Locoregional lung ventilation distribution in girls with adolescent idiopathic scoliosis and healthy adolescents. The immediate effect of Schroth 'derotational breathing' exercise in a controlled-trial.

BACKGROUND: Scoliosis curves present transverse plane deviations due to vertebral rotation. The Schroth method supports thoracic derotation by training patients to exert "derotational" breathing based on assumed enhanced ventilation in areas called "humps" in scoliosis and a patient's ability to voluntarily direct ventilation in less ventilated areas called "flats." OBJECTIVE: To assess the asymmetric ventilation distribution and the ability of patients to direct their ventilation to perform derotational breathing. METHODS: Twelve girls with adolescent idiopathic scoliosis and 12 healthy girls performed 3 × 3 min of rest, maximal, and derotational breathing. Electrical impedance tomography was used to record locoregional lung ventilation distribution (LLVD) within 4 thoracic regions of interest: anterior right (ROI 1), anterior left (ROI 2), posterior right (ROI 3), and posterior left (ROI 4) quadrants. Humps and flats were the sums of ROI '2 + 3' and ROI '1 + 4,' respectively. RESULTS: Overall, no difference in LLVD was observed in the flats and humps between groups. At rest, the LLVD in the humps was more elevated than that in the flats (51.5 ± 8.1% versus 43.6 ± 7.9%; p = .021) when considering both groups. Maximal and derotational breathing led to a more homogeneous LLVD between the humps and flats. CONCLUSION: The postulated derotational breathing effect was not confirmed.

A preliminary study in classification of the severity of spine deformation in adolescents with lumbar/thoracolumbar idiopathic scoliosis using machine learning algorithms based on lumbosacral joint efforts during gait.

To assess the severity and progression of adolescents with idiopathic scoliosis (AIS), radiography with X-rays is usually used. The methods based on statistical observations have been developed from 3D reconstruction of the trunk or topography. Machine learning has shown great potential to classify the severity of scoliosis on imaging data, generally on X-ray measurements. It is also known that AIS leads to the development of gait disorder. To our knowledge, machine learning has never been tested on spine intervertebral efforts during gait as a radiation-free method to classify the severity of spinal deformity in AIS. Develop automated machine learning algorithms in lumbar/thoracolumbar scoliosis to classify the severity of spinal deformity of AIS based on the lumbosacral joint (L5-S1) efforts during gait. The lumbosacral joint efforts of 30 individuals with lumbar/thoracolumbar AIS were used as distinctive features fed to the machine learning algorithms. Several tests were run using various classification algorithms. The labeling consisted of three classes reflecting the severity of scoliosis i.e. mild, moderate and severe. The ensemble classifier algorithm including k-nearest neighbors, support vector machine, random forest and multilayer perceptron achieved the most promising results, with accuracy scores of 91.4%. This preliminary study shows lumbosacral joint efforts can be used to classify the severity of spinal deformity in lumbar/thoracolumbar AIS. This method showed the potential of being used as an assessment tool to follow-up the progression of AIS as a radiation-free method, alternative to radiography. Future studies should be performed to test the method on other categories of AIS.

Transcutaneous Functional Electrical Stimulation Controlled by a System of Sensors for the Lower Limbs: A Systematic Review.

In the field of transcutaneous functional electrical stimulation (FES), open-loop and closed-loop control strategies have been developed to restore functions of the lower limbs: walking, standing up, maintaining posture, and cycling. These strategies require sensors that provide feedback information on muscle activity or biomechanics of movement. Since muscle response induced by transcutaneous FES is nonlinear, time-varying, and dependent on muscle fatigue evolution, the choice of sensor type and control strategy becomes critical. The main objective of this review is to provide state-of-the-art, emerging, current, and previous solutions in terms of control strategies. Focus is given on transcutaneous FES systems for the lower limbs. Using Compendex and Inspec databases, a total of 135 review and conference articles were included in this review. Recent studies mainly use inertial sensors, although the use of electromyograms for lower limbs has become more frequent. Currently, several researchers are opting for nonlinear controllers to overcome the nonlinear and time-varying effects of FES. More development is needed in the field of systems using inertial sensors for nonlinear control. Further studies are needed to validate nonlinear control systems in patients with neuromuscular disorders.

Current Trends and Challenges in Pediatric Access to Sensorless and Sensor-Based Upper Limb Exoskeletons.

Sensorless and sensor-based upper limb exoskeletons that enhance or support daily motor function are limited for children. This review presents the different needs in pediatrics and the latest trends when developing an upper limb exoskeleton and discusses future prospects to improve accessibility. First, the principal diagnoses in pediatrics and their respective challenge are presented. A total of 14 upper limb exoskeletons aimed for pediatric use were identified in the literature. The exoskeletons were then classified as sensorless or sensor-based, and categorized with respect to the application domain, the motorization solution, the targeted population(s), and the supported movement(s). The relative absence of upper limb exoskeleton in pediatrics is mainly due to the additional complexity required in order to adapt to children's growth and answer their specific needs and usage. This review highlights that research should focus on sensor-based exoskeletons, which would benefit the majority of children by allowing easier adjustment to the children's needs. Sensor-based exoskeletons are often the best solution for children to improve their participation in activities of daily living and limit cognitive, social, and motor impairments during their development.

Braces Designed Using CAD/CAM Combined or Not With Finite Element Modeling Lead to Effective Treatment and Quality of Life After 2 Years: A Randomized Controlled Trial.

STUDY DESIGN: Single-center prospective randomized controlled trial. OBJECTIVE: The aim of this study was to assess the computer-aided design/manufacturing (CAD/CAM) brace design approach, with and without added finite element modeling (FEM) simulations, after 2 years in terms of clinical outcomes, 3D correction, compliance, and quality of life (QoL). SUMMARY OF BACKGROUND DATA: .: Previous studies demonstrated that braces designed using a combination of CAD/CAM and FEM induced promising in-brace corrections, were lighter, thinner, and covered less trunk surface. Yet, their long-term impact on treatment quality has not been evaluated. METHODS: One-hundred twenty adolescent idiopathic scoliosis patients were recruited following Scoliosis Research Society standardized criteria for brace treatment; 61 patients in the first subgroup (CAD) were given braces designed using CAD/CAM; 59 in the second subgroup (CAD-FEM) received braces additionally simulated and refined using a patient-specific FEM built from 3D reconstructions of the spine, rib cage and pelvis. Main thoracic (MT) and thoraco-lumbar/lumbar (TL/L) Cobb angles, sagittal curves, and apical rotations were compared at the initial visit and after 2 years. Patient compliance and QoL were tracked respectively by using embedded temperature sensors and SRS-22r questionnaires. RESULTS: Forty-four patients with CAD-FEM braces and 50 with CAD braces completed the study. Average in-brace correction was 9° MT (8° CAD-FEM, 10° CAD, P = 0.054) and 12° TL/L (same for both subgroups, P = 0.91). Out-of-brace 2-year progression from initial deformity was <4° for all 3D measurements. Sixty-six percent of all cases (30 CAD-FEM, 35 CAD) met the ≤5° curve progression criterion, 83% (38 CAD-FEM, 43 CAD) stayed <45°, and 6% (5 CAD-FEM, 1 CAD) underwent fusion surgery. 3D correction, compliance, and QoL were not significantly different between both subgroups (P > 0.05). CONCLUSION: After 2 years, patients with braces designed using CAD/CAM with/without FEM had satisfying clinical outcomes (compared to the BrAIST study), 3D corrections, compliance and QoL. A more comprehensive optimization of brace treatment remains to be accomplished. LEVEL OF EVIDENCE: 2.

Second-order simultaneous components model for the overshoot and "slow component" in V̇O2 kinetics.

The human oxygen uptake responses to exercise step on-transients present different shapes depending on the overshoot and/or the "slow component" manifestations. The conventional First-Order Multi-Exponential (FOME) model incorporates delayed add-on terms to comprise these phenomena, increasing parameter quantity, requiring a delayed recruitment of type II fibers to explain the "slow component," and not offering a unified structure for different individuals and intensity domains. We hypothesized that a model composed of two Second-Order Simultaneous Components (SOSC) would present a better overall fitting performance than the FOME. Fourteen well-trained male cyclists performed repeated step on-transitions to moderate, heavy, and severe cycling intensities, whose responses were fitted with FOME and SOSC models. The SOSC presented significantly smaller (p < 0.05) root mean squared errors for moderate, supra-moderate, and all intensities combined. Along with conceptual analyses, these findings suggest the SOSC as a comprehensive alternative to the FOME model, explaining all oxygen uptake step responses with as many parameters and without delayed add-on components.

Proof of Concept of an Assistive Robotic Arm Control Using Artificial Stereovision and Eye-Tracking.

Assistive robotic arms have become popular to help users with upper limb disabilities achieve autonomy in their daily tasks, such as drinking and grasping objects in general. Usually, these robotic arms are controlled with an adapted joystick. Joysticks are user-friendly when it comes to a general approach to an object. However, they are not as intuitive when having to accurately approach an object, especially when obstacles are present. Alternatively, the combined use of artificial stereovision and eye-tracking seems to be a promising solution, as the user's vision is usually dissociated from their upper limb disability. Hence, the objective of this study was to develop a proof of concept for the control of an assistive robotic arm using a low-cost combination of stereovision and eye-tracking. Using the developed control system, a typically developed person was able to control the robotic arm successfully reaching and grasping an object for 92% of the trials without obstacles with an average time of 13.8 seconds. Then, another set of trials with one obstacle had a success rate of 91% with an average time of 17.3 seconds. Finally, the last set of trials with two obstacles had a success rate of 98% with an average time of 18.4 seconds. Furthermore, the cost of an eye-tracker and stereovision remains below 400$.

Detection of pronator muscle overactivity in children with unilateral spastic cerebral palsy: Development of a semi-automatic method using EMG data.

BACKGROUND: The pronator teres and pronator quadratus muscles are frequently injected with neuromuscular blocking agents to improve supination in children with spastic cerebral palsy and limited active elbow supination. However, determining by simple clinical examination whether these muscles are overactive during active movement is difficult. OBJECTIVE: This study aimed to develop a semi-automatic method to detect pronator muscle overactivity by using surface electromyography (EMG) during active supination movements in children with cerebral palsy. METHODS: In total, 25 children with unilateral spastic cerebral palsy (10 males; mean [SD] age 10.6 [3.0] years) and 12 typically developing children (7 males; mean age 11.0 [3.0] years) performed pronation-supination movements at 0.50Hz. Kinematic parameters and surface EMG signals were recorded for both pronator muscles. Three experts visually assessed muscle overactivity in the EMG signals of the children with cerebral palsy, in comparison with the reference group. The reliability and discrimination ability of the visual assessments were analysed. Overactivity detection thresholds for the semi-automatic method were adjusted by using the visual assessment by the EMG experts. The positive and negative predictive values of the semi-automatic detection method were calculated. RESULTS: Intra-rater reliability of visual assessment by EMG experts was excellent and inter-rater reliability was moderate. For the 25 children with unilateral spastic cerebral palsy, EMG experts could discriminate different profiles of pronator overactivity during active supination: no pronator overactivity, one overactive pronator, or overactivity of both pronators. The positive and negative predictive values were 96% and 91%, respectively, for this semi-automatic detection method. CONCLUSIONS: Detection of pronator overactivity by using surface EMG provides an important complement to the clinical examination. This method can be used clinically, with the condition that clinicians be aware of surface EMG limitations. We believe use of this method can increase the accuracy of treatment for muscle overactivity, resulting in improved motor function and no worsening of paresis.

Development of a multibody model to assess efforts along the spine for the rehabilitation of adolescents with idiopathic scoliosis.

INTRODUCTION: Gait analysis has often been recognized as helpful for the therapeutic follow-up of adolescents with idiopathic scoliosis (IS). METHODS: A multibody model of the human body was developed to display the intervertebral efforts along the spine of each adolescent with IS, and highlight the efforts that significantly differ from typical age-matched healthy adolescents. The intervertebral efforts of one adolescent with IS and an age-matched adolescent during a complete gait cycle were computed and compared. RESULTS: All intervertebral efforts are larger in the adolescent with IS compared to the healthy adolescent, except for the vertical torque. The average medio-lateral torque and force for the participant with IS are respectively 200% and 114% higher. CONCLUSION: This study revealed that the pathological efforts are not concentrated around critical points but distributed along the spine. Thus, higher average efforts along the spine in adolescent with IS may influence the spine deformity due to mechanical modulations according to the Hueter-Volkmann Law. The potential of this model is promising for the therapeutic follow-up of adolescents with IS because it provides real-time efforts along the spine, as well as the corresponding information about the asymmetrical behavior of the spine during gait.

Patterns of upper limb muscle activation in children with unilateral spastic cerebral palsy: Variability and detection of deviations.

BACKGROUND: The aim of this study was two-fold: (1) to quantify the variability of upper limb electromyographic patterns during elbow movements in typically developing children and children with unilateral spastic cerebral palsy, and to compare different amplitude normalization methods; (2) to develop a method using this variability to detect (a) deviations in the patterns of a child with unilateral spastic cerebral palsy from the average patterns of typically developing children, and (b) changes after treatment to reduce muscle activation. METHODS: Twelve typically developing children ([6.7-15.9yo]; mean 11.0 SD 3.0yo) and six children with unilateral spastic cerebral palsy ([7.9-17.4yo]; mean 12.4 SD 4.0yo) attended two sessions during which they performed elbow extension-flexion and pronation-supination movements. Surface electromyography of the biceps, triceps, brachioradialis, pronator teres, pronator quadratus, and brachialis muscles was recorded. The Likelihood method was used to estimate the inter-trial, inter-session, and inter-subject variability of the electromyography patterns for each time point in the movement cycle. Deviations in muscle patterns from the patterns of typically developing children and changes following treatment were evaluated in a case study of a child with cerebral palsy. FINDINGS: Normalization of electromyographic amplitude by the mean peak yielded the lowest variability. The variability data were then used in the case study. This method detected higher levels of activation in specific muscles compared with typically developing children, and a reduction in muscle activation after botulinum toxin A injections. INTERPRETATION: Upper limb surface electromyography pattern analysis can be used for clinical applications in children with cerebral palsy.

Second-order modeling for the pulmonary oxygen uptake on-kinetics: a comprehensive solution for overshooting and nonovershooting responses to exercise.

The human oxygen uptake (V̇o2) response to step-like increases in work rate is currently modeled by a First Order System Multi-Exponential (FOME) arrangement. Because of their first-order nature, none of FOME model's exponentials is able to model an overshoot in the oxygen uptake kinetics (OV̇o2K). Nevertheless, OV̇o2K phenomena are observed in the fundamental component of trained individuals' step responses. We hypothesized that a Mixed Multi-Exponential (MiME) model, where the fundamental component is modeled with a second- instead of a first-order system, would present a better overall performance than that of the traditional FOME model in fitting V̇o2 on-kinetics at all work rates, either presenting or not OV̇o2K. Fourteen well-trained male cyclists performed three step on-transitions at each of three work rates below their individual lactate thresholds' work rate (WRLT), and two step on-transitions at each of two exercise intensities above WRLT. Averaged responses for each work rate were fitted with MiME and FOME models. Root mean standard errors were used for comparisons between fitting performances. Additionally, a methodology for detecting and quantifying OV̇o2K phenomena is proposed. Second order solutions performed better (P < 0.000) than the first-order exponential when the OV̇o2K was present, and did not differ statistically (P = 0.973) in its absence. OV̇o2K occurrences were observed below and, for the first time, above WRLT (88 and 7%, respectively). We concluded that the MiME model is more adequate and comprehensive than the FOME model in explaining V̇o2 step on-transient responses, considering cases with or without OV̇o2K altogether.NEW & NOTEWORTHY To our knowledge, this is the first study applying second-order system equations to model V̇o2 on-kinetics, which is useful for both mathematical representation and physiological understanding of the overshoot phenomenon manifesting in the fundamental components of some step responses. Moreover, an objective methodology for detecting and quantifying this overshoot that considers data from the whole response is proposed. Finally, this is the first work detecting overshoot occurrences outside the moderate domain of exercise.

Socioeconomic disparities and difficulties to access to healthcare services among Canadian children with neurodevelopmental disorders and disabilities.

