Impact of visual rotations on heading direction and center of mass control during steady state gait.

Visual information is essential to navigate the environment and maintain postural stability during gait. Visual field rotations alter the perceived heading direction and center of mass (CoM) trajectory. This interaction, referred to as visual coupling, is poorly characterized during steady-state gait. Moreover, it is unclear how visual field rotations affect CoM control relative to the continuously changing base of support (BoS). This study aimed to characterize the role of visual information in heading and mediolateral (ML) balance control during unperturbed, steady-state gait. Sixteen healthy participants walked on an instrumented treadmill, naïve to sinusoidal low-frequency (0.1 Hz) rotations of the virtual environment. Rotations had a 1) high (CMH) or 2) low amplitude (CML), or were 3) periodical left-right manipulations (PM) with 10 second intervals. Coupling between CoM trajectory and visual manipulations was in-phase and showed strong cross-correlations on group level (CML: 0.88, CMH: 0.91 and PM: 0.95) and moderate to strong on individual level (CML: 0.52 ± 0.15, CMH: 0.56 ± 0.17 and PM: 0.80 ± 0.07). Higher manipulation amplitudes induced stronger CoM trajectory deviations. The margin of stability (MoSML), characterizing ML balance control, decreased towards the deviation direction and increased at the opposite side. Furthermore, a pelvis and feet reorientation towards the manipulation direction was observed. We concluded that visual information is continuously used to determine and adjust heading direction during steady-state gait. To facilitate these adjustments, the body was reorientated and the CoM-ML shifted closer to the lateral BoS boundary towards the adjusted heading direction, while preserving CoM excursion.

Efficacy of Walking Adaptability Training on Walking Capacity in Ambulatory People With Motor Incomplete Spinal Cord Injury: A Multicenter Pragmatic Randomized Controlled Trial.

BACKGROUND AND OBJECTIVE: Balance and walking capacity are often impaired in people with motor incomplete spinal cord injury (iSCI), frequently resulting in reduced functional ambulation and participation. This study aimed to assess the efficacy of walking adaptability training compared to similarly dosed conventional locomotor and strength training for improving walking capacity, functional ambulation, balance confidence, and participation in ambulatory people with iSCI. METHODS: We conducted a 2-center, parallel-group, pragmatic randomized controlled trial. Forty-one people with iSCI were randomized to 6 weeks of (i) walking adaptability training (11 hours of Gait Real-time Analysis Interactive Lab (GRAIL) training-a treadmill in a virtual reality environment) or (ii) conventional locomotor and strength training (11 hours of treadmill training and lower-body strength exercises). The primary measure of walking capacity was maximal walking speed, measured with an overground 2-minute walk test. Secondary outcome measures included the Spinal Cord Injury Functional Ambulation Profile (SCI-FAP), the Activities-specific Balance Confidence (ABC) scale, and the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-P). RESULTS: No significant difference in maximal walking speed between the walking adaptability (n = 17) and conventional locomotor and strength (n = 18) training groups was found 6 weeks after training at follow-up (-0.05 m/s; 95% CI = -0.12-0.03). In addition, no significant group differences in secondary outcomes were found. However, independent of intervention, significant improvements over time were found for maximal walking speed, SCI-FAP, ABC, and USER-P restrictions scores. Conclusions. Our findings suggest that walking adaptability training may not be superior to conventional locomotor and strength training for improving walking capacity, functional ambulation, balance confidence, or participation in ambulatory people with iSCI. TRIAL REGISTRATION: Dutch Trial Register; Effect of GRAIL training in iSCI.

Assessment of Foot Strike Angle and Forward Propulsion with Wearable Sensors in People with Stroke.

