Trunk and hip muscle activity in early walkers with and without cerebral palsy--a frequency analysis

Motor adaptation to continuous lateral trunk support force during walking improves trunk postural control and walking in children with cerebral palsy: A pilot study

PURPOSE

To determine whether the application of continuous lateral trunk support forces during walking would improve trunk postural control and improve gait performance in children with CP.

MATERIALS AND METHODS

Nineteen children with spastic CP participated in this study (8 boys; mean age 10.6 ± 3.4 years old). Fourteen of them were tested in the following sessions: 1) walking on a treadmill without force for 1-min (baseline), 2) with lateral trunk support force for 7-min (adaptation), and 3) without force for 1-min (post-adaptation). Overground walking pre/post treadmill walking. Five of them were tested using a similar protocol but without trunk support force (i.e., control).

RESULTS

Participants from the experimental group showed enhancement in gait phase dependent muscle activation of rectus abdominis in late adaptation period compared to baseline (P = 0.005), which was retained during the post-adaptation period (P = 0.036), reduced variability of the peak trunk oblique angle during the late post-adaptation period (P = 0.023), and increased overground walking speed after treadmill walking (P = 0.032). Participants from the control group showed modest changes in kinematics and EMG during treadmill and overground walking performance. These results suggest that applying continuous lateral trunk support during walking is likely to induce learning of improved trunk postural control in children with CP, which may partially transfer to overground walking, although we do not have a firm conclusion due to the small sample size in the control group.

Impaired Neuromotor Control During Gait in Concussed Adolescents-A Frequency Analysis

Disruptions in gait function are common after concussion in adolescents; however, the neuromotor control deficits driving these gait disruptions are not well known. Fifteen concussed (age mean [SD]): 17.4 [0.6], 13 females, days since injury: 26.3 [9.9]) and 17 uninjured (age: 18.0 [0.7], 10 females) adolescents completed 3 trials each of single-task gait and dual-task gait (DT). During DT, participants simultaneously walked while completing a serial subtraction task. Gait metrics and variability in instantaneous mean frequency in lower extremity muscles were captured by inertial sensors and surface electromyography, respectively. A 2-way analysis of covariance was used to compare gait metrics across groups and conditions. Functional principal components analysis was used to identify regions of variability in instantaneous mean frequency curves. Functional principal component scores were compared across groups using a Welch statistic. Both groups displayed worse performance on gait metrics during DT condition compared to single-task, with no differences between groups (P < .001). Concussed adolescents displayed significantly greater instantaneous mean frequency, indicated by functional principal component 1, in the tibialis anterior, biceps femoris, and semitendinosus (P < .05) during single-task and DT compared with uninjured adolescents. Our observations suggest that concussed adolescents display inefficient motor unit recruitment lasting longer than 2 weeks following injury, regardless of the addition of a secondary task.

Effects of structured training on spinal posture and selective motor control in children with unilateral spastic cerebral palsy

BACKGROUND

Children with Unilateral Spastic Cerebral Palsy (USCP) have an asymmetrical postural pattern. Although functional limitations are less, deteriorations in spinal posture are observed.

RESEARCH QUESTION

What is the effect of structured training on spinal posture and selective motor control of upper extremity?

METHODS

Forty five children with USCP were included in the study. Participants were children ages 3-18 with GMFCS levels 1 and 2. Spinal posture and mobility was assessed by Spinal Mouse (SM) and the Spinal Alignment and Range of Motion Measure (SAROMM), and selective motor control of upper extremity was evaluated by the Selective Control of the Upper Extremity Scale (SCUES). Children were divided into two groups: structured training group (STG) (n = 22) and conventional physiotherapy group (CPG) (n = 23). Groups received treatment sessions lasting 45 min, 2 days a week for 8 weeks. Evaluations were made baseline and after treatment.

RESULTS

In sagittal plane, there was a significant decrease in the degree of thoracic kyphosis after treatment in the STG (p = 0.004). A significant difference was found in total spine angulation (p = 0.015) and mobility from flexion to extension in the STG group. There was a difference in total spine angulation (p = 0.014) in the CPG group, but no difference in spinal mobility. Post-training differences were found in thoracic angulation (p = 0.006) and lateral flexion mobility to the affected side in the STG in thoracic (p = 0.020), lumbar (p = 0.035) and total spine (p = 0.008) in the frontal plane. When SCUES-shoulder, elbow, wrist, total scores changes was significant in CPG (p < 0.001), SCUES-forearm (p = 0.002) and fingers (p = 0.007) changes was significant in STG.

SIGNIFICANCE

This study showed that although children with USCP are more mildly affected, there are adverse effects on their selective motor control and spinal posture. This study reveals the contribution of structured training in terms of selective movement, spinal smoothness and mobility in children.

Back geometry and mobility function changes in cerebral palsy children after backward walking training: arandomized controlled trial

AIM

To compare the effects of backward (BW) and forward (FW) walking training on back geometry and mobility function in children with hemiparetic cerebral palsy (CP).

METHODS

Fifty-five children with hemiparetic CP participated in this study. They were randomly assigned into two groups. For 12 weeks, both groups got a conventional physical therapy program three days/week. Groups A and B got a specifically developed FW walking training (25 minutes/session) and a specially designed BW walking training (25 minutes/session), respectively.

RESULTS

The trunk imbalance, lateral deviation, pelvic tilting, pelvic torsion, surface motion, and dynamic gait index of group B improved significantly more than group A (p < .05). Both groups showed significant improvements in all measured variables (p < .05).

CONCLUSION

BW walking training might be considered as an effective therapy modality for improving back geometry and mobility function in hemiparetic CP children compared with FW walking training combined with a typical program.

A longitudinal analysis of selective motor control during gait in individuals with cerebral palsy and the relation to gait deviations

OBJECTIVE

To investigate longitudinal changes in selective motor control during gait (SMCg) in individuals with cerebral palsy (CP), and to assess if they are related to changes in gait deviations.

METHOD

Twenty-three children/adolescents with spastic CP (mean ± SD age = 9.0±2.5 years) and two 3D gait assessments (separated by 590±202 days) with no interim surgical intervention, were included. SMCg was assessed using muscle synergy analysis to determine the dynamic motor control index (walk-DMC). Gait deviation was assessed using the Gait profile score (GPS) and Gait variable scores (GVS).

RESULTS

There were no mean changes in walk-DMC score, GPS or GVS between assessments. However, changes in walk-DMC scores in the more involved leg related to changes in hip flexion-extension and hip internal-external GVS (rp = -0.56; p = 0.017 and rp = 0.65; p = 0.004, respectively).

CONCLUSIONS

On average, there were no significant longitudinal changes in SMCg. However, there was considerable variability between individuals, which may relate to changes in hip joint kinematics. This suggests that a combination of neural capacity and biomechanical factors influence lower limb muscle co-activation in individuals with CP, with a potential important role for the hip muscles. These findings highlight the importance of taking an individualized approach when evaluating SMCg in individuals with CP.

Abdominal and lower extremity muscles activity and thickness in typically developing children and children with developmental delay

We investigated abdominal and lower extremity muscle activity and thickness in typically developing children and children with developmental delays. A total of 35 children participated: typically developing peers (n=13), children with hypotonia (n=10), and children with spasticity (n=12). Muscle activity and thickness were measured at rest and during activity. Electromyography was used to measure abdominal and lower extremity muscle activities, and abdominal muscle thickness was measured using ultrasonography. There was a significant difference between the groups in the activity of the rectus abdominis and quadriceps muscles at rest and during activity (P<0.05). There was a significant difference between the groups in the thickness of the external oblique and transversus abdominis muscles during activity (P<0.05). There was a significant difference between the groups in the thickness of the external oblique and internal oblique muscles in the sitting position (P<0.05). Therefore, the characteristics of muscle tone should be considered when applying interventions to children with developmental delay.

Glycine receptor subunit-ß -deficiency in a mouse model of spasticity results in attenuated physical performance, growth and muscle strength

Spasticity is the most common neurological disorder associated with increased muscle contraction causing impaired movement and gait. The aim of this study was to characterize the physical performance, skeletal muscle function, and phenotype of mice with a hereditary spastic mutation (B6.Cg-Glrb^spa/J). Motor function, gait, and physical activity of juvenile and adult spastic mice and the morphological, histological, and mechanical characteristics of their soleus and gastrocnemius medialis muscles were compared with those of their wild-type (WT) littermates. Spastic mice showed attenuated growth, impaired motor function, and low physical activity. Gait of spastic mice was characterized by a typical hopping pattern. Spastic mice showed lower muscle forces, which were related to the smaller physiological cross-sectional area of spastic muscles. The muscle-tendon complex length-force relationship of adult gastrocnemius medialis was shifted toward shorter lengths, which was explained by attenuated longitudinal tibia growth. Spastic gastrocnemius medialis was more fatigue resistant than WT gastrocnemius medialis. This was largely explained by a higher mitochondrial content in muscle fibers and relatively higher percentage of slow-type muscle fibers. Muscles of juvenile spastic mice showed similar differences compared with WT juvenile mice, but these were less pronounced than between adult mice. This study shows that in spastic mice, disturbed motor function and gait is likely to be the result of hyperactivity of skeletal muscle and impaired skeletal muscle growth, which progress with age.

Effects of modified pilates on trunk, postural control, gait and balance in children with cerebral palsy: a single-blinded randomized controlled study

OBJECTIVE

This study aimed to determine the effects of modified pilates exercises (MPE) and neurodevelopmental therapy (NDT) on trunk, postural control, gait, and balance in children with cerebral palsy (CP).

METHODS

18 children with CP between gross motor function classification system (GMFCS) I and III were randomized into two groups as study (Group A, MPE) and control (Group B, NDT). Physiotherapy (PT) took place 2 days a week for 8 weeks. Trunk control measurement scale (TCMS), seated postural control measurement (SPCM), pediatric reach test (PRT), pediatric berg balance measurement (PBBM), 6 minute walking test (6MWT), observational gait scale (OGS), core stability performance measurements, and muscle strength tests were performed.

RESULTS

Mean age of group A (n = 9) was 9 ± 1.58 years, and group B (n = 9) was 10 ± 2.73 years. Significant differences were found in the SPCM posture (p = 0.000), TCMS (p = 0.004), OGS right (p = 0.019) and left (p = 0.001) scores, abdominal fatigue test (AFT) (p = 0.014), modified side bridge (MSBT) test (right p = 0.04, left p = 0.031), pressure biofeedback unit test (PBU) (p = 0.024), and sit-ups test (SUT) (p = 0.011) in favor of group A. According to the initial measurements of the percentage changes of the tests, significantly difference was found in PBBMR (p = 0.001), PBBML (p = 0.000), SPCM posture (0.001), TCMS (0.000), MBSTET (0.000), MSBT left (p = 0.034), AFT (p = 0.002), PBU (p = 0.015), SUT (p = 0.000), MPUT (p = 0.018), and OGS right (p = 0.029) in favor of group A.

CONCLUSION

The results revealed that MPEs in children with CP positively affects trunk, postural control, gait, and balance compared to NDT. It is concluded that MPE can be used as an alternative treatment approach in children with CP. TRIAL REGISTRATION NUMBER/DATE OF REGISTRATION/STUDY START DATE/URL OF THE RECORD: NCT04035954/ 24/07/2019/ August 1, 2019/ https://clinicaltrials.gov/ct2/show/NCT04035954 .

Effects of Hinged versus Floor-Reaction Ankle-Foot Orthoses on Standing Stability and Sit-to-Stand Performance in Children with Spastic Diplegic Cerebral Palsy

Hinged ankle-foot orthoses (HAFOs) and floor reaction ankle-foot orthoses (FRAFOs) are frequently prescribed to improve gait performance in children with spastic diplegic cerebral palsy (CP). No study has investigated the effects of FRAFO on sit-to-stand (STS) performance nor scrutinized differences between the application of HAFOs and FRAFOs on postural control. This study compared the effects of HAFOs and FRAFOs on standing stability and STS performance in children with spastic diplegic CP. Nine children with spastic diplegic CP participated in this crossover repeated-measures design research. Kinematic and kinetic data were collected during static standing and STS performance using 3-D motion analysis and force plates. Wilcoxon signed ranks test was used to compare the differences in standing stability and STS performance between wearing HAFOs and FRAFOs. The results showed that during static standing, all center of pressure (COP) parameters (maximal anteroposterior/mediolateral displacement, maximal velocity, and sway area) were not significantly different between FRAFOs and HAFOs. During STS, the floor reaction force in the vertical direction was significantly higher with FRAFOs than with HAFOs (p = 0.018). There were no significant differences in the range of motion in the trunk, knee, and ankle, the maximal velocity of COP forward displacement, completion time, and the force of hip, knee, and ankle joints between the two orthoses. The results suggest both FRAFOs and HAFOs have a similar effect on standing stability, while FRAFOs may benefit STS performance more compared to HAFOs.

Reliability and sources of variability of 3D kinematics and electromyography measurements to assess newly-acquired gait in toddlers with typical development and unilateral cerebral palsy

The aim was to 1) determine intersession and intertrial reliability and 2) assess three sources of variability (intersubject, intersession and intertrial) of lower limb kinematic and electromyographic (EMG) variables during gait in toddlers with typical development (TD) and unilateral cerebral palsy (UCP) (age <3 years, independent walking experience ≤6 months). Gait kinematics and surface EMG were recorded in 30 toddlers (19 TD and 11 UCP), during two, 3D-motion capture sessions. Standard error of measurement (SEM) between trials (gait cycles) of the same session and between sessions was calculated to assess reliability. Standard deviations (SD) between subjects, sessions and trials were calculated to estimate sources of variability. Sixty-four percent of kinematic SEM-values were acceptable (2°-5°). Frontal plane measurements were most reliable (SEM 2°-4.6°). In toddlers with UCP, EMG variables were most reliable for affected side, distal muscles. Intrinsic (intertrial and intersubject) variability was high, reflecting both motor immaturity and the high variability of toddler gait patterns. In toddlers with UCP, variability was amplified by motor impairment and delayed motor development. 3D gait analysis and surface EMG are partially reliable tools to study individual gait patterns in toddlers in clinical practice and research, although some variables must be interpreted with caution.

Kinematic cluster analysis of the crouch gait pattern in children with spastic diplegic cerebral palsy using sparse K-means method

BACKGROUND

Crouch gait pattern is a common gait pattern in children with diplegic cerebral palsy with excessive knee flexion throughout stance phase. Few studies have grouped this pattern of gait and usually have examined only the features of gait in the sagittal plane and mostly lower extremities without considering pelvis and trunk behavior. Studies usually categorize the gait pattern according to important variables from the researcher's point of view. Sparse K-means is high dimensional clustering methods that perform clustering and variable selection simultaneously even with low sample size and large number of variables. Our aim was to define existing clusters of crouch gait pattern in children with spastic diplegic cerebral palsy.

METHODS

Cluster analysis was applied on the lower extremity, pelvis and trunk gait kinematics data of 64 limbs of children with crouch gait pattern and 64 limbs of typically developing children. Eighty-nine kinematic variables were used as input variables for clustering.

FINDINGS

Four clusters of crouch gait pattern were defined. Sparse K-means identified influential variables and identified the knee and hip flexion as a major factor in clustering. Kinematic of the trunk, pelvis and ankle was determined in each cluster. Trunk and pelvis kinematic features were strongly correlated with the knee and hip joint flexion severity.

INTERPRETATION

Obtained clusters were confirmed observationally. With increasing knee flexion, the kinematic of the trunk and pelvis were further away from the patterns of typically developing individuals. The clusters ranking appear to be reasonable based on the crouch severity.

Characteristics of Lower Limb Muscle Activity in Elderly Persons After Ergometric Exercise

This study examined the characteristics of lower limb muscle activity in elderly persons after ergometric pedaling exercise for 1 month. To determine the effect of the exercise, surface electromyography (SEMG) of lower limb muscles was subjected to Daubechies-4 wavelet transformation, and mean wavelet coefficients were compared with the pre-exercise coefficients and the post-exercise coefficients in each wavelet level. The characteristics of muscle activity after pedaling exercise were also compared between the elderly subjects and young subjects. For the elderly subjects, the mean wavelet coefficients were significantly decreased in the tibialis anterior and the gastrocnemius medialis at wavelet levels of 3, 4, and 5 (125–62.5, 62.5–31.25, and 31.25–15.625 Hz, respectively), by pedaling exercise. However, the mean power of wavelet levels of 2 and 3 (250–125 and 125–62.5 Hz) within the rectus femoris and the biceps femoris were significantly increased in the young subjects. The effect of pedaling exercise is different from the effects of heavy-resistance training. It was suggested that the muscle coordination, motor unit (MU) firing frequency, and firing fiber type of lower limb muscles are changed with the different characteristics between elderly and young persons by pedaling exercise for 1 month.

Effect of whole-body vibration on abdominal thickness and sitting ability in children with spastic diplegia

Objective

Reduced muscle and bone mass, improper muscle function, and varying degrees of mobility dysfunctions are the main complications of cerebral palsy (CP). Many children with CP also present with poor abdominal muscle activation. Whole-body vibration (WBV) is a unique approach for enhancing strength and motor abilities in several clinical conditions. This study aimed to determine the influence of a 12-week WBV intervention on the thickness of the abdominal muscles and the sitting ability of children with diplegia.

Methods

A total of 30 children with spastic diplegic CP (aged 4–6 years) were randomly divided into two groups (control and experimental). The control group received a selected physical therapy program for 1 h, and the study group received WBV training for 10 min in addition to the same selected program for the control group for 3 times/week over a period of 12 weeks. Thereafter, abdominal muscle thickness and sitting ability were measured using ultrasonography and the Gross Motor Function Measure-88 (GMFM-88, sitting domain).

Results

Post treatment values revealed significant improvement in the measured variables in favour of the experimental group (p < 0.05), as there was improvement in the thickness of the four abdominal muscles compared to the control group (external oblique: F = 38.783; internal oblique: F = 99.547; transverse abdominis: F = 111.557, and rectus abdominis: F = 129.940, p < 0.05). Additionally, the study group showed a significantly greater improvement in GMFM-88 values compared to the control group (F = 129.940, p < 0.05).

Conclusion

WBV can be a viable strategy for improving sitting ability and abdominal muscle thickness among children with spastic diplegia.

Application of functional data analysis to explore movements: walking, running and jumping - A systematic review

Background Signals are continuously captured during the recording of motion data. Statistical analysis, however, usually uses only a few aspects of the recorded data. Functional data analysis offers the possibility to analyze the entire signal over time. Research question The review is based on the question of how functional data analysis is used in the study of lower limb movements. Methods The literature search was based on the databases EMBASE, PUBMED and OVID MEDLINE. All articles on the application of functional data analysis to motion-associated variables trajectories, ground reaction force,electromyography were included. The references were assessed independently by two reviewers. Results In total 1448 articles were found in the search. Finally, 13 articles were included in the review. All were of moderate methodological quality. The publication year of the studies ranges from 2009 to 2019. Healthy volunteers and persons with cruciate ligament injuries, knee osteoarthritis, gluteal tendinopathy, idiopathic torsional deformities, slipped capital femoral epiphysis and chronic ankle instability were examined in the studies. Movements were analyzed on basis of kinematics (3D motion analysis), ground reaction forces and electromyography. Functional Data Analysis was used in terms of landmark registration, functional principal component analysis, functional t-test and functional ANOVA. Significance Functional data analysis provides the possibility to gain detailed and in-depth insights into the analysis of motion patterns. As a result of the increase in references over the past year, the FDA is becoming more important in the analysis of continuous signals and the explorative analysis of movement data.

Characteristics of newly acquired gait in toddlers with unilateral cerebral palsy: Implications for early rehabilitation

BACKGROUND

Knowledge of the characteristics of newly acquired gait in toddlers with cerebral palsy (CP) is limited.

OBJECTIVES

This study compared gait characteristics (spatiotemporal parameters, kinematics and lower-limb muscle activation) within the first 6 months of independent walking in toddlers with unilateral cerebral palsy (UCP) and typically developing (TD) children.

METHODS

The gait of 28 TD toddlers and 13 toddlers with UCP, all up to 3 years old with maximum walking experience of 6 months, was recorded by using a 3-D optoelectronic system and surface electromyography (EMG). Statistical parametric mapping was used to compare the kinematic parameters and EMG envelopes. Mann-Whitney U test was used to compare spatiotemporal parameters between groups. Principal component analysis was used to determine whether the main kinematic results were related to the clinical measures.

RESULTS

Toddlers with UCP had bilateral modifications of the spatiotemporal parameters during gait as compared with TD toddlers and temporal asymmetry. The largest kinematic difference between the UCP and TD groups was external pelvic rotation on the affected side (13.3°). Foot progression angle was external during swing phase on the affected side. The groups did not differ in muscle activation for the set of muscles recorded. Pelvic rotation was not associated with any of the clinical measures on the affected or non-affected sides of toddlers with UCP.

CONCLUSIONS

Alterations in kinematic gait parameters were mostly found at the pelvis in toddlers with UCP and newly acquired gait. At that age, the external pelvic rotation on the affected side is more likely due to primary motor control disorders than compensatory mechanisms. These findings suggest that early rehabilitation should focus on proximal motor control, balance and symmetry to optimize gait development from the early stages in children with UCP.

Children With Cerebral Palsy Have Greater Stride-to-Stride Variability of Muscle Synergies During Gait Than Typically Developing Children: Implications for Motor Control Complexity

BACKGROUND

There is mounting evidence that the central nervous system utilizes a modular approach for neuromuscular control of walking by activating groups of muscles in units termed muscle synergies. Examination of muscle synergies in clinical populations may provide insights into alteration of neuromuscular control underlying pathological gait patterns. Previous studies utilizing synergy analysis have reported reduced motor control complexity during walking in those with neurological deficits, revealing the potential clinical utility of this approach.

METHODS

We extracted muscle synergies on a stride-to-stride basis from 20 children with cerebral palsy (CP; Gross Motor Function Classification System levels I-II) and 8 children without CP, allowing the number of synergies to vary for each stride. Similar muscle synergies across all participants and strides were grouped using a k-means clustering and discriminant analysis.

RESULTS

In total, 10 clusters representing 10 distinct synergies were found across the 28 individuals. Relative to their total number of synergies deployed during walking, synergies from children with CP were present in a higher number of clusters than in children with typical development (TD), indicating significantly greater stride-to-stride variability. This increased variability was present despite reduced complexity, as measured by the mean number of synergies in each stride. Whereas children with CP demonstrate some novel synergies, they also deploy some of the same muscle synergies as those with TD, although less frequently and with more variability.

CONCLUSION

A stride-by-stride approach to muscle synergy analysis expands its clinical utility and may provide a method to tailor rehabilitation strategies by revealing inconsistent but functional synergies in each child with CP.

Degraded Synergistic Recruitment of sEMG Oscillations for Cerebral Palsy Infants Crawling

Background: Synergistic recruitment of muscular activities is a generally accepted mechanism for motor function control, and motor dysfunction, such as cerebral palsy (CP), destroyed the synergistic electromyography activities of muscle group for limb movement. However, very little is known how motor dysfunction of CP affects the organization of the myoelectric frequency components due to the abnormal motor unit recruiting patterns. Objectives: Exploring whether the myoelectric activity can be represented with synergistic recruitment of surface electromyography (sEMG) frequency components; evaluating the effect of CP motor dysfunction on the synergistic recruitment of sEMG oscillations. Methods: Twelve CP infants and 17 typically developed (TD) infants are recruited for self-paced crawling on hands and knees. sEMG signals have been recorded from bilateral biceps brachii (BB) and triceps brachii (TB) muscles. Multi-scale oscillations are extracted via multivariate empirical mode decomposition (MEMD), and non-negative matrix factorization (NMF) method is employed to obtain synergistic pattern of these sEMG oscillations. The coefficient curve of sEMG oscillation synergies are adopted to quantify the time-varying recruitment of BB and TB myoelectric activity during infants crawling. Results: Three patterns of sEMG oscillation synergies with specific frequency ranges are extracted in BB and TB of CP or TD infants. The contribution of low-frequency oscillation synergy of BB in CP group is significantly less than that in TD group (p < 0.05) during forward swing phase for slow contraction; however, this low-frequency oscillation synergy keep higher level during the backward swing phase crawling. For the myoelectric activities of TB, there is not enough high-frequency oscillation recruitment of sEMG for the fast contraction in propulsive phase of CP infants crawling. Conclusion: Our results reveal that, the myoelectric activities of a muscle can be manifested as sEMG oscillation synergies, and motor dysfunction of CP degrade the synergistic recruitment of sEMG oscillations due to the impaired CNS regulation and destroyed MU/muscle fiber. Our preliminary work suggests that time-varying coefficient curve of sEMG oscillation synergies is a potential index to evaluate the abnormal recruitment of electromyography activities affected by CP disorders.

An electromyographic study of abdominal muscle activity in children with spastic cerebral palsy

Background

Inadequate knowledge in the recruitment patterns of abdominal muscles in individuals with spastic-type cerebral palsy (STCP).

Objectives

To determine whether there is any difference between the neuromuscular activity (activation pattern) of the abdominal muscles in children with STCP and those of their typically developing (TD) peers.

Method

The NORAXAN^® electromyography (EMG) was used to monitor the neuromuscular activity in abdominal muscles of individuals with STCP (n = 63), and the results were compared with the findings from age-matched TD individuals (n = 82).

Results

EMG frequencies were recorded during rest and during active states and compared using repeated measures ANOVA. Spearman's rank order correlation was used to explore relationships between age, body mass index and abdominal muscle activity. With the exception of the rectus abdominis (RA) muscle, the pattern of neuromuscular activity in children with STCP differs significantly from that of their TD peers. Three of the muscles - external oblique abdominis (EO), internal oblique abdominis (IO) and RA - in both groups showed significant changes (p < 0.001) in the frequency of EMG activity between the resting and active states. An elevated EMG activity at rest in the EO and IO was recorded in the STCP group, whereas the RA during resting and active stages showed similar results to TD individuals.

Conclusion

The findings from this study suggest that the RA could be targeted during rehabilitation regimens; however, the force generated by this muscle may not be sufficient for the maintenance of trunk stability without optimal support from the EO and IO muscles.

An ultrasonographic analysis of the activation patterns of abdominal muscles in children with spastic type cerebral palsy and in typically developing individuals: a comparative study

Background

Abdominal muscles have stiffer appearance in individuals with spastic type cerebral palsy (STCP) than in their typically developing (TD) peers. This apparent stiffness has been implicated in pelvic instability, mal-rotation, poor gait and locomotion. This study was aimed at investigating whether abdominal muscles activation patterns from rest to activity differ in the two groups.

Method

From ultrasound images, abdominal muscles thickness during the resting and active stages was measured in 63 STCP and 82 TD children. The thickness at each stage and the change in thickness from rest to activity were compared between the two groups.

Results

Rectus abdominis (RA) muscle was the thickest muscle at rest as well as in active stage in both groups. At rest, all muscles were significantly thicker in the STCP children (p <  0.001). From rest to active stages muscle thickness significantly increased (p <  0.001) in the TD group and significantly decreased (p <  0.001) in the STCP children, except for RA, which became thicker during activity in both groups. In active stages, no significant differences in the thickness in the four abdominal muscles were found between the STCP and the TD children.

Conclusion

Apart from the RA muscle, the activation pattern of abdominal muscles in individuals with STCP differs from that of TD individuals. Further studies required for understanding the activation patterns of abdominal muscles prior to any physical fitness programmes aimed at improving the quality of life in individuals with STCP.

Trial registration

HREC REF: 490/2011. Human Research Ethics Committee, Faculty of Health Sciences, University of Cape Town, South Africa. November 17, 2011.

Functional vs. Traditional Analysis in Biomechanical Gait Data: An Alternative Statistical Approach

In human motion studies, discrete points such as peak or average kinematic values are commonly selected to test hypotheses. The purpose of this study was to describe a functional data analysis and describe the advantages of using functional data analyses when compared with a traditional analysis of variance (ANOVA) approach. Nineteen healthy participants (age: 22 ± 2 yrs, body height: 1.7 ± 0.1 m, body mass: 73 ± 16 kg) walked under two different conditions: control and pain+effusion. Pain+effusion was induced by injection of sterile saline into the joint capsule and hypertonic saline into the infrapatellar fat pad. Sagittal-plane ankle, knee, and hip joint kinematics were recorded and compared following injections using 2×2 mixed model ANOVAs and FANOVAs. The results of ANOVAs detected a condition × time interaction for the peak ankle (F1,18 = 8.56, p = 0.01) and hip joint angle (F1,18 = 5.77, p = 0.03), but did not for the knee joint angle (F1,18 = 0.36, p = 0.56). The functional data analysis, however, found several differences at initial contact (ankle and knee joint), in the mid-stance (each joint) and at toe off (ankle). Although a traditional ANOVA is often appropriate for discrete or summary data, in biomechanical applications, the functional data analysis could be a beneficial alternative. When using the functional data analysis approach, a researcher can (1) evaluate the entire data as a function, and (2) detect the location and magnitude of differences within the evaluated function.

Are postural adjustments during reaching related to walking development in typically developing infants and infants at risk of cerebral palsy?

BACKGROUND

In typical development, postural adjustments during reaching change in the second half of infancy, including increasing rates of direction-specific adjustments. These changes are absent or different in infants at risk of cerebral palsy (CP). To discover whether these changes are related to acquisition of independent walking, we studied postural adjustments during reaching in infants before and after they learned to walk.

METHODS

Ten typically developing (TD) infants and 11 infants at very high risk (VHR) of CP were assessed before and after they learned to walk. Reaching movements were elicited during supported sitting, while surface electromyography was recorded of arm, neck, and trunk muscles. Percentages of direction-specific adjustments (first level of control), and recruitment patterns and anticipatory activation (second level of control) were calculated.

RESULTS

In both groups, postural adjustments during reaching were similar before and after acquisition of independent walking. Direction-specificity increased with age in typically developing infants but not in VHR-infants.

CONCLUSION

Increasing age rather than the transition to independent walking is associated with increasing direction-specificity of TD-infants during reaching while sitting, while infants at very high risk of CP show no increase in direction-specificity, suggesting that they gradually grow into a postural deficit.

Long-Term Effects of Orthoses Use on the Changes of Foot and Ankle Joint Motions of Children With Spastic Cerebral Palsy

BACKGROUND

Orthoses commonly are prescribed to children with cerebral palsy (CP) to provide foot correction and to improve ambulatory function. Immediate effects of ankle foot orthosis (AFOs) have been investigated, but long-term kinematic effects are lacking clinical evidence.

OBJECTIVE

To determine changes in 3-dimensional ankle and foot segment motion in pediatric patients with CP between initial and follow-up visits (18-month average time differences) in both barefoot gait and gait with their AFO. We also investigated intravisit changes between barefoot and AFO gait.

DESIGN

A prospective cohort study.

SETTING

Children's Hospital of Wisconsin, Department of Orthopaedic Surgery, Medical College of Wisconsin.

PATIENTS

A total of 23 children with CP, mean age 10.5 years (6.2-18.1 years) were clinically prescribed either a solid ankle foot orthotic (SAFO), hinged ankle foot orthotic (HAFO), or supramalleolar orthotic.

METHODS

Holes were cut in the study orthoses so that electromagnetic markers could be directly placed on the skin. A 6-foot segment model was used.

OUTCOME MEASUREMENTS

Kinematic and kinetic data were recorded for each patient's initial and follow-up visit (18-month follow-up average, 15-20 months range).

RESULTS

For the SAFO group (gait with AFO), a significant decrease in dorsiflexion was found between the initial and third visit (P = .008). Furthermore, the SAFO group (barefoot gait) had an increased eversion at the midfoot for most of the gait cycle (P < .008). Sagittal forefoot range of motion was reduced for all 3 groups between the barefoot and AFO groups.

CONCLUSION

The use of AFOs long term either maintained or improved foot deformities or dysfunction.

LEVEL OF EVIDENCE

Level II.

A new parameter for quantifying the variability of surface electromyographic signals during gait: The occurrence frequency

Natural variability of myoelectric activity during walking was recently analyzed considering hundreds of strides. This allowed assessing a parameter seldom considered in classic surface EMG (sEMG) studies: the occurrence frequency, defined as the frequency each muscle activation occurs with, quantified by the number of strides when a muscle is recruited with that specific activation modality. Aim of present study was to propose the occurrence frequency as a new parameter for assessing sEMG-signal variability during walking. Aim was addressed by processing sEMG signals acquired from Gastrocnemius Lateralis, Tibialis Anterior, Rectus Femoris and Biceps femoris in 40 healthy subjects in order to: (1) show that occurrence frequency is not correlated with ON/OFF instants (R_mean=0.11±0.07; P>0.05) and total time of activation (R_mean=0.15±0.08; P>0.05); (2) confirm the above results by two handy examples of application (analysis of gender and age) which highlighted that significant (P<0.05) gender-related and age-related differences within population were detected in occurrence frequency, but not in temporal sEMG parameters. In conclusion, present study demonstrated that occurrence frequency is able to provide further information, besides those supplied by classical temporal sEMG parameters and thus it is suitable to complement them in the evaluation of variability of myoelectric activity during walking.

Position Between Trunk and Pelvis During Gait Depending on the Gross Motor Function Classification System

PURPOSE

To understand whether there is a trunk postural control threshold in the sagittal plane for the transition between the Gross Motor Function Classification System (GMFCS) levels measured with 3-dimensional gait analysis.

METHOD

Kinematics from 97 children with spastic bilateral cerebral palsy from spine angles according to Plug-In Gait model (Vicon) were plotted relative to their GMFCS level.

RESULTS

Only average and minimum values of the lumbar spine segment correlated with GMFCS levels. Maximal values at loading response correlated independently with age at all functional levels. Average and minimum values were significant when analyzing age in combination with GMFCS level.

CONCLUSION

There are specific postural control patterns in the average and minimum values for the position between trunk and pelvis in the sagittal plane during gait, for the transition among GMFCS I-III levels. Higher classifications of gross motor skills correlate with more extended spine angles.

Effect of supporting 3D-garment on gait postural stability in children with bilateral spastic cerebral palsy

BACKGROUND

Children with cerebral palsy show dysfunctional postural control which interferes with their functional performance and daily-life activities.

OBJECTIVE

The aim of the study was to identify the effect of a 3D supporting garment on trunk postural control and interjoint coordination during gait in children with bilateral cerebral palsy.

METHODS

We analyzed tridimensional trunk motion, trunk-thigh and interjoint coordination in 15 4-10 year-old children with bilateral spastic cerebral palsy (GMFCS I or II) and 16 4-10 year-old typically developing children while walking with or without a supporting garment.

RESULTS

We found significantly changes in the coordination between trunk and lower limbs in children with cerebral palsy. Step velocity and cadence both increased significantly in children with cerebral palsy but in controls, the cadence remained unaltered. Interjoint coordination between hip-knee and knee-ankle was altered during the stance phase only in the subgroup of children with cerebral palsy without any limitations in ankle joint passive range of motion.

CONCLUSION

3D supporting garments improve trunk-thigh and lower limb interjoint coordination in walking in children with bilateral cerebral palsy.

Do quiet standing centre of pressure measures within specific frequencies differ based on ability to recover balance in individuals with stroke?

OBJECTIVE

To determine whether quiet standing measures at specific frequency levels (representative of reactive control) differed between individuals with stroke based on their ability to recover balance (Failed or Successful Responses to external perturbations).

METHODS

Individuals with stroke completed a clinical assessment, including 30 s of quiet standing and lean-and-release postural perturbations, at admission to in-patient rehabilitation. Quiet standing centre of pressure (COP) signals were calculated and discrete wavelet decomposition was performed. Net COP amplitude, between-limb synchronization, and ratios of individual-limb COP were determined for each frequency level of interest, and for the non-decomposed signal (all frequency levels). Outcome measures were compared between individuals who exhibited Failed and Successful Responses during (a) unconstrained and (b) encouraged-use lean-and-release trials.

RESULTS

Individuals with Failed Responses during the unconstrained lean-and-release trials displayed greater net COP amplitude than those with Successful Responses, specifically within a frequency range of 0.40-3.20Hz.

CONCLUSIONS

Reduced ability to recover balance among individuals with stroke may be reflected in impaired reactive control of quiet standing.

SIGNIFICANCE

These results provide insight into the mechanism by which reactive control of quiet standing is impaired in individuals with stroke, and may inform assessment and rehabilitation strategies for post-stroke reactive balance control.

The Assessment of Muscular Effort, Fatigue, and Physiological Adaptation Using EMG and Wavelet Analysis

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a transcription factor co-activator that helps coordinate mitochondrial biogenesis within skeletal muscle following exercise. While evidence gleaned from submaximal exercise suggests that intracellular pathways associated with the activation of PGC-1α, as well as the expression of PGC-1α itself are activated to a greater extent following higher intensities of exercise, we have recently shown that this effect does not extend to supramaximal exercise, despite corresponding increases in muscle activation amplitude measured with electromyography (EMG). Spectral analyses of EMG data may provide a more in-depth assessment of changes in muscle electrophysiology occurring across different exercise intensities, and therefore the goal of the present study was to apply continuous wavelet transforms (CWTs) to our previous data to comprehensively evaluate: 1) differences in muscle electrophysiological properties at different exercise intensities (i.e. 73%, 100%, and 133% of peak aerobic power), and 2) muscular effort and fatigue across a single interval of exercise at each intensity, in an attempt to shed mechanistic insight into our previous observations that the increase in PGC-1α is dissociated from exercise intensity following supramaximal exercise. In general, the CWTs revealed that localized muscle fatigue was only greater than the 73% condition in the 133% exercise intensity condition, which directly matched the work rate results. Specifically, there were greater drop-offs in frequency, larger changes in burst power, as well as greater changes in burst area under this intensity, which were already observable during the first interval. As a whole, the results from the present study suggest that supramaximal exercise causes extreme localized muscular fatigue, and it is possible that the blunted PGC-1α effects observed in our previous study are the result of fatigue-associated increases in muscle acidosis. This should be explored in future research using further combinations of EMG and muscle biochemistry and histology.

[Impact of a virtual reality-based intervention on motor performance and balance of a child with cerebral palsy: a case study]

OBJECTIVE

To verify the effect of an intervention protocol using virtual reality (VR) on the motor performance and balance of a child with cerebral palsy (CP).

CASE DESCRIPTION

To comply with the proposed objectives, a 7-year old child with spastic hemiplegic cerebral palsy (cP), GMFcS level I, was submitted to a physiotherapy intervention protocol of 12 45-minute sessions, twice a week, using virtual reality-based therapy. The protocol used a commercially-available console (XBOX(®)360 Kinect(®)) able to track and reproduce body movements on a screen. Prior to the intervention protocol, the child was evaluated using the Motor Development Scale (MDS) and the Pediatric Balance Scale (PBS) in order to assess motor development and balance, respectively. Two baseline assessments with a 2-week interval between each other were carried out for each tool. Then, the child was re-evaluated after the twelfth session. The results showed no changes in the two baseline scores. After the intervention protocol, the child improved his scores in both tools used: the PBS score increased by 3 points, reaching the maximal score, and the MDS increased from a much inferior motor performance to just an inferior motor performance.

COMMENTS

The evidence presented in this case supports the use of virtual reality as a promising tool to be incorporated into the rehabilitation process of patients with neuromotor dysfunction.

Impact of a virtual reality-based intervention on motor performance and balance of a child with cerebral palsy: a case study

OBJECTIVE: To verify the effect of an intervention protocol using virtual reality (VR) on the motor performance and balance of a child with cerebral palsy (CP).CASE DESCRIPTION: To comply with the proposed objectives, a 7-year old child with spastic hemiplegic cerebral palsy (CP), GMFCS level I, was submitted to a physiotherapy intervention protocol of 12 45-minute sessions, twice a week, using virtual reality-based therapy. The protocol used a commercially-available console (XBOX(r)360Kinect(r)) able to track and reproduce body movements on a screen. Prior to the intervention protocol, the child was evaluated using the Motor Development Scale (MDS) and the Pediatric Balance Scale (PBS) in order to assess motor development and balance, respectively. Two baseline assessments with a 2-week interval between each other were carried out for each tool. Then, the child was re-evaluated after the twelfth session. The results showed no changes in the two baseline scores. After the intervention protocol, the child improved his scores in both tools used: the PBS score increased by 3 points, reaching the maximal score, and the MDS increased from a much inferior motor performance to just an inferior motor performance.COMMENTS: The evidence presented in this case supports the use of virtual reality as a promising tool to be incorporated into the rehabilitation process of patients with neuromotor dysfunction.

Differences in muscle activation patterns during sit to stand task among subjects with and without intellectual disability

The aim of this study is to analyse the differences in muscle activity between subjects who have intellectual disability and healthy subjects when they make the transition from sitting to standing positions. A cross-sectional study. A group of adults was divided into two subgroups: with and without intellectual disability (ID). The means of the basic features in both groups were 22.13 and 22.83 for age, 66.38 and 67.67 for weight, and 173.38 and 174.33 for height, for the ID (n = 8) and without ID (n = 7) groups, respectively. Each subject performed three sets of five repetitions during which, starting from sitting, they had to get up and sit on the chair. The recording of muscle activity was performed using surface electromyography taking the measures of muscle activity of different muscles of the lower limbs. The results showed differences in the pattern of muscle activity between groups during sitting to standing movement.

Postural responses of adults with cerebral palsy to combined base of support and visual field rotation

We employed a virtual environment to examine the postural behaviors of adults with cerebral palsy (CP). Four adults with CP (22-32 years) and nine healthy adults (21-27 years) were tested with a Rod and Frame protocol. They then stood quietly on a platform within a three-wall virtual environment. The platform was either kept stationary or tilted 3(°) into dorsiflexion in the dark or with pitch up and down visual field rotations at 30(°)/s and 45(°)/s. While the visual field rotated, the platform was held tilted for 30 s and then slowly returned to a neutral position over 30 s. Center of pressure (CoP) was recorded and center of mass (CoM) as well as trunk and ankle angles were calculated. Electromyography (EMG) responses of the ankle and the hip muscles were recorded and analyzed using wavelets. Larger angular deviations from vertical and horizontal in the Rod and Frame test indicated that adults with CP were more visually dependent than healthy adults. Adults with CP had difficulty maintaining balance when standing on a stationary platform during pitch upward rotation of the visual scene. When the platform was tilted during visual field rotations, adults with CP took longer to stabilize their posture and had larger CoM oscillations than when in the dark. The inability to compensate for busy visual environments could impede maintenance of functional locomotion in adults with CP. Employing a visual field stimulus for assessment and training of postural behaviors would be more meaningful than testing in the dark.

To what extent is mean EMG frequency during gait a reflection of functional muscle strength in children with cerebral palsy?

The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded during 3D gait analysis (3DGA), for the evaluation of functional muscle strength in children with cerebral palsy (CP). As walking velocity is known to also influence EMG frequency, it was investigated to which extent the mean EMG frequency is a reflection of underlying muscle strength and/or the applied walking velocity. Surface EMG data of the lateral gastrocnemius (LGAS) and medial hamstrings (MEH) were collected during 3DGA. For each muscle, 20 CP children characterized by a weak and 20 characterized by a strong muscle (LGAS or MEH) were selected. A weak muscle was defined as a manual muscle testing score <3; a strong muscle was defined as a manual muscle testing score ≥4. Patient selection was based on the following inclusion criteria: (a) predominantly spastic type of CP (3-15 years old), (b) either (near) normal muscle strength or muscle weakness in at least one of the studied lower limb muscles, (c) no lower limb Botulinum Toxin-A treatment within 6 months prior to the 3DGA, (d) no history of lower limb surgery, and (e) high-quality noise-free EMG-data. For each muscle, twenty age-related typically developing (TD) children were included as controls. In both muscles a consistent pattern of increasing mean EMG frequency with decreasing muscle strength was observed. This was significant in the LGAS (TD versus weak CP). Walking velocity also had a significant effect on mean EMG frequency in the LGAS. Furthermore, based on R(2) and partial correlations, it could be concluded that both walking velocity and muscle strength have an impact on EMG, but the contribution of muscle strength was always higher. These findings underscore the potential of the mean EMG frequency recorded during 3DGA, for the evaluation of functional muscle strength in children with CP.

Sit-to-stand movement in children with cerebral palsy: a critical review

Sit-to-stand (STS) movement is widely performed in daily life and an important pre requisite for acquisition of functional abilities. However, STS is a biomechanical demanding task which requires high levels of neuromuscular coordination, muscle strength and postural control. As children with cerebral palsy (CP) exhibit a series of impairments in body structures and functions, STS movement performance could be impaired in this population. Thus, this article aimed to review studies that had described how STS movement is performed by children with CP, the factors that influence it and the methodological procedures adopted in it analyses. A search was performed by one reviewer in relevant databases. In all, 12 articles were identified and 9 were selected for the present review. It was detected a large variation in sample characteristics and methodological issues among studies. In fact, standardization of the method applied to STS movement analysis is not fully established. With regard to STS performance, children with CP exhibited variations among them and also when compared with their typical peers. Moreover extrinsic factors appear to influence STS movement performance in these children and its manipulation could be incorporated into rehabilitation protocols. Moreover, the relationship between STS movement and functionality in reviewed articles was not reported. Therefore the review allowed to observe that STS movement has been under-explored in children with CP, with a lack of standardized methodologies and a not well established relationship between this movement and functionality. Thus, further studies about STS movement in CP are necessary.

Intra- and inter-observer reliability of the Trunk Impairment Scale for children with cerebral palsy

Standardized scales to evaluate qualities of trunk movements in children with dysfunction are sparse. An examination of the reliability of scales that may be useful in the clinic is important. The aim of this study was to examine the reliability of the Trunk Impairment Scale (TIS) for children with cerebral palsy (CP). Standardized scales are useful for treatment planning and evaluation. This was an intra- and inter-observer reliability study. Video recordings of 25 children, 20 with CP and 5 with no motor impairment, in the age group 5-12 years of age, were analyzed by three observers on two occasions. Intraclass correlation coefficients (ICC [1,1] and [3,1]) with 95% confidence intervals, standard error of measurement, kappa values and percent agreement, and Bland-Altman Plots were calculated. The relative reliability (intra- and inter-observer reliability) was very high for the total score and subscale score of the TIS: ICC [1,1] and [3,1] varied between .94 and 1.00. Kappa values for the items ranged from .45 to 1.00. The absolute reliability values for the parameters are reported. The Bland-Altman analysis showed consistency of scores. This study indicates that TIS is a reliable measure of trunk control for children, 5-12 years of age, with CP.