Activity-Based Therapies for Repair of the Corticospinal System Injured during Development

The efficiency and use of a reciprocating system aid for standing and walking in children affected by severe cerebral palsy

Cerebral Palsy (CP) is a leading cause of childhood motor disability, making independent walking a crucial therapeutic goal. Robotic assistive devices offer potential to enhance mobility, promoting community engagement and quality of life. This is an observational report of 22 cases of children with CP in which we evaluated the Moonwalker exoskeleton (a dynamic moving aid system) usability, functional changes, and caregivers' perspectives based on the International Classification of Functioning (ICF). All children (aged 2-8 years, with a severe gait impairment and inability to use a conventional walker) underwent Moonwalker training for 20 sessions, followed by home use for five months. Post-treatment, majority of children showed improved endurance assessed by the 10-m walk test with a notable involvement of the upper trunk and arm movements for gait assistance. Many of them achieved rather remarkable results reaching a velocity of ≥0.5 m/s given the constraints of the walking exoskeleton and the children's size, while at admission all children walked at a speed of less than 0.5 m/s. Several positive environmental factors and family adherence were noted, as assessed by ICF in a subgroup of children. This study on a sample of children demonstrated that the Moonwalker exoskeleton allows walking and training at home in children with severe CP, enhancing development, social interaction, and endurance, while being well-received by families.

Upper Limb Therapy for Infants and Young Children with Unilateral Cerebral Palsy: A Clinical Framework

Early detection and rehabilitation interventions are essential to optimise motor function in infants and young children with unilateral cerebral palsy. In this paper we report a clinical framework aimed at enhancing upper limb therapy for infants and young children with unilateral cerebral palsy during a sensitive period of brain development. We describe two major therapeutic approaches based on motor learning principles and evidence: constraint-induced movement therapy and bimanual therapy. These two therapies have demonstrated efficacy in older children and emerging evidence is available for their application to infants younger than 2 years of age. To provide clinicians with guidance as to when to implement these therapies, we discuss the key consideration when undertaking upper limb therapy programs. In addition, we describe the factors to consider when choosing which approach may be suitable for an individual child and family. Detailed strategies for implementing these therapies in infants and young children of different ability levels are given.

Changes Induced by Early Hand-Arm Bimanual Intensive Therapy Including Lower Extremities in Young Children With Unilateral Cerebral Palsy: A Randomized Clinical Trial

Importance

Intensive interventions are provided to young children with unilateral cerebral palsy (UCP), classically focused on the upper extremity despite the frequent impairment of gross motor function. Hand-Arm Bimanual Intensive Therapy Including Lower Extremities (HABIT-ILE) effectively improves manual dexterity and gross motor function in school-aged children.

Objective

To verify if HABIT-ILE would improve manual abilities in young children with UCP more than usual motor activity.

Design, Setting, and Participants

This prospective randomized clinical trial (November 2018 to December 2021), including 2 parallel groups and a 1:1 allocation, recruitment took place at European university hospitals, cerebral palsy specialized centers, and spontaneous applications at 3 sites: Brussels, Belgium; Brest, France; and Pisa, Italy. Matched (age at inclusion, lesion type, cause of cerebral palsy, and affected side) pairs randomization was performed. Young children were assessed at baseline (T0), 2 weeks after baseline (T1), and 3 months after baseline (T2). Health care professionals and assessors of main outcomes were blinded to group allocation. At least 23 young children (in each group) aged 12 to 59 months with spastic/dyskinetic UCP and able to follow instructions were needed. Exclusion criteria included uncontrolled seizures, scheduled botulinum toxin injections, orthopedic surgery scheduled during the 6 months before or during the study period, severe visual/cognitive impairments, or contraindications to magnetic resonance imaging.

Interventions

Two weeks of usual motor activity including usual rehabilitation (control group) vs 2 weeks (50 hours) of HABIT-ILE (HABIT-ILE group).

Main Outcomes and Measures

Primary outcome: Assisting Hand Assessment (AHA); secondary outcomes: Gross Motor Function Measure-66 (GMFM-66), Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT), and Canadian Occupational Performance Measure (COPM).

Results

Of 50 recruited young children (26 girls [52%], median age; 35.3 months for HABIT-ILE group; median age, 32.8 months for control group), 49 were included in the final analyses. Change in AHA score from T0 to T2 was significantly greater in the HABIT-ILE group (adjusted mean score difference [MD], 5.19; 95% CI, 2.84-7.55; P < .001). Changes in GMFM-66 (MD, 4.72; 95% CI, 2.66-6.78), PEDI-CAT daily activities (MD, 1.40; 95% CI, 0.29-2.51), COPM performance (MD, 3.62; 95% CI, 2.91-4.32), and satisfaction (MD, 3.53; 95% CI, 2.70-4.36) scores were greater in the HABIT ILE group.

Conclusions and Relevance

In this clinical trial, early HABIT-ILE was shown to be an effective treatment to improve motor performance in young children with UCP. Moreover, the improvements had an impact on daily life activities of these children.

Trial registration

ClinicalTrials.gov Identifier: NCT04020354.

Muscle Activity during Passive and Active Movements in Preterm and Full-Term Infants

Manifestation of muscle reactions at an early developmental stage may reflect the processes underlying the generation of appropriate muscle tone, which is also an integral part of all movements. In preterm infants, some aspects of muscular development may occur differently than in infants born at term. Here we evaluated early manifestations of muscle tone by measuring muscle responses to passive stretching (StR) and shortening (ShR) in both upper and lower limbs in preterm infants (at the corrected age from 0 weeks to 12 months), and compared them to those reported in our previous study on full-term infants. In a subgroup of participants, we also assessed spontaneous muscle activity during episodes of relatively large limb movements. The results showed very frequent StR and ShR, and also responses in muscles not being primarily stretched/shortened, in both preterm and full-term infants. A reduction of sensorimotor responses to muscle lengthening and shortening with age suggests a reduction in excitability and/or the acquisition of functionally appropriate muscle tone during the first year of life. The alterations of responses during passive and active movements in preterm infants were primarily seen in the early months, perhaps reflecting temporal changes in the excitability of the sensorimotor networks.

Exoskeleton gait training with spinal cord neuromodulation

Neuromodulating the locomotor network through spinal cord electrical stimulation (SCES) is effective for restoring function in individuals with gait deficits. However, SCES alone has limited effectiveness without concurrent locomotor function training that enhances activity-dependent plasticity of spinal neuronal networks by sensory feedback. This mini review discusses recent developments in using combined interventions, such as SCES added to exoskeleton gait training (EGT). To develop personalized therapies, it is crucial to assess the state of spinal circuitry through a physiologically relevant approach that identifies individual characteristics of spinal cord function to develop person-specific SCES and EGT. The existing literature suggests that combining SCES and EGT to activate the locomotor network can have a synergistic rehabilitative effect on restoring walking abilities, somatic sensation, and cardiovascular and bladder function in paralyzed individuals.

Comparison of the forward and sideways locomotor patterns in children with Cerebral Palsy

Switching locomotion direction is a common task in daily life, and it has been studied extensively in healthy people. Little is known, however, about the locomotor adjustments involved in changing locomotion direction from forward (FW) to sideways (SW) in children with cerebral palsy (CP). The importance of testing the ability of children with CP in this task lies in the assessment of flexible, adaptable adjustments of locomotion as a function of the environmental context. On the one hand, the ability of a child to cope with novel task requirements may provide prognostic cues as to the chances of modifying the gait adaptively. On the other hand, challenging the child with the novel task may represent a useful rehabilitation tool to improve the locomotor performance. SW is an asymmetrical locomotor task and requires a differential control of right and left limb muscles. Here, we report the results of a cross-sectional study comparing FW and SW in 27 children with CP (17 diplegic, 10 hemiplegic, 2-10 years) and 18 age-matched typically developing (TD) children. We analyzed gait kinematics, joint moments, EMG activity of 12 pairs of bilateral muscles, and muscle modules evaluated by factorization of EMG signals. Task performance in several children with CP differed drastically from that of TD children. Only 2/3 of children with CP met the primary outcome, i.e. they succeeded to step sideways, and they often demonstrated attempts to step forward. They tended to rotate their trunk FW, cross one leg over the other, flex the knee and hip. Moreover, in contrast to TD children, children with CP often exhibited similar motor modules for FW and SW. Overall, the results reflect developmental deficits in the control of gait, bilateral coordination and adjustment of basic motor modules in children with CP. We suggest that the sideways (along with the backward) style of locomotion represents a novel rehabilitation protocol that challenges the child to cope with novel contextual requirements.

Development of Hand Use with and Without Intensive Training Among Children with Unilateral Cerebral Palsy in Scandinavia

AIM

To describe hand use development in children with unilateral cerebral palsy who did/did not participate in constraint-induced movement therapy (CIMT) before 7 years of age.

METHOD

The study included 334 participants (18 months-12 years) who were assessed with 1,565 Assisting Hand Assessments (AHAs) and categorized into no intensive training (NIT), CIMT (18 months-7 years), and Baby-CIMT (<18 months) groups.

RESULTS

AHA performance at 18 months (AHA-18) was positively associated with development regardless of training. The CIMT group had lower AHA-18 performance than the NIT group (p = .028), but higher stable limit (p = .076). The age when 90% of development was reached was highest in the CIMT group (p = .014). Although non-significant, the Baby-CIMT group had higher mean curve than NIT and CIMT combined (AHA-18 p = .459, limit p = .477).

CONCLUSION

The CIMT group improved more over time than the NIT group. Intensive training extended the window of development, and Baby-CIMT might promote early development.

Restoring After Central Nervous System Injuries: Neural Mechanisms and Translational Applications of Motor Recovery

Central nervous system (CNS) injuries, including stroke, traumatic brain injury, and spinal cord injury, are leading causes of long-term disability. It is estimated that more than half of the survivors of severe unilateral injury are unable to use the denervated limb. Previous studies have focused on neuroprotective interventions in the affected hemisphere to limit brain lesions and neurorepair measures to promote recovery. However, the ability to increase plasticity in the injured brain is restricted and difficult to improve. Therefore, over several decades, researchers have been prompted to enhance the compensation by the unaffected hemisphere. Animal experiments have revealed that regrowth of ipsilateral descending fibers from the unaffected hemisphere to denervated motor neurons plays a significant role in the restoration of motor function. In addition, several clinical treatments have been designed to restore ipsilateral motor control, including brain stimulation, nerve transfer surgery, and brain–computer interface systems. Here, we comprehensively review the neural mechanisms as well as translational applications of ipsilateral motor control upon rehabilitation after CNS injuries.

Genetic control of neuronal activity enhances axonal growth only on permissive substrates

Background

Neural tissue has limited regenerative ability. To cope with that, in recent years a diverse set of novel tools has been used to tailor neurostimulation therapies and promote functional regeneration after axonal injuries.

Method

In this report, we explore cell-specific methods to modulate neuronal activity, including opto- and chemogenetics to assess the effect of specific neuronal stimulation in the promotion of axonal regeneration after injury.

Results

Opto- and chemogenetic stimulations of neuronal activity elicited increased in vitro neurite outgrowth in both sensory and cortical neurons, as well as in vivo regeneration in the sciatic nerve, but not after spinal cord injury. Mechanistically, inhibitory substrates such as chondroitin sulfate proteoglycans block the activity induced increase in axonal growth.

Conclusions

We found that genetic modulations of neuronal activity on both dorsal root ganglia and corticospinal motor neurons increase their axonal growth capacity but only on permissive environments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00524-2.

Higher Responsiveness of Pattern Generation Circuitry to Sensory Stimulation in Healthy Humans Is Associated with a Larger Hoffmann Reflex

Simple Summary

Individual differences in the sensorimotor circuitry play an important role for understanding the nature of behavioral variability and developing personalized therapies. While the spinal network likely requires relatively rigid organization, it becomes increasingly evident that adaptability and inter-individual variability in the functioning of the neuronal circuitry is present not only in the brain but also in the spinal cord. In this study we investigated the relationship between the excitability of pattern generation circuitry and segmental reflexes in healthy humans. We found that the high individual responsiveness of pattern generation circuitries to tonic sensory input in both the upper and lower limbs was related to larger H-reflexes. The results provide further evidence for the importance of physiologically relevant assessments of spinal cord neuromodulation and the individual physiological state of reflex pathways.

Abstract

The state and excitability of pattern generators are attracting the increasing interest of neurophysiologists and clinicians for understanding the mechanisms of the rhythmogenesis and neuromodulation of the human spinal cord. It has been previously shown that tonic sensory stimulation can elicit non-voluntary stepping-like movements in non-injured subjects when their limbs were placed in a gravity-neutral unloading apparatus. However, large individual differences in responsiveness to such stimuli were observed, so that the effects of sensory neuromodulation manifest only in some of the subjects. Given that spinal reflexes are an integral part of the neuronal circuitry, here we investigated the extent to which spinal pattern generation excitability in response to the vibrostimulation of muscle proprioceptors can be related to the H-reflex magnitude, in both the lower and upper limbs. For the H-reflex measurements, three conditions were used: stationary limbs, voluntary limb movement and passive limb movement. The results showed that the H-reflex was considerably higher in the group of participants who demonstrated non-voluntary rhythmic responses than it was in the participants who did not demonstrate them. Our findings are consistent with the idea that spinal reflex measurements play important roles in assessing the rhythmogenesis of the spinal cord.

Motivating Selective Motor Control of Infants at High Risk of Cerebral Palsy Using an In-Home Kicking-Activated Mobile Task: A Pilot Study

OBJECTIVE

Decreased selective motor control limits gait function of children with spastic cerebral palsy (CP). Infants at high risk of CP demonstrate decreased selective motor control by 1 month of age. To motivate more selective hip-knee control, infants at high risk of CP participated in an in-home kicking-activated mobile task. The purpose of this study was to determine whether infants at high risk of CP and infants with typical development (TD) demonstrated increased selective hip-knee control during 2-minute intervals of the mobile task when they demonstrated learning of the association between their leg movement and mobile activation vs during 2-minute intervals when they did not demonstrate learning.

METHODS

Participants in this cohort study included 10 infants at high risk of CP based on neuroimaging and 11 infants with TD at 3.5 to 4.5 months of age. Each infant participated in the in-home kicking-activated mobile task for 8 to 10 min/d, 5 d/wk, for 6 weeks. Over 80,000 kicks were extracted and classified for each infant as occurring during 2-minute intervals of the task when the infant demonstrated learning vs not learning based on mobile activation time above baseline.

RESULTS

Infants demonstrated kicks with more selective hip-knee control during 2-minute intervals of the mobile task when they demonstrated learning compared with when they did not demonstrate learning for 4 of 6 weeks in the cohort at high risk of CP and for 2 of 6 weeks in the cohort with TD.

CONCLUSION

Participation in the in-home kicking-activated mobile task may motivate more selective hip-knee control of infants at high risk of CP.

IMPACT

This study is a first step toward developing an intervention to promote selective hip-knee control of infants at high risk of CP, with the ultimate goal of optimizing future walking function.

LAY SUMMARY

This study showed that playing with an in-home infant kicking-activated mobile may motivate infants at high risk of CP to produce more age-appropriate leg movements.

Measurement and Analysis of Human Infant Crawling for Rehabilitation: A Narrative Review

When a child shows signs of potential motor developmental disorders, early diagnosis of central nervous system (CNS) impairment is beneficial. Known as the first CNS-controlled mobility for most of infants, mobility during crawling usually has been used in clinical assessments to identify motor development disorders. The current clinical scales of motor development during crawling stage are relatively subjective. Objective and quantitative measures of infant crawling afford the possibilities to identify those infants who might benefit from early intervention, as well as the evaluation of intervention progress. Thus, increasing researchers have explored objective measurements of infant crawling in typical and atypical developing infants. However, there is a lack of comprehensive review on infant-crawling measurement and analysis toward bridging the gap between research crawling analysis and potential clinical applications. In this narrative review, we provide a practical overview of the most relevant measurements in human infant crawling, including acquisition techniques, data processing methods, features extraction, and the potential value in objective assessment of motor function in infancy; meanwhile, the possibilities to develop crawling training as early intervention to promote the locomotor function for infants with locomotor delays are also discussed.

Perinatal stroke: mapping and modulating developmental plasticity

Most cases of hemiparetic cerebral palsy are caused by perinatal stroke, resulting in lifelong disability for millions of people. However, our understanding of how the motor system develops following such early unilateral brain injury is increasing. Tools such as neuroimaging and brain stimulation are generating informed maps of the unique motor networks that emerge following perinatal stroke. As a focal injury of defined timing in an otherwise healthy brain, perinatal stroke represents an ideal human model of developmental plasticity. Here, we provide an introduction to perinatal stroke epidemiology and outcomes, before reviewing models of developmental plasticity after perinatal stroke. We then examine existing therapeutic approaches, including constraint, bimanual and other occupational therapies, and their potential synergy with non-invasive neurostimulation. We end by discussing the promise of exciting new therapies, including novel neurostimulation, brain-computer interfaces and robotics, all focused on improving outcomes after perinatal stroke.

Assessment of mirror movements in children and adolescents with unilateral cerebral palsy: reliability of the Woods and Teuber scale

AIM

To investigate the inter- and intrarater reliability of the Woods and Teuber scale to detect mirror movements in children and adolescents with unilateral cerebral palsy (CP).

METHOD

A convenience sample of children and adolescents with unilateral CP (n=68; 31 males, 37 females; mean age 12y 2mo, SD 3y 6mo) in Manual Ability Classification levels I to III was recruited from Norway, Australia, and Belgium. Three therapists scored mirror movements according to the Woods and Teuber scale from three video-recorded tasks at two separate time points. A two-way, mixed model regression was used to calculate intraclass correlation coefficients (ICCs) reflecting overall inter- and intrarater reliability. In addition, ICCs for each hand and task were calculated separately.

RESULTS

The overall interrater reliability ICC was 0.90 and the corresponding intrarater reliability ICC was 0.92. The ICCs for each hand ranged from 0.86 to 0.92 and for each task from 0.63 to 0.89.

INTERPRETATION

The Woods and Teuber scale shows excellent reliability for scoring mirror movements in children and adolescents with unilateral CP. The assessment is easy to administer with no need for specific equipment and scoring can be determined from short video recordings, making it a feasible instrument in research and clinical practice.

Improvements in Upper Extremity Function Following Intensive Training Are Independent of Corticospinal Tract Organization in Children With Unilateral Spastic Cerebral Palsy: A Clinical Randomized Trial

Background/Objectives: Intensive training of the more affected upper extremity (UE) has been shown to be effective for children with unilateral spastic cerebral palsy (USCP). Two types of UE training have been particularly successful: Constraint-Induced Movement Therapy (CIMT) and Bimanual training. Reorganization of the corticospinal tract (CST) early during development often occurs in USCP. Prior studies have suggested that children with an ipsilateral CST controlling the affected UE may improve less following CIMT than children with a contralateral CST. We tested the hypothesis that improvements in UE function after intensive training depend on CST laterality.

Study Participants and Setting: Eighty-two children with USCP, age 5 years 10 months to 17 years, University laboratory setting.

Materials/Methods: Single-pulse transcranial magnetic stimulation (TMS) was used to determine each child's CST connectivity pattern. Children were stratified by age, sex, baseline hand function and CST connectivity pattern, and randomized to receive either CIMT or Bimanual training, each of which were provided in a day-camp setting (90 h). Hand function was tested before, immediately and 6 months after the intervention with the Jebsen-Taylor Test of Hand Function, the Assisting Hand Assessment, the Box and Block Test, and ABILHAND-Kids. The Canadian Occupational Performance Measure was used to track goal achievement and the Pediatric Evaluation of Disability Inventory was used to assess functioning in daily living activities at home.

Results: In contrast to our hypothesis, participants had statistically similar improvements for both CIMT and Bimanual training for all measures independent of their CST connectivity pattern (contralateral, ipsilateral, or bilateral) (p < 0.05 in all cases).

Conclusions/Significance: The efficacy of CIMT and Bimanual training is independent of CST connectivity pattern. Children with an ipsilateral CST, previously thought to be maladaptive, have the capacity to improve as well as children with a contralateral or bilateral CST following intensive CIMT or Bimanual training.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT02918890.

Neuromuscular Control before and after Independent Walking Onset in Children with Cerebral Palsy

Early brain lesions which produce cerebral palsy (CP) may affect the development of walking. It is unclear whether or how neuromuscular control, as evaluated by muscle synergy analysis, differs in young children with CP compared to typically developing (TD) children with the same walking ability, before and after the onset of independent walking. Here we grouped twenty children with (high risk of) CP and twenty TD children (age 6.5–52.4 months) based on their walking ability, supported or independent walking. Muscle synergies were extracted from electromyography data of bilateral leg muscles using non-negative matrix factorization. Number, synergies’ structure and variability accounted for when extracting one (VAF₁) or two (VAF₂) synergies were compared between CP and TD. Children in the CP group recruited fewer synergies with higher VAF₁ and VAF₂ compared to TD children in the supported and independent walking group. The most affected side in children with asymmetric CP walking independently recruited fewer synergies with higher VAF₁ compared to the least affected side. Our findings suggest that early brain lesions result in early alterations of neuromuscular control, specific for the most affected side in asymmetric CP.

Constraint-induced intervention as an emergent phenomenon from synaptic competition in biological systems

The principle of constraint-induced therapy is widely practiced in rehabilitation. In hemiplegic cerebral palsy (CP) with impaired contralateral corticospinal projection due to unilateral injury, function improves after imposing a temporary constraint on limbs from the less affected hemisphere. This type of partially-reversible impairment in motor control by early brain injury bears a resemblance to the experience-dependent plastic acquisition and modification of neuronal response selectivity in the visual cortex. Previously, such mechanism was modeled within the framework of BCM (Bienenstock-Cooper-Munro) theory, a rate-based synaptic modification theory. Here, we demonstrate a minimally complex yet sufficient neural network model which provides a fundamental explanation for inter-hemispheric competition using a simplified spike-based model of information transmission and plasticity. We emulate the restoration of function in hemiplegic CP by simulating the competition between cells of the ipsilateral and contralateral corticospinal tracts. We use a high-speed hardware neural simulation to provide realistic numbers of spikes and realistic magnitudes of synaptic modification. We demonstrate that the phenomenon of constraint-induced partial reversal of hemiplegia can be modeled by simplified neural descending tracts with 2 layers of spiking neurons and synapses with spike-timing-dependent plasticity (STDP). We further demonstrate that persistent hemiplegia following unilateral cortical inactivation or deprivation is predicted by the STDP-based model but is inconsistent with BCM model. Although our model is a highly simplified and limited representation of the corticospinal system, it offers an explanation of how constraint as an intervention can help the system to escape from a suboptimal solution. This is a display of an emergent phenomenon from the synaptic competition.

Preschool HABIT-ILE: study protocol for a randomised controlled trial to determine efficacy of intensive rehabilitation compared with usual care to improve motor skills of children, aged 2-5 years, with bilateral cerebral palsy

INTRODUCTION

Young children with bilateral cerebral palsy (BCP) often experience difficulties with gross motor function, manual ability and posture, impacting developing independence in daily life activities, participation and quality of life. Hand Arm Bimanual Intensive Training Including Lower Extremity (HABIT-ILE) is a novel intensive motor intervention integrating upper and lower extremity training that has been developed and tested in older school-aged children with unilateral and BCP. This study aims to compare an adapted preschool version of HABIT-ILE to usual care in a randomised controlled trial.

METHODS AND ANALYSIS

60 children with BCP aged 2-5 years, Gross Motor Function Classification System (GMFCS) II-IV will be recruited. Children will be stratified by GMFCS and randomised using concealed allocation to either receive Preschool HABIT-ILE or usual care. Preschool HABIT-ILE will be delivered in groups of four to six children, for 3 hours/day for 10 days (total 30 hours). Children receiving Preschool HABIT-ILE be provided a written home programme with the aim of achieving an additional 10 hours of home practice (total dose 40 hours). Outcomes will be assessed at baseline, immediately following intervention and then retention of effects will be tested at 26 weeks. The primary outcome will be the Peabody Developmental Motors Scales-Second Edition to evaluate gross and fine motor skills. Secondary outcomes will be gross motor function (Gross Motor Function Measure-66), bimanual hand performance (Both Hands Assessment), self-care and mobility (Pediatric Evaluation of Disability Inventory-Computer Adapted Test), goal attainment (Canadian Occupational Performance Measure), global performance of daily activities (ACTIVLIM-CP), cognition and adaptive function (Behavior Rating Inventory of Executive Function-Preschool Version), habitual physical activity (ActiGraph GT3X+) and quality of life (Infant Toddler Quality of Life Questionnaire and Child Health Utility Index-9). Analyses will follow standard principles for RCTs using two-group comparisons on all participants on an intention-to-treat basis. Comparisons between groups for primary and secondary outcomes will be conducted using regression models.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Medical Research Ethics Committee Children's Health Queensland Hospital and Health Service Human Research Ethics Committee (HREC/19/QCHQ/59444) and The University of Queensland (2020000336/HREC/19/QCHQ/59444).

TRIAL REGISTRATION NUMBER

ACTRN126200000719.

In-Home Kicking-Activated Mobile Task to Motivate Selective Motor Control of Infants at High Risk of Cerebral Palsy: A Feasibility Study

OBJECTIVE

Children with spastic cerebral palsy (CP) have gait impairments resulting from decreased selective motor control, an inability to move the leg joints independently of one another, relying on excessive flexion or extension coupling across the 3 joints. Infants with white matter injury are at high risk of CP and have decreased selective motor control as early as 1 month corrected age. An in-home kicking-activated mobile task was developed to motivate more selective hip-knee control of infants at high risk of CP. The purposes of this study were to determine the feasibility of the in-home mobile task and to determine whether infants at high risk of CP and infants with typical development (TD) learn the association between their leg movements and mobile activation.

METHODS

Ten infants at high risk of CP based on neuroimaging and 11 infants with TD participated in this cohort study at 3.5 to 4.5 months corrected age. Each infant participated in the in-home kicking-activated mobile task for 8 to 10 min/d, 5 d/wk, for 6 weeks. Learning was assessed weekly based on an increase in the time that the infant demonstrated the reinforced leg actions when interacting with the kicking-activated mobile compared with spontaneous kicking.

RESULTS

With regard to feasibility, participation averaged 92% for infants at high risk of CP and 99% for infants with TD. With regard to learning, the group at high risk of CP demonstrated learning of the task for 2 of 6 weeks, whereas the group with TD demonstrated learning for all 6 weeks.

CONCLUSIONS

Infants at high risk of CP demonstrated learning of the kicking-activated mobile task but at a reduced amount compared with infants with TD. Further research is necessary to determine whether the kicking-activated mobile task has potential as an intervention to motivate more selective hip-knee control and improve walking outcomes of infants at high risk of CP.

IMPACT

This study investigated the feasibility of an in-home kicking-activated mobile task, a discovery learning task designed to motivate infants at high risk of CP to engage in the intensive task practice necessary to promote their learning abilities and selective motor control.

LAY SUMMARY

CP is a lifelong disorder of movement caused by abnormal development or early damage to the brain. If an in-home infant kicking-activated mobile task could be used to motivate certain types of age-appropriate leg movements of infants who are at high risk of CP, the task could help improve walking outcomes, which eventually could contribute to improving children's ability to participate in daily life. This study showed that infants at high risk of CP did learn the infant kicking-activated mobile task but at a much reduced amount compared with infants who are developing typically; so, this is a first step in determining whether the task has potential to motivate more age-appropriate leg movements in infants at high risk of cerebral palsy.

Maturation of the Locomotor Circuitry in Children With Cerebral Palsy

The first years of life represent an important phase of maturation of the central nervous system, processing of sensory information, posture control and acquisition of the locomotor function. Cerebral palsy (CP) is the most common group of motor disorders in childhood attributed to disturbances in the fetal or infant brain, frequently resulting in impaired gait. Here we will consider various findings about functional maturation of the locomotor output in early infancy, and how much the dysfunction of gait in children with CP can be related to spinal neuronal networks vs. supraspinal dysfunction. A better knowledge about pattern generation circuitries in infancy may improve our understanding of developmental motor disorders, highlighting the necessity for regulating the functional properties of abnormally developed neuronal locomotor networks as a target for early sensorimotor rehabilitation. Various clinical approaches and advances in biotechnology are also considered that might promote acquisition of the locomotor function in infants at risk for locomotor delays.

Locomotor patterns during obstacle avoidance in children with cerebral palsy

Previous studies mainly evaluated the neuromuscular pattern generation in cerebral palsy (CP) during unobstructed gait. Here we characterized impairments in the obstacle task performance associated with a limited adaptation of the task-relevant muscle module timed to the foot lift during obstacle crossing. Impaired task performance in children with CP may reflect basic developmental deficits in the adaptable control of gait when the locomotor task is superimposed with the voluntary movement.

Do Infants at Risk of Developing Cerebral Palsy or Other Neurodevelopmental Disorders Learn What They Practice?

Through secondary analyses of the Small Step. Randomized Control Trial, we tested the hypothesis that children at risk of developing cerebral palsy (CP) or other neurodevelopmental disorders would learn what they practice, i.e., that they would have a more rapid development within the specifically trained foci (hand use or mobility) of each time period compared to the development rate within the foci not trained at that time. Nineteen infants (6.3 (1.62) months corrected age) included in the Small Step program were assessed at six time points during the intervention. For statistical analysis, general and mixed linear models were used, and the independent variables were the Peabody Developmental Motor scale (stationary, locomotion, grasping and visuomotor sub scales), the Gross Motor Function Measure-66 and the Hand Assessment for Infants. Outcomes related to gross motor function improved significantly more after mobility training than after hand use training, while fine motor function was improved to the same extent following both training types. Significantly higher improvements after the first training period were seen in one out of three outcome measures in both gross and fine motor assessments. The improvements observed were all independent of diagnosis at two years. The concept “you learn what you practice” was most clearly confirmed in the case of gross motor development.

Protocol of changes induced by early Hand-Arm Bimanual Intensive Therapy Including Lower Extremities (e-HABIT-ILE) in pre-school children with bilateral cerebral palsy: a multisite randomized controlled trial

BACKGROUND

Cerebral palsy (CP), which is the leading cause of motor disability during childhood, can produce sensory and cognitive impairments at different degrees. Most recent therapeutic interventions for these patients have solely focused on upper extremities (UE), although more than 60% of these patients present lower extremities (LE) deficits. Recently, a new therapeutic concept, Hand-arm Bimanual Intensive Therapy Including Lower Extremities (HABIT-ILE), has been proposed, involving the constant stimulation of UE and LE. Based on motor skill learning principles, HABIT-ILE is delivered in a day-camp setting, promoting voluntary movements for several hours per day during 10 consecutive week days. Interestingly, the effects of this intervention in a large scale of youngsters are yet to be observed. This is of interest due to the lack of knowledge on functional, neuroplastic and biomechanical changes in infants with bilateral CP. The aim of this randomized controlled study is to assess the effects of HABIT-ILE adapted for pre-school children with bilateral CP regarding functional, neuroplastic and biomechanical factors.

METHODS

This international, multicentric study will include 50 pre-school children with CP from 12 to 60 months of age, comparing the effect of 50 h (2 weeks) of HABIT-ILE versus regular motor activity and/or customary rehabilitation. HABIT-ILE presents structured activities and functional tasks with continuous increase in difficulty while the child evolves. Assessments will be performed at 3 period times: baseline, two weeks later and 3 months later. The primary outcome will be the Gross Motor Function Measure 66. Secondary outcomes will include Both Hands Assessment, Melbourne Assessment-2, Semmes-Weinstein Monofilament Test, algometry assessments, executive function tests, ACTIVLIM-CP questionnaire, Pediatric Evaluation of Disability Inventory (computer adaptative test), Young Children's Participation and Environment Measure, Measure of the Process of Care, Canadian Occupational Performance Measure, neuroimaging and kinematics.

DISCUSSION

The results of this study should highlight the impact of a motor, intensive, goal-directed therapy (HABIT-ILE) in pre-school children at a functional, neuroplastic and biomechanical level. In addition, this changes could demonstrated the impact of this intervention in the developmental curve of each child, improving functional ability, activity and participation in short-, mid- and long-term.

NAME OF THE REGISTRY

Evaluation of Functional, Neuroplastic and Biomechanical Changes Induced by an Intensive, Playful Early-morning Treatment Including Lower Limbs (EARLY-HABIT-ILE) in Preschool Children With Uni and Bilateral Cerebral Palsy (HABIT-ILE).

TRIAL REGISTRATION

NCT04017871 REGISTRATION DATE: July 12, 2019.

Transcranial Static Magnetic Field Stimulation of the Motor Cortex in Children

BACKGROUND

Non-invasive neuromodulation is an emerging therapy for children with early brain injury but is difficult to apply to preschoolers when windows of developmental plasticity are optimal. Transcranial static magnetic field stimulation (tSMS) decreases primary motor cortex (M1) excitability in adults but effects on the developing brain are unstudied.

OBJECTIVE/HYPOTHESIS

We aimed to determine the effects of tSMS on cortical excitability and motor learning in healthy children. We hypothesized that tSMS over right M1 would reduce cortical excitability and inhibit contralateral motor learning.

METHODS

This randomized, sham-controlled, double-blinded, three-arm, cross-over trial enrolled 24 healthy children aged 10-18 years. Transcranial Magnetic Stimulation (TMS) assessed cortical excitability via motor-evoked potential (MEP) amplitude and paired pulse measures. Motor learning was assessed via the Purdue Pegboard Test (PPT). A tSMS magnet (677 Newtons) or sham was held over left or right M1 for 30 min while participants trained the non-dominant hand. A linear mixed effect model was used to examine intervention effects.

RESULTS

All 72 tSMS sessions were well tolerated without serious adverse effects. Neither cortical excitability as measured by MEPs nor paired-pulse intracortical neurophysiology was altered by tSMS. Possible behavioral effects included contralateral tSMS inhibiting early motor learning (p < 0.01) and ipsilateral tSMS facilitating later stages of motor learning (p < 0.01) in the trained non-dominant hand.

CONCLUSION

tSMS is feasible in pediatric populations. Unlike adults, tSMS did not produce measurable changes in MEP amplitude. Possible effects of M1 tSMS on motor learning require further study. Our findings support further exploration of tSMS neuromodulation in young children with cerebral palsy.

Motor Skill Training May Restore Impaired Corticospinal Tract Fibers in Children With Cerebral Palsy

Background. In children with unilateral cerebral palsy (UCP), the fibers of the corticospinal tract (CST) emerging from the lesioned hemisphere are damaged following the initial brain injury. The extent to which the integrity of these fibers is restorable with training is unknown. Objective. To assess changes in CST integrity in children with UCP following Hand-and-Arm-Bimanual-Intensive-Therapy-Including-Lower-Extremity (HABIT-ILE) compared to a control group. Methods. Forty-four children with UCP participated in this study. Integrity of the CSTs was measured using diffusion tensor imaging before and after 2 weeks of HABIT-ILE (treatment group, n = 23) or 2 weeks apart without intensive treatment (control group, n = 18). Fractional anisotropy (FA) and mean diffusivity (MD) were the endpoints for assessing the integrity of CST. Results. As highlighted in our whole tract analysis, the FA of the CST originating from the nonlesioned and lesioned hemispheres increased significantly after therapy in the treatment group compared to the control group (group * test session interaction: P < .001 and P = .049, respectively). A decrease in MD was also observed in the CST emerging from the nonlesioned and lesioned hemispheres (group * time interaction: both P < .001). In addition, changes in manual ability correlated with changes in FA in both CSTs (r = 0.463, P = .024; r = 0.643, P < .001) and changes in MD in CST emerging from nonlesioned hemisphere (r = -0.662, P < .001). Conclusions. HABIT-ILE improves FA/MD in the CST and hand function of children with UCP, suggesting that CST fibers retain a capacity for functional restoration. This finding supports the application of intensive motor skill training in clinical practice for the benefit of numerous patients.

Functional, neuroplastic and biomechanical changes induced by early Hand-Arm Bimanual Intensive Therapy Including Lower Extremities (e-HABIT-ILE) in pre-school children with unilateral cerebral palsy: study protocol of a randomized control trial

BACKGROUND

Cerebral palsy (CP) causes motor, cognitive and sensory impairment at different extents. Many recent rehabilitation developments (therapies) have focused solely on the upper extremities (UE), although the lower extremities (LE) are commonly affected. Hand-arm Bimanual Intensive Therapy Including Lower Extremities (HABIT-ILE) applies the concepts of motor skill learning and intensive training to both the UE and LE. It involves constant stimulation of the UE and LE, for several hours each day over a 2-week period. The effects of HABIT-ILE have never been evaluated in a large sample of young children. Furthermore, understanding of functional, neuroplastic and biomechanical changes in infants with CP is lacking. The aim of this study is to carry out a multi-center randomized controlled trial (RCT) to evaluate the effects of HABIT-ILE in pre-school children with unilateral CP on functional, neuroplastic and biomechanical parameters.

METHODS

This multi-center, 3-country study will include 50 pre-school children with CP aged 1-4 years. The RCT will compare the effect of 50 h (two weeks) of HABIT-ILE versus usual motor activity, including regular rehabilitation. HABIT-ILE will be delivered in a day-camp setting, with structured activities and functional tasks that will be continuously progressed in terms of difficulty. Assessments will be performed at 3 intervals: baseline (T0), two weeks later and 3 months later. Primary outcomes will be the Assisting Hand Assessment; secondary outcomes include the Melbourne Assessment-2, executive function assessments, questionnaires ACTIVLIM-CP, Pediatric Evaluation of Disability Inventory, Young Children's Participation and Environment Measure, Measure of the Process of Care, Canadian Occupational Performance Measure, as well as neuroimaging and kinematics measures.

DISCUSSION

We expect that HABIT-ILE will induce functional, neuroplastic and biomechanical changes as a result of the intense, activity-based rehabilitation process and these changes will impact the whole developmental curve of each child, improving functional ability, activity and participation in the short-, mid- and long-term. Name of the registry: Changes Induced by Early HABIT-ILE in Pre-school Children With Uni- and Bilateral Cerebral Palsy (EarlyHABIT-ILE).

TRIAL REGISTRATION

Trial registration number: NCT04020354-Registration date on the International Clinical Trials Registry Platform (ICTRP): November 20th, 2018; Registration date on NIH Clinical Trials Registry: July 16th, 2019.

Anatomical and Functional Characterization in Children With Unilateral Cerebral Palsy: An Atlas-Based Analysis

Background. Variability in hand function among children with unilateral cerebral palsy (UCP) might reflect the type of brain injury and resulting anatomical sequelae. Objective. We used atlas-based analysis of structural images to determine whether children with periventricular (PV) versus middle cerebral artery (MCA) injuries might exhibit unique anatomical characteristics that account for differences in hand function. Methods. Forty children with UCP underwent structural brain imaging using 3-T magnetic resonance imaging. Brain lesions were classified as PV or MCA. A group of 40 typically developing (TD) children served as comparison controls. Whole brains were parcellated into 198 structures (regions of interest) to obtain volume estimates. Dexterity and bimanual hand function were assessed. Unbiased, differential expression analysis was performed to determine volumetric differences between PV and MCA groups. Principal component analysis (PCA) was performed and the top 3 components were extracted to perform regression on hand function. Results. Children with PV had significantly better hand function than children with MCA. Multidimensional scaling analysis of volumetric data revealed separate clustering of children with MCA, PV, and TD children. PCA extracted anatomical components that comprised the 2 types of brain injury. In the MCA group, reductions of volume were concentrated in sensorimotor structures of the injured hemisphere. Models using PCA predicted hand function with greater accuracy than models based on qualitative brain injury type. Conclusions. Our results highlight unique quantitative differences in children with UCP that also predict differences in hand function. The systematic discrimination between groups found in our study reveals future questions about the potential prognostic utility of this approach.

Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy-part 2: gender differences and left-biased asymmetry

INTRODUCTION

Spinal reflexes reorganize in cerebral palsy (CP), producing hyperreflexia and spasticity. CP is more common among male infants, and gender might also influence brain and spinal-cord reorganization. This retrospective study investigated the frequency of higher-graded EMG responses elicited by electrical nerve-root stimulation during selective dorsal rhizotomy (SDR), prior to partial nerve- root deafferentation, considering not only segmental level and body side, but also gender.

METHODS

Intraoperative neuromonitoring (IOM) was used in SDR to pinpoint the rootlets most responsible for exacerbated stimulation-evoked EMG patterns recorded from lower-limb muscle groups. Responses were graded according to an objective response-classification system, ranging from no abnormalities (grade 0) to highly abnormal (grade 4+), based on ipsilateral spread and contralateral involvement. Non-parametric analysis of data with repeated measures was primarily used in investigating the frequency distribution of these various EMG response grades. Over 7000 rootlets were stimulated, and the results for 65 girls and 81 boys were evaluated, taking changes in the composition of patient groups into account when considering GMFCS levels.

RESULTS

The distribution of graded EMG responses varied according to gender, laterality, and level. Higher-graded EMG responses were markedly more frequent in the boys and at lower segmental levels (L5, S1). Left-biased asymmetry in higher-graded rootlets was also more noticeable in the boys and in patients with GMFCS level I. A close link was observed between higher-grade assessments and left-biased asymmetry.

CONCLUSIONS

Detailed insight into the patient's initial spinal-neurofunctional state prior to deafferentation suggests that differences in asymmetrical spinal reorganization might be attributable to a hemispheric imbalance.

Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy-part 1: clinical setting and neurophysiological procedure

INTRODUCTION

Selective dorsal rhizotomy (SDR) consists of microsurgical partial deafferentation of sensory nerve roots (L1-S2). It is primarily used today in decreasing spasticity in young cerebral palsy (CP) patients. Intraoperative monitoring (IOM) is an essential part of the surgical decision-making process, aimed at improving functional results. The role played by SDR-IOM is examined, while realizing that connections between complex EMG responses to nerve-root stimulation and a patient's individual motor ability remain to be clarified.

METHODS

We conducted this retrospective study, analyzing EMG responses in 146 patients evoked by dorsal-root and rootlet stimulation, applying an objective response-classification system, and investigating the prevalence and distribution of the assessed grades. Part1 describes the clinical setting and SDR procedure, reintroduced in Germany by the senior author in 2007.

RESULTS

Stimulation-evoked EMG response patterns revealed significant differences along the segmental levels. More specifically, a comparison of grade 3+4 prevalence showed that higher-graded rootlets were more noticeable at lower nerve root levels (L5, S1), resulting in a typical rostro-caudal anatomical distribution.

CONCLUSIONS

In view of its prophylactic potential, SDR should be carried out at an early stage in all CP patients suffering from severe spasticity. It is particularly effective when used as an integral part of a coordinated, comprehensive spasticity program in which a team of experts pool their information. The IOM findings pertaining to the anatomical grouping of grades could be of potential importance in adjusting the SDR-IOM intervention to suit the specific individual constellation, pending further validation.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03079362.

Constraint-induced movement therapy in children with unilateral cerebral palsy

BACKGROUND

Unilateral cerebral palsy (CP) is a condition that affects muscle control and function on one side of the body. Children with unilateral CP experience difficulties using their hands together secondary to disturbances that occur in the developing fetal or infant brain. Often, the more affected limb is disregarded. Constraint-induced movement therapy (CIMT) aims to increase use of the more affected upper limb and improve bimanual performance. CIMT is based on two principles: restraining the use of the less affected limb (for example, using a splint, mitt or sling) and intensive therapeutic practice of the more affected limb.

OBJECTIVES

To evaluate the effect of constraint-induced movement therapy (CIMT) in the treatment of the more affected upper limb in children with unilateral CP.

SEARCH METHODS

In March 2018 we searched CENTRAL, MEDLINE, Embase, CINAHL, PEDro, OTseeker, five other databases and three trials registers. We also ran citation searches, checked reference lists, contacted experts, handsearched key journals and searched using Google Scholar.

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster-RCTs or clinically controlled trials implemented with children with unilateral CP, aged between 0 and 19 years, where CIMT was compared with a different form of CIMT, or a low dose, high-dose or dose-matched alternative form of upper-limb intervention such as bimanual intervention. Primarily, outcomes were bimanual performance, unimanual capacity and manual ability. Secondary outcomes included measures of self-care, body function, participation and quality of life.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts to eliminate ineligible studies. Five review authors were paired to extract data and assess risk of bias in each included study. GRADE assessments were undertaken by two review authors.

MAIN RESULTS

We included 36 trials (1264 participants), published between 2004 and 2018. Sample sizes ranged from 11 to 105 (mean 35). Mean age was 5.96 years (standard deviation (SD) 1.82), range three months to 19.8 years; 53% male and 47% participants had left hemiplegia. Fifty-seven outcome measures were used across studies. Average length of CIMT programs was four weeks (range one to 10 weeks). Frequency of sessions ranged from twice weekly to seven days per week. Duration of intervention sessions ranged from 0.5 to eight hours per day. The mean total number of hours of CIMT provided was 137 hours (range 20 to 504 hours). The most common constraint devices were a mitt/glove or a sling (11 studies each).We judged the risk of bias as moderate to high across the studies.

KEY RESULTS

Primary outcomes at primary endpoint (immediately after intervention)CIMT versus low-dose comparison (e.g. occupational therapy)We found low-quality evidence that CIMT was more effective than a low-dose comparison for improving bimanual performance (mean difference (MD) 5.44 Assisting Hand Assessment (AHA) units, 95% confidence interval (CI) 2.37 to 8.51).CIMT was more effective than a low-dose comparison for improving unimanual capacity (Quality of upper extremity skills test (QUEST) - Dissociated movement MD 5.95, 95% CI 2.02 to 9.87; Grasps; MD 7.57, 95% CI 2.10 to 13.05; Weight bearing MD 5.92, 95% CI 2.21 to 9.6; Protective extension MD 12.54, 95% CI 8.60 to 16.47). Three studies reported adverse events, including frustration, constraint refusal and reversible skin irritations from casting.CIMT versus high-dose comparison (e.g. individualised occupational therapy, bimanual therapy)When compared with a high-dose comparison, CIMT was not more effective for improving bimanual performance (MD -0.39 AHA Units, 95% CI -3.14 to 2.36). There was no evidence that CIMT was more effective than a high-dose comparison for improving unimanual capacity in a single study using QUEST (Dissociated movement MD 0.49, 95% CI -10.71 to 11.69; Grasp MD -0.20, 95% CI -11.84 to 11.44). Two studies reported that some children experienced frustration participating in CIMT.CIMT versus dose-matched comparison (e.g. Hand Arm Bimanual Intensive Therapy, bimanual therapy, occupational therapy)There was no evidence of differences in bimanual performance between groups receiving CIMT or a dose-matched comparison (MD 0.80 AHA units, 95% CI -0.78 to 2.38).There was no evidence that CIMT was more effective than a dose-matched comparison for improving unimanual capacity (Box and Blocks Test MD 1.11, 95% CI -0.06 to 2.28; Melbourne Assessment MD 1.48, 95% CI -0.49 to 3.44; QUEST Dissociated movement MD 6.51, 95% CI -0.74 to 13.76; Grasp, MD 6.63, 95% CI -2.38 to 15.65; Weightbearing MD -2.31, 95% CI -8.02 to 3.40) except for the Protective extension domain (MD 6.86, 95% CI 0.14 to 13.58).There was no evidence of differences in manual ability between groups receiving CIMT or a dose-matched comparison (ABILHAND-Kids MD 0.74, 95% CI 0.31 to 1.18). From 15 studies, two children did not tolerate CIMT and three experienced difficulty.

AUTHORS' CONCLUSIONS

The quality of evidence for all conclusions was low to very low. For children with unilateral CP, there was some evidence that CIMT resulted in improved bimanual performance and unimanual capacity when compared to a low-dose comparison, but not when compared to a high-dose or dose-matched comparison. Based on the evidence available, CIMT appears to be safe for children with CP.

Brain Lesions as a Predictor of Therapeutic Outcomes of Hand Function in Infants With Unilateral Cerebral Palsy

AIM

The present study aimed to investigate whether the response variability of infants to modified constraint-induced movement therapy and bimanual therapy are associated with different types of brain lesions.

METHOD

Infants with unilateral cerebral palsy (N = 22) ages 8-15 months (mean = 10.95, standard deviation = 2.15 months) were grouped according to having either a periventricular brain lesion or a middle cerebral artery infarct lesion. Improvement in hand function was analyzed based on the mini-Assistive Hand Assessment results.

RESULTS

Infants with periventricular brain lesion displayed greater positive response to upper limb treatment compared to those with middle cerebral artery infarct ( P = .02). A significant difference in improvement according to type of treatment was found in the middle cerebral artery infarct group but not in the periventricular brain lesion.

CONCLUSION

The present study showed an association between the type of brain lesion and the efficacy of upper limb treatment in infants. Infants with periventricular brain lesions displayed greater positive responses than those with middle cerebral artery infarct.

The effectiveness of Baby-CIMT in infants younger than 12 months with clinical signs of unilateral-cerebral palsy; an explorative study with randomized design

AIM

To explore the effectiveness of baby-CIMT (constraint-induced movement therapy) and baby-massage for improving the manual ability of infants younger than 12 months with unilateral cerebral palsy (CP).

METHOD

Infants eligible for inclusion were 3-8 months old with asymmetric hand function and at high risk of developing unilateral CP. Thirty-seven infants were assigned randomly to receive baby-CIMT or baby-massage. At one year of age 31 children were diagnosed with unilateral CP, 18 (8 boys, 6.1±1.7months) of these had received baby-CIMT and 13 (8 boys, 5.0±1.6months) baby-massage. There were two 6-week training periods separated by a 6-week pause. The Hand Assessment for Infants (HAI), Assisting Hand Assessment (AHA), the Parenting Sense of Competence Scale (PSCS) and a questionnaire concerning feasibility were applied.

RESULTS

There was improvement in the "Affected hand score" of HAI from median 10 (6;13 IQR) to 13 (7;17 IQR) raw score in the baby-CIMT group and from 5 (4;11 IQR) to 6 (3;12 IQR) for baby-massage with a significant between group difference (p=0.041). At 18-month of age, the median AHA score were 51 (38;72 IQR) after baby-CIMT (n=18) compared to 24 (19;43 IQR) baby-massage (n=9). The PSCS revealed an enhanced sense of competence of being a parent among fathers in the baby-CIMT group compared to fathers in the baby-massage (p=0.002). Parents considered both interventions to be feasible.

CONCLUSION

Baby-CIMT appears to improve the unimanual ability of young children with unilateral CP more than massage.

Backward walking highlights gait asymmetries in children with cerebral palsy

To investigate how early injuries to developing motor regions of the brain affect different forms of gait, we compared the spatiotemporal locomotor patterns during forward (FW) and backward (BW) walking in children with cerebral palsy (CP). Bilateral gait kinematics and EMG activity of 11 pairs of leg muscles were recorded in 14 children with CP (9 diplegic, 5 hemiplegic; 3.0-11.1 yr) and 14 typically developing (TD) children (3.3-11.8 yr). During BW, children with CP showed a significant increase of gait asymmetry in foot trajectory characteristics and limb intersegmental coordination. Furthermore, gait asymmetries, which were not evident during FW in diplegic children, became evident during BW. Factorization of the EMG signals revealed a comparable structure of the motor output during FW and BW in all groups of children, but we found differences in the basic temporal activation patterns. Overall, the results are consistent with the idea that both forms of gait share pattern generation control circuits providing similar (though reversed) kinematic patterns. However, BW requires different muscle activation timings associated with muscle modules, highlighting subtle gait asymmetