The dynamic balance of the children with cerebral palsy and typical developing during gait. Part I: Spatial relationship between COM and COP trajectories

The effects of improvement in upper extremity function on gait and balance in children with upper extremity affected

BACKGROUND

This study aimed to investigate the effects of functional improvement in the upper extremity on gait and balance in children with upper extremity affected.

RESEARCH QUESTION

What are the effects of functional improvement in the upper extremity on gait and balance in children with upper extremity affected?

METHODS

Eighteen children with a diagnosis of rheumatologic diseases and 15 healthy children were evaluated with Shriners Hospital Upper Extremity Assessment, Jebsen-Taylor Hand Function Test, Abilhand Rheumatoid Arthritis Scale, 10-meter walk test and Childhood Health Assessment Questionnaire. For static balance assessment, the Biodex Balance was used. Ground reaction forces (peak forces (heel strike and push-off) and minimum force (loading response), single-limb support duration, Center-of-Force displacement and walking speed were evaluated with the Sensor Medica. Arm swing was evaluated with the Kinovea 2D motion analysis.

RESULTS

Before treatment, single-limb support duration and push-off force was higher and center-of-force displacement was lower on affected side compared to unaffected side in rheumatologic group. After the 6-week rehabilitation program, upper extremity function, quality of life and functional gait score improved. Single-limb support duration decreased on affected side and increased on unaffected side. On affected side, push-off force decreased. The arm swing parameters were similar before and after treatment.

SIGNIFICANCE

Improving upper extremity function can help with gait balance by decreasing the difference in walking and balance parameters between the affected and unaffected sides and providing for more symmetrical weight transfer.

Structured Program for Developing the Psychomotor Skills of Institutionalized Children with Special Educational Needs

Tailoring motor activities to the unique needs of children with special educational requirements has shown considerable efficacy. Our study aimed to develop a structured program specifically designed to enhance psychomotor abilities, focusing on balance and motor-cognitive skills among 28 students (aged 12-14) from two institutional centers in Romania. The program spanned 36 weeks, with biweekly 30 min sessions. Psychomotor skills were assessed through tests measuring balance, speed of movements, and upper limb motor laterality. Initial and final data were collected for evaluation. A statistical analysis, employing the Kolmogorov-Smirnov and Wilcoxon Z tests, compared the assessments. The results indicated significant improvements in movement speed, with a notable increase in stimulus identification (averaging from approximately 13 to 14) (p < 0.05) and reduced processing time (decreasing from about 28.7 to 28 s) (p < 0.05). However, while the structured program demonstrated substantial enhancements in specific motor and cognitive-motor skills, it did not yield significant changes in dynamic balance, maintaining values close to 0.9 (p > 0.05) for open-eyed balance and 0.88 (p > 0.05) for closed-eyed balance. Additionally, an analysis of the processing speed in pulses per second showcased a marginal decline, from approximately 0.46 to 0.45, revealing notable disparities between the initial and final measurements (p < 0.05).

Motion-based technology to support motor skills screening in developing children: A scoping review

BACKGROUND

Acquiring motor skills is fundamental for children's development since it is linked to cognitive development. However, access to early detection of motor development delays is limited.

AIM

This review explores the use and potential of motion-based technology (MBT) as a complement to support and increase access to motor screening in developing children.

METHODS

Six databases were searched following the PRISMA guidelines to search, select, and assess relevant works where MBT recognised the execution of children's motor skills.

RESULTS

164 studies were analysed to understand the type of MBT used, the motor skills detected, the purpose of using MBT and the age group targeted.

CONCLUSIONS

There is a gap in the literature aiming to integrate MBT in motor skills development screening and assessment processes. Depth sensors are the prevailing technology offering the largest detection range for children from age 2. Nonetheless, the motor skills detected by MBT represent about half of the motor skills usually observed to screen and assess motor development. Overall, research in this field is underexplored. The use of multimodal approaches, combining various motion-based sensors, may support professionals in the health domain and increase access to early detection programmes.

Auditory Stimulation Improves Gait and Posture in Cerebral Palsy: A Systematic Review with Between- and Within-Group Meta-Analysis

The past decade has seen an increased interest in the implementation of auditory stimulation (AStim) for managing gait and postural deficits in people with cerebral palsy. Although existing reviews report beneficial effects of AStim on the spatiotemporal and kinematic parameters of gait, there are still numerous limitations that need to be addressed to correctly interpret these results. For instance, existing reviews have failed to characterize the effects of AStim by conducting separate between and within-group meta-analyses, these reviews have not evaluated the influence of AStim on postural outcomes, and nor have included several high-quality existing trials. In this study, we conducted between- and within-group meta-analyses to establish a state of evidence for the influence of AStim on gait and postural outcomes in people with cerebral palsy. We searched the literature according to PRISMA-P guidelines across 10 databases. Of 1414 records, 14 studies, including a total of 325 people with cerebral palsy, met the inclusion criterion. We report a significant enhancement in gait speed, stride length, cadence, and gross motor function (standing and walking) outcomes with AStim compared to conventional physiotherapy. The findings from this analysis reveal the beneficial influence of AStim on the spatiotemporal and kinematic parameters of gait and postural stability in people with cerebral palsy. Furthermore, we discuss the futurized implementation of smart wearables that can deliver person-centred AStim rehabilitation in people with cerebral palsy.

The effects of balance board on the balance parameters in five children with spastic cerebral palsy

PURPOSE

This study evaluated the effects of an instrumented balance board on the balance parameters in children with spastic cerebral palsy by carrying out a pilot single-group pre-post clinical trial.

METHODS

Five children aged 5 to 15 years with spastic diplegia and a Gross Motor Function Classification System level of I or II were included. All participants attended 20 sessions with an instrumented balance board, 45 minutes per session, 3 times a week for 7 weeks. The main outcome measures included the center of pressure excursion, velocity, and overshoot during quiet standing with open and closed eyes. The assessments were performed in the mediolateral and anteroposterior directions at pre- and one week post-intervention.

RESULTS

Non-parametric tests showed that the excursion did not change significantly except in the mediolateral direction with eyes closed (p <  0.05). The velocity of the center of pressure improved in both directions and eye conditions (p <  0.05). Also, the maximum velocity decreased with eyes open (mediolateral, anteroposterior, and total) (p <  0.05), while the change was not significant with the eyes closed. The overshoot measurements did not change significantly.

CONCLUSION

It is recommended to consider balance board training for improving balance parameters in children with cerebral palsy.

Reliability, validity, and minimal clinically important differences of the Japanese version of the early clinical assessment of balance in children with cerebral palsy

PURPOSE

We aimed to translate the Early Clinical Assessment of Balance (ECAB) from English to Japanese and examine the content validity, inter-rater reliability, intra-rater reliability, construct validity, and minimal clinically important difference (MCID) for children with cerebral palsy (CP).

METHODS

The ECAB was translated into Japanese per international standards. The study included 106 children with CP and, aged 1.5-12 years. The ECAB, the Gross Motor Function Classification System (GMFCS), and the Gross Motor Function Measure 66 Basal & Ceiling (GMFM-66-B&C) were measured. The content and construct validity were examined based on therapist feedback and correlations between the ECAB and GMFM-66-B&C. The inter-rater reliability and the intra-rater reliability were examined by the intra-class correlation coefficient (ICC). The MCID was calculated by the anchor-based method with the GMFM-66-B&C.

RESULTS

High content validity (more than 80% agreement), inter-rater and intra-rater reliability (ICC = 0.99 & 0.99, respectively), and construct validity (r = 0.96) were demonstrated, with MCID values of 7.39, 5.32, and 6.88 observed for the GMFCS I/II, III, and IV/V, respectively.