OBJECTIVES: The aims of this study were to identify the associations of levels of severity of neurodevelopmental disorders and disabilities (NDD/D) in children with their household socioeconomic status (SES) and their frequency of visits to a healthcare provider, and to examine how the severity of disability varied with these determinants among NDD/D subgroups, in order to inform possible social policy changes and to improve access to the healthcare system. METHODS: Data from the 2006 Participation and Activity Limitation Survey on children aged 5-14 years, collected by Statistics Canada, were analyzed (n=7,072 and weighted n=340,340). Children with NDD/D constituted those with impairments in motor, speech, neurosensory, and psychological functioning, as well as those who had issues with learning/cognition and social interactions. The weighted sample size for this group was n=111,630 (total sample size for children with limitations: n=174,810). We used logistic regression to assess the associations of household SES and frequency of visits to a healthcare provider with disability level. We included NDD/D subgroups as interaction terms in the model. Multiple correspondence analysis (MCA) was conducted to develop a profile of disability level. RESULTS: After-tax low income, family assistance, out-of-pocket expenses, needing but not receiving health services from a social worker, condition of the dwelling, and residential location were associated with the severity of NDD/D. Using MCA, 2 disability profiles could be identified based on access to healthcare, household income status, and condition of the dwelling. CONCLUSIONS: More social interventions are needed to reduce difficulties in accessing healthcare and to diminish the socially determined health inequalities faced by children with NDD/D.

Reproducibility analysis of upper limbs reachable workspace, and effects of acquisition protocol, sex and hand dominancy.

None of the physical testing, nor the goniometers currently used to assess upper limb function have a high validity, sensitivity or reliability. The reachable workspace, i.e. the area covered by the farthest points a subject can reach by hand without moving his/her body, shows promise but has yet to be validated, particularly in terms of reproducibility. Therefore, this study aims to evaluate the reproducibility of the reachable workspace over a period of several weeks, and to assess the effects of two proposed acquisition protocols, as well as those of gender, and hand dominancy. Shoulder movements were recorded using a motion capture system on 10 female and 10 male healthy subjects during a random protocol, i.e. simply asking them to achieve the farthest points they could reach with their hands, and during a standardized protocol, i.e. asking them to perform predefined shoulder elevations while keeping their trunk and elbow straight. The standardized protocol was repeated 7 weeks later. Repeated measures showed no significant difference, good to excellent intraclass correlation coefficients (0.46-0.81) and small bias (0.0-1.2%). The random protocol provided significantly lower and more scattered values for the reachable workspace (80.0 ±â€¯22.6% vs. 91.0 ±â€¯8.1%, p = .004), whereas gender and hand-dominancy had no effect. This study showed that the reachable workspace was highly reliable over a period of 7 weeks and that both upper limbs provided similar results. It could be used to monitor various pathologies of the upper limbs and to assess treatment efficiency, using a subject's healthy limb as reference.

Classification of upper limb disability levels of children with spastic unilateral cerebral palsy using K-means algorithm.

Treatment for cerebral palsy depends upon the severity of the child's condition and requires knowledge about upper limb disability. The aim of this study was to develop a systematic quantitative classification method of the upper limb disability levels for children with spastic unilateral cerebral palsy based on upper limb movements and muscle activation. Thirteen children with spastic unilateral cerebral palsy and six typically developing children participated in this study. Patients were matched on age and manual ability classification system levels I to III. Twenty-three kinematic and electromyographic variables were collected from two tasks. Discriminative analysis and K-means clustering algorithm were applied using 23 kinematic and EMG variables of each participant. Among the 23 kinematic and electromyographic variables, only two variables containing the most relevant information for the prediction of the four levels of severity of spastic unilateral cerebral palsy, which are fixed by manual ability classification system, were identified by discriminant analysis: (1) the Falconer index (CAI E ) which represents the ratio of biceps to triceps brachii activity during extension and (2) the maximal angle extension (θ Extension,max). A good correlation (Kendall Rank correlation coefficient = -0.53, p = 0.01) was found between levels fixed by manual ability classification system and the obtained classes. These findings suggest that the cost and effort needed to assess and characterize the disability level of a child can be further reduced.

Methodology to Customize Maximal Isometric Forces for Hill-Type Muscle Models.

One approach to increasing the confidence of muscle force estimation via musculoskeletal models is to minimize the root mean square error (RMSE) between joint torques estimated from electromyographic-driven musculoskeletal models and those computed using inverse dynamics. We propose a method that reduces RMSE by selecting subsets of combinations of maximal voluntary isometric contraction (MVIC) trials that minimize RMSE. Twelve participants performed 3 elbow MVIC in flexion and in extension. An upper-limb electromyographic-driven musculoskeletal model was created to optimize maximum muscle stress and estimate the maximal isometric force of the biceps brachii, brachialis, brachioradialis, and triceps brachii. Maximal isometric forces were computed from all possible combinations of flexion-extension trials. The combinations producing the smallest RMSE significantly reduced the normalized RMSE to 7.4% compared with the combination containing all trials (9.0%). Maximal isometric forces ranged between 114-806 N, 64-409 N, 236-1511 N, and 556-3434 N for the brachii, brachialis, brachioradialis, and triceps brachii, respectively. These large variations suggest that customization is required to reduce the difference between models and actual participants' maximal isometric force. While the smallest previously reported RMSE was 10.3%, the proposed method reduced the RMSE to 7.4%, which may increase the confidence of muscle force estimation.

Three-dimensional analysis of the locked position in patients with recurrent shoulder instability.

BACKGROUND: Although recurrent anterior shoulder instability (RASI) is a common condition in young patients, no studies to date have measured the 3-dimensional (3D) locked position of the glenohumeral joint during an anterior dislocation. Therefore, our goal was to estimate it with 3D computed tomography (CT) scans. METHODS: Patients in this prospective observational study were separated in 3 groups: normal laxity, hyperlaxity, and epilepsy. They were characterized by questionnaires (Western Ontario Shoulder Instability Index, 11-item version of the Disabilities of the Arm, Shoulder and Hand, and Beighton Laxity Score), and a CT scan revealing bipolar bone defects. 3D models of the humeral head and the glenoid were reconstructed from the CT scan, and the rotations and displacements of the humerus relative to the glenoid, from initial to locked position, were calculated. Intraobserver and interobserver reliability by intraclass correlation coefficient (ICC), analysis of variance test, and the Pearson correlation were used to evaluate data. RESULTS: This study involved 44 patients (46 shoulders): 18 with "normal" laxity, 18 with hyperlaxity and 8 (2 bilateral) with epilepsy. The mean locked position was of 12° of abduction, 90° of external rotation, and 21° of extension. The intraobserver and interobserver reliability was excellent for all the rotations and displacements (ICCs, 0.751-0.977) except the proximal-distal displacement (ICCs, 0.409-0.688). Significant differences were found for external rotation, anterior displacement, and medial displacement among the 3 groups of patients. Correlation was found between locked position and function. CONCLUSIONS: This study produced highly reliable measurements, with abduction angles proving to be lower than expected. Future work should focus on the effect of this low abduction angle on Hill-Sachs lesion management.

Intra- and Intersession Reliability of Surface Electromyography on Muscles Actuating the Forearm During Maximum Voluntary Contractions.

The aim of this study is to determine the intra- and intersession reliability of nonnormalized surface electromyography (sEMG) on the muscles actuating the forearm during maximum voluntary isometric contractions (MVIC). A subobjective of this study is to determine the intra- and intersession reliability of forearm MVIC force or torque, which is a prerequisite to assess sEMG reliability. Eighteen healthy adults participated at 4 different times: baseline, 1-h post, 6-h post, and 24-h post. They performed 3 MVIC trials of forearm flexion, extension, pronation, and supination. sEMG of the biceps brachii short head, brachialis, brachioradialis, triceps brachii long head, pronator teres, and pronator quadratus were measured. The intraclass correlation coefficient (ICC) on MVIC ranged from 0.36 to 0.99. Reliability was excellent for flexion, extension, and supination MVIC for both intra- and intersession. The ICC on sEMG ranged from 0.58 to 0.99. sEMG reliability was excellent for brachialis, brachioradialis, and pronator quadratus, and good to excellent for triceps brachii, biceps brachii, and pronator teres. This study shows that performing 3 MVICs is sufficient to obtain highly reliable maximal sEMG over 24 h for the main muscles actuating the forearm. These results confirm the potential of sEMG for muscle motor functional monitoring.