Reliability of a qualitative movement assessment tool during a single-leg triple hop landing

OBJECTIVE

Assess inter- and intra-rater reliability of the Qualitative Analysis of Single Leg Squat (QASLS) during a single-leg triple hop landing in subjects following anterior cruciate ligament reconstruction (ACLR). Explore if differences in reliability existed between novice and experienced clinicians. Determine if QASLS scores differed between the surgical and nonsurgical limbs.

DESIGN

Repeated Measures.

PARTICIPANTS

20 subjects ≥6 months post-ACLR.

METHODS

Subjects were recorded performing a single-leg triple hop bilaterally. Videos were independently rated by five raters (2 physical therapists and 3 physical therapy students). Intraclass correlation coefficient (ICC) was calculated to measure reliability of the QASLS on the surgical limb. Wilcoxon signed-rank test was utilized to assess if differences in QASLS scores existed between limbs.

RESULTS

The cumulative inter-rater reliability was moderate (ICC (2,1): 0.703) and the cumulative intra-rater reliability was good (ICC (3,1): 0.857). Little difference was found between experienced and novice raters for inter- and intra-rater reliability. There was no statistically significant difference in QASLS scores between limbs (P = 0.64).

CONCLUSION

The QASLS tool offers moderate inter- and good intra-rater reliability for evaluating movement quality during a single-leg triple hop landing, irrespective of rater experience. Additionally, there was no observed difference in QASLS scores between surgical and nonsurgical limbs.

ORTEGA v1.0: an open-source Python package for context-aware interaction analysis using movement data

BACKGROUND

Interaction analysis via movement in space and time contributes to understanding social relationships among individuals and their dynamics in ecological systems. While there is an exciting growth in research in computational methods for interaction analysis using movement data, there remain challenges regarding reproducibility and replicability of the existing approaches. The current movement interaction analysis tools are often less accessible or tested for broader use in ecological research.

RESULTS

To address these challenges, this paper presents ORTEGA, an Object-oRiented TimE-Geographic Analytical tool, as an open-source Python package for analyzing potential interactions between pairs of moving entities based on the observation of their movement. ORTEGA is developed based on one of the newly emerged time-geographic approaches for quantifying space-time interaction patterns among animals. A case study is presented to demonstrate and evaluate the functionalities of ORTEGA in tracing dynamic interaction patterns in animal movement data. Besides making the analytical code and data freely available to the community, the developed package also offers an extension of the existing theoretical development of ORTEGA for incorporating a context-aware ability to inform interaction analysis.

CONCLUSIONS

ORTEGA contributes two significant capabilities: (1) the functions to identify potential interactions (e.g., encounters, concurrent interactions, delayed interactions) from movement data of two or more entities using a time-geographic-based approach; and (2) the capacity to compute attributes of potential interaction events including start time, end time, interaction duration, and difference in movement parameters such as speed and moving direction, and also contextualize the identified potential interaction events.

Clubfoot patients show more anterior-posterior displacement during one-leg-standing and less ankle power and plantarflexor moment during one-leg-hopping than typically developing children

BACKGROUND

Clubfoot patients show good-to-excellent foot correction after the Ponseti method. Nevertheless, underlying functional problems that limit motor abilities such as one-leg-standing and one-leg-hopping still persist. These restrictions have been proposed to arise due to problems with maintaining balance and the limited force-generating capacity of clubfoot patients. More insight is needed to understand the underlying limiting factors to improve overall motor ability in clubfoot patients.

RESEARCH QUESTION

The aim of this study was to determine the differences between clubfoot patients and typically developing children (TDC) in force and balance parameters during walking, one-leg-standing and hopping.

METHODS

Three-dimensional motion analysis was performed in 19 TDC and 16 idiopathic Ponseti-treated clubfoot patients between 5-9 years old. Kinematic and kinetic parameters were calculated during walking and one-leg-hopping. To describe the balance parameters, center of pressure (CoP) data was assessed during walking, one-leg-hopping and one-leg-standing. Mean group values were calculated and compared using nonparametric statistical tests. A general linear model with repeated measures was used to determine which activity showed the largest group differences.

RESULTS

Clubfoot patients showed lower peak plantarflexor moment and peak ankle power absorption and generation during one-leg-hopping compared to TDC. Furthermore, clubfoot patients showed a lower hop length and velocity than TDC. The difference in peak plantarflexor moment and ankle power between the study groups was larger during one-leg-hopping than during walking. Finally, clubfoot patients showed a higher anterior-posterior CoP range during one-leg-standing.

SIGNIFICANCE

Deviations in force parameters seemed to limit one-leg-hopping in clubfoot patients, and impaired anterior-posterior static balance was thought to be the underlying cause of problems with one-leg-standing. Furthermore, one-leg-hopping was more sensitive to distinguish between clubfoot patients and TDC than walking. Individualized physiotherapy targeting static balance and force parameters, with extra emphasis on including eccentric contractions, might improve the overall motor abilities of clubfoot patients.

Mining Bodily Cues to Deception

A significant body of research has investigated potential correlates of deception and bodily behavior. The vast majority of these studies consider discrete, subjectively coded bodily movements such as specific hand or head gestures. Such studies fail to consider quantitative aspects of body movement such as the precise movement direction, magnitude and timing. In this paper, we employ an innovative data mining approach to systematically study bodily correlates of deception. We re-analyze motion capture data from a previously published deception study, and experiment with different data coding options. We report how deception detection rates are affected by variables such as body part, the coding of the pose and movement, the length of the observation, and the amount of measurement noise. Our results demonstrate the feasibility of a data mining approach, with detection rates above 65%, significantly outperforming human judgement (52.80%). Owing to the systematic analysis, our analyses allow for an understanding of the importance of various coding factor. Moreover, we can reconcile seemingly discrepant findings in previous research. Our approach highlights the merits of data-driven research to support the validation and development of deception theory.

Exercise and gait/movement analyses in treatment and diagnosis of Parkinson's Disease

Cardinal motor symptoms in Parkinson's disease (PD) include bradykinesia, rest tremor and/or rigidity. This symptomatology can additionally encompass abnormal gait, balance and postural patterns at advanced stages of the disease. Besides pharmacological and surgical therapies, physical exercise represents an important strategy for the management of these advanced impairments. Traditionally, diagnosis and classification of such abnormalities have relied on partially subjective evaluations performed by neurologists during short and temporally scattered hospital appointments. Emerging sports medical methods, including wearable sensor-based movement assessment and computational-statistical analysis, are paving the way for more objective and systematic diagnoses in everyday life conditions. These approaches hold promise to facilitate customizing clinical trials to specific PD groups, as well as personalizing neuromodulation therapies and exercise prescriptions for each individual, remotely and regularly, according to disease progression or specific motor symptoms. We aim to summarize exercise benefits for PD with a specific emphasis on gait and balance deficits, and to provide an overview of recent advances in movement analysis approaches, notably from the sports science community, with value for diagnosis and prognosis. Although such techniques are becoming increasingly available, their standardization and optimization for clinical purposes is critically missing, especially in their translation to complex neurodegenerative disorders such as PD. We highlight the importance of integrating state-of-the-art gait and movement analysis approaches, in combination with other motor, electrophysiological or neural biomarkers, to improve the understanding of the diversity of PD phenotypes, their response to therapies and the dynamics of their disease progression.

Automated anomalous child repetitive head movement identification through transformer networks

The increasing prevalence of behavioral disorders in children is of growing concern within the medical community. Recognising the significance of early identification and intervention for atypical behaviors, there is a consensus on their pivotal role in improving outcomes. Due to inadequate facilities and a shortage of medical professionals with specialized expertise, traditional diagnostic methods have been unable to effectively address the rising incidence of behavioral disorders. Hence, there is a need to develop automated approaches for the diagnosis of behavioral disorders in children, to overcome the challenges with traditional methods. The purpose of this study is to develop an automated model capable of analyzing videos to differentiate between typical and atypical repetitive head movements in. To address problems resulting from the limited availability of child datasets, various learning methods are employed to mitigate these issues. In this work, we present a fusion of transformer networks, and Non-deterministic Finite Automata (NFA) techniques, which classify repetitive head movements of a child as typical or atypical based on an analysis of gender, age, and type of repetitive head movement, along with count, duration, and frequency of each repetitive head movement. Experimentation was carried out with different transfer learning methods to enhance the performance of the model. The experimental results on five datasets: NIR face dataset, Bosphorus 3D face dataset, ASD dataset, SSBD dataset, and the Head Movements in the Wild dataset, indicate that our proposed model has outperformed many state-of-the-art frameworks when distinguishing typical and atypical repetitive head movements in children.

Extraction of canine gait characteristics using a mobile gait analysis system based on inertial measurement units

This study aims to investigate two simple algorithms for extracting gait features from an inertial measurement unit (IMU) based canine gait analysis system. The first algorithm was developed to determine the hip/shoulder extension/flexion range of motion. The second algorithm automatically determines the stance and swing phase per leg. To investigate the accuracy of the algorithms, two dogs were walked on a treadmill and measured simultaneously with an IMU system, an optical tracking system and two cameras. The range of motion estimation was compared to the optical tracking systems, with a total of 280 steps recorded. To test the stance and swing phase detection, a total of 63 steps were manually annotated in the video recordings and compared with the output of the algorithm. The IMU's-based estimation of the range of motion showed an average deviation of 1.4° to 5.6° from the optical reference, while the average deviation in the detection of the beginning and end of the stance and swing phases ranged from -0.01 to 0.09 s. This study shows that even simple algorithms can extract relevant information from inertial measurements that are comparable to results from more complex approaches. However, additional studies including a wider subject pool need to be conducted to investigate the significance of the presented findings.

Why do children with unilateral cerebral palsy struggle with the single leg stance test? A kinematic and centre of pressure analysis

BACKGROUND

Children with unilateral cerebral palsy often report difficulty with balance in everyday life. The single leg stance test is a challenging task, requiring rapid sensory input and precise motor adjustment. The purpose of this study was to examine how children with cerebral palsy perform this test, compared to typically developing children.

METHODS

Three-dimensional kinematics of the trunk and lower limbs of 10 children with cerebral palsy and 15 children with typical development were captured as they performed a single leg stance test on their non-dominant leg on a force platform. Stance time, joint kinematics and centre of pressure sway were measured and examined.

FINDINGS

There was evidence of shorter single leg stance performance and increased mediolateral centre of pressure sway in children with cerebral palsy. Coronal plane movement at the subtalar joint and foot was reduced (-6.0° (-10.9, -1.2°)), while proximally there was greater trunk movement in the coronal (13.5° (2.4°, 24.5°)) and transverse planes (9.9° (0.7, 19°)) and pelvis movement in the transverse plane (6.1° (1.7, 10.5°). An association existed between stance time and mediolateral centre of pressure sway (p < 0.01), with an average reduction in stance time of 0.15 s for every 1 mm/s increase in mediolateral sway.

INTERPRETATION

Children with cerebral palsy showed poor mediolateral control of centre of pressure sway, leading to shorter stance time. They have a less effective coronal foot-tilt strategy and excessive trunk and pelvis movement. Interventions aimed at improving single leg stance performance should consider addressing both ankle / foot and trunk motor control.

How to improve movement execution in sidestep cutting? Involve me and I will learn

Providing choices, i.e., autonomy, to athletes during practice increases intrinsic motivation and positively influences the motor learning process. The effects of autonomy on the timing of feedback (self-controlled timing of feedback) when optimizing the movement execution of sidestep cutting (SSC), a task that is highly related with ACL injury risk, are unknown. The aim of this study was to investigate the effect of self-controlled timing of video and EF-feedback on movement execution of SSC in team sport athletes. Thirty healthy ball team sport athletes (22.9 ± 1.7 years, 185.5 ± 7.2 cm, 79.3 ± 9.2 kg) were recruited from local sports clubs. Participants were alternately assigned to the self-control (SC) or the yoked (YK) group based on arrival and performed five anticipated and five unanticipated 45° SSC trials as pre-, immediate-post and one-week retention test. Movement execution was measured with the Cutting Movement Assessment Score (CMAS). Training consisted of three randomized 45° SSC conditions: one anticipated and two unanticipated conditions. All participants received expert video instructions and were instructed to 'try to do your best in copying the movement of the expert'. The SC group was allowed to request feedback whenever they wanted during training. The feedback consisted of 1) CMAS score, 2) posterior and sagittal videos of the last trial and 3) an external focus verbal cue on how to improve their execution. The participants were told to lower their score and they knew the lower the score, the better. The YK group received feedback after the same trial on which their matched participant in the SC group had requested feedback. Data of twenty-two participants (50% in SC group) was analyzed. Pre-test and training CMAS scores between groups were equal (p > 0.05). In the anticipated condition, the SC group (1.7 ± 0.9) had better CMAS scores than the YK group (2.4 ± 1.1) at the retention test (p < 0.001). Additionally, in the anticipated condition, the SC group showed improved movement execution during immediate-post (2.0 ± 1.1) compared to pre-test (3.0 ± 1.0), which was maintained during retention (p < 0.001). The YK group also improved in the anticipated condition during immediate-post (1.8 ± 1.1) compared to pre-test (2.6 ± 1.0) (p < 0.001) but showed decreased movement execution during retention compared to immediate-post test (p = 0.001). In conclusion, self-controlled timing of feedback resulted in better learning and greater improvements in movement execution compared to the control group in the anticipated condition. Self-controlled timing of feedback seems beneficial in optimizing movement execution in SSC and is advised to be implemented in ACL injury prevention programs.

Criterion validity of neural networks to assess lower limb motion during cycling

The use of marker-less methods to automatically obtain kinematics of movement is expanding but validity to high-velocity tasks such as cycling with the presence of the bicycle on the field of view is needed when standard video footage is obtained. The purpose of this study was to assess if pre-trained neural networks are valid for calculations of lower limb joint kinematics during cycling. Motion of twenty-six cyclists pedalling on a cycle trainer was captured by a video camera capturing frames from the sagittal plane whilst reflective markers were attached to their lower limb. The marker-tracking method was compared to two established deep learning-based approaches (Microsoft Research Asia-MSRA and OpenPose) to estimate hip, knee and ankle joint angles. Poor to moderate agreement was found for both methods, with OpenPose differing from the criterion by 4-8° for the hip and knee joints. Larger errors were observed for the ankle joint (15-22°) but no significant differences between methods throughout the crank cycle when assessed using Statistical Parametric Mapping were observed for any of the joints. OpenPose presented stronger agreement with marker-tracking (criterion) than the MSRA for the hip and knee joints but resulted in poor agreement for the ankle joint.

Perspective on "in the wild" movement analysis using machine learning

Recent advances in wearable sensing and machine learning have created ample opportunities for "in the wild" movement analysis in sports, since the combination of both enables real-time feedback to be provided to athletes and coaches, as well as long-term monitoring of movements. The potential for real-time feedback is useful for performance enhancement or technique analysis, and can be achieved by training efficient models and implementing them on dedicated hardware. Long-term monitoring of movement can be used for injury prevention, among others. Such applications are often enabled by training a machine learned model from large datasets that have been collected using wearable sensors. Therefore, in this perspective paper, we provide an overview of approaches for studies that aim to analyze sports movement "in the wild" using wearable sensors and machine learning. First, we discuss how a measurement protocol can be set up by answering six questions. Then, we discuss the benefits and pitfalls and provide recommendations for effective training of machine learning models from movement data, focusing on data pre-processing, feature calculation, and model selection and tuning. Finally, we highlight two application domains where "in the wild" data recording was combined with machine learning for injury prevention and technique analysis, respectively.

Perceived pain and disability but not fear of movement are associated with altered cervical kinematics in people with acute neck pain following a whiplash injury

OBJECTIVES

To determine if measures of cervical kinematics are altered in people with acute whiplash associated disorders (WAD) and secondarily, to examine whether kinematic variables are associated with self-reported outcomes.

METHODS

We recruited people with acute WAD within 15 days after a motor vehicle collision and asymptomatic control participants. All participants performed active neck movements at a self-determined velocity. Maximal range of motion (ROM), peak and mean velocity of movement, smoothness of movement, and cervical joint position error were assessed. Moreover, self-reported measures of perceived pain and disability, pain catastrophising, and fear of movement were obtained.

RESULTS

Sixty people participated: 18 with acute WAD (mean age [SD] 38.7 [12.0]) and 42 as asymptomatic controls (mean age [SD] 38.4 [10.2]). Participants with acute WAD showed significantly decreased ROM in all movement directions (p < 0.0001). All participants with acute WAD showed a reduction in the mean and peak velocity of movement in all directions (p < 0.0001) and the number of velocity peaks was significantly higher (i.e., reduced smoothness of movement) in those with acute WAD in all directions (p < 0.0001). Repositioning acuity following cervical rotation was not significantly different between groups. Neck pain-related disability showed the largest number of significant associations with kinematic features, while fear of movement was not associated with measures of cervical kinematics.

CONCLUSIONS

Participants with acute WAD presented with altered cervical kinematics compared to asymptomatic participants. Several measures of cervical kinematics were associated with the level of pain and disability in people with acute WAD but not their fear of movement.

A feasibility study to assess the effectiveness of Muvity: A telerehabilitation system for chronic post-stroke subjects

OBJECTIVES

To assess the feasibility of a telerehabilitation system for chronic post-stroke subjects compared to a conventional treatment.

METHODS

A feasibility cross-over analysis was conducted in ten chronic post-stroke subjects. Two randomized groups followed two eight-weeks treatments, one with the telerehabilitation system Muvity and the other following conventional therapy (in random order). Before and after each treatment, physical evaluations were performed assessing functional independence, the perceived level of pain, balance control and self-reported health status. After the study, the participants answered a short questionnaire to measure the usability of the system.

RESULTS

Four out of six subjects demonstrated better performance in ADLs (equal or higher FIM scores) and five out of six reported lower pain (VAS score) after the treatment with Muvity when compared to the treatment without. There were no clear trends in terms of balance control (Berg scale) or self-reported health status (PCS score within SF-36).

CONCLUSIONS

The results suggest that the proposed telerehabilitation system aids users to overall maintain or improve their ability to perform ADLs without increasing pain, when compared to conventional therapy. Most subjects found the use of Muvity more motivating than the conventional rehabilitation treatment. This provides initial evidence that Muvity might be an appropriate complement for the telerehabilitation of patients with physical disabilities. However, the differences observed between both treatments were not statistically significant. A clinical study with a larger sample size will be necessary to obtain more robust results.