Effective retraining of foot elevation and forward propulsion is a critical aspect of gait rehabilitation therapy after stroke, but valuable feedback to enhance these functions is often absent during home-based training. To enable feedback at home, this study assesses the validity of an inertial measurement unit (IMU) to measure the foot strike angle (FSA), and explores eight different kinematic parameters as potential indicators for forward propulsion. Twelve people with stroke performed walking trials while equipped with five IMUs and markers for optical motion analysis (the gold standard). The validity of the IMU-based FSA was assessed via Bland-Altman analysis, ICC, and the repeatability coefficient. Eight different kinematic parameters were compared to the forward propulsion via Pearson correlation. Analyses were performed on a stride-by-stride level and within-subject level. On a stride-by-stride level, the mean difference between the IMU-based FSA and OMCS-based FSA was 1.4 (95% confidence: -3.0; 5.9) degrees, with ICC = 0.97, and a repeatability coefficient of 5.3 degrees. The mean difference for the within-subject analysis was 1.5 (95% confidence: -1.0; 3.9) degrees, with a mean repeatability coefficient of 3.1 (SD: 2.0) degrees. Pearson's r value for all the studied parameters with forward propulsion were below 0.75 for the within-subject analysis, while on a stride-by-stride level the foot angle upon terminal contact and maximum foot angular velocity could be indicative for the peak forward propulsion. In conclusion, the FSA can accurately be assessed with an IMU on the foot in people with stroke during regular walking. However, no suitable kinematic indicator for forward propulsion was identified based on foot and shank movement that could be used for feedback in people with stroke.

Orthopedic footwear has a positive influence on gait adaptability in individuals with hereditary motor and sensory neuropathy.

BACKGROUND: Individuals with Hereditary Motor and Sensory Neuropathy (HMSN) are commonly provided with orthopedic footwear to improve gait. Although orthopedic footwear has shown to improve walking speed and spatiotemporal parameters, its effect on gait adaptability has not been established. RESEARCH QUESTION: What is the effect of orthopedic footwear on gait adaptability in individuals with HMSN? METHODS: Fifteen individuals with HMSN performed a precision stepping task on an instrumented treadmill projecting visual targets, while wearing either custom-made orthopedic or standardized footwear (i.e. minimally supportive, flexible sneakers). Primary measure of gait adaptability was the absolute Euclidean distance [mm] between the target center and the middle of the foot (absolute error). Secondary outcomes included the relative and variable error [mm] in both anterior-posterior (AP) and medial-lateral (ML) directions. Dynamic balance was assessed by the prediction of ML foot placement based on the ML center of mass position and velocity, using linear regression. Dynamic balance was primarily determined by foot placement deviation in terms of root mean square error. Another aspect of dynamic balance was foot placement adherence in terms of the coefficient of determination (R2). Differences between the footwear conditions were analyzed with a paired t-test or Wilcoxon signed-rank test (α = 0.05). RESULTS: The absolute error, relative error (AP) and variable error (AP and ML) decreased with orthopedic footwear, whereas the relative error in ML-direction slightly increased. As for dynamic balance, no effect on foot placement deviation or adherence was found. SIGNIFICANCE: Gait adaptability improved with orthopedic compared to standardized footwear in people with HMSN, as indicated by improved precision stepping. Dynamic balance, as a possible underlying mechanism, was not affected by orthopedic footwear.

Improved walking capacity after complementary ankle-foot surgery and gait training in a person with an incomplete tetraplegia; a case report.

INTRODUCTION: The population of people with a spinal cord injury (SCI) is changing to a diverse population with an increasing number of incomplete lesions. Often, these individuals have the capacity to walk, but experience disabling gait impairments. CASE PRESENTATION: The course of a 34-year-old male with a chronic incomplete traumatic cervical SCI who initially could walk no more than a few steps with supervision or a wheeled walker is described. He participated in a clinical trial with Targeted Epidural Spinal Stimulation (TESS). After this trial, he was able to walk with a wheeled walker and bilateral orthosis over a distance of 100 meters. Despite these improvements, his main complaints were (1) difficulty to correctly preposition the feet, and (2) pain in his toe and calf muscles. An interdisciplinary approach and the use of structured gait analysis formed the basis for shared decision-making with the team and the patient to perform ankle-foot surgery followed by 2-month gait training with a body weight support system. After this trajectory his walking distance increased to 250 meters, with a wheeled walker; but now without orthosis and with an increased walking speed compared to pre-surgery. Additionally, there was reduction of pain and he experienced no disturbances during sleeping, washing and clothing anymore. DISCUSSION: This case shows that surgical interventions can improve the gait capacity even in case of chronic incomplete SCI. Furthermore, training with a body weight support system after medical-technical interventions is useful to utilize the full potential of these interventions.

Quantitative assessment of plantar pressure patterns in relation to foot deformities in people with hereditary motor and sensory neuropathies.

BACKGROUND: Hereditary motor and sensory neuropathies (HMSN), also known as Charcot-Marie-Tooth disease, are characterized by affected peripheral nerves. This often results in foot deformities that can be classified into four categories: (1) plantar flexed first metatarsal, neutral hindfoot, (2) plantar flexed first metatarsal, correctable hindfoot varus, (3) plantar flexed first metatarsal, uncorrectable hindfoot varus, and (4) hindfoot valgus. To improve management and for the evaluation of surgical interventions, a quantitative evaluation of foot function is required. The first aim of this study was to provide insight into plantar pressure of people with HMSN in relation to foot deformities. The second aim was to propose a quantitative outcome measure for the evaluation of surgical interventions based on plantar pressure. METHODS: In this historic cohort study, plantar pressure measurements of 52 people with HMSN and 586 healthy controls were evaluated. In addition to the evaluation of complete plantar pressure patterns, root mean square deviations (RMSD) of plantar pressure patterns from the mean plantar pressure pattern of healthy controls were calculated as a measure of abnormality. Furthermore, center of pressure trajectories were calculated to investigate temporal characteristics. Additionally, plantar pressure ratios of the lateral foot, toes, first metatarsal head, second/third metatarsal heads, fifth metatarsal head, and midfoot were calculated to measure overloading of foot areas. RESULTS: Larger RMSD values were found for all foot deformity categories compared to healthy controls (p < 0.001). Evaluation of the complete plantar pressure patterns revealed differences in plantar pressure between people with HMSN and healthy controls underneath the rearfoot, lateral foot, and second/third metatarsal heads. Center of pressure trajectories differed between people with HMSN and healthy controls in the medio-lateral and anterior-posterior direction. The plantar pressure ratios, and especially the fifth metatarsal head pressure ratio, differed between healthy controls and people with HMSN (p < 0.05) and between the four foot deformity categories (p < 0.05). CONCLUSIONS: Spatially and temporally distinct plantar pressure patterns were found for the four foot deformity categories in people with HMSN. We suggest to consider the RMSD in combination with the fifth metatarsal head pressure ratio as outcome measures for the evaluation of surgical interventions in people with HMSN.

Examining the role of intrinsic and reflexive contributions to ankle joint hyper-resistance treated with botulinum toxin-A.

BACKGROUND: Spasticity, i.e. stretch hyperreflexia, increases joint resistance similar to symptoms like hypertonia and contractures. Botulinum neurotoxin-A (BoNT-A) injections are a widely used intervention to reduce spasticity. BoNT-A effects on spasticity are poorly understood, because clinical measures, e.g. modified Ashworth scale (MAS), cannot differentiate between the symptoms affecting joint resistance. This paper distinguishes the contributions of the reflexive and intrinsic pathways to ankle joint hyper-resistance for participants treated with BoNT-A injections. We hypothesized that the overall joint resistance and reflexive contribution decrease 6 weeks after injection, while returning close to baseline after 12 weeks. METHODS: Nine participants with spasticity after spinal cord injury or after stroke were evaluated across three sessions: 0, 6 and 12 weeks after BoNT-A injection in the calf muscles. Evaluation included clinical measures (MAS, Tardieu Scale) and motorized instrumented assessment using the instrumented spasticity test (SPAT) and parallel-cascade (PC) system identification. Assessments included measures for: (1) overall resistance from MAS and fast velocity SPAT; (2) reflexive resistance contribution from Tardieu Scale, difference between fast and slow velocity SPAT and PC reflexive gain; and (3) intrinsic resistance contribution from slow velocity SPAT and PC intrinsic stiffness/damping. RESULTS: Individually, the hypothesized BoNT-A effect, the combination of a reduced resistance (week 6) and return towards baseline (week 12), was observed in the MAS (5 participants), fast velocity SPAT (2 participants), Tardieu Scale (2 participants), SPAT (1 participant) and reflexive gain (4 participants). On group-level, the hypothesis was only confirmed for the MAS, which showed a significant resistance reduction at week 6. All instrumented measures were strongly correlated when quantifying the same resistance contribution. CONCLUSION: At group-level, the expected joint resistance reduction due to BoNT-A injections was only observed in the MAS (overall resistance). This observed reduction could not be attributed to an unambiguous group-level reduction of the reflexive resistance contribution, as no instrumented measure confirmed the hypothesis. Validity of the instrumented measures was supported through a strong association between different assessment methods. Therefore, further quantification of the individual contributions to joint resistance changes using instrumented measures across a large sample size are essential to understand the heterogeneous response to BoNT-A injections.

The Influence of Stride Selection on Gait Parameters Collected with Inertial Sensors.

Different methods exist to select strides that represent preferred, steady-state gait. The aim of this study was to identify the effect of different stride-selection methods on spatiotemporal gait parameters to analyze steady-state gait. A total of 191 patients with hip or knee osteoarthritis (aged 38-85) wearing inertial sensors walked back and forth over 10 m for two minutes. After the removal of strides in turns, five stride-selection methods were compared: (ALL) include all strides, others removed (REFERENCE) two strides around turns, (ONE) one stride around turns, (LENGTH) strides <63% of median stride length, and (SPEED) strides that fall outside the 95% confidence interval of gait speed over the strides included in REFERENCE. Means and SDs of gait parameters were compared for each trial against the most conservative definition (REFERENCE). ONE and SPEED definitions resulted in similar means and SDs compared to REFERENCE, while ALL and LENGTH definitions resulted in substantially higher SDs of all gait parameters. An in-depth analysis of individual strides showed that the first two strides after and last two strides before a turn were significantly different from steady-state walking. Therefore, it is suggested to exclude the first two strides around turns to assess steady-state gait.

Needs and wishes for the future lower limb exoskeleton: an interview study among people with spinal cord injury with community-based exoskeleton experience.

PURPOSE: Exoskeleton use by people with complete spinal cord injury (SCI) in daily life is challenging. To optimize daily exoskeleton use, a better understanding of the purpose of use and the accompanying improvements are needed. The perspective of experienced exoskeleton users could guide design improvements. METHODS: Face-to-face semi-structured interviews were held with 13 people with SCI with exoskeleton experience. Interviews were audio-taped, transcribed, and analysed thematically. RESULTS: Participants expressed three future purposes of exoskeleton use: for daily activities (e.g., stair climbing), exercise (e.g., staying healthy), and social interaction (e.g., standing at parties). Exoskeleton use during daily activities was the ultimate goal. Therefore, the future exoskeleton should be: easy to use, small and lightweight, tailor made, safe, comfortable, less distinctive, durable, and affordable. Improving the ease of use was relevant for all purposes, for all participants. The other suggestions for improvement varied depending on the purpose of use and the participant. CONCLUSION: Increasingly more advanced improvements are needed to transition from an exercise purpose to social interaction, and ultimately use during daily activities. In the current study, detailed suggestions for improvements have been made. Only when multiple of these suggestions are adjusted, can the exoskeleton be used to its full potential.IMPLICATIONS FOR REHABILITATIONThe use of an exoskeleton by people with a complete spinal cord injury in daily life is still in its infancy.To optimize daily exoskeleton use, a better understanding of the purpose of use and exoskeleton improvements is needed.More advanced improvements to future exoskeletons are needed to make a transition from use as an exercise device to use during social interaction and daily activities.Improving the ease of use of future exoskeletons is considered a priority by experienced users, followed by making the exoskeleton small, lightweight, and tailor made.

Translation and validation of the System Usability Scale to a Dutch version: D-SUS.

PURPOSE: The System Usability Scale (SUS) is the most commonly used questionnaire to assess usability of healthcare innovations but is not available in Dutch (D-SUS). This study aims to translate the SUS to Dutch and to determine its internal consistency, test-retest reliability, and construct validity in healthcare innovations focused on rehabilitation technologies. METHODS: Translation of the SUS was performed according to the WHO recommendations. Fifty-four participants filled out the D-SUS and Dutch Quebec User Evaluation of Satisfaction with assistive Technology (D-QUEST) twice. Internal consistency was assessed by Cronbach's alpha. Test-retest reliability was evaluated by Gwet's agreement coefficient (Gwet's AC2) on item scale, and Pearson correlation coefficient (PCC) for the overall D-SUS scores. Construct validity was assessed with the PCC between the D-SUS and D-QUEST overall scores (Netherlands Trial Register, ID: NL9169). RESULTS: After translation, Cronbach's alpha was 0.74. Gwet's AC2 was 0.68 and the PCC between the first and second overall D-SUS scores was 0.75. No significant difference in D-SUS score between the two measurements was found. Repeatability coefficient was 18.4. The PCC between the D-SUS and D-QUEST overall scores was 0.49. CONCLUSIONS: The D-SUS is a valid and reliable tool for usability assessment of healthcare innovations, specifically rehabilitation technologies.

Successful implementation of new rehabilitation technologies is partially dependent on good system usability.The System Usability Scale is translated to Dutch (D-SUS) to evaluate usability of healthcare innovations in the Netherlands.The D-SUS is a reliable and valid method to measure usability of rehabilitation technologies and eHealth applications.

Impaired foot placement strategy during walking in people with incomplete spinal cord injury.

BACKGROUND: Impaired balance during walking is a common problem in people with incomplete spinal cord injury (iSCI). To improve walking capacity, it is crucial to characterize balance control and how it is affected in this population. The foot placement strategy, a dominant mechanism to maintain balance in the mediolateral (ML) direction during walking, can be affected in people with iSCI due to impaired sensorimotor control. This study aimed to determine if the ML foot placement strategy is impaired in people with iSCI compared to healthy controls. METHODS: People with iSCI (n = 28) and healthy controls (n = 19) performed a two-minute walk test at a self-paced walking speed on an instrumented treadmill. Healthy controls performed one extra test at a fixed speed set at 50% of their preferred speed. To study the foot placement strategy of a participant, linear regression was used to predict the ML foot placement based on the ML center of mass position and velocity. The accuracy of the foot placement strategy was evaluated by the root mean square error between the predicted and actual foot placements and was referred to as foot placement deviation. Independent t-tests were performed to compare foot placement deviation of people with iSCI versus healthy controls walking at two different walking speeds. RESULTS: Foot placement deviation was significantly higher in people with iSCI compared to healthy controls independent of walking speed. Participants with iSCI walking in the self-paced condition exhibited 0.40 cm (51%) and 0.33 cm (38%) higher foot placement deviation compared to healthy controls walking in the self-paced and the fixed-speed 50% condition, respectively. CONCLUSIONS: Higher foot placement deviation in people with iSCI indicates an impaired ML foot placement strategy in individuals with iSCI compared to healthy controls.

Using Sensor Technology to Measure Gait Capacity and Gait Performance in Rehabilitation Inpatients with Neurological Disorders.

The aim of this study was to objectively assess and compare gait capacity and gait performance in rehabilitation inpatients with stroke or incomplete spinal cord injury (iSCI) using inertial measurement units (IMUs). We investigated how gait capacity (what someone can do) is related to gait performance (what someone does). Twenty-two inpatients (11 strokes, 11 iSCI) wore ankle positioned IMUs during the daytime to assess gait. Participants completed two circuits to assess gait capacity. These were videotaped to certify the validity of the IMU algorithm. Regression analyses were used to investigate if gait capacity was associated with gait performance (i.e., walking activity and spontaneous gait characteristics beyond therapy time). The ankle positioned IMUs validly assessed the number of steps, walking time, gait speed, and stride length (r ≥ 0.81). The walking activity was strongly (r ≥ 0.76) related to capacity-based gait speed. Maximum spontaneous gait speed and stride length were similar to gait capacity. However, the average spontaneous gait speed was half the capacity-based gait speed. Gait capacity can validly be assessed using IMUs and is strongly related to gait performance in rehabilitation inpatients with neurological disorders. Measuring gait performance with IMUs provides valuable additional information about walking activity and spontaneous gait characteristics to inform about functional recovery.

Improvement of quality of life after 2-month exoskeleton training in patients with chronic spinal cord injury.

OBJECTIVE: To examine changes in quality of life (QoL) after an eight-week period of robotic exoskeleton training in a homogeneous group of patients with chronic complete spinal cord injury (SCI). DESIGN: Prospective single-group pre-post study. SETTING: Rehabilitation center. PARTICIPANTS: Patients with a chronic (>6 months) motor complete SCI (T1-L1). INTERVENTION: Twenty-four training sessions with the ReWalk exoskeleton over an eight-week period. MAIN OUTCOME MEASURE: QoL, assessed with the sum score of the Short Form-36 with Walk Wheel modification (SF-36ww). Secondary outcome measures were the eight SF-36ww subdomains, satisfaction with bladder and bowel management, lower extremity joint passive range of motion (pROM), and lower extremity spasticity. RESULTS: Twenty-one participants completed the training. QoL significantly improved after the training period (average SF-36 sum score 621 ± 90) compared to baseline (571 ± 133) (t(20)=-2.5, P=.02). Improvements were seen on the SF-36ww subdomains for pain (P=.003), social functioning (P=.03), mental health (P=.02), and general health perception (P=.01). Satisfaction with bladder management (range 1-5) improved from median 3 at baseline to 4 after exoskeleton training (P=0.01). No changes in satisfaction with bowel management (P=.11), pROM (hip-extension (P=.49), knee-extension (P=.36), ankle dorsiflexion (P=.69)), or spasticity (P=.94) were found. CONCLUSION: Even in patients with chronic motor complete SCI and a relatively high level of QoL at baseline, a short-term exoskeleton training improved their QoL, pain and satisfaction with bladder management; findings that warrant further controlled studies in this specific SCI population.

Effects of orthopedic footwear on postural stability and walking in individuals with Hereditary Motor Sensory Neuropathy.

BACKGROUND: Orthopedic footwear is often prescribed to improve postural stability during standing and walking in individuals with Hereditary Motor Sensory Neuropathy. However, supporting evidence in literature is scarce. The aim of this study was to investigate the effect of orthopedic footwear on quiet standing balance, gait speed, spatiotemporal parameters, kinematics, kinetics and dynamic balance in individuals with Hereditary Motor Sensory Neuropathy. METHODS: Fifteen individuals with Hereditary Motor Sensory Neuropathy performed a quiet standing task and 2-min walk test on customized orthopedic footwear and standardized footwear. Primary outcome measures were the mean velocity of the center of pressure during quiet standing and gait speed during walking. Secondary outcome measures included center of pressure amplitude and frequency during quiet standing, and spatiotemporal parameters, kinematics, kinetics, and dynamic balance during walking. Two-way repeated measures ANOVA and paired t-tests were performed to identify differences between footwear conditions. FINDINGS: Neither quiet standing balance nor dynamic balance differed between orthopedic and standardized footwear, but orthopedic footwear improved spatiotemporal parameters (higher gait speed, longer step length, shorter step time and smaller step width) during walking. Moreover, less sagittal shank-footwear range of motion, more frontal shank-footwear range of motion, more dorsiflexion of the footwear-to-horizontal angle at initial contact and more hip adduction during the stance phase were found. INTERPRETATION: Orthopedic footwear improved walking in individuals with Hereditary Motor Sensory Neuropathy, whereas it did not affect postural stability during quiet standing or dynamic balance. Especially gait speed and spatiotemporal parameters improved. An improved heel landing at initial contact for all footwear and reduced foot drop during swing for mid and high orthopedic footwear contributed to the gait improvements wearing orthopedic footwear.

Musculoskeletal complaints in military recruits during their basic training.

INTRODUCTION: Overuse injuries often start with a musculoskeletal complaint, which can progress over time to an injury. Little or no information is known about the development and severity of overuse injuries in military recruits. This study describes the musculoskeletal complaints in Dutch military recruits during their basic training and examines potential predictive factors for dropout due to injury. METHODS: In this prospective cohort study, Dutch military recruits reported complaints of the lower body weekly using a Numeric Rating Scale (NRS) pain score chart during their basic training. Number, location and severity of complaints during each of the first 12 weeks of basic training were analysed. RESULTS: Of the 930 recruits, 61% reported an NRS pain score of 3 or higher and 34% reported an NRS pain score of 5 or higher at least once. Complaints were mostly reported in the foot and ankle region and least reported in the upper leg region. Injury dropouts (11%) showed significantly higher proportions of complaints and higher maximal pain scores throughout most weeks of basic training. The maximal NRS pain score of the first two weeks was the strongest predictor of dropping out due to injury. CONCLUSIONS: Recruits who drop out due to injury report more severe complaints throughout basic training. Focusing on musculoskeletal complaints in the first phase of training seems helpful to identify recruits who are at risk of developing an injury.

Validation of new measures of arm coordination impairment in Wheelchair Rugby.

