstrate the technique, we report on a study in which the variability in timing and signal magnitude of data collected during the performance of two functional tasks is compared between a group of subjects with stroke and a group of individually matched control subjects. METHODS: We employ dynamic time warping for curve registration to quantify two aspects of movement variability: 1) variability of the timing of the accelerometer signals' characteristics and 2) variability of the signals' magnitude. Six stroke patients and six matched controls performed several trials of a unilateral ('drinking') and a bilateral ('moving a plate') functional task on two different days, approximately 1 month apart. Group differences for the two variability metrics were investigated on both days. RESULTS: For 'drinking from a glass' significant group differences were obtained on both days for the timing variability of the acceleration signals' characteristics (p = 0.002 and p = 0.008 for test and retest, respectively); all stroke patients showed increased signal timing variability as compared to their corresponding control subject. 'Moving a plate' provided less distinct group differences. CONCLUSION: This initial application establishes that movement variability metrics, as determined by our methodology, appear different in stroke patients as compared to matched controls during unilateral task performance ('drinking'). Use of a user-friendly, inexpensive accelerometer makes this methodology feasible for routine clinical evaluations. We are encouraged to perform larger studies to further investigate the metrics' usefulness when quantifying levels of impairment.

Upper limb activity of twenty myoelectric prosthesis users and twenty healthy anatomically intact adults.

The upper limb activity of twenty unilateral upper limb myoelectric prosthesis users and twenty anatomically intact adults were recorded over a 7-day period using two wrist worn accelerometers (Actigraph, LLC). This dataset reflects the real-world activities of the participants during their normal day-to-day routines. Participants included students, working adults, and retirees recruited from across the United Kingdom. This dataset offers a potential wealth of knowledge into a poorly understood cohort. The raw unprocessed data files and the activity count data exported from the Actilife software are provided. We also provide a non-wear algorithm developed for the removal of prosthesis non-wear periods and resulting activity count data corresponding to prothesis wear periods. Finally, we have included the transposed activity diaries provided by the participants. Analysis to date has primarily involved assessment of the symmetry of upper limb activity, however, there is potential to undertake additional analysis such as understanding the differences in the way a prosthesis is used compared to an anatomical arm.

Objective measures of rollator user stability and device loading during different walking scenarios.

Walking aids are widely used by older adults, however, alarmingly, their use has been linked to increased falls-risk, yet clinicians have no objective way of assessing user stability. This work aims to demonstrate the application of a novel methodology to investigate how the type of walking task, the amount of body weight supported by the device (i.e., device loading), and task performance strategy affect stability of rollator users. In this context, ten users performed six walking tasks with an instrumented rollator. The combined stability margin "SM" was calculated, which considers user and rollator as a combined system. A Friedman Test was used to investigate the effects of task on SM and a least-squares regression model was applied to investigate the relationship between device loading and SM. In addition, the effects of task performance strategy on SM were explored. As a result, it was found that: the minimum SM for straight line walking was higher than for more complex tasks (p<0.05); an increase in device loading was associated with an increase in SM (p<0.05); stepping up a kerb with at least 1 rollator wheel in ground contact at all times resulted in higher SM than lifting all four wheels simultaneously. Hence, we conclude that training should not be limited to straight line walking but should include various everyday tasks. Within person, SM informs on which tasks need practicing, and which strategy facilitates stability, thereby enabling person-specific guidance/training. The relevance of this work lies in an increase in walking aid users, and the costs arising from fall-related injuries.

An exploration of step time variability on smooth and irregular surfaces in older persons with neuropathy.

BACKGROUND: Increased step time variability, particularly on an irregular surface, has been associated with impaired mobility function and a variety of diseases. However the biomechanical necessity, or advantage, of increasing step time variability has not been identified. METHODS: We performed a secondary analysis of gait data previously obtained on 42 subjects age 50 or older with neuropathy who walked on smooth and irregular surfaces, the latter with and without three interventions (cane, ankle orthosis and wall touch) that provided frontal plane support. FINDINGS: Step time variability on smooth and irregular surfaces was most strongly associated with reduction in step length on the irregular surface as compared to the smooth. More specifically, the greater the decrease in step length on the irregular surface the greater the step time variability on both surfaces and the greater the increase in step time variability on the irregular surface. The increase in step length on the irregular surface afforded by the interventions coincided with a decrease in step time variability. The subjects did not simultaneously demonstrate increased step time variability and step width range on the irregular surface. INTERPRETATION: Among adults age 50 and older with neuropathy, increased step time variability is strongly associated with the need to shorten step length on an irregular surface. Therefore step time variability may be a marker for instability during single limb stance which necessitates rapidly placed, shortened recovery steps. Such steps may also offer the advantage of reducing extremes in lateral foot placement of the swing limb, and so assist in maintaining frontal plane stability.

Visualisation of upper limb activity using spirals: A new approach to the assessment of daily prosthesis usage.

BACKGROUND: Current outcome measures used in upper limb myoelectric prosthesis studies include clinical tests of function and self-report questionnaires on real-world prosthesis use. Research in other cohorts has questioned both the validity of self-report as an activity assessment tool and the relationship between clinical functionality and real-world upper limb activity. Previously,1 we reported the first results of monitoring upper limb prosthesis use. However, the data visualisation technique used was limited in scope. STUDY DESIGN: Methodology development. OBJECTIVES: To introduce two new methods for the analysis and display of upper limb activity monitoring data and to demonstrate the potential value of the approach with example real-world data. METHODS: Upper limb activity monitors, worn on each wrist, recorded data on two anatomically intact participants and two prosthesis users over 1 week. Participants also filled in a diary to record upper limb activity. Data visualisation was carried out using histograms, and Archimedean spirals to illustrate temporal patterns of upper limb activity. RESULTS: Anatomically intact participants' activity was largely bilateral in nature, interspersed with frequent bursts of unilateral activity of each arm. At times when the prosthesis was worn prosthesis users showed very little unilateral use of the prosthesis (≈20-40 min/week compared to ≈350 min/week unilateral activity on each arm for anatomically intact participants), with consistent bias towards the intact arm throughout. The Archimedean spiral plots illustrated participant-specific patterns of non-use in prosthesis users. CONCLUSION: The data visualisation techniques allow detailed and objective assessment of temporal patterns in the upper limb activity of prosthesis users. Clinical relevance Activity monitoring offers an objective method for the assessment of upper limb prosthesis users' (PUs) activity outside of the clinic. By plotting data using Archimedean spirals, it is possible to visualise, in detail, the temporal patterns of upper limb activity. Further work is needed to explore the relationship between traditional functional outcome measures and real-world prosthesis activity.

Corrigendum: The Reality of Myoelectric Prostheses: Understanding What Makes These Devices Difficult for Some Users to Control.

[This corrects the article on p. 7 in vol. 10, PMID: 27597823.].

What causes a crossover step when walking on uneven ground? A study in healthy young women.

We hypothesized that, during gait, the perturbation caused by stepping on a 1.2-cm high protuberance with the medial forefoot would not only alter stance foot kinematics and kinetics, but also alter subsequent step location and timing, even to the point of causing a crossover step. Twelve healthy young women performed at least three flat surface and three perturbation trials while walking along a level walkway. To obstruct visual monitoring of their upcoming foot placement they used both hands to carry a large tray in front of their abdomen. Kinematic data from optoelectronic markers and force plate data were recorded at 50 and 100Hz, respectively. The results showed that the medial forefoot perturbation significantly decreased the net ankle eversion moment (p<0.001) and increased the maximum inversional foot acceleration (p=0.007). Step width (SW) and time (ST) of the post-perturbation recovery step were significantly decreased compared with normal steps (p=0.002 and 0.049, respectively). The maximum inversional foot acceleration correlated negatively with SW and ST of the recovery step (both p=0.001). Finally, four of 36 (12%) recovery steps were crossover steps. We conclude that a medial forefoot perturbation results in an increased inversional acceleration of the stance foot followed by a decrease in recovery SW and ST. In some cases, a medial forefoot perturbation can result in a crossover step, an extreme form of a narrow recovery step.

Skill assessment in upper limb myoelectric prosthesis users: Validation of a clinically feasible method for characterising upper limb temporal and amplitude variability during the performance of functional tasks.

Upper limb myoelectric prostheses remain challenging to use and are often abandoned. A proficient user must be able to plan/execute arm movements while activating the residual muscle(s), accounting for delays and unpredictability in prosthesis response. There is no validated, low cost measure of skill in performing such actions. Trial-trial variability of joint angle trajectories measured during functional task performance, linearly normalised by time, shows promise. However, linear normalisation of time introduces errors, and expensive camera systems are required for joint angle measurements. This study investigated whether trial-trial variability, assessed using dynamic time warping (DTW) of limb segment acceleration measured during functional task performance, is a valid measure of user skill. Temporal and amplitude variability of forearm accelerations were determined in (1) seven myoelectric prosthesis users and six anatomically-intact controls and (2) seven anatomically-intact subjects learning to use a prosthesis simulator over repeated sessions. (1): temporal variability showed clear group differences (p<0.05). (2): temporal variability considerably increased on first use of a prosthesis simulator, then declined with training (both p<0.05). Amplitude variability showed less obvious differences. Analysing forearm accelerations using DTW appears to be a valid low-cost method for quantifying movement quality of upper limb prosthesis use during goal-oriented task performance.