CONCLUSION

The Japanese version of the ECAB is a reliable and valid measure of balance ability in children with CP. Furthermore, the MCID of the ECAB was established, appears to be useful in helping to provide rehabilitation.Implications for RehabilitationThe Japanese version of the Early Clinical Assessment of Balance is easy, safe, and low-cost, and has high reliability and validity for assessing balance ability in children with cerebral palsy.The use of the Japanese version of the Early Clinical Assessment of Balance is beneficial for determining the therapeutic effect, appropriate treatment, and prediction of prognosis regarding balance ability in children with cerebral palsy.The minimal detectable change of the Japanese version of the ECAB suggest that a score exceeding 6 is a true change and the minimal clinically important difference of the Japanese version of the ECAB suggest that the scores exceeding 8, 6, and 7 for the GMFCS I/II, III, and IV/V, respectively, is a clinically useful change.

Influence of Different Load Conditions on Lower Extremity Biomechanics during the Lunge Squat in Novice Men

Objective: The lunge squat is one of the exercises to strengthen the lower limbs, however, there is little evidence of the effects of different equipment. The purpose of this study was to investigate the biomechanical effects of different types of equipment and loads on the lunge squat’s effect on the lower limbs. Methods: Fourteen male fitness novices participated in the experiment. Kinematics and kinetics in the sagittal plane using dumbbells, barbells, and weighted vests were measured using OpenSim. Two-way repeated measures ANOVA and one-dimensional statistical parametric mapping were used in the statistical analysis (SPM1D). Results: Range of motion (ROM) change in the knee joint was more obvious when using a barbell, whereas ROM when using a dumbbell was minimal. Compared to other joints, the joint moment at the hip joint was the largest and changed more significantly with increasing weight-bearing intensity, and the change was more pronounced with the dumbbell. For the center of pressure (COP) overall displacement, the dumbbell produced a smaller range of displacement. Conclusions: Dumbbells are suggested for male beginners to improve stability, barbells for the more experienced, and a low-weighted vest may be more appropriate for those with knee pain.

Exercise Prescription Improve the Rehabilitation of a Child With Viral Encephalitis Sequelae: A Case Report

This study conducted a personalized exercise prescription intervention on a child with viral encephalitis sequelae (VES). The purpose was to observe the rehabilitation process from the aspects of brain activation, and the curative effects on balance function and gait. A further aim was to explore the possible nerve biomechanical mechanisms between the extent of brain activation and the improvement in balance function and gait. A 12-week exercise prescription was used as the treatment method, and functional near-infrared spectroscopy (fNIRS), balance function test system, plantar pressure distribution system, and 3D gait system were used to assess the effects of the rehabilitation process pre and post the intervention. Following the exercise prescription intervention: (1) fNIRS showed that brain activation in the S1-D1, S1-D2, S1-D3, S2-D1, S3-D2, S3-D3, S4-D3, S5-D5, S5-D6, S5-D7, S7-D6, S7-D7, S8-D7, and S8-D8 increased significantly (P < 0.05). (2) The balance test showed that the area of motion ellipse and movement length of the child with eyes open decreased significantly and area of motion ellipse, back and forth swing, left and right swing and movement length of the child with eyes closed all decreased significantly (P < 0.05). (3) The static plantar pressure distribution demonstrated that the pressure center of the left and right foot decreased significantly (P < 0.05) from 5.3° dislocation in a straight line in the sagittal plane to 1°; an increment of the pressure loading was found on the forefoot of both feet compared with what was recorded in the pre-test. (4) The testing results of the 3D gait system showed that she had a shortened time of unilateral support phase and prolonged swing phase on the affected leg (P < 0.05), compared to that of the non-affected leg. Furthermore, the dual support phase had also been prolonged (P < 0.05). Conclusion: 12 weeks' individualized exercise training can enhance the activation in the motor areas and improve balance function and gait in a child with VES.

Machine Learning Strategies for Low-Cost Insole-Based Prediction of Center of Gravity during Gait in Healthy Males

Whole-body center of gravity (CG) movements in relation to the center of pressure (COP) offer insights into the balance control strategies of the human body. Existing CG measurement methods using expensive measurement equipment fixed in a laboratory environment are not intended for continuous monitoring. The development of wireless sensing technology makes it possible to expand the measurement in daily life. The insole system is a wearable device that can evaluate human balance ability by measuring pressure distribution on the ground. In this study, a novel protocol (data preparation and model training) for estimating the 3-axis CG trajectory from vertical plantar pressures was proposed and its performance was evaluated. Input and target data were obtained through gait experiments conducted on 15 adult and 15 elderly males using a self-made insole prototype and optical motion capture system. One gait cycle was divided into four semantic phases. Features specified for each phase were extracted and the CG trajectory was predicted using a bi-directional long short-term memory (Bi-LSTM) network. The performance of the proposed CG prediction model was evaluated by a comparative study with four prediction models having no gait phase segmentation. The CG trajectory calculated with the optoelectronic system was used as a golden standard. The relative root mean square error of the proposed model on the 3-axis of anterior/posterior, medial/lateral, and proximal/distal showed the best prediction performance, with 2.12%, 12.97%, and 12.47%. Biomechanical analysis of two healthy male groups was conducted. A statistically significant difference between CG trajectories of the two groups was shown in the proposed model. Large CG sway of the medial/lateral axis trajectory and CG fall of the proximal/distal axis trajectory is shown in the old group. The protocol proposed in this study is a basic step to have gait analysis in daily life. It is expected to be utilized as a key element for clinical applications.

Analysis of gait synchrony and balance in neurodevelopmental disorders using computer vision techniques

Gait tasks are commonly administered during motor assessments of children with neurodevelopmental disorders (NDDs). Gait analyses are often conducted in laboratory settings using costly and cumbersome experiments. In this paper, we propose a computational pipeline using computer vision techniques as an ecological and precise method to quantify gait in children with NDDs with challenging behaviors. We analyzed videos of 15 probands (PB) and 12 typically developing (TD) siblings, engaged in a preferred-pace walking task, using pose estimation software to track points of interest on their bodies over time. Analyzing the extracted information revealed that PB children had significantly less whole-body gait synchrony and poorer balance compared to their TD siblings. Our work offers a cost-effective method while preserving the validity of its results. This remote approach increases access to more diverse and distant cohorts and thus lowers barriers to research participation, further enriching our understanding of motor outcomes in NDDs.

Analysis of center of mass and center of pressure displacement in the transverse plane during gait termination in children with cerebral palsy

BACKGROUND

While gait termination is challenging for children with spastic cerebral palsy (CCP), few studies have quantitatively assessed this issue.

RESEARCH QUESTION

What are the characteristics of center of mass (COM) and center of pressure (COP) displacement during gait termination in CCP, and how do they compare with those in children with typical development (CTD)?

METHODS

This cross-sectional study included 13 adults with typical development (19.85 ± 0.52 years), 12 CTD (10.41 ± 2.98 years), and 16 CCP (11.15 ± 2.71 years). Participants were instructed to immediately stop walking when a stop sign appeared on a screen, which was placed at the end of an 8-m walkway. COM and COP were determined via 3-dimensional motion analysis and force plate data. Differences between the groups were assessed using the two sample t-test or Wilcoxon rank sum test. The level of statistical significance was set at P < 0.05.

RESULTS

The normalized time for stopping in CCP (4.556 ± 0.602) was higher than that in CTD (3.617 ± 0.545, P < 0.001). The normalized COP displacement (P < 0.001) and divergence between COM and COP (P < 0.001) in the mediolateral (ML) direction were significantly higher in CCP than CTD. However, the normalized divergence between COM and COP in the anteroposterior (AP) direction in CCP was lower than that in CTD (P = 0.034).

SIGNIFICANCE

The more minor divergence between COM and COP in the AP direction and the more significant COP displacement in the ML direction cause difficulty to exert braking force during gait termination. Thus, CCP require a longer time for gait termination. This finding may facilitate the development of interventions for improving gait in CCP.

An Accessible Training Device for Children With Cerebral Palsy

Walking and balance capabilities can be improved upon using repetitive ankle dorsiflexion exercises. Here we developed two types of pedal switches incorporated with training devices to improve their walking and balance performance of children with cerebral palsy. The first type of pedal switch can be used to operate a home appliance, while the second type of pedal switch can connect them to web games. Pedal switches can be used for home rehabilitation. This randomized controlled trial included patients in the intervention (n = 24) and control (n = 24) groups who completed 15 weeks of ankle training. The experimental group performed ankle dorsiflexion using a pressure-activated pedal switch connected to the web games. The control group performed ankle dorsiflexion exercises using a pedal switch that operated a home appliance (a fan). Standing balance and walking performance were estimated using the Zebris FDM system, a pressure force platform, the Pediatric Balance Scale score, and the 1-minute walk test. The pre- and posttest data were analyzed using analysis of variance and analysis of covariance, which revealed that the intervention group had more significant improvements in sway patterns and balance and walking. The developed facility of a modified pedal switch integrated with web games can achieve better exercise adherence to promote balance and walking performance than that with home appliances. Maintaining motivation in children with cerebral palsy plays a very important role in the rehabilitation process.

Reliability, standard error of measurement, and minimal detectable change of the star excursion balance test in children with cerebral palsy

OBJECTIVE

The present study aimed to estimate the reliability, standard error of measurement (SEM), and minimum detectable change (MDC) of the star excursion balance test (SEBT) in children with cerebral palsy (CP).

METHODS

Eight children with CP (five boys and three girls, sixteen legs) participated in this study. Each child carried out the SEBT and was assessed by two examiners. To determine intra-rater reliability, the intra-class correlation coefficient (ICC) model (3, 3) was calculated. To determine the inter-rater reliability, the ICC model (2, 3) was computed.

RESULTS

In terms of the intra-rater reliability of the SEBT, the ICC varied from 0.98 to 0.99 and the total ICC score was 0.99 (p< 0.001). For the inter-rater reliability, the ICC varied from 0.98 to 1.00 and the total ICC score was 0.99 (p< 0.001). The SEBT had an SEM of 2.63 and an MDC of 7.31.

CONCLUSION

The SEBT is not only reliable with a small SEM, but is also a simple and cheap assessment of dynamic balance in children with CP.

Using Decision Trees to Support Classifiers' Decision-Making about Activity Limitation of Cerebral Palsy Footballers

This study aimed (1) to determine the appropriateness of using decision trees as a classification tool for determining the allocation of sport classes of para-footballers with "moderate vs. mild" cerebral palsy (CP) profiles of spastic diplegia/hemiplegia and ataxia/athetosis based on observational outcomes by international classifiers, and (2) to identify what key observational features were relevant to discriminating among different impairment levels. A sample of 16 experienced international classifiers from five world regions participated in this study, observing activity limitation of a final sample of 21 international CP footballers when performing 16 gross-motor and sports-specific tests for balance (n = 3), coordination (n = 5), running, accelerations and decelerations (n = 3), jumping (n = 4), and change of direction ability (n = 1). For the overall sample (336 observations), the model included eight decision nodes and 24 branches with 17 leaves, including side-step, side-stepping, and triple hop as the tests with the best sensitivity (precision = 67.0%). For those with spastic diplegia (64 observations: Two nodes, six branches with five leaves), the range of motion in the side-step test and the balance in the tandem walk tests correctly classified 89.1% of the observations. In those with athetosis and ataxia (96 observations), the model included five nodes, 15 branches, and 11 leaves (176 observations, precision = 86.5%). For those with spastic hemiplegia, a model containing two nodes, six branches, and five leaves had 90.9% accuracy, including observational features of balance in the side-step test and symmetry in the side-stepping test. The observational tool used in this study, based on the impact of specific impairment measurements of hypertonia, athetosis, and ataxia, can be used to determine which assessments are more appropriate for discriminating between functional profiles in para-footballers with CP.

Effectiveness of Robot-Assisted Gait Training on Functional Skills in Children with Cerebral Palsy

This study was aimed to investigate the effects of robot-assisted gait training (RAGT) on motor functions, spasticity status, balance, and functionality in children with cerebral palsy (CP). A total of 26 patients who were diagnosed with CP (diplegic, with gross motor function classification system [GMFCS] levels of 2–5) and who regularly participated in a rehabilitation program were recruited in the study after obtaining approval from their parents. The patients were randomly assigned to two groups. Group 1 (n = 13) received conventional physical therapy (65 minutes, 2 days/week × 8) and group 2 (n = 13) received 25 minutes of RAGT (RoboGait) in addition to conventional therapy (CT; 40 minutes, 2 days/week × 8). GMFCS was used to evaluate motor functions and the Modified Ashworth Scale was used to evaluate spasticity. The pediatric Berg balance scale, pediatric functional independence measure, and timed up and go tests were employed to assess balance and functional status. The evaluations were performed at baseline and after 8 weeks of therapy. Both rehabilitation methods led to a statistically significant decrease in spasticity (p < 0.05); however, there was no difference in this improvement of spasticity between the groups (p > 0.05). Both groups exhibited significant improvements in functional independence, balance, and performance at the end of therapy (p < 0.05), and there was no significant difference between the groups (p > 0.05). The results of this study show that addition of RAGT to CT for 8 weeks is not superior to CT alone in children with CP.

Dynamic and static stability in para-athletes with cerebral palsy considering their impairment profile

BACKGROUND

Balance impairment is a common feature in people with cerebral palsy (CP), affecting the performance of daily-life and physical activities.

OBJECTIVES

To (1) explore the absolute and relative intrasession reliability of two balance tests to assess dynamic and static balance in ambulant para-athletes with CP; (2) explore the relationships between the two balance tests to determine potential application in sport classification; (3) assess the differences between CP profiles (ie, spastic diplegia, athetosis/ataxia, and spastic hemiplegia) in comparison to those with a minimum impairment; and (4) compare the outcomes of the static and dynamic balance of ambulant para-athletes with CP regarding controls.

METHODS

A group of 129 male well-trained para-footballers with CP, classified as Level I according to the Gross Motor Function Classification System, participated in the present study. Static balance was assessed using the One-Leg Stance test, performed bilaterally on a force platform, and the dynamic balance was assessed in two conditions of the Tandem Walk test (TW): walking heel-toe contact over a 5 -m straight line and performing 10 steps.

RESULTS

Moderate-to-excellent intrasession reliability (intraclass correlation coefficient = 0.60-0.98) was obtained for all the measurements and groups. However, only small to moderate correlations were found between the dynamic and the static measurements of balance for the CP group when performing the One-Leg Stance test with the unimpaired or dominant leg (0.23 < r < 0.30; P < .01). The TW performed over 10 steps revealed more sensitivity to discriminate between CP profiles. Those para-athletes with ataxia/athetosis performed worse in all the tests whereas all CP profiles performed worse than the control group (P < .01).

CONCLUSIONS

Balance performance and postural control are constrained to a higher extent in those with impaired voluntary control due to ataxia or with involuntary contractions of the muscles due to athetosis.

Tai Chi practitioners have lower fall risks under dual-task conditions during stair descending

Stairs are among the most hazardous locations, and stair descending contributes to a high risk of falls among the elderly under dual-task (DT) conditions. The purpose of this study was to determine whether the practitioners of Tai Chi (TC), one type of mind-body exercise, have lower fall risks under DT conditions during stair descending, compared with their no-exercise (NE) counterparts. Fifteen TC practitioners with at least 10 years of experience in TC and fifteen NE participants were recruited in this study. They were asked to descend a six-step staircase under single-task (ST) and DT conditions. An eight-camera motion analysis system and two force plates were used for data collection. Results showed group by DT interactions in walking velocity (p = 0.016) and center of mass–center of pressure inclination angle (COM–COP IA) in the anteroposterior directions (p = 0.026). Group effects observed with foot clearance (p = 0.031), trunk (p = 0.041) and head (p = 0.002) tilt angles, and COM–COP IA in the mediolateral (p = 0.006) directions. Significant DT effects only detected in foot clearance (p = 0.004). Although both groups of participants adopted a more cautious gait strategy under the dual-task condition, the TC practitioners were less influenced by the DT paradigm than their NE counterparts. Our observations indicated that TC practitioners have lower fall risks under DT conditions during stair descending.

The gait is less stable in children with cerebral palsy in normal and dual-task gait compared to typically developed peers

There is limited evidence about gait stability and its alteration by concurrent motor and cognitive tasks in children with cerebral palsy (CP). We examined gait stability and how it is altered by constrained cognitive or motor task in CP and their typically developed (TD) controls. Gait kinematics were recorded using inertial-measurement units (IMU) from 18 patients with hemiplegia (13.5 ± 2.4 years), 12 with diplegia (13.0 ± 2.1 years), and 31 TD controls (13.5 ± 2.2 years) during unconstrained gait, and motor (carrying a tray) and cognitive (word naming) task constrained gait at preferred speed (~400 steps/task). Step duration, its standard deviation and refined-compound-multiscale entropy (RCME) were computed independently for vertical and resultant horizontal accelerations. Gait complexity was higher for patients with CP than TD in all tasks and directions (p < 0.001-0.01), being pronounced in vertical direction, cognitive task and for diplegic patients (p < 0.05-0.001). The gait complexity increased more (i.e. higher dual-task cost) from the unconstrained to the constrained gait in CP compared to TD (p < 0.05). Step duration was similar in all groups (p > 0.586), but its variation was higher in CP than TD (p < 0.001-0.05), and during the constrained than unconstrained gait in all groups (p < 0.01-0.001). The gait in children with CP was more complex and the dual-task cost was higher primarily for children with diplegic CP than TD during cognitive task, indicating that attentional load hinders their gait more. This raises the hypothesis that more attention and cortical resources are needed to compensate for the impaired gait in children with CP.

Bidirectional causal control in the dynamics of handstand balance

The aim of this study was to identify motor control solutions associated with the ability to maintain handstand balance. Using a novel approach, we investigated the dynamical interactions between centre of pressure (CoP) and centre of mass (CoM) motion. A gymnastics cohort was divided into a ‘less skilled’ group, who held handstands for 4–6 s, and a ‘more skilled’ group, who held handstands in excess of 10 s. CoP–CoM causality was investigated in anterior–posterior (AP) and medio-lateral (ML) directions, in addition to time–space, time–frequency and Hurst Exponent (H) analyses. Lower AP CoP to CoM causal drive and lower H values (> 0.6) indicated the more skilled gymnasts were less reliant on CoP mechanics to drive CoM motion. More skilled performance demonstrated greater adaptability through use of reactive, as opposed to anticipatory, control strategies. Skilled performers additionally exploited mechanical advantages in ML (e.g. a wider base of support), compared to the less skilled athletes. A multiple regression analysis revealed H and frequency domain measures to be better predictors of handstand balance duration than time–space domain measures. The study findings highlight the advantage of an adaptable motor control system with a directional profile, and provide new insight into the clear, measurable footprint of CoP on the dynamics of CoM.

Continuous inter-limb coordination deficits in children with unilateral spastic cerebral palsy

BACKGROUND

Continuous inter-limb coordination and the ability to offset perturbations to a movement pattern (i.e., stability) are important factors in efficient motor performance. Patients with movement disorders often show deficits in coordination and stability, although little is known about these features in children with cerebral palsy. The purpose of this study was to identify the continuous inter-limb coordination and stability deficits in children with cerebral palsy and determine if improvement occurs with upper extremity intervention.

METHODS

Children with cerebral palsy participated in bimanual or unimanual intensive therapy. Continuous inter-limb coordination between the arms and between the more-affected arm and leg was evaluated using relative phase analysis during four gross motor tasks, including in-place marching and standing with asymmetric and symmetric arm swing. A control group of children with cerebral palsy and a group of typically developing children were also evaluated.

FINDINGS

Children with cerebral palsy displayed coordination deficits compared to typically developing children (p<0.01), yet both groups presented similarly poor levels of stability (p=0.39). Compared to standing, adding legs to the task negatively impacted the coordination (p<0.01) and stability (p<0.01) of all children. Both groups improved coordination between the arms post-intervention (p<0.05 for all cases), however neither group improved stability (p>0.05 for all cases).

INTERPRETATION

Relative phase analysis successfully provided a sensitive measurement of coordination and stability in pathologic and non-pathologic populations. Findings indicate that all children have difficulty producing consistent movement patterns and suggest that both bimanual and unimanual interventions can improve continuous coordination in children with cerebral palsy.

Impact of dual task on postural sway during sit-to-stand movement in children with unilateral cerebral palsy

BACKGROUND

To verify the effect of dual-task on postural oscillation during sit-to-stand movement in children with Cerebral Palsy.

METHODS

17 children with spastic unilateral cerebral palsy and 20 typically-developing children, aged 5 to 12 years, performed the following tasks: Simple task: sit-to-stand with arms crossed against the chest; bimanual dual-task: sit-to-stand while carrying a tray; unimanual dual-task: sit-to-stand while holding a plastic cup with one hand. For data analysis, sit-to-stand was divided in three phases: preparation (phase 1), rising (phase 2), and stabilization (phase 3). Postural control was measured using a force plate, and the variables analyzed were: area, anterior-posterior and medial-lateral velocity, and STS duration. Analysis of variance was applied to test the effects of group; task conditions and interactions.

FINDINGS

Children with cerebral palsy presented higher values of postural oscillation when compared to their typical pairs. Bimanual and Unimanual dual tasks presented greater postural oscillation values in sit-to-stand phase 1 compared to simple task. In bimanual dual-task, children with cerebral palsy presented lower values of velocity in phases 3, and greater postural oscillation and duration of the task when compared to single-task and unimanual dual-tasks. I.

INTERPRETATION

The insertion of a secondary task seems to interfere differently children with cerebral palsy, depending on the specific demands of each task. Thus, the importance of inserting dual tasks in the interventions is emphasized, considering that they are executed extensively in the day to day, and can act as facilitators or challenge in the execution of functional tasks.

Balance Tests in Pre-Adolescent Children: Retest Reliability, Construct Validity, and Relative Ability

Balance is an essential prerequisite for the normal physical development of a child. It consists of the ability to maintain the body’s centre of mass over its base of support, which is enabled by automatic postural adjustments, and maintain posture and stability in various conditions and activities. The present study aimed to determine the measurement characteristics (reliability and concurrent validity) and the relative ability of balance tests and different motor tests in healthy 11-year-olds. We also evaluated the impact of vision on balance ability. Our results showed high interrater reliability (from 0.810 to 0.910) and confirmed the construct validity of the included balance tests. Girls performed significantly better than boys in laboratory tandem stance in following balance components: total sway path with eyes open (BSEO) (t = 2.68, p = 0.01, effect size (ES) = 0.81), total body sway with eyes closed of centre of pressure (CoP) displacement in the a-p direction (BSEC) (t = 1.86, p = 0.07, ES = 0.57), mean velocity of CoP displacements (VEO) (t = 2.67, p = 0.01, ES = 0.83), mean amplitude of CoP displacements in the a-p direction (AapEO) (t = 3.38. p = 0.00, ES = 1.01) and in mean amplitude of CoP displacements in the m-l direction (AmlEO) (t = 3.68, p = 0.00, ES = 1.19). With eyes closed, girls performed significantly better (t = 2.28, p = 0.03, ES = 0.70) than boys did in the mean amplitude of COP displacements in the a-p direction (AapEO) and significantly better (t = 2.37, p = 0.03, ES = 0.71) in the mean amplitude of COP displacements in the m-l direction (AmlEC). Insignificant correlations between different balance tests, except for a correlation between the flamingo test and one-leg stance on a low beam (r = 0.558, p < 0.01), show that each test assesses different aspects of balance ability; therefore, balance cannot be assessed with a single test.

Walking on uneven ground: How do patients with unilateral cerebral palsy adapt?

BACKGROUND

Children with cerebral palsy experience movement disorders that influence gait stability. It is likely that gait stability further decreases when walking on uneven compared to even ground. Therefore, the aim of this study was to investigate gait on uneven ground in children with unilateral cerebral palsy.

METHODS

Twenty children with unilateral cerebral palsy and twenty typically developing children performed a three-dimensional gait analysis when walking on even and uneven ground. Spatio-temporal parameters, full-body joint kinematics and centre of mass displacements were compared.

FINDINGS

On uneven versus even ground, both groups showed decreased cadence, increased stance phase and double support time, increased toe clearance height, and increased knee and hip flexion during swing phase. Whereas only the typically developing children walked slower and had increased dorsiflexion and external foot progression during stance phase, only the patients showed increased stride width, increased elbow flexion (affected and non-affected side), and kept the centre of mass more medial when standing on the affected leg.

INTERPRETATION

Patients and healthy children use similar adaptation mechanisms when walking on uneven ground. Both groups increased the toe clearance height by increasing knee and hip flexion during swing. However, whereas patients enlarge their base of support by increasing stride width, healthy children do so by increasing their external foot progression angle. Furthermore, patients seem to feel more insecure and hold their arms in a position to prepare for falls on uneven ground. They also do not compensate with their non-affected side for their affected side on uneven ground.

Effects of a Dual-Task Paradigm and Gait Velocity on Dynamic Gait Stability during Stair Descent

Falls during stair negotiation have become one of the leading causes of accidental death. The effects of a concurrent cognitive or manual dual-task paradigm on dynamic gait stability remain uncertain. How much dynamic gait stability is influenced by gait velocity is also not clear. A total of 16 healthy young females descended a staircase under three different walking conditions: descend stairs only (single task), descend stairs while performing subtraction (cognitive dual-task), and descend stairs while carrying a glass of water (manual dual-task). An eight-camera Vicon motion analysis system and a Kistler force plate embedded into the third step of the staircase were used synchronously to collect kinematic and kinetic data. Gait velocity decreased and dynamic gait stability increased with both cognitive and manual dual-task conditions. The center of mass–center of pressure inclination angle increased with gait velocity but decreased with the manual dual-task condition compared to the single-task condition. Changes in gait velocity caused by the dual-task paradigm can partially explain the effects of dual-task dynamic gait stability. The influence of gait velocity should be considered in the assessment of dual-task effects.

Does repetitive Transcranial Magnetic Stimulation (rTMS) have therapeutic effects on Dynamic Balance of Children with Cerebral Palsy?. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020;2019:425-428. [PMID: 31945929 DOI: 10.1109/embc.2019.8857947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Our big goal in this research was to evaluate the therapeutic effects of repetitive Transcranial Magnetic Stimulation (rTMS) on cerebral palsy (CP) children with balance deficits. Four spastic hemiplegic CP children were participated; the experimental group received rTMS training 4 days a week for 3 weeks and then for the next 3 weeks they received typical occupational therapy just after rTMS therapy. The control group received placebo rTMS instead of real one accordingly. Their dynamic balance was evaluated before the start of the treatment and 6 weeks after it. Center of pressure (COP) and center of mass (COM) features were regarded as dynamic balance parameters. Our results showed that the peak to peak of COP, COM, COM-COP, COM-COP inclination angles all improved for both experimental (15-86%) and control group patients, though there was less improvement about 8-46% in features of the control patients. Our results demonstrate that intensive sessions of the rTMS training could have the potential to enhance the therapeutic effects of typical occupational therapy that can produce dynamic balance improvements in CP children compared to using the occupational therapy by itself.

The Effects of Anti-gravity Treadmill Training on Gait Characteristics in Children with Cerebral Palsy

Cerebral palsy is a disorder that affects muscle tone, movement and motor skills. Most of the children with cerebral palsy (CP) are not able to walk or can walk in incorrect pattern and are dependent on assistive devices. Recently an antigravity treadmill has been found to be beneficial as a new therapeutic approach. Thus, we aimed to investigate the effects of antigravity treadmill training (AlterG) on gait characteristic in children with cerebral palsy. We provided a 45-minute training program, 3 times a week for 8 weeks for six CP children as our experimental group. Our control group was a group consisted of four CP children who took typical occupational therapy, accordingly. All subjects in both AlterG and control groups were evaluated at the gait lab before and after 8 weeks training. Gait patterns were characterized using spatiotemporal parameters and dynamic balance features. We also evaluated the popular clinical gait measures including walking speed and endurance, and mobility and balance.Our results demonstrated that spatiotemporal, dynamic balance and clinical features all improved more after 8 weeks AlterG training rather than control group ones. These findings suggest that AlterG training can be considered as an effective approach for improving walking ability and gait characteristics in children with cerebral palsy.

Gait deficits and dynamic stability in children and adolescents with cerebral palsy: A systematic review and meta-analysis

BACKGROUND

Studies have demonstrated that ambulatory children and adolescents with cerebral palsy demonstrate atypical gait patterns. Out of numerous gait variables, identification of the most deteriorated gait parameters is important for targeted and effective gait rehabilitation. Therefore, this study aimed to identify the gait parameters with the most discriminating nature to distinguish cerebral palsy gait from normal gait.

METHODS

Multiple databases were searched to include studies on ambulatory children and adolescents with cerebral palsy that included gait (spatio-temporal, kinematic, and kinetic) and dynamic stability variables.

FINDINGS

Of 68 studies that met the inclusion criteria, 35 studies were included in the meta analysis. Effect size was used to assess the discriminative strength of each variable. A large effect (≥ 0.8) of cerebral palsy on double limb support time (Standardized Mean Difference = 0.98), step length (Standardized Mean Difference = 1.65), step width (Standardized Mean Difference = 1.21), stride length (Standardized Mean Difference = 1.75), and velocity (Standardized Mean Difference = 1.42) was observed at preferred-walking speed. At fast-walking speed, some gait variables (i.e. velocity and stride length) exhibited larger effect size compared to preferred-walking speed. For some kinematic variables (e.g. range of motion of pelvis), the effect size varied across the body planes.

INTERPRETATION

Our systematic review detects the most discriminative features of cerebral palsy gait. Non-uniform effects on joint kinematics across the anatomical planes support the importance of 3D gait analysis. Differential effects at fast versus preferred speeds emphasize the importance of measuring gait at a range of speeds.

Longitudinal Change in Common Impairments in Children With Cerebral Palsy From Age 1.5 to 11 Years

PURPOSE

This project aimed to determine whether change occurs over time for impairments of balance, range of motion, endurance, and strength of children with cerebral palsy, by Gross Motor Function Classification System (GMFCS) levels.

METHODS

Measurements were completed in 77 children at 2 sessions (T1, T2) on average 5.8 years apart. Mean ages were 2.9 years (SD = 0.9) and 8.7 years (SD = 1.1) at T1 and T2, respectively.

RESULTS

There were significant differences from T1 to T2 for some children (GMFCS levels I, II, and III/IV: balance increased; GMFCS levels I and II: strength increased; and GMFCS levels III/IV and V: range of motion decreased). Endurance scores were not different and did not change.

CONCLUSIONS

Longitudinal changes in most impairments occurred in children with cerebral palsy. Monitoring and targeted interventions should support each child's development.

Kinematic Analysis of Postural Stability During Ballet Turns (pirouettes) in Experienced and Novice Dancers

Turning is an important but difficult movement, often performed in ballet choreography. Understanding the postural sway during ballet turns is beneficial to both dancers and dance teachers alike. Accordingly, this study evaluated the postural sway angle during ballet turns in female novice and experienced ballet dancers by means of the inclination angle, determined from the center of mass (COM) and center of pressure (COP). Thirteen experienced dancers and 13 novice dancers performed ballet turns (pirouettes). The COM-COP inclination angle was measured during the preparatory, double-leg support, and single-leg support phases of the turn. The novice dancers exhibited significantly greater ranges of the COM-COP inclination angle in the anterior-posterior (AP) and medial-lateral (ML) directions during the preparatory (AP direction, p < 0.001; ML direction p = 0.035), double-leg support (AP direction p < 0.038; ML direction p = 0.011), and ending phases (AP direction p < 0.001; ML direction p = 0.024). Moreover, during the preparatory phase, the novice dancers failed to adjust their posture in a timely manner, and therefore showed overshooting errors. Finally, during the ending phase, the novice dancers showed a greater standard deviation of the COM-COP inclination angles and performed continual postural adjustments, leading to a less smooth movement than the experienced dancers. In conclusion, the novice dancers were suggested to focus on the COM-COP adjustment during both preparatory and ending phases.

Machine learning approach to predict center of pressure trajectories in a complete gait cycle: a feedforward neural network vs. LSTM network

Center of pressure (COP) trajectories of human can maintain regulation of forward progression and stability of lateral sway during walking. The insole pressure system can only detect COP trajectories of each foot during single stance. In this study, we developed artificial neural network models that could present COP trajectories in an integrated coordinate system during a complete gait cycle using pressure information of the insole system. A feed forward artificial neural network (FFANN) and a long short-term memory (LSTM) model were developed. For FFANN, among 198 pressure sensors from Pedar-X insoles, proper input variables were selected using sequential forward selection to reduce input dimension. The LSTM model used all 198 signals as inputs because of its self-learning characteristic. As results of cross-validation, the FFANN model showed correlation coefficients of 0.98-0.99 and 0.93-0.95 in anterior/posterior and medial/lateral directions, respectively. For the LSTM model, correlation coefficients were similar to those of FFANN. However, the relative root mean square error (12.5%) of the FFANN model was higher than that (9.8%) of the LSTM model in medial/lateral direction (p = 0.03). This study can be used for quantitative evaluation of clinical diagnosis and rehabilitation status for patient with various diseases through further training using varied databases. Graphical abstract Architectures of neural networks developed in this study (a feed forward artificial neural network; b LSTM network).

Preliminary Study of the Effect of Training With a Gaming Balance Board on Balance Control in Children With Cerebral Palsy: A Randomized Controlled Trial

OBJECTIVE

A new protocol based on the use of a gaming balance board for children with cerebral palsy was tested.

DESIGN

A total of 56 children with cerebral palsy were enrolled and randomly divided into two groups: experimental and control. The children in experimental group underwent 12 wks of rehabilitation using their foot to play personal computer games with the proposed balance board, whereas those in the control group played personal computer games with a computer mouse in the standing position. Balance control was assessed before and after the intervention using the Zebris FDM System for measuring the center of pressure. The Pediatric Balance Scale and 2-min walk test were used for evaluating functional balance.

RESULTS

In the analysis of covariance, the proposed new balance board used for the personal computer games decreased the postural sway (sway path, F = 6.95, P = 0.011; sway area, F = 11.79, P = 0.001) and improved the performance of the functional balance tests.

CONCLUSIONS

This study demonstrated the possibility that this new gaming balance board can be used for balance control in children with cerebral palsy.

Gait Characteristics of Children with Spastic Cerebral Palsy during Inclined Treadmill Walking under a Virtual Reality Environment

OBJECTIVE

To investigate gait characteristics in children with spastic cerebral palsy during inclined treadmill walking under a virtual reality environment.

METHODS

Ten spastic cerebral palsy (CP) children and ten typically developing (TD) children were asked to walk at their comfortable speed on a treadmill at a ground level and 10° inclined. Three-dimensional kinematic data and ground reaction force data were captured in a computer-assisted rehabilitation environment system. Kinetic parameters and dynamic balance parameters were calculated using a standard biomechanical approach.

RESULTS

During uphill walking, both groups decreased walking speed and stride length and increased peak pelvis tilt, ankle dorsiflexion, and hip flexion. Compared with TD children, CP children had decreased walking speed and stride length, decreased peak hip abduction moment, increased stance phase percentage, increased peak ankle dorsiflexion and knee flexion, and increased peak hip extension moment. The peak trunk rotation angle, ankle angle at initial contact, and stride length showed a significant group∗walking condition interaction effect.

CONCLUSIONS

CP children showed similar adjustments for most gait parameters during uphill walking as TD children. With a lower walking speed, CP children could maintain similar dynamic balance as TD children. Uphill walking magnifies the existing abnormal gait patterns of the cerebral palsy children. We suggest that during a treadmill training with an inclination, the walking speed should be carefully controlled in the case of improving peak joint loading too much.

Single Inertial Sensor-Based Neural Networks to Estimate COM-COP Inclination Angle During Walking

A biomechanical understanding of gait stability is needed to reduce falling risk. As a typical parameter, the COM-COP (center of mass-center of pressure) inclination angle (IA) could provide valuable insight into postural control and balance recovery ability. In this study, an artificial neural network (ANN) model was developed to estimate COM-COP IA based on signals using an inertial sensor. Also, we evaluated how different types of ANN and the cutoff frequency of the low-pass filter applied to input signals could affect the accuracy of the model. An inertial measurement unit (IMU) including an accelerometer, gyroscope, and magnetometer sensors was fabricated as a prototype. The COM-COP IA was calculated using a 3D motion analysis system including force plates. In order to predict the COM-COP IA, a feed-forward ANN and long-short term memory (LSTM) network was developed. As a result, the feed-forward ANN showed a relative root-mean-square error (rRMSE) of 15% while the LSTM showed an improved accuracy of 9% rRMSE. Additionally, the LSTM displayed a stable accuracy regardless of the cutoff frequency of the filter applied to the input signals. This study showed that estimating the COM-COP IA was possible with a cheap inertial sensor system. Furthermore, the neural network models in this study can be implemented in systems to monitor the balancing ability of the elderly or patients with impaired balancing ability.

Dynamic stability during walking in children with and without cerebral palsy

BACKGROUND

Cerebral palsy (CP) is associated with a high risk of falling during walking. Many gait abnormalities associated with CP likely alter foot placement and center of mass (CoM) movement in a way that affects anterior or lateral dynamic stability, in turn influencing fall risk.

RESEARCH QUESTION

Do children with CP demonstrate altered anterior or lateral dynamic stability compared to typically-developing (TD) children?

METHODS

In this case-control, observational study, we measured gait kinematics of two groups of children (15 CP, 11 GMFCS level I, 4 GMFCS level II; 14 TD; age 5-12) in walking conditions of a preferred speed, a fast speed, and a preferred speed while completing a cognitive task. For dominant and non-dominant limbs, the margin of stability (MoS), a spatial measure of dynamic stability, was calculated as the distance between the edge of the base of support and the CoM position after accounting for scaled velocity. Statistical comparisons of were made using mixed factorial ANOVAs. Post hoc comparisons were Sidak adjusted.

RESULTS

The anterior MoS before foot strike and at mid-swing differed between each condition but not between groups. Based on the minimum lateral MoS, children with CP had more stability when bearing weight on their non-dominant limb compared to TD children. These differences were not apparent when on the dominant limb.

SIGNIFICANCE

This high-functioning group of children with CP exhibited a more conservative lateral stability strategy during walking when bearing weight with the non-dominant limb. This strategy may be protective against lateral falls. We observed no between-group differences in anterior stability. Because CP has been previously associated with impaired anterior balance reactions, and there was no observed compensation in anterior gait stability, this lack of group differences could contribute to a higher risk of falling in that direction.

Effects of transcranial direct current stimulation (tDCS) on balance improvement: a systematic review and meta-analysis

Background: Transcranial direct current stimulation (tDCS) has emerged as a promising therapeutic tool to improve balance and optimize rehabilitation strategies. However, current literature shows the methodological heterogeneity of tDCS protocols and results, hindering any clear conclusions about the effects of tDCS on postural control. Objective: Evaluate the effectiveness of tDCS on postural control, and identify the most beneficial target brain areas and the effect on different populations. Methods: Two independent reviewers selected randomized tDCS clinical-trials studies from PubMed, Scopus, Web of Science, and reference lists of retrieved articles published between 1998 and 2017. Most frequently reported centre of pressure (COP) variables were selected for meta-analysis. Other postural control outcomes were discussed in the review. Results: Thirty studies were included in the systematic review, and 11 were submitted to a meta-analysis. A reduction of COP displacement area has been significantly achieved by tDCS, evidencing an improvement in balance control. Individuals with cerebral palsy (CP) and healthy young adults are mostly affected by stimulation. The analysis of the impact of tDCS over different brain areas revealed a significant effect after primary motor cortex (M1) stimulation, however, with no clear results after cerebellar stimulation due to divergent results among studies. Conclusions: tDCS appears to improve balance control, more evident in healthy and CP subjects. Effects are observed when primary MI is stimulated. Cerebellar stimulation should be better investigated.

Developmental Trajectories for the Early Clinical Assessment of Balance by Gross Motor Function Classification System Level for Children With Cerebral Palsy

BACKGROUND

Children with cerebral palsy (CP) characteristically present with impairments in balance. Currently, the pattern and timing of the development of balance ability have not been described for children with CP of varying Gross Motor Function Classification System (GMFCS) levels.

OBJECTIVE

The purpose of this study was to document longitudinal developmental trajectories in a measure of balance, the Early Clinical Assessment of Balance (ECAB) scores, along with age-specific reference percentiles and the amount of change typical over a 1-year period for children within different GMFCS levels.

DESIGN

The design was a longitudinal cohort study.

METHODS

Participants included 708 children with CP, aged 18 months through their 12th birthday, and their families. Children participated in 2 to 5 assessments using the GMFCS and ECAB.

RESULTS

Longitudinal trajectories describing the average change in the ECAB score with respect to age were created by fitting separate nonlinear mixed-effect models for children in each GMFCS level. Reference percentiles were constructed using quantile regression of ECAB data from the first visit (baseline) and 12-month and 24-month visits. Using these reference points, the amount of change in percentiles was calculated for all children by subtracting the baseline percentile score from the 12-month percentile score. Children whose percentile changes are within the 80% limits can usually be described as "developing as expected" for their age and GMFCS levels.

LIMITATIONS

Limitations of this study included use of a convenience sample, a ceiling effect of the ECAB for some children in GMFCS levels I and II, and the use of both a 12-month and 24-month study protocol that impacted the number of children available for each assessment session.

CONCLUSIONS

When used appropriately to monitor development and change over time for children with CP, the ECAB longitudinal trajectories, reference percentiles, and the associated change scores presented here should assist therapists and families in collaborative interaction to proactively plan services and interventions relative to balance ability.

The Effects of Lower Body Positive Pressure Treadmill Training on Dynamic Balance of Children with Cerebral Palsy

We aimed to characterize the therapeutic effects of Anti-gravity (AlterG) body weight supported treadmill training on the impaired balance of children with cerebral palsy (CP). Four spastic CP children participated; two received AlterG training 3 times a week for 8 weeks and the other two received typical occupational therapy accordingly. Their dynamic balance was evaluated before the start of the treatment and 2 months after it. Features related to the center of pressure (COP) and the center of mass (COM) were considered as dynamic balance parameters. Our results showed that the maximum velocity and acceleration of the COP and COM, the average variability (RMS) and peak to peak of the COM-COP separation, and RMS of velocity and acceleration of the COM and COP were all improved for both AlterG training patients (15-90%), though there was a limited improvement of 0.2-24% in some features of the control patients. Our results demonstrate that intensive sessions of the AlterG training program could have the potential to be used as a therapeutic tool that can produce dynamic balance improvements in CP children compared to that of typical occupational therapy.

Leg Length Discrepancy: Dynamic Balance Response during Gait

Balance in the human body's movement is generally associated with different synergistic pathologies. The trunk is supported by one's leg most of the time when walking. A person with poor balance may face limitation when performing their physical activities on a daily basis, and they may be more prone to having risk of fall. The ground reaction forces (GRFs), centre of pressure (COP), and centre of mass (COM) in quite standing posture were often measured for the evaluation of balance. Currently, there is still no experimental evidence or study on leg length discrepancy (LLD) during walking. Analysis of the stability parameters is more representative of the functional activity undergone by the person who has a LLD. Therefore, this study hopes to shed new light on the effects of LLD on the dynamic stability associated with VGRF, COP, and COM during walking. Eighteen healthy subjects were selected among the university population with normal BMIs. Each subject was asked to walk with 1.0 to 2.0 ms^-1 of walking speed for three to five trials each. Insoles of 0.5 cm thickness were added, and the thickness of the insoles was subsequently raised until 4 cm and placed under the right foot as we simulated LLD. The captured data obtained from a force plate and motion analysis present Peak VGRF (single-leg stance) and WD (double-leg stance) that showed more forces exerted on the short leg rather than long leg. Obviously, changes occurred on the displacement of COM trajectories in the ML and vertical directions as LLD increased at the whole gait cycle. Displacement of COP trajectories demonstrated that more distribution was on the short leg rather than on the long leg. The root mean square (RMS) of COP-COM distance showed, obviously, changes only in ML direction with the value at 3 cm and 3.5 cm. The cutoff value via receiver operating characteristic (ROC) indicates the significant differences starting at the level 2.5 cm up to 4 cm in long and short legs for both AP and ML directions. The present study performed included all the proposed parameters on the effect of dynamic stability on LLD during walking and thus helps to determine and evaluate the balance pattern.

A comparison of running kinetics in children with and without genu varus: A cross sectional study

INTRODUCTION

Varus knee alignment has been identified as a risk factor for the progression of medial knee osteoarthritis. However, the underlying mechanisms have not been elucidated yet in children. Thus, the aims of the present study were to examine differences in ground reaction forces, loading rate, impulses, and free moment values during running in children with and without genu varus.

METHODS

Thirty-six boys aged 9-14 volunteered to participate in this study. They were divided in two age-matched groups (genu varus versus healthy controls). Body weight adjusted three dimensional kinetic data (Fx, Fy, Fz) were collected during running at preferred speed using two Kistler force plates for the dominant and non-dominant limb.

RESULTS

Individuals with knee genu varus produced significantly higher (p = .01; d = 1.09; 95%) body weight adjusted ground reaction forces in the lateral direction (Fx) of the dominant limb compared to controls. On the non-dominant limb, genu varus patients showed significantly higher body weight adjusted ground reaction forces values in the lateral (p = .01; d = 1.08; 86%) and medial (p < .001; d = 1.55; 102%) directions (Fx). Further, genu varus patients demonstrated 55% and 36% greater body weight adjusted loading rates in the dominant (p < .001; d = 2.09) and non-dominant (p < .001; d = 1.02) leg, respectively. No significant between-group differences were observed for adjusted free moment values (p>.05).

DISCUSSION

Higher mediolateral ground reaction forces and vertical loading rate amplitudes in boys with genu varus during running at preferred running speed may accelerate the development of progressive joint degeneration in terms of the age at knee osteoarthritis onset. Therefore, practitioners and therapists are advised to conduct balance and strength training programs to improve lower limb alignment and mediolateral control during dynamic movements.

Spastic diparetic does not directly affect the capacity to ascend and descend access ramps: three-dimensional analysis

Abstract Introduction: Diplegic children have difficulties in gait and therefore ramps are used as strategies of accessibility. Objective: The present study investigated the influence of an inclined surface (ascending and descending) on the kinematic characteristics during gait of the diplegic group (DG) when compared to typically developing children of the control group (CG). Methods: Study participants included 20 children (10 with DG and 10 CG) matched by age, which were evaluated in three experimental conditions (horizontal and inclined ascending and inclined descending surfaces of 7º) through an optoelectronic imaging system. Results: Among the linear kinematic variables, only step width differed among groups, however, without influence of the surface. The foot height differed among the groups only in the descending phase, where DG had greater difficulty in raising the foot. The 3-dimensional gait analyses could not provide more evidences of differences in kinematics variables, especially in transverse plane, between DG and CG, but provide some evidence to support that hip range of motion (ROM) during the gait cycle, hip flexion-extension in initial contact, knee ROM and the 2nd anterior-posterior trunk peak amplitude of the DG were influenced on descent by their flexor pattern. Conclusion: The DG was most affected by the inclination plane than CG especially on descent. Although a hip and knee flexor pattern is evident for DG on inclination of 7º, this angle is accessible since it allows independent gait functional activity.

Wearable Devices for Classification of Inadequate Posture at Work Using Neural Networks

Inadequate postures adopted by an operator at work are among the most important risk factors in Work-related Musculoskeletal Disorders (WMSDs). Although several studies have focused on inadequate posture, there is limited information on its identification in a work context. The aim of this study is to automatically differentiate between adequate and inadequate postures using two wearable devices (helmet and instrumented insole) with an inertial measurement unit (IMU) and force sensors. From the force sensors located inside the insole, the center of pressure (COP) is computed since it is considered an important parameter in the analysis of posture. In a first step, a set of 60 features is computed with a direct approach, and later reduced to eight via a hybrid feature selection. A neural network is then employed to classify the current posture of a worker, yielding a recognition rate of 90%. In a second step, an innovative graphic approach is proposed to extract three additional features for the classification. This approach represents the main contribution of this study. Combining both approaches improves the recognition rate to 95%. Our results suggest that neural network could be applied successfully for the classification of adequate and inadequate posture.

On the Adaptation of Pelvic Motion by Applying 3-dimensional Guidance Forces Using TPAD

Pelvic movement is important to human locomotion as the center of mass is located near the center of pelvis. Lateral pelvic motion plays a crucial role to shift the center of mass on the stance leg, while swinging the other leg and keeping the body balanced. In addition, vertical pelvic movement helps to reduce metabolic energy expenditure by exchanging potential and kinetic energy during the gait cycle. However, patient groups with cerebral palsy or stroke have excessive pelvic motion that leads to high energy expenditure. In addition, they have higher chances of falls as the center ofmass could deviate outside the base of support. In this paper, a novel control method is suggested using tethered pelvic assist device (TPAD) to teach subjects to walk with a specified target pelvic trajectory while walking on a treadmill. In this method, a force field is applied to the pelvis to guide it to move on a target trajectory and correctional forces are applied, if the pelvis motion has excessive deviations from the target trajectory. Three different experimentswith healthy subjects were conducted to teach them to walk on a new target pelvic trajectory with the presented control method. For all three experiments, the baseline trajectory of the pelvis was experimentally determined for each participating subject. To design a target pelvic trajectory which is different from the baseline, Experiment I scaled up the lateral component of the baseline pelvic trajectory, while Experiment II scaled down the lateral component of the baseline trajectory. For both Experiments I and II, the controller generated a 2-D force field in the transverse plane to provide the guidance force. In this paper, seven subjects were recruited for each experiment who walked on the treadmill with suggested control methods and visual feedback of their pelvic trajectory. The results show that the subjects were able to learn the target pelvic trajectory in each experiment and also retained the training effects after the completion of the experiment. In Experiment III, both lateral and vertical components of the pelvic trajectory were scaled down from the baseline trajectory. The force field was extended to three dimensions in order to correct the vertical pelvic movement as well. Three subgroups (force feedback alone, visual feedback alone, and both force and visual feedback) were recruited to understand the effects of force feedback and visual feedback alone to distinguish the results from Experiments I and II. The results showthat a trainingmethod that combines visual and force feedback is superior to the training methods with visual or force feedback alone. We believe that the present control strategy holds potential in training and correcting abnormal pelvic movements in different patient populations.

Limb dominance, foot orientation and functional asymmetry during walking gait

While healthy gait is often characterized as, or assumed to be symmetric, consistent asymmetries often exist. In this study, we test the hypotheses that asymmetries in lower limb function, as measured by ground reaction force characteristics, may be explained by differences in foot orientation or limb dominance. Peak ground reaction force (GRF) measurements, and impulses were obtained for thirty-six healthy subjects with simultaneous kinematic estimates of foot posture. Three gait tasks were performed: subjects walked i) with normal foot orientation, ii) with feet laterally rotated (outward), and iii) with feet aligned in the direction of movement (straight). All subjects reported right limb dominance. Our results indicate that vertical, braking and propulsive GRF components are largely symmetrical, but significant asymmetries exist in the mediolateral peak forces and impulses with higher lateral and lower medially-directed GRF components being generated by the dominant right limbs. While foot orientations used during the different tasks do explain some differences in mediolateral peak forces and impulses, foot orientation did not explain this variation within normal walking. We conclude that limb dominance is a better predictor of asymmetry in force generation than foot posture.