This study aims were twofold: (1) to evaluate the construct validity of the Repetitive Movement Test (RMT) a novel test developed for Wheelchair Rugby classification which evaluates arm coordination impairment at five joints - shoulder, elbow, forearm, wrist and fingers - and (2), pending sufficiently positive results, propose objective minimum impairment criteria (MIC). Forty-two WR athletes with an eligible coordination impairment, and 20 volunteers without impairment completed the RMT and two clinically established coordination tests: the finger-nose test (FNT) and the spiral test (ST). Coordination deduction (CD), an ordinal observational coordination scale, currently used in WR classification, was obtained. Spearman-rank correlation coefficients (SCC) between RMT and ST (0.40 to 0.67) and between RMT and CD (0.31 to 0.53) generally supported RMT construct validity, SCC between RMT and FNT were lower (0.12-0.31). When the scores on ST, FNT and RMT from the sample of WR players were compared with the scores from volunteers without impairment, 93.5% to 100% of WR players had scores > 2SD below the mean of volunteers without impairment on the same test. In conclusion, RMT at the elbow, forearm, wrist and fingers have sufficient construct validity for use in WR. MIC were recommended with ST and RMT.

Assessment of the Shank-to-Vertical Angle While Changing Heel Heights Using a Single Inertial Measurement Unit in Individuals with Incomplete Spinal Cord Injury Wearing an Ankle-Foot-Orthosis.

Previous research showed that an Inertial Measurement Unit (IMU) on the anterior side of the shank can accurately measure the Shank-to-Vertical Angle (SVA), which is a clinically-used parameter to guide tuning of ankle-foot orthoses (AFOs). However, in this context it is specifically important that differences in the SVA are detected during the tuning process, i.e., when adjusting heel height. This study investigated the validity of the SVA as measured by an IMU and its responsiveness to changes in AFO-footwear combination (AFO-FC) heel height in persons with incomplete spinal cord injury (iSCI). Additionally, the effect of heel height on knee flexion-extension angle and internal moment was evaluated. Twelve persons with an iSCI walked with their own AFO-FC in three different conditions: (1) without a heel wedge (refHH), (2) with 5 mm heel wedge (lowHH) and (3) with 10 mm heel wedge (highHH). Walking was recorded by a single IMU on the anterior side of the shank and a 3D gait analysis (3DGA) simultaneously. To estimate validity, a paired t-test and intraclass correlation coefficient (ICC) between the SVAIMU and SVA3DGA were calculated for the refHH. A repeated measures ANOVA was performed to evaluate the differences between the heel heights. A good validity with a mean difference smaller than 1 and an ICC above 0.9 was found for the SVA during midstance phase and at midstance. Significant differences between the heel heights were found for changes in SVAIMU (p = 0.036) and knee moment (p = 0.020) during the midstance phase and in SVAIMU (p = 0.042) and SVA3DGA (p = 0.006) at midstance. Post-hoc analysis revealed a significant difference between the ref and high heel height condition for the SVAIMU (p = 0.005) and knee moment (p = 0.006) during the midstance phase and for the SVAIMU (p = 0.010) and SVA3DGA (p = 0.006) at the instant of midstance. The SVA measured with an IMU is valid and responsive to changing heel heights and equivalent to the gold standard 3DGA. The knee joint angle and knee joint moment showed concomitant changes compared to SVA as a result of changing heel height.

Bed Sensor Technology for Objective Sleep Monitoring Within the Clinical Rehabilitation Setting: Observational Feasibility Study.

BACKGROUND: Since adequate sleep is essential for optimal inpatient rehabilitation, there is an increased interest in sleep assessment. Unobtrusive, contactless, portable bed sensors show great potential for objective sleep analysis. OBJECTIVE: The aim of this study was to investigate the feasibility of a bed sensor for continuous sleep monitoring overnight in a clinical rehabilitation center. METHODS: Patients with incomplete spinal cord injury (iSCI) or stroke were monitored overnight for a 1-week period during their in-hospital rehabilitation using the Emfit QS bed sensor. Feasibility was examined based on missing measurement nights, coverage percentages, and missing periods of heart rate (HR) and respiratory rate (RR). Furthermore, descriptive data of sleep-related parameters (nocturnal HR, RR, movement activity, and bed exits) were reported. RESULTS: In total, 24 participants (12 iSCI, 12 stroke) were measured. Of the 132 nights, 5 (3.8%) missed sensor data due to Wi-Fi (2), slipping away (1), or unknown (2) errors. Coverage percentages of HR and RR were 97% and 93% for iSCI and 99% and 97% for stroke participants. Two-thirds of the missing HR and RR periods had a short duration of ≤120 seconds. Patients with an iSCI had an average nocturnal HR of 72 (SD 13) beats per minute (bpm), RR of 16 (SD 3) cycles per minute (cpm), and movement activity of 239 (SD 116) activity points, and had 86 reported and 84 recorded bed exits. Patients with a stroke had an average nocturnal HR of 61 (SD 8) bpm, RR of 15 (SD 1) cpm, and movement activity of 136 (SD 49) activity points, and 42 reported and 57 recorded bed exits. Patients with an iSCI had significantly higher nocturnal HR (t18=-2.1, P=.04) and movement activity (t18=-1.2, P=.02) compared to stroke patients. Furthermore, there was a difference between self-reported and recorded bed exits per night in 26% and 38% of the nights for iSCI and stroke patients, respectively. CONCLUSIONS: It is feasible to implement the bed sensor for continuous sleep monitoring in the clinical rehabilitation setting. This study provides a good foundation for further bed sensor development addressing sleep types and sleep disorders to optimize care for rehabilitants.

Predictors of exoskeleton motor learning in spinal cord injured patients.

PURPOSE OF THE ARTICLE: Learning to use an exoskeleton is time consuming and diverse between users. Knowledge about trainability of exoskeleton skills is relevant for planning and expectation management. The objective was to assess predictors of exoskeleton skill performance during and after exoskeleton training. MATERIALS AND METHODS: Twenty-four participants with a motor complete spinal cord injury were given 24 training sessions in 8 weeks. Nine potential predictors were identified: lesion level, age, gender, age at injury, time since injury, BMI, sport, active lifestyle, and anxiety. Univariate and multivariate linear regression analyses were performed to examine predictors of skill performance after 2, 4, 6, and 8 weeks. RESULTS AND CONCLUSIONS: Twenty participants completed the training. Univariate analysis revealed that positive predictors were: low lesion level and more active lifestyle after 2 weeks, whereas low age at injury, low BMI, and more active lifestyle were positive predictors after 6 weeks. Multivariate regression model explained 65% of the performance after 2 weeks (predictors: lesion level, anxiety, active lifestyle) and 66% after 6 weeks (predictors: BMI, active lifestyle, age). Lesion level was a predictor during the first 4 weeks, but did not influence participants' final skill level. BMI, age, and active lifestyle were predictors toward the end of the training period.Implications for rehabilitationWith the help of wearable exoskeletons people with a complete spinal cord injury can regain their standing and walking mobility.Learning to use an exoskeleton is time consuming and the number of training sessions required to walk independently differs greatly between users.This study shows that lesion level was an important predictor of exoskeleton motor learning in the first 4 weeks of training.BMI, age, and active lifestyle were predictors of exoskeleton skill performance toward the end of the 8 week training period.

Measurement of range-of-motion in infants with indications of upper cervical dysfunction using the Flexion-Rotation-Test and Lateral-Flexion-Test: a blinded inter-rater reliability study in a clinical practice setting.

Background: In infants with indications of upper cervical dysfunction, the Flexion-Rotation-Test and Lateral-Flexion-Test are used to indicate reduced upper cervical range-of-motion (ROM). In infants, the inter-rater reliability of these tests is unknown. Objective: To assess the inter-rater reliability of subjectively and objectively measured ROM by using the Flexion-Rotation-Test and Lateral-Flexion-Test. Methods: 36 infants (<6 months) and three manual therapists participated in this cross-sectional observational study. Pairs of two manual therapists independently assessed infants' upper cervical ROM using the Flexion-Rotation-Test and Lateral-Flexion-Test, blinded for each other's outcomes. Two inertial motion sensors objectively measured cervical ROM. Inter-rater reliability was determined between each pair of manual therapists. For subjective outcomes, Cohen's kappa (ĸ) and the proportion of agreement (Pra) were calculated. For objectively measured ROM, Bland Altman plots were conducted and Limits of Agreement and Intraclass Correlation Coefficients (ICC) were calculated. Results: The inter-rater reliability of the Flexion-Rotation-Test and Lateral-Flexion-Test for subjective (ĸ: 0.077-0.727; Pra: 0.46-0.86) and objective outcomes (ICC: 0.019-0.496) varied between pairs of manual therapists. Conclusion: Assessed ROM largely depends on the performance of the assessment and its interpretation by manual therapists, leading to high variation in outcomes. Therefore, the Flexion-Rotation-Test and Lateral-Flexion-Test cannot be used solely as a reliable outcome measure in clinical practice and research context.