The Reality of Myoelectric Prostheses: Understanding What Makes These Devices Difficult for Some Users to Control.

Users of myoelectric prostheses can often find them difficult to control. This can lead to passive-use of the device or total rejection, which can have detrimental effects on the contralateral limb due to overuse. Current clinically available prostheses are "open loop" systems, and although considerable effort has been focused on developing biofeedback to "close the loop," there is evidence from laboratory-based studies that other factors, notably improving predictability of response, may be as, if not more, important. Interestingly, despite a large volume of research aimed at improving myoelectric prostheses, it is not currently known which aspect of clinically available systems has the greatest impact on overall functionality and everyday usage. A protocol has, therefore, been designed to assess electromyographic (EMG) skill of the user and predictability of the prosthesis response as significant parts of the control chain, and to relate these to functionality and everyday usage. Here, we present the protocol and results from early pilot work. A set of experiments has been developed. First, to characterize user skill in generating the required level of EMG signal, as well as the speed with which users are able to make the decision to activate the appropriate muscles. Second, to measure unpredictability introduced at the skin-electrode interface, in order to understand the effects of the socket-mounted electrode fit under different loads on the variability of time taken for the prosthetic hand to respond. To evaluate prosthesis user functionality, four different outcome measures are assessed. Using a simple upper limb functional task prosthesis users are assessed for (1) success of task completion, (2) task duration, (3) quality of movement, and (4) gaze behavior. To evaluate everyday usage away from the clinic, the symmetricity of their real-world arm use is assessed using activity monitoring. These methods will later be used to assess a prosthesis user cohort to establish the relative contribution of each control factor to the individual measures of functionality and everyday usage (using multiple regression models). The results will support future researchers, designers, and clinicians in concentrating their efforts on the area that will have the greatest impact on improving prosthesis use.

Characterisation of rollator use using inertial sensors.

The use of walking aids is prevalent among older people and people with mobility impairment. Rollators are designed to support outdoor mobility and require the user to negotiate curbs and slopes in the urban environment. Despite the prevalence of rollators, analysis of their use outside of controlled environments has received relatively little attention. This Letter reports on an initial study to characterise rollator movement. An inertial measurement unit (IMU) was used to measure the motion of the rollator and analytical approaches were developed to extract features characterising the rollator movement, properties of the surface and push events. The analytics were tested in two situations: first, a healthy participant used a rollator in a laboratory using a motion capture system to obtain ground truth. Second, the IMU was used to measure the movement of a rollator being used by a user with multiple sclerosis on a flat surface, cross-slope, up and down slopes and up and down a step. The results showed that surface inclination and distance travelled measured by the IMU have close approximation to the results from ground truth; therefore, demonstrating the potential for IMU-derived metrics to characterise rollator movement and user's pushing style in the outdoor environment.

Effects of surface irregularity and lighting on step variability during gait: a study in healthy young and older women.

Relatively few studies have examined how uneven surfaces affect human gait. To study this, along with the effects of advancing age and low light conditions, we measured step width and step time variability, as well as comfortable gait speed, in 12 healthy young women (YW) and 12 healthy older women (OW) as they walked at a comfortable speed along a 10-m walkway. Ten trials were completed for each cell of a 2 x 2 factorial design: (1) flat surface with regular lighting; (2) flat surface with low lighting; (3) irregular surface with regular lighting; and (4) irregular surface with low lighting. Effects of surface type, incident lighting, and age on gait parameters were tested via repeated measures ANOVA. Surface type significantly affected step width variability (P < 0.001) and step time variability (P < 0.001). Light level showed no significant effect on any of the gait parameters. One significant age group difference was found: step width variability was significantly greater in OW than YW (P = 0.010). We conclude that the irregular surface had a greater effect on the gait variability of healthy OW than on that of healthy YW.

Influence of an irregular surface and low light on the step variability of patients with peripheral neuropathy during level gait.

Patients with peripheral neuropathy (PN) report greater difficulty walking on irregular surfaces with low light (IL) than on flat surfaces with regular lighting (FR). We tested the primary hypothesis that older PN patients would demonstrate greater step width and step width variability under IL conditions than under FR conditions. Forty-two subjects (22 male, 20 female: mean +/- S.D.: 64.7 +/- 9.8 years) with PN underwent history, physical examination, and electrodiagnostic testing. Subjects were asked to walk 10 m at a comfortable speed while kinematic and force data were measured at 100 Hz using optoelectronic markers and foot switches. Ten trials were conducted under both IL and FR conditions. Step width, time, length, and speed were calculated with a MATLAB algorithm, with the standard deviation serving as the measure of variability. The results showed that under IL, as compared to FR, conditions subjects demonstrated greater step width (197.1 +/- 40.8 mm versus 180.5 +/- 32.4 mm; P < 0.001) and step width variability (40.4 +/- 9.0 mm versus 34.5 +/- 8.4 mm; P < 0.001), step time and its variability (P < 0.001 and P = 0.003, respectively), and step length variability (P < 0.001). Average step length and gait speed decreased under IL conditions (P < 0.001 for both). Step width variability and step time variability correlated best under IL conditions with a clinical measure of PN severity and fall history, respectively. We conclude that IL conditions cause PN patients to increase the variability of their step width and other gait parameters.

Interventions improve gait regularity in patients with peripheral neuropathy while walking on an irregular surface under low light.

OBJECTIVES: To determine which, if any, of three inexpensive interventions improve gait regularity in patients with peripheral neuropathy (PN) while walking on an irregular surface under low-light conditions. DESIGN: Observational. SETTING: University of Michigan Biomechanics Research Laboratory. PARTICIPANTS: Forty-two patients with PN (20 women), mean age+/-standard deviation=64.5+/-9.7. INTERVENTIONS: A straight cane, touch of a vertical surface, or semirigid ankle orthoses. MEASUREMENTS: Step-width variability and range, step-time variability, and speed. RESULTS: Subjects demonstrated significantly less step-width variability (mean=41.0+/-1.5, 36.9+/-1.6, 37.2+/-1.3, and 35.9+/-1.5 mm for baseline, cane, orthoses, and vertical surface, respectively; P<.0001) and range (182.7+/-7.4, 163.7+/-8.3, 164.3+/-7.4, 154.3+/-6.9 mm for baseline, cane, orthoses and vertical surface, respectively; P=.0006) with each of the interventions than under baseline conditions. Step-time variability significantly decreased with use of the orthoses and vertical surface but not the cane (P=.0001). Use of a cane, but not orthoses or vertical surface, was associated with decreased speed (0.79+/-0.03, 0.73+/-0.03, 0.79+/-0.03, 0.80+/-0.03 m/s for baseline, cane, orthoses, and vertical surface, respectively; P=.0001). CONCLUSION: Older patients with PN demonstrate improved spatial and temporal measures of gait regularity with the use of a cane, ankle orthoses, or touch of a vertical surface while walking under challenging conditions. The decreased speed and stigma associated with the cane and uncertain availability of a vertical surface suggest that the ankle orthoses may be the most practical intervention.

A comparison of gait characteristics between older women with and without peripheral neuropathy in standard and challenging environments.

OBJECTIVES: To compare gait patterns in older women with and without peripheral neuropathy (PN) in standard (smooth surface, normal lighting) and challenging environments (CE) (irregular surface, low lighting). DESIGN: Observational, controlled study of 24 subjects. SETTING: Biomechanical research laboratory. PARTICIPANTS: Twenty-four older women, 12 with PN and 12 without PN (mean age +/- standard deviation =67.1 +/- 7.9 and 70.2 +/- 4.3, respectively). MEASUREMENTS: Gait parameters and, in the 12 PN subjects, neuropathy severity. RESULTS: The CE was associated with increases in step width, step-width variability, step-width range, step width-to-step length ratio, step time and step-time variability, and decreases in step length and speed. The PN subjects demonstrated a greater step width-to-step length ratio and step time and shorter step length and slower speed than the control subjects. In adapting to the CE, the PN subjects demonstrated greater increases in step width-to-step length ratio and step-time variability and a greater decrease in step length than did the control subjects. In the standard environment, only one gait parameter correlated with PN severity, whereas in the CE, four gait parameters did so. CONCLUSION: The subjects demonstrated a gait that was slower, less efficient, and more variable temporally and in the frontal plane in the CE. Control and PN subjects demonstrated similar variability in medial-lateral step placement in the CE but at the cost of speed and efficiency for the PN subjects. Because the CE magnified gait differences between the two groups of subjects and caused gait changes in the PN subjects that correlated with PN severity, the CE may offer improved resolution for detecting gait abnormalities.