Alison Oates

Evaluation of an inertial sensor system for analysis of timed-up-and-go under dual-task demands.

Functional tests, such as the timed-up-and-go (TUG), are routinely used to screen for mobility issues and fall risk. While the TUG is easy to administer and evaluate, its single time-to-completion outcome may not discriminate between different mobility challenges. Wearable sensors provide an opportunity to collect a variety of additional variables during clinical tests. The purpose of this study was to assess a new wearable inertial sensor system (iTUG) by investigating the effects of cognitive tasks in a dual-task paradigm on spatiotemporal and kinematic variables during the TUG. No previous studies have looked at both spatiotemporal variables and kinematics during dual-task TUG tests. 20 healthy young participants (10 males) performed a total 15 TUG trials with two different cognitive tasks and a normal control condition. Total time, along with spatiotemporal gait parameters and kinematics for all TUG subtasks (sit-to-stand, walking, turn, turn-to-sit), were measured using the inertial sensors. Time-to-completion from iTUG was highly correlated with concurrent manual timing. Spatiotemporal variables during walking showed expected differences between control and cognitive dual-tasks while trunk kinematics appeared to show more sensitivity to dual-tasks than reported previously in straight line walking. Non-walking TUG subtasks showed only minor changes during dual-task conditions indicating a possible attentional shift away from the cognitive task. Stride length and some variability measures were significantly different between the two cognitive tasks suggesting an ability to discriminate between tasks. Overall, the use of the iTUG system allows the collection of both traditional and potentially more discriminatory variables with a protocol that is easily used in a clinical setting.

Validation of a commercial inertial sensor system for spatiotemporal gait measurements in children

Although inertial sensor systems are becoming a popular tool for gait analysis in both healthy and pathological adult populations, there are currently no data on the validity of these systems for use with children. The purpose of this study was to validate spatiotemporal data from a commercial inertial sensor system (MobilityLab) in typically-developing children. Data from 10 children (5 males; 3.0-8.3 years, mean=5.1) were collected simultaneously from MobilityLab and 3D motion capture during gait at self-selected and fast walking speeds. Spatiotemporal parameters were compared between the two methods using a Bland-Altman method. The results indicate that, while the temporal gait measurements were similar between the two systems, MobilityLab demonstrated a consistent bias with respect to measurement of the spatial data (stride length). This error is likely due to differences in relative leg length and gait characteristics in children compared to the MobilityLab adult reference population used to develop the stride length algorithm. A regression-based equation was developed based on the current data to correct the MobilityLab stride length output. The correction was based on leg length, stride time, and shank range-of-motion, each of which were independently associated with stride length. Once the correction was applied, all of the spatiotemporal parameters evaluated showed good agreement. The results of this study indicate that MobilityLab is a valid tool for gait analysis in typically-developing children. Further research is needed to determine the efficacy of this system for use in children suffering from pathologies that impact gait mechanics.

The Relationship of Anticipatory Gluteus Medius Activity to Pelvic and Knee Stability in the Transition to Single-Leg Stance.

The knee abduction moment in a weight‐bearing limb is an important risk factor of conditions such as patellofemoral pain and knee osteoarthritis. Excessive pelvic drop in single‐leg stance can increase the knee abduction moment. The gluteus medius muscle is crucial to prevent pelvic drop and must be activated in anticipation of the transition from double‐leg to single‐leg stance.

The effects of haptic input on biomechanical and neurophysiological parameters of walking: A scoping review

Walking is an important component of daily life requiring sensorimotor integration to be successful. Adding haptic input via light touch or anchors has been shown to improve standing balance; however, the effect of adding haptic input on walking is not clear. This scoping review systematically summarizes the current evidence regarding the addition of haptic input on walking in adults. Following an established protocol, relevant studies were identified using indexed data bases (Medline, EMBASE, PsychINFO, Google Scholar) and hand searches of published review articles on related topics. 644 references were identified and screened by a minimum of two independent researchers before data was extracted from 17 studies. A modified TREND tool was used to assess quality of the references which showed that the majority of studies were of moderate or high quality. Results show that adding haptic input changes walking behaviour. In particular, there is an immediate reduction in variability of gait step parameters and whole body stability, as well as a decrease in lower limb muscle activity. The effect of added haptic input on reflex modulation may depend on the limb of interest (i.e., upper or lower limb). Many studies did not clearly describe the amount and/or direction of haptic input applied. This information is needed to replicate and/or advance their results. More investigations into the use and design of the haptic tools, the attentional demands of adding haptic input, and clarity on short-term effects are needed. In addition, more is research needed to determine whether adding haptic input has significant, lasting benefits that may translate to fall prevention efforts.

Different haptic tools reduce trunk velocity in the frontal plane during walking, but haptic anchors have advantages over lightly touching a railing

There are different ways to add haptic input during walking which may affect walking balance. This study compared the use of two different haptic tools (rigid railing and haptic anchors) and investigated whether any effects on walking were the result of the added sensory input and/or the posture generated when using those tools. Data from 28 young healthy adults were collected using the Mobility Lab inertial sensor system (APDM, Oregon, USA). Participants walked with and without both haptic tools and while pretending to use both haptic tools (placebo trials), with eyes opened and eyes closed. Using the tools or pretending to use both tools decreased normalized stride velocity (p < .001–0.008) and peak medial–lateral (ML) trunk velocity (p < .001–0.001). Normalized stride velocity was slower when actually using the railing compared to placebo railing trials (p = .006). Using the anchors resulted in lower peak ML trunk velocity than the railing (p = .002). The anchors had lower peak ML trunk velocity than placebo anchors (p < .001), but there was no difference between railing and placebo railing (p > .999). These findings highlight a difference in the type of tool used to add haptic input and suggest that changes in balance control strategy resulting from using the railing are based on arm placement, where it is the posture combined with added sensory input that affects balance control strategies with the haptic anchors. These findings provide a strong framework for additional research to be conducted on the effects of haptic input on walking in populations known to have decreased walking balance.

Measuring balance confidence after spinal cord injury: the reliability and validity of the Activities-specific Balance Confidence Scale

Context/Objective: The study objectives were to evaluate the test-retest reliability, convergent validity, and discriminative validity of the Activities-specific Balance Confidence (ABC) scale in individuals with incomplete spinal cord injury (iSCI). Design: Prospective, cross-sectional study. Setting: Laboratory. Participants: Twenty-six community-dwelling individuals with chronic iSCI (20 males, 59.7 + 18.9 years old) and 26 age- and sex-matched able-bodied (AB) individuals participated. Interventions: None. Outcome Measures: Measures of balance and gait were collected over two days. Clinical measures included the ABC scale, Mini-Balance Evaluation System’s Test, 10-meter Walk Test, SCI Functional Ambulation Profile, manual muscle testing of lower extremity muscles, and measures of lower extremity proprioception and cutaneous pressure sensitivity. Biomechanical measures included the velocity and sway area of centre of pressure (COP) movement during quiet standing. Results: The ABC scale demonstrated high test-retest reliability (intraclass correlation coefficient = 0.93) among participants with iSCI. The minimal detectable change was 14.87%. ABC scale scores correlated with performance on all clinical measures (ρ=0.60-0.80, P<0.01), with the exception of proprioception and cutaneous pressure sensitivity (P=0.20–0.70), demonstrating convergent validity. ABC scale scores also correlated with overall COP velocity (ρ=-0.69, P<0.001) and COP velocity in the anterior-posterior direction (ρ=-0.71, P<0.001). Participants with iSCI scored significantly lower on the ABC scale than the AB participants (P<0.001), and the area under the receiver operating characteristic curve was 0.95, demonstrating discriminative validity. Conclusion: The ABC scale is a reliable and valid measure of balance confidence in community-dwelling, ambulatory individuals with chronic iSCI.

The Feasibility and Validity of Body-Worn Sensors to Supplement Timed Walking Tests for Children with Neurological Conditions

ABSTRACT Aims: The 10-meter walk test (10 mWT) and Timed Up and Go (TUG) are assessments of speed/time with a ceiling effect in pediatric populations. This study aimed to (1) determine whether collecting spatiotemporal data with inertial sensors (Mobility Lab, APDM Inc.) during these tests improves their discriminative validity, and (2) evaluate the clinical feasibility of Mobility Lab. Methods: Fifteen children with spina bifida (SB) or cerebral palsy (CP) (7.9 ± 3.1 years old) and fifteen age- and sex-matched typically-developing (TD) children completed the 10 mWT and TUG wearing Mobility Lab. Spatiotemporal data were compared between groups. Mobility Labs potential to distinguish children with SB/CP from TD children was examined using conditional logistic regression. Feasibility was evaluated through participant adherence and a clinical utility scale. Results: For the 10 mWT, group differences (p < 0.01) were found in horizontal and frontal trunk range of motion, horizontal trunk velocity, and swing asymmetry. Children with SB/CP took significantly longer to turn during the TUG. These five variables together distinguished the two groups (p = 0.006). 78% of participants with SB/CP completed the testing protocol. Mobility Lab scored 4/10 on the clinical utility scale. Conclusions: Instrumenting the 10 mWT and TUG improves the tests’ ability to discriminate between children with SB/CP and TD children.

Balance Assessment Practices of Saskatchewan Physiotherapists: A Brief Report of Survey Findings

Purpose: This study was conducted to determine the balance assessment practices of physiotherapists in Saskatchewan. Methods: Practising physiotherapists who assess and treat adults with balance and mobility impairments were eligible to participate in this cross-sectional, online survey. The questions investigated the use of balance assessment measures, the balance components assessed, and practice area. Results: Of the 72 respondents, most reported regularly assessing five or more of the nine balance components listed. Movement observation was the most commonly reported measure used, followed by the Berg Balance Scale, single-leg stance test, and tandem standing/walking. Conclusions: Most physiotherapists in Saskatchewan use a variety of tools to assess balance. Gaps in practices related to fall prevention were noted in the mismatch between the tools used and the components reportedly assessed.

Effect of haptic input on standing balance among individuals with incomplete spinal cord injury

The present study investigated the effect of haptic input via light touch on standing balance of individuals with incomplete spinal cord injury (iSCI). Centre of pressure (COP) measures during standing were assessed in 16 participants with iSCI (13 males; 61.1±19.9years; C1-L4; AIS C and D) and 13 able-bodied (AB) participants (10 males; 59.4±19.7years). The effects of light touch (touch/no touch), vision (eyes open/closed), and group (iSCI/AB) on COP measures were assessed using a two-way mixed design MANOVA. Correlations were examined between changes in COP measures with touch (ΔCOP), and clinical measures of cutaneous pressure and proprioception in the upper (UE) and lower (LE) extremities in participants with iSCI. Significant main effects for touch (p<0.001), vision (p<0.001), and group (p=0.01) for all COP measures were found. There was a significant interaction between vision and group (p=0.01) for a subset of COP measures. With eyes closed, ΔCOP was positively correlated with UE cutaneous pressure sensation and negatively correlated with LE proprioception. Compared with AB adults, individuals with iSCI show a greater increase in postural sway when standing with eyes closed than with eyes open. Individuals with iSCI can use light touch to reduce postural sway, and the effect is greater in those with more intact UE cutaneous pressure sensation and more impaired LE proprioception.

Preliminary study of novel, timed walking tests for children with spina bifida or cerebral palsy

Objective: Walking assessment is an important aspect of rehabilitation practice; yet, clinicians have few psychometrically sound options for evaluating walking in highly ambulatory children. The purpose of this study was to evaluate the validity and reliability of two new measures of walking function—the Obstacles and Curb tests—relative to the 10-Meter Walk test and Timed Up and Go test in children with spina bifida or cerebral palsy. Methods: A total of 16 ambulatory children with spina bifida (n=9) or cerebral palsy (n=7) (9 boys; mean age 7years, 7months; standard deviation 3years, 4months) and 16 age- and gender-matched typically developing children participated. Children completed the walking tests, at both self-selected and fast speeds, twice. To evaluate discriminative validity, scores were compared between typically developing and spina bifida/cerebral palsy groups. Within the spina bifida/cerebral palsy group, inter-test correlations evaluated convergent validity and intraclass correlation coefficients evaluated within-session test–retest reliability. Results: At fast speeds, all tests showed discriminative validity (p<0.006 for typically developing and spina bifida/cerebral palsy comparisons) and convergent validity (rho=0.81–0.90, p⩽0.001, for inter-test correlations). At self-selected speeds, only the Obstacles test discriminated between groups (p=0.001). Moderately strong correlations (rho=0.73–0.78, p⩽0.001) were seen between the 10-Meter Walk test, Curb test, and Timed Up and Go test. Intraclass correlation coefficients ranged from 0.81 to 0.97, with higher test–retest reliability for tests performed at fast speeds rather than self-selected speeds. Conclusion: The Obstacles and Curb tests are promising measures for assessing walking in this population. Performing tests at fast walking speeds may improve their validity and test–retest reliability for children with spina bifida/cerebral palsy.