Biomechanical analysis of lifting on stable versus unstable surfaces-a laboratory-based proof-of-concept study

Background

Many workers performing manual handling tasks suffer from musculoskeletal disorders (MSD). Previous research has identified several loading aspects associated with manual handling, but it is still unknown if lifting on an unstable surface is associated with increased biomechanical loading of different body parts.

Aim

This proof-of-concept study aims to study what kinematic and kinetic movement parameters, such as movement time, joint angles, torque, and muscle activity are feasible and of importance when studying the effect of lifting on surfaces with varying degrees of stability in an experimental set-up.

Methods

Measurements were taken during three different surface conditions: stable, slightly unstable, and unstable. The participants were instructed to lift a box from the floor and place it on a table in front of them. The weight of the box varied from 0.5 to 15.5 kg. By using a motion capture system (VICON) with 28 reflective markers placed on the participants and one on the box, one Kistler force plate for measuring force levels and center of pressure movements (CoP), and four electromyographic transmitters (EMG), we analyzed the downward and upward phases of the lifting movement, using the Friedman’s test for repeated measures.

Results

Statistically significant results with less joint movements in the lower and upper back were seen with increased instability during both the downward and upward phases. The decrease in trunk movements with increased instability resulted in a somewhat more flexed knee position during the movement, a lower torque in the lower back, and a decrease in CoP movements, but no differences in movement time or muscle activity in back and knee muscles.

Conclusion

Lifting while standing on unstable surfaces resulted in an alteration of both kinematics and kinetics parameters; however, further studies regarding whether this is an additional risk factor for developing lower back pain are needed. Muscle activity levels were not altered due to instability and due to the complexity of the measurement, and we suggest not including EMG measures in future experiments of this type.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01157-2.

Harmonic ratio is the most responsive trunk-acceleration derived gait index to rehabilitation in people with Parkinson's disease at moderate disease stages

BACKGROUND

Harmonic ratios (HRs), recurrence quantification analysis in the antero-posterior direction (RQA_detAP), and stride length coefficient of variation (CV) have recently been shown to characterize gait abnormalities and fall risk in people with Parkinson's disease (pwPD) at moderate disease stages.

RESEARCH QUESTION

This study aimed to i) assess the internal and external responsiveness to rehabilitation of HR, RQA_detAP, and CV, ii) identify the baseline predictors of normalization of the gait stability indexes, and iii) investigate the correlations between the gait indexes modifications (∆) and clinical and kinematic ∆s in pwPD at Hoehn and Yahr disease staging classification 3.

METHODS

The trunk acceleration patterns of 21 pwPD and 21 age- and speed-matched healthy subjects (HSmatched) were acquired during gait using an inertial measurement unit at baseline (T0). pwPD were also assessed after a 4-week rehabilitation period (T1). Each participant's HR in the antero-posterior (HR_AP), medio-lateral (HR_ML), and vertical directions, RQA_detAP, CV, spatio-temporal, and kinematic variables were calculated.

RESULTS

At T1, HR_AP and HR_ML improved to normative values and showed high internal and external responsiveness. Lower HRs and higher pelvic rotation values at baseline were predictors of ∆HRs. A minimal clinically important difference (MCID) ≥ 21.5 % is required to normalize HR_AP with 95 % probability. MCID ≥ 36.9 % is required to normalize HR_ML with 92 % probability. ∆HR_AP correlated with ∆HR_ML and both correlated with ∆stride length and ∆pelvic rotation, regardless of ∆gait speed. RQAdetAP and step length CV were not responsive to rehabilitation.

SIGNIFICANCE

When using inertial measurement units, HR_AP and HR_ML can be considered as responsive outcome measures for assessing the effectiveness of rehabilitation on trunk smoothness during walking in pwPD at moderate disease stages.

Lower-limb joint-coordination and coordination variability during gait in children with cerebral palsy

BACKGROUND

Children with cerebral palsy present with poor motor control, altering their ability to perform tasks such as walking. Continuous relative phase analysis is a popular method to quantify motor control impairments via inter-joint coordination and coordination variability; however, it has not been explored in children with cerebral palsy.

METHODS

45 children with cerebral palsy and 45 typically developing children walked while fit with retroreflective markers. Continuous relative phase analysis for knee-hip and ankle-knee joint pairs quantified inter-joint coordination and coordination variability. The Gait Profile Score estimated gait pathology. Group differences were assessed with unpaired t-tests for coordination amplitude and variability (knee-hip, ankle-knee) across gait events. For the cerebral palsy group, correlations assessed the relation between the gait profile score and coordination metrics.

FINDINGS

The cerebral palsy group showed more in-phase patterns for knee-hip coupling compared to the typically developing group (initial contact, loading response, mid-stance, terminal swing) (p ≤ 0.03). The cerebral palsy group showed lower knee-hip coordination variability (mid-stance, mid-swing) (p ≤ 0.037) and lower ankle-knee coordination variability (initial contact, loading response, terminal swing) (p < 0.001). The gait profile score correlated weakly to moderately (r = [0.323-0.472]), and negatively with the knee-hip inter-joint coordination (initial contact, loading response, mid-stance, terminal swing) (p ≤ 0.042).

INTERPRETATION

Children with cerebral palsy showed a more in-phase gait strategy during challenging transitional gait cycle phases (beginning and end) and less flexible and adaptable motor behaviors. Moreover, the correlation between in-phase joint patterns and increased gait deviations (gait profile score) reinforces the relevance of coordination analysis to assess motor control impairment.

An exploratory analysis of gait biomechanics and muscle activation in pregnant females with high and low scores for low back or pelvic girdle pain during and after pregnancy

BACKGROUND

The purpose of this study was to compare gait kinematics, kinetics, and muscle activation between pregnant females with high and low scores for low back and/or pelvic girdle pain during and after pregnancy.

METHODS

Twenty participants tested during second trimester, third trimester, and again post-partum. At each session, motion capture, force plates, and surface electromyography data were captured during self-selected velocity over-ground walking. Participants completed the Quebec Back Pain Disability Scale (QBPDS) and were assigned to high (QBPDS ≥15) or low pain groups (QBPDS <15) based on third trimester scores. Two-way mixed model ANOVAs were used to compare high and low pain groups over time.

FINDINGS

Nine participants met the high pain group criteria and 11 were low pain. During second trimester the high pain group compared to the low pain group demonstrated smaller peak hip flexor moments, total hip work, percent hip contribution to work, and larger percent ankle contribution to work. Pregnant females demonstrated greater hip, knee, and ankle moments, ankle work, and gluteus maximus muscle activation third trimester than second trimester.

INTERPRETATION

Reduced hip and greater ankle contribution to work in the high pain group during second trimester could indicate decreased hip utilization early in pregnancy and may contribute to disability as pregnancy progresses. It is also possible kinetic differences during second trimester reflect an early strategy to reduce pain by avoiding hip joint loading. Increased moments and work during third trimester indicate a clinical imperative to better prepare pregnant females to accommodate increased joint loading and muscular demand.

Preliminary study on acute effects of an intervention to increase dorsiflexion range of motion in reducing medial knee displacement

BACKGROUND

Dynamic knee valgus, visually represented as medial knee displacement, is associated with anterior cruciate ligament injury. Recently, restrictions in ankle dorsiflexion range of motion have been associated with medial knee displacement. Therefore, interventions potentially increasing ankle dorsiflexion range of motion could alleviate medial knee displacement. The purpose of this pilot study was to explore the acute effects of an intervention to increase ankle dorsiflexion range of motion and reduce medial knee displacement in individuals who display medial knee displacement that is corrected with a heel lift.

METHODS

Eight young participants who displayed medial knee displacement corrected with a heel lift completed a single-session intervention aimed at increasing dorsiflexion range of motion. Immediately before and after the intervention session, dorsiflexion range of motion in three static conditions (passive straight-knee, passive bent-knee, and weight-bearing lunge) and medial knee displacement during an overhead squat were assessed.

FINDINGS

The single-session training program increased participants' dorsiflexion range of motion in all three static conditions (p = 0.0005 for straight-knee, 0.02 for bent-knee, and 0.01 for lunge) with moderate to large effect sizes (0.55-1.18). Additionally, the training resulted in a significant reduction in medial knee displacement during the overhead squat (p = 0.02).

INTERPRETATION

The finding indicate that our interventional protocol appears beneficial in increasing dorsiflexion range of motion among individuals with medial knee displacement. Additionally, improving dorsiflexion range of motion may be a promising direction for reducing medial knee displacement, which is a risk factor for anterior cruciate ligament injury.

The contribution of plant spatial arrangement to bumble bee flower constancy

Floral constancy of foraging bees influences plant reproduction. Constancy as observed in nature arises from at least four distinct mechanisms frequently confounded in the literature: context-independent preferences for particular plant species, preferential visitation to the same species as the previous plant visited (simple constancy), the spatial arrangement of plants, and the relative abundances of co-flowering species. To disentangle these mechanisms, we followed individual bee flight paths within patches where all flowering plants were mapped, and we used step selection models to estimate how each mechanism influences the probability of selecting any particular plant given the available plants in a multi-species community. We found that simple constancy was positive: bees preferred to visit the same species sequentially. In addition, bees preferred to travel short distances and maintain their direction of travel between plants. After accounting for distance, we found no significant effect of site-level plant relative abundances on bee foraging choices. To explore the importance of the spatial arrangement of plants for bee foraging choices, we compared our full model containing all parameters to one with spatial arrangement removed. Due to bees' tendency to select nearby plants, combined with strong intraspecific plant clumping, spatial arrangement was responsible for about 50% of the total observed constancy. Our results suggest that floral constancy may be overestimated in studies that do not account for the spatial arrangement of plants, especially in systems with intraspecific plant clumping. Plant spatial patterns at within-site scales are important for pollinator foraging behavior and pollination success.

Characteristics of gaze tracking during movement analysis by therapists

[Purpose] Visual assessment of the quality of movement is a common and important component of physiotherapy. The purpose of this study is to quantify the level of proficiency of therapists and to obtain a new index of proficiency by measuring the coordinates of the gaze tracking trajectories of therapists with years of experience. [Participants and Methods] Eighteen voluntary physiotherapists (1st year (n=4), 7th year (n=1), 9th year (n=4), 10th year (n=3), 11th year (n=4), 13th year (n=1), and 21st year (n=1)) were recruited for this study. [Results] Discriminant analysis according to the size of the deviation between the X-axis and Y-axis of the range of gaze tracking during movement analysis measured from each therapist showed that the percentage of classification accuracy in the 10th year or less was 72.2%. Cluster analysis showed that two clusters were formed. Thirteen therapists in Cluster 2 were in their 9th year or more. Eye tracking trajectories can be classified by the 10th year of experience as a therapist. [Conclusion] It was shown that full-fledged therapists with 10 years of experience also expanded the range of eye tracking. The trajectory in the Y-axis direction tends to be extended with their 9th year or more of experience. In this point, quantitative judgments of eye-tracking results can serve as indicators of proficiency. The eye movements are important as a tool to objectively measure skills from experience.

Assessing biomechanics and associated factors in individuals with patellofemoral pain in a clinical setting: A qualitative study based on interviews with expert clinicians

OBJECTIVES

To explore the perspectives of ten clinicians from different medical disciplines with experience in managing PFP on how to conduct biomechanical assessments in individuals with PFP in a clinical setting.

METHODS

An explorative qualitative design was used to explore the perspectives of ten clinicians with at least five years of experience managing patients with patellofemoral pain. A series of semi-structured interviews were done over Zoom video chat. The participants were from six different medical disciplines (physiotherapy, biokinetics, podiatry, sport science, sports medicine, orthopaedic surgery). Data was analysed thematically.

RESULTS

Four main themes emerged from the data. These were: 1) biomechanical contributing factors that clinicians routinely screen for in patients with PFP; 2) relevant functional activities for biomechanical screening in patients with PFP; 3) conducting gait analysis assessments in a clinical setting; and 4) challenges of biomechanical assessment in patients with PFP. The clinicians expressed conflicting opinions on the usefulness of clinical gait analysis. The clinicians questioned the clinical applicability of some of the biomechanical factors identified as important in the evidence.

CONCLUSIONS

It is important for clinicians to include the biomechanical assessment of functional activities linked to pain when managing patients with PFP. However, some of the biomechanical factors identified in the evidence are too difficult to observe without 3D movement analysis equipment and should not be considered clinically relevant. Expert clinical opinion is important to provide contextual information when addressing biomechanics in individuals with PFP.

Proximal and distal movement patterns during a graphomotor task in typically developing children and children with handwriting problems

BACKGROUND

Therapists specializing in handwriting difficulties in children often address motor problems including both proximal and distal movements in the upper extremity. Kinematic measures can be used to investigate various aspects of handwriting. This study examined differences in movement patterns in proximal and distal joints of the upper extremity during graphomotor tasks between typically developing children with and without handwriting problems. Additionally, it explored relationships between movement patterns, speed, and legibility of writing.

METHODS

Forty-one children, aged 7-11 years, were assessed with the Aleph Aleph Ktav Yad Hebrew Handwriting assessment and the Beery Test of Visual Motor Integration and, based on their scores, were divided into a research group (with handwriting difficulties) and a control group (without handwriting difficulties). Upper extremity joint movement patterns were analyzed with a motion capture system. Differences in the quality of shapes traced and copied on a graphics tablet positioned horizontally and vertically were compared. Between-group differences and relationships with speed and legibility were analyzed.

RESULTS

In both groups, there was greater movement in the distal compared to the proximal joints, greater movement when performing the task in a horizontal compared to a vertical plane, and greater movement when tracing than copying. Joint movements in the arm executed scaled-down versions of the shapes being drawn. While the amount of joint displacement was similar between groups, children in the research group showed greater dissimilarity between the drawn shape and the shape produced by the proximal joints. Finally, the drawing measure on the tablet was a significant predictor of legibility, speed of writing, visual motor integration and motor coordination, whereas the dissimilarity measure of joint movement was a significant predictor of speed of writing and motor coordination.

CONCLUSIONS

This study provides support for the role of the distal upper extremity joints in the writing process and some guidance to assist clinicians in devising treatment strategies for movement-related handwriting problems. While we observed differences in proximal joint movements between the children with and without handwriting difficulties, the extent to which they are responsible for the differences in drawing quality remains to be determined. Further studies should use a similar methodology to examine additional tasks such as drawing shapes of varying sizes.

Associations between upper extremity functioning and kinematics in people with spinal cord injury

Introduction

More knowledge of the relationships between kinematic measures and clinical assessments is required to guide clinical decision making and future research.

Objectives

To determine which kinematic variables obtained during a drinking task were associated with clinical assessments of upper extremity functioning in people with spinal cord injury (SCI).

Methods

In total, 25 individuals with chronic cervical (n = 17) or thoracic (n = 8) complete (n = 14) or motor incomplete (n = 11) SCI (mean age 58.4, SD 13.8) were included. Kinematic data, including movement time, smoothness and joint angles was captured with a 5-camera optoelectronic system during a unimanual drinking task. Action Research Arm Test (ARAT), Sollerman Hand Function Test (SHFT) and basic hand classification of the Upper Extremity Data Set (ISCI-Hand) were used as clinical assessments. Multiple regression analysis was used to identify kinematic variables associated with clinical assessments after controlling for potential confounding factors, such as, age, severity of SCI, sensory function, and hand surgery.

Results

Movement time, smoothness and movement pattern kinematics including trunk displacement, elbow and wrist joint angles were correlated (p < 0.05) with all three clinical scales while the velocity-related kinematics and inter-joint coordination showed low correlations. Multiple regression analysis revealed that wrist angle combined with movement time or smoothness explained 82% and 77% of the total variance in ARAT and SHFT, respectively. Wrist angle alone explained 59% of the variance in ISCI-Hand. The proprioception of the hand increased the explanatory power in the models of ARAT and SHFT. Associations between kinematics and clinical assessments in the subgroup with cervical SCI were equivalent to the whole group analyses. The number of participants in the subgroup with thoracic SCI was small and only allowed limited analysis.

Conclusions

Wrist angle, movement time, movement smoothness are the most important kinematic variables associated with upper extremity clinical assessments in people with SCI. The results are most valid for individuals with cervical SCI. All three assessments are appropriate for SCI. Further research with larger representative sample of thoracic SCI needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00938-9.

The use of Horizon graphs to visualize bilateral biomechanical time-series of multiple joints

Movement analysis provides a vast amount of data, which, frequently, are not used in the clinical decision-making process. For example, traditional gait data visualization is based on a time-based display of joint angles, but part of the information is lost when these time-series are averaged across different gait strides. Horizon graph is a data display method that increases the density of time-series data by horizontally dividing and layering multiple filled line graphs. This higher data density increases the amount of information displayed in the same graph and, consequently, enables visual data comparisons between multiple time series. Horizon graph of kinematic data allows displaying several cycles of different joints and their respective continuous symmetry ratio between sides. The aim of this work is to introduce the Horizon graph as a method to analyze kinematic gait data and help to characterize its symmetry. Examples of Horizon graph application to running is offered. Horizon graph may prove to be a useful clinical tool to visualize kinematic time-series and facilitate their clinical interpretation.•

Continuous gait time series is a powerful tool for clinical analysis.

•

Horizon graph, higher data density graph, increases the information displayed.

•

Horizon graph is a clinical tool to visualize kinematic curves.

Clinical validation of kinematic assessments of post-stroke upper limb movements with a multi-joint arm exoskeleton

Background

The clinical evaluation of the upper limb of severely impaired stroke patient is challenging. Sensor-based assessments may allow for an objective evaluation of this patient population. This study investigated the validity of a device-assisted approach in comparison to the clinical outcome that it is supposed to reflect.

Methods

In nineteen severely impaired chronic stroke patients, we applied a gravity-compensating, multi-joint arm exoskeleton (Armeo Spring) and compared this sensor-based assessment with the clinical outcome measure Upper Extremity Fugl-Meyer Assessment (UE-FMA) scale. Specifically, we assessed separately and subsequently the range of motion in joint space for four single joints (i.e., wrist, elbow and shoulder flexion/extension (FE), and shoulder internal/external rotation (IER)), and the closing and opening of the hand with a pressure sensor placed in the handle.

Results

Within the kinematic parameters, a strong correlation was observed between wrist and elbow FE (r > 0.7, p < 0.003; Bonferroni corrected). The UE-FMA was significantly predicted by a multiple regression model (F (5, 13) = 12.22, p < 0.0005, adj. R² = 0.83). Both shoulder IER and grip pressure added significantly (p < 0.05) to the prediction with the standardized coefficients β of 0.55 and 0.38, respectively.

Conclusions

By applying an exoskeleton-based self-contained evaluation of single-joint movements, a clinically valid assessment of the upper limb range of motion in severely impaired stroke patients is feasible. Shoulder IER contributed most relevantly to the prediction of the clinical status. These findings need to be confirmed in a large, independent patient cohort.

How accurate are visual assessments by physical therapists of lumbo-pelvic movements during the squat and deadlift?

OBJECTIVES

To investigate the accuracy of visual assessments made by physical therapists of lumbo-pelvic movements during the squat and deadlift and how much movement is considered injurious.

DESIGN

Quantitative Cross-sectional.

PARTICIPANTS

14 powerlifters, 10 Olympic weightlifters and six physical therapists.

SETTING

The lifters were recorded simultaneously by video and an inertial measurement unit (IMU) system while performing squats and deadlifts. The physical therapists assessed the videos and rated whether specific lumbo-pelvic movements were visible during the lifts and whether the movement amplitude was considered injurious.

MAIN OUTCOME MEASURES

The nominal visual assessments, if there was a movement and if it was considered injurious, were compared to the degrees of movement attained from the IMU system.

RESULTS

During the squat, a posterior pelvic tilt of ≥34° was required to visually detect the movement. For other lumbo-pelvic movements, there was no significant difference in the amount of movement between those who were assessed as moving or not moving their lumbo-pelvic area, nor was there a difference in movement amplitude between those who were assessed as having an increased risk of injury or not.

CONCLUSIONS

Physical therapists did not consistently detect lumbo-pelvic movements during squats and deadlifts when performed by competitive lifters.

Optimal multi-field functional electrical stimulation parameters for the "drinking task - reaching phase" and related upper limb kinematics repeatability in post stroke subjects

BACKGROUND

No specific guidelines for the management of functional electrical stimulation (FES) parameters in post stroke patients have been defined yet, despite its frequent use. The purpose of this study is to characterize the optimal FES parameters that assist the reaching phase of drinking task ("drinking task - reaching phase") on post stroke subjects and to analyze the related upper limb (UL) movement quality indicators repeatability.

METHODS

An observational study with a test and re-test design involving ten post stroke subjects with UL dysfunction was performed. End-point and joint kinematics of contralesional UL were assessed during the "drinking task - reaching phase" with FES through a test and retest design. FES parameters were adjusted to improve UL function according to a consensus between physiotherapists and patients' perspective.

FINDINGS

It was possible to establish reliable FES parameters that assisted the "drinking task - reaching phase". All FES parameters presented high to very high repeatability and led to moderate to very high repeatability in almost UL movement quality indicators during the "drinking task - reaching phase".

INTERPRETATION

These findings show that the main characteristics of FES parameters that improves patient perception of change are quite stable, which facilitate its implementation in clinical practice by allowing consistence between intervention sessions.

Final results of the NINFA project: impact of new technologies in the daily life of elderly people

BACKGROUND

The paper presents the work carried out within NINFA (iNtelligent Integrated Network For Aged people), a project for the wellbeing of the elderly people at home.

AIMS

The impact of new technologies on elderly people is evaluated with respect to the three main topics faced by NINFA.

METHODS

NINFA was structured into three main topics: (1) active user engagement from the very beginning of the planning stage: the use of specially designed questionnaires to evaluate the acceptability of new technology in general and robot caregiver specifically; (2) assessment of the well-being through non-invasive techniques: natural language processing for language change monitoring in elderly subjects; (3) automated assessment of motor and cognitive functions at home: systems to deliver tests and exergames through user interfaces compliant with elderly subjects.

RESULTS

The analysis shows that there is no a priori closure to support the technology, but it must not be invasive and must allow social interactions. The study of speech transcripts shows that a large variations in the number of words used to describe the same situation could be a sign on the onset of cognitive impairments. The specifically designed systems highlight, after the training period, significant improvements in the performances of the participants and a satisfaction with regards to the systems usability.

CONCLUSIONS

The outcomes of NINFA project highlight some important aspects of the relationship between elderly people and new technologies concerning: engagement and acceptability, assessment of the wellbeing and of the modifications of motor, cognitive and language functions.

Three dimensional validation of an instrumented handrail for stair gait

Some studies have used load cells (LC) to measure the force applied to horizontal handrails, but no work has validated an inclined set-up that can be used to bring new insights into handrail use during staircase gait. The aim of this study was to validate the accuracy of an inclined handrail set-up instrumented with LC. A handrail set-up designed to be easily reconstructed and integrating two commercial LC is proposed. Twenty points were tested along the handrail, with four reference weights in the three orthogonal directions of the sensors (Medio-Lateral, Antero-Posterior, Vertical). For each direction, the percentage (%) of error and the cross-talk between the known and recorded forces were calculated. A linear regression of the % error was performed to evaluate measurement accuracy in relation to point of application along the handrail. The current easily replicated set-up of an inclined handrail showed accurate measures with low cross-talk. The percentage of error and cross-talk were below 3.7% and 3.7%, respectively, consistent with previous studies evaluating inclined handrail with other methods. The error and cross-talk were greater in the Medio-Lateral and Antero-Posterior directions. The error in the Antero-Posterior direction was larger over the upper part of the handrail.

Upper limb kinematics during the first year after stroke: the stroke arm longitudinal study at the University of Gothenburg (SALGOT)

Background

Reduction of compensation and improved movement quality indicate recovery after stroke. Since clinical measures alone are often inadequate to distinguish between behavioral recovery and compensation, kinematic analysis of functional tasks has been recommended.

Objective

To quantify longitudinal changes and residual deficits in movement performance and quality during the first year after stroke using kinematic analysis of drinking task.

Methods

A total of 56 participants with first ever stroke causing upper extremity impairment were extracted from a non-selected stroke unit cohort (Stroke Arm Longitudinal Study at the University of Gothenburg-SALGOT). Participants needed to able to perform the drinking task with the more-affected arm at least on 2 occasions out of 6 (3 days, 10 days, 4 weeks, and 3, 6, and 12 months) during the first year to be included. A cohort of 60 healthy individuals was used as reference. Longitudinal changes were analyzed using linear mixed models.

Results

Movement time, number of movement units, peak angular velocity of the elbow, peak hand velocity, and trunk displacement improved significantly over the first 3 months with a peak at 6 months. Movement time and peak hand velocity reached levels comparable to healthy at 3 months, but number of movement units, peak elbow angular velocity, trunk displacement, and arm abduction remained different from healthy over the first year after stroke.

Conclusions

Even when the recovery patterns of kinematics follow the known nonlinear pattern, not all kinematic measures reach the levels in par with healthy controls at one year post stroke. Since the number of movement units, peak angular velocity, trunk displacement, and arm abduction remained impaired over the first year, they might be the most suited measures to distinguish behavioral recovery from compensation strategies.

Trial registration

ClinicalTrials: NCT01115348. 4 May 2010. Retrospectively registered.

Gait analysis - Available platforms for outcome assessment

Movement or gait analysis has become a viable assessment tool not only used in sports science or basic biomechanical research, but has also expanded to be a very valuable instrument in clinical diagnostics, monitoring functional recovery and musculoskeletal rehabilitation. In this context, this method has long been an integral part solely in neurological disorders such as cerebral palsy. However, in the meantime the benefits have also become apparent in other medical areas, such as foot surgery, orthopaedic technology, or in patients after lower limb amputation. These procedures proved to better understand, objectify and quantify the individual causes of gait and movement disorders in order to optimize patient-specific therapy. Currently we are able to rely on a multitude of available measurement systems. These can either be used in everyday life for simple monitoring of one's own activity or to complement therapeutic approaches in the clinical and scientific environment. The following review highlights the various fields of movement analysis, including markerless motion capture, marker-based analysis, pedobarography and wearable sensors. Each of these areas presents its own field of application and potential usage as well as the advantages and disadvantages arising in this context. The following article will give an overview of the type of measurement technology used, the respective fields of application, and the selected parameters and their interpretation possibilities for each of the areas mentioned.

Pinnipeds orient and control their whiskers: a study on Pacific walrus, California sea lion and Harbor seal

Whisker touch is an active sensory system. Previous studies in Pinnipeds have adopted relatively stationary tasks to judge tactile sensitivity, which may not accurately promote natural whisker movements and behaviours. This study developed a novel feeding task, termed fish sweeping to encourage whisker movements. Head and whisker movements were tracked from video footage in Harbor seal (Phoca vitulina), California sea lion (Zalophus californianus) and Pacific walrus (Odobenus rosmarus divergens). All species oriented their head towards the moving fish target and moved their whiskers during the task. Some species also engaged in whisker control behaviours, including head-turning asymmetry in the Pacific walrus, and contact-induced asymmetry in the Pacific walrus and California sea lion: behaviours that have only previously been observed in terrestrial mammals. This study confirms that Pinnipeds should be thought of as whisker specialists, and that whisker control (movement and positioning) is an important aspect of touch sensing in these animals, especially in sea lions and walruses. That the California sea lion controls whisker movement in relation to an object, and also had large values of whisker amplitude, spread and asymmetry, suggests that California sea lions are a promising model with which to further explore active touch sensing.

Surgery for the Pronated Forearm and Flexed Wrist in Children with Cerebral Palsy

AIM

There is no consensus in the literature on how best to manage wrist flexion and forearm pronation deformities in children with cerebral palsy (CP). The aim of this research was to come up with a treatment algorithm for the surgical management of such cases.

METHODS

Children with CP who underwent upper limb surgery between 2009 and 2016 at a single centre and by a single lead surgeon were reviewed retrospectively. Movement analysis and Shriners Hospital Upper Extremity Evaluation (SHUEE) data collected pre- and post-operatively.

RESULTS

Thirteen patients were recruited. Most patients underwent a flexor carpi ulnaris (FCU) to extensor carpi radialis brevis (ECRB) transfer, with or without pronator teres (PT) re-routing, and finger flexor or elbow flexor releases. Mean increase in active range of supination was 40.8° (p = 0.002) and wrist extension 28.9° (p = 0.004). The mean increase in dynamic positional analysis (part of the SHUEE) was 25.4% (of which 40.3% was due the increases in wrist function and 16.8% due to forearm function). The loss of wrist flexion was not significant (p = 0.125). The mean follow-up was 14 months (range 9-21).

CONCLUSIONS

To tackle both a pronation and flexion deformity, the authors favour performing a FCU to ECRB transfer in isolation if there is active supination to neutral; if active supination is short of neutral, then a FCU to ECRB with a PT release and possible re-routing performed. A treatment algorithm is proposed.

LEVEL OF EVIDENCE

IV.

Measurement of three-dimensional cervical segmental kinematics: Reliability of whole vertebrae and facet-based approaches

BACKGROUND

Previous studies have used orientation and translation of whole-vertebrae to describe three-dimensional cervical segmental kinematics. Describing kinematics using facet joint movement may be more relevant to pathology and effects of interventions but has not been investigated in the cervical spine. This study compared the reliability of two different methods (whole-vertebrae vs facet joint) to evaluate cervical kinematics.

METHODS

Two healthy adults each had six cervical (C1 to T1) magnetic resonance imaging scans, two each in neutral and left and right rotation. A semi-automated method of segmentation and alignment determined the relative orientation and translation of each whole-vertebrae and translation of each facet joint. Intra-rater and inter-rater reliability was determined using limits of agreement (LOA) with 95% confidence intervals and intraclass correlation coefficients (ICC_3,1 for intra- and ICC_2,1 for inter-rater).

RESULTS

The LOA for intra-rater evaluation of facet movement was superior to whole vertebra translation. Both methods showed excellent intra-rater ICC_3,1 (0.80-0.99) and inter-rater ICC_2,1 (0.79-0.85) for all variables except for Euler angle for flexion/extension which was good (0.65). Intra-and inter-rater ICCs were better for facet movement than all measures of whole of vertebrae movement except Euler angles of axial rotation where no difference was detected.

CONCLUSIONS

Measurement of three-dimensional segmental kinematics using either the facet joint or the whole-vertebrae method demonstrated excellent and comparable reliability. These findings support the use of the facet joint method as an option for describing and investigating cervical segmental kinematics.

Personalised profiling to identify clinically relevant changes in tremor due to multiple sclerosis

Background

There is growing interest in sensor-based assessment of upper limb tremor in multiple sclerosis and other movement disorders. However, previously such assessments have not been found to offer any improvement over conventional clinical observation in identifying clinically relevant changes in an individual’s tremor symptoms, due to poor test-retest repeatability.

Method

We hypothesised that this barrier could be overcome by constructing a tremor change metric that is customised to each individual’s tremor characteristics, such that random variability can be distinguished from clinically relevant changes in symptoms. In a cohort of 24 people with tremor due to multiple sclerosis, the newly proposed metrics were compared against conventional clinical and sensor-based metrics. Each metric was evaluated based on Spearman rank correlation with two reference metrics extracted from the Fahn-Tolosa-Marin Tremor Rating Scale: a task-based measure of functional disability (FTMTRS B) and the subject’s self-assessment of the impact of tremor on their activities of daily living (FTMTRS C).

Results

Unlike the conventional sensor-based and clinical metrics, the newly proposed ’change in scale’ metrics presented statistically significant correlations with changes in self-assessed impact of tremor (maxR²>0.5,p<0.05 after correction for false discovery rate control). They also outperformed all other metrics in terms of correlations with changes in task-based functional performance (R²=0.25 vs. R²=0.15 for conventional clinical observation, both p<0.05).

Conclusions

The proposed metrics achieve an elusive goal of sensor-based tremor assessment: improving on conventional visual observation in terms of sensitivity to change. Further refinement and evaluation of the proposed techniques is required, but our core findings imply that the main barrier to translational impact for this application can be overcome. Sensor-based tremor assessments may improve personalised treatment selection and the efficiency of clinical trials for new treatments by enabling greater standardisation and sensitivity to clinically relevant changes in symptoms.

Quantifying physical functional trajectory in hospitalized older adults using body worn inertial sensors

Acute medical illness requiring hospitalization usually is a critical event in the trajectory leading to disability in older adults. Functional decline frequently occurs during hospitalization, resulting in a loss of Independence in activities of daily living after discharge. The aim of the study was to assess the functional decline in different ADLs of hospitalized elderly patients in an Acute Care for Elderly (ACE) unit incorporating a body-worn inertial sensor and accompanying custom algorithms. 38 hospitalized older adults (age ≥ 75) were included. The patients completed different functional tasks, including a balance test, Gait Velocity Test (GVT), verbal and arithmetic dual-task gait, and a sit-to-stand ability test at admission and discharge. Movement-related parameters were acquired from a unique tri-axial inertial sensor unit. Maximal muscle strength and muscle power output endpoints were also assessed. The results indicated that significant improvements (p < 0.05) were found at discharge compared with the admission values for gait variability and spatiotemporal parameters in the 4- and 6-meter GVT. These significant gains were also obtained in the verbal GVT. In contrast, a significant reduction was found in the functional status measured with the Barthel Index scale. Regarding to the sit-to-stand ability, lower peak power was observed in the sit-to-stand phase of the task at discharge. In conclusion, inertial sensor unit and our custom, validated, algorithms represent a feasible tool for measuring and monitoring functional trajectory during hospitalization in older adults and they are sensitive to detect differences in movement pattern parameters in different ADLs such as walking and the ability to stand from a seated position.

Comparison of the kinematics and kinetics of shoulder exercises performed with constant and elastic resistance

Background

Internal and external rotation exercises of the shoulder are frequently performed to avoid injury and pain. Knowledge about the motion and loadings of the upper extremities during these exercises is crucial for the development of optimal training recommendations. However, a comparison of the angles and corresponding moments in the upper extremities that are achieved during internal and external rotation exercises for the shoulder by using different resistance types has not yet been performed. Therefore, the aim of the study was to examine upper extremity kinetics and kinematics in 3D of the internal and external rotation exercises.

Methods

The kinematics and kinetics of 12 participants while they performed 10 different exercises with a constant and with an elastic external load corresponding to 2% body mass was assessed. The motion of the upper extremities was recorded three-dimensionally with a motion capture system, using a newly developed marker set and joint coordinate systems with 28 markers. The applied external load was measured with a load cell placed in series with the external resistance, and moments were calculated using an inverse dynamics approach.

Results

The range of motion and the joint loading was highly dependent on the exercises. The range of motion in the glenohumeral joint did not differ significantly between the two resistance types, whereas internal/external rotation moments were significantly higher with constant resistance than those with elastic resistance.

Conclusions

Larger or lower moments can, therefore, be achieved through selection of the appropriate resistance type, while the range of motion can be altered through the selection of exercise type. Therefore, the loading motion patterns identified in this study can help to choose suitable shoulder exercises dependent on the training objective.

Electronic supplementary material

The online version of this article (10.1186/s13102-018-0111-7) contains supplementary material, which is available to authorized users.

Chinese Children's Knowledge of Topicalization: Experimental Evidence from a Comprehension Study

There is a debate as to whether topic structures in Chinese involve A'-movement or result from base-generation of the topic in the left periphery. If Chinese topicalization was derived by movement, under the assumptions of Friedmann et al.'s Relativized Minimality (Lingua 119:67-88, 2009), we would expect children's comprehension of object topicalization (with OSV order) to be worse than their comprehension of subject topicalization (with SVO order). This study examined 146 Mandarin-speaking children from age three to age six by means of a picture-sentence matching task with an appropriate context. The results showed a subject/object asymmetry when the topic marker is overt, and no asymmetry when the topic marker is covert. This suggests that the presence or absence of topic markers play an important role in children's comprehension of topicalization. We propose that both structures involve movement in the adult grammar, but not in the child grammar, at least initially. Sentences without overt topic markers are base-generated on a par with gapless sentences with a topic, and the base-generation analysis is abandoned as soon as children learn the syntax and semantics of topic markers, which function as attractors of topics.

Kinect-based assessment of proximal arm non-use after a stroke

Background

After a stroke, during seated reaching with their paretic upper limb, many patients spontaneously replace the use of their arm by trunk compensation movements, even though they are able to use their arm when forced to do so. We previously quantified this proximal arm non-use (PANU) with a motion capture system (Zebris, CMS20s). The aim of this study was to validate a low-cost Microsoft Kinect-based system against the CMS20s reference system to diagnose PANU.

Methods

In 19 hemiparetic stroke individuals, the PANU score, reach length, trunk length, and proximal arm use (PAU) were measured during seated reaching simultaneously by the Kinect (v2) and the CMS20s over two testing sessions separated by two hours.

Results

Intraclass correlation coefficients (ICC) and linear regression analysis showed that the PANU score (ICC = 0.96, r² = 0.92), reach length (ICC = 0.81, r² = 0.68), trunk length (ICC = 0.97, r² = 0.94) and PAU (ICC = 0.97, r² = 0.94) measured using the Kinect were strongly related to those measured using the CMS20s. The PANU scores showed good test-retest reliability for both the Kinect (ICC = 0.76) and CMS20s (ICC = 0.72). Bland and Altman plots showed slightly reduced PANU scores in the re-test session for both systems (Kinect: − 4.25 ± 6.76; CMS20s: − 4.71 ± 7.88), which suggests a practice effect.

Conclusion

We showed that the Kinect could accurately and reliably assess PANU, reach length, trunk length and PAU during seated reaching in post stroke individuals. We conclude that the Kinect can offer a low-cost and widely available solution to clinically assess PANU for individualised rehabilitation and to monitor the progress of paretic arm recovery.

Trial registration

The study was approved by The Ethics Committee of Montpellier, France (N°ID-RCB: 2014-A00395–42) and registered in Clinical Trial (N° NCT02326688, Registered on 15 December 2014, https://clinicaltrials.gov/ct2/show/results/NCT02326688).

Dissociating motor learning from recovery in exoskeleton training post-stroke

Background

A large number of robotic or gravity-supporting devices have been developed for rehabilitation of upper extremity post-stroke. Because these devices continuously monitor performance data during training, they could potentially help to develop predictive models of the effects of motor training on recovery. However, during training with such devices, patients must become adept at using the new “tool” of the exoskeleton, including learning the new forces and visuomotor transformations associated with the device. We thus hypothesized that the changes in performance during extensive training with a passive, gravity-supporting, exoskeleton device (the Armeo Spring) will follow an initial fast phase, due to learning to use the device, and a slower phase that corresponds to reduction in overall arm impairment. Of interest was whether these fast and slow processes were related.

Methods

To test the two-process hypothesis, we used mixed-effect exponential models to identify putative fast and slow changes in smoothness of arm movements during 80 arm reaching tests performed during 20 days of exoskeleton training in 53 individuals with post-acute stroke.

Results

In line with our hypothesis, we found that double exponential models better fit the changes in smoothness of arm movements than single exponential models. In contrast, single exponential models better fit the data for a group of young healthy control subjects. In addition, in the stroke group, we showed that smoothness correlated with a measure of impairment (the upper extremity Fugl Meyer score - UEFM) at the end, but not at the beginning, of training. Furthermore, the improvement in movement smoothness due to the slow component, but not to the fast component, strongly correlated with the improvement in the UEFM between the beginning and end of training. There was no correlation between the change of peaks due to the fast process and the changes due to the slow process. Finally, the improvement in smoothness due to the slow, but not the fast, component correlated with the number of days since stroke at the onset of training – i.e. participants who started exoskeleton training sooner after stroke improved their smoothness more.

Conclusions

Our results therefore demonstrate that at least two processes are involved in in performance improvements measured during mechanized training post-stroke. The fast process is consistent with learning to use the exoskeleton, while the slow process independently reflects the reduction in upper extremity impairment.

Recovery of kinematic arm function in well-performing people with subacute stroke: a longitudinal cohort study

BACKGROUND

Most motor function improvements in people who have experienced strokes occur within the first 3 months. However, individuals showing complete or nearly complete arm function recovery, as assessed using clinical scales, still show certain movement kinematic deficits at 3 months, post-stroke. This study evaluated the changes in upper extremity kinematics, in individuals demonstrating minor clinical motor impairments, 3-12 months post-stroke, and also examined the association between kinematics and the subjects's self-perceived hand abilities during the chronic stage, 12 months post-stroke.

METHODS

Forty-two subjects recovering from strokes and having Fugl-Meyer upper extremity motor assessment scores ≥60 were included from the Stroke Arm Longitudinal Study at the University of Gothenburg (SALGOT). Kinematic analyses of a drinking task, performed 3, 6, and 12 months post-stroke, were compared with kinematic analyses performed in 35 healthy controls. The Stroke Impact Scale-Hand domain was evaluated at the 12-month follow-up.

RESULTS

There were no significant changes in kinematic performance between 3 and 12 months, post-stroke. The patients recovering from stroke showed lower peak elbow extension velocities, and increased shoulder abduction and trunk displacement during drinking than did healthy controls, at all time points. At 12 months, post-stroke, better self-perceived arm functions correlated with improved trunk displacements, movement times, movement units, and time to peak velocity percentages.

CONCLUSION

Kinematic movement deficits, observed at 3 months post-stroke, remained unchanged at 12 months. Movement kinematics were associated with the patient's self-perceived ability to use their more affected hand.

TRIAL REGISTRATION

ClinicalTrials: NCT01115348 .

Virtual reality in the rehabilitation process for individuals with cerebral palsy and Down syndrome: A systematic review

BACKGROUND

Childhood neurological diseases result in neuromotor impairment, which affects selective motor control, compromising the acquisition of motor skills and functional independence. The positive results achieved with virtual reality are believed to be related to training in an interactive environment that provides a broad range of activities and scenarios with multiple sensory channels, enabling the creation of exercises at an intensity based on individual need. Therefore, a review was conducted to answer the following question: What are the possible effects of virtual reality for the pediatric population, specifically children with cerebral palsy and Down syndrome?

OBJECTIVE

The objective of the present study was to conduct a systematic review of the literature to determine the possible effects of virtual reality therapy in children with cerebral palsy and Down's syndrome.

METHODS

The PubMed, Bireme, Scielo and PEDro electronic databases were searched in the period from January to March 2016 using the following keywords: Down syndrome and virtual reality, virtual reality and cerebral palsy, virtual reality and neuropediatrics, and Down's syndrome and virtual reality. Only randomized controlled trials published in English in the previous 10 years (2007-2016) that addressed the specific purpose of this review and achieved a score of at least 4 points on the PEDro methodological quality scale were eligible for inclusion.

RESULTS

The initial research led to the retrieval of 214 articles, which were analyzed considering the inclusion criteria. Eighteen articles were submitted to an appraisal of methodological quality using the PEDro scale, only five of which received a score of four or more points and were described in the present review. Three of the studies selected analyzed children with cerebral palsy and two analyzed children with Down syndrome. Despite the different physiopathological characteristics of the two conditions, the authors employed similar therapeutic methods and evaluations. The results of the studies demonstrated that virtual reality training either alone or combined with motor training leads to improvements in sensory-motor functions and can be used as a complement to other successful rehabilitation interventions in the two populations.

CONCLUSION

Based on the results of the studies included in the present systematic review, despite differences in the characteristics of each population, the objectives and methods proposed by the authors were similar and virtual reality demonstrated promising effects for individuals with cerebral palsy and Down syndrome.

Quantitative assessment of drawing tests in children with dyslexia and dysgraphia

Drawing tests in children diagnosed with dyslexia and dysgraphia were quantitatively compared. Fourteen children with dysgraphia, 19 with dyslexia and 13 normally developing were asked to copy 3 figures: a circle, a square and a cross. An optoelectronic system allowed the acquisition of the drawing track in three-dimensions. The participants' head position and upper limb movements were measured as well. A set of parameters including movement duration, velocity, length of the trace, Range of Motion of the upper limb, was computed and compared among the 3 groups. Children with dyslexia traced the circle faster than the other groups. In the cross test, dyslexic participants showed a reduced execution time and increased velocity while drawing the horizontal line. Children with dyslexia were also faster in drawing certain sides of square with respect to the other groups.

Low rates of patients meeting return to sport criteria 9 months after anterior cruciate ligament reconstruction: a prospective longitudinal study

PURPOSE

The purpose of the current prospective study was to assess the changes over time in patients tested at 6 months and 9 months after anterior cruciate ligament reconstruction (ACLR) with a return to sport (RTS) test battery. It was hypothesized that more patients passed RTS criteria at 9 months compared to 6 months.

METHODS

Sixty-two ACLR patients performed a test battery at an average of 6.5 ± 0.7 and 9.5 ± 0.9 months after ACLR. All patients underwent a standardized rehabilitation protocol. The test battery consisted of the following tests: a jump-landing task assessed with the Landing Error Scoring System (LESS), three single-leg hop tasks (single-leg hop test, triple-leg hop test, side hop test), isokinetic quadriceps and hamstring strength at 60, 180 and 300°/s and two questionnaires (IKDC and ACL-RSI). Cut off criteria were set as Limb Symmetry Index (LSI) > 90% (for isokinetic strength and for single-leg hop tasks), LESS < 5, IKDC score within 15th percentage of healthy subjects and ACL-RSI > 56 respectively.

RESULTS

At 6 months, two patients (3.2%) passed all criteria. At 9 months, seven patients (11.3%) passed all criteria. Patients improved in all RTS criteria over time except for the IKDC score. Twenty-nine patients (46.8%) did not pass the strength criterion at 60°/s at 9 months after ACLR.

CONCLUSIONS

The percentages of patients passing all RTS criteria were low at both 6 and 9 months after ACLR. Quadriceps strength revealed persistent deficits and the lack of improvement in the IKDC score questionnaires shows insufficient self-reported knee function for RTS.

LEVEL OF EVIDENCE

III.

Altered movement during single leg hop test after ACL reconstruction: implications to incorporate 2-D video movement analysis for hop tests

PURPOSE

There is a lack of objective factors which can be used in guiding the return to sport (RTS) decision after an anterior cruciate ligament reconstruction (ACLR). The purpose of the current study was to conduct qualitative analysis of the single leg hop (SLH) in patients after ACLR with a simple and clinical friendly method and to compare the possible difference in movement pattern between male and female patients.

METHODS

Sixty-five patients performed the single leg hop (SLH) test at 6.8 ± 1.0 months following isolated ACLR. Digital video camcorders recorded frontal and sagittal plane views of the patient performing the SLH. Knee flexion at initial contact (IC), peak knee flexion, knee flexion range of motion (RoM), and knee valgus RoM were calculated. In addition, limb symmetry index (LSI) scores were calculated.

RESULTS

No differences were found in movement pattern between males and females. Movement analysis revealed that males had a decrease in knee flexion at IC (p = 0.018), peak knee flexion (p = 0.002), and knee flexion RoM (p = 0.017) in the injured leg compared to the non-injured leg. Females demonstrated a decrease in peak knee flexion (p = 0.011) and knee flexion RoM (p = 0.023) in the injured leg compared to the non-injured leg. Average LSI scores were 92.4% for males and 94.5% for females.

CONCLUSIONS

Although LSI scores were > 90%, clinical relevant altered movement patterns were detected in the injured leg compared to the non-injured leg. Caution is warranted to solely rely on LSI scores to determine RTS readiness.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION

The University of Groningen, ID 2012.362.

LEVEL OF EVIDENCE

III.

A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries

Why females would mate with multiple partners and have multiple fathers for clutches or litters is a long-standing enigma. There is a broad dichotomy in hypotheses ranging from polyandry having benefits to simply being an unavoidable consequence of a high incidence of male-female encounters. If females simply give in to mating when it is too costly to avoid being harassed by males (convenience polyandry), then there should be a higher rate of mating as density increases. However, if females actively seek males because they benefit from multiple mating, then mating frequency, and consequently the incidence of multiple paternity of clutches, should be high throughout. To explore these competing explanations, here we review the incidence of multiple paternity for sea turtles nesting around the World. Across 30 rookeries, including all 7 species of sea turtle, the incidence of multiple paternity was only weakly linked to rookery size (r²=0.14). However, using high resolution at-sea GPS tracking we show that the specifics of movement patterns play a key role in driving packing density and hence the likely rate of male-female encounters. When individuals use the same focal areas, packing density could be 100× greater than when assuming individuals move independently. Once the extent of adult movements in the breeding season was considered so that movements and abundance could be combined to produce a measure of density, then across rookeries we found a very tight relationship (r²=0.96) between packing density and the incidence of multiple paternity. These findings suggest that multiple paternity in sea turtles may have no benefit, but is simply a consequence of the incidence of male-female encounters.

Quantification of Hand Motor Symptoms in Parkinson's Disease: A Proof-of-Principle Study Using Inertial and Force Sensors

This proof-of-principle study describes the methodology and explores and demonstrates the applicability of a system, existing of miniature inertial sensors on the hand and a separate force sensor, to objectively quantify hand motor symptoms in patients with Parkinson’s disease (PD) in a clinical setting (off- and on-medication condition). Four PD patients were measured in off- and on- dopaminergic medication condition. Finger tapping, rapid hand opening/closing, hand pro/supination, tremor during rest, mental task and kinetic task, and wrist rigidity movements were measured with the system (called the PowerGlove). To demonstrate applicability, various outcome parameters of measured hand motor symptoms of the patients in off- vs. on-medication condition are presented. The methodology described and results presented show applicability of the PowerGlove in a clinical research setting, to objectively quantify hand bradykinesia, tremor and rigidity in PD patients, using a single system. The PowerGlove measured a difference in off- vs. on-medication condition in all tasks in the presented patients with most of its outcome parameters. Further study into the validity and reliability of the outcome parameters is required in a larger cohort of patients, to arrive at an optimal set of parameters that can assist in clinical evaluation and decision-making.

Modeling Movement Primitives with Hidden Markov Models for Robotic and Biomedical Applications

Movement primitives are elementary motion units and can be combined sequentially or simultaneously to compose more complex movement sequences. A movement primitive timeseries consist of a sequence of motion phases. This progression through a set of motion phases can be modeled by Hidden Markov Models (HMMs). HMMs are stochastic processes that model time series data as the evolution of a hidden state variable through a discrete set of possible values, where each state value is associated with an observation (emission) probability. Each motion phase is represented by one of the hidden states and the sequential order by their transition probabilities. The observations of the MP-HMM are the sensor measurements of the human movement, for example, motion capture or inertial measurements. The emission probabilities are modeled as Gaussians. In this chapter, the MP-HMM modeling framework is described and applications to motion recognition and motion performance assessment are discussed. The selected applications include parametric MP-HMMs for explicitly modeling variability in movement performance and the comparison of MP-HMMs based on the loglikelihood, the Kullback-Leibler divergence, the extended HMM-based F-statistic, and gait-specific reference-based measures.

MirrARbilitation: A clinically-related gesture recognition interactive tool for an AR rehabilitation system

BACKGROUND AND OBJECTIVE

Interactive systems for rehabilitation have been widely investigated for motivational purposes. However, more attention should be given to the manner in which user movements are recognized and categorized. This paper aims to evaluate the efficacy of using a clinically-related gesture recognition tool, based on the international biomechanical standards (ISB) for the reporting of human joint motion, for the development of an interactive augmented reality (AR) rehabilitation system -mirrARbilitation.

METHODS

This work presents an AR rehabilitation system based on ISB standards, which enables the system to interact and to be configured according to therapeutic needs. The Kinect(TM) skeleton tracking technology was exploited and a new movement recognition method was developed to recognize and classify biomechanical movements. Further, our mirrARbilitation system provides exercise instructions while simultaneously motivating the patient. The system was evaluated on a cohort of 33 patients, physiotherapists, and software developers when performing shoulder abduction therapy exercises. Tests were performed in three moments: (i) users performed the exercise until they feel tired without the help of the system, (ii) the same however using the mirrARbilitation for motivation and guidance, and (iii) users performed the exercise again without the system. Users performing the movement without the help of the system worked as baseline reference.

RESULTS

We demonstrated that the percentage of correct exercises, measured by the movement analysis method we developed, improved from 69.02% to 93.73% when users interacted with the mirrARbilitation. The number of exercise repetitions also improved from 34.06 to 66.09 signifying that our system increased motivation of the users. The system also prevented the users from performing the exercises in a completely wrong manner. Finally, with the help of our system the users' worst result was performing 73.68% of the rehabilitation movements correctly. Besides the engagement, these results suggest that the use of biomechanical standards to recognize movements is valuable in guiding users during rehabilitation exercises.

CONCLUSION

The proposed system proved to be efficient by improving the user engagement and exercise performance outcomes. The results also suggest that the use of biomechanical standards to recognize movements is valuable in guiding users during rehabilitation exercises.

Optogenetic stimulation of cortico-subthalamic projections is sufficient to ameliorate bradykinesia in 6-ohda lesioned mice

Electrical deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective for ameliorating the motor symptoms of Parkinson's disease (PD) including bradykinesia. The STN receives its main excitatory input from cortex; however, the contribution of cortico-subthalamic projection neurons to the effects of DBS remains unclear. To isolate the consequences of stimulating layer 5 primary motor cortex (M1) projections to the STN, we used a dual virus transfection technique to selectively express opsins in these neurons in mice made parkinsonian by unilateral nigrostriatal 6-OHDA lesioning. AAVs containing WGA-Cre constructs were injected in the STN to retrogradely place Cre in STN afferents, while AAVs containing Cre-dependent ultrafast hChR2(E123T/T159C)-EYFP opsin constructs were injected in M1 layer 5, producing specific opsin expression in M1-STN projections. Under unstimulated conditions, lesioned mice showed bradykinesia and hypokinesia (decreased movement), along with electrophysiological changes similar to those observed in PD patients. Specifically, low frequency power (theta, alpha, low beta) was increased and gamma power was decreased, while M1/STN coherence and STN phase-amplitude-coupling (PAC) were increased. Optogenetic stimulation (100-130Hz) of STN afferents in these mice ameliorated bradykinesia and hypokinesia and brought the neural dynamics closer to the non-parkinsonian state by reducing theta and alpha and increasing gamma power in M1, decreasing STN PAC, and reducing theta band coherence. Histological examination of the EYFP expression revealed that, in addition to orthodromic and antidromic effects, stimulation of cortico-subthalamic neurons may cause wide-spread increased glutamatergic activity due to collaterals that project to areas of the thalamus and other brain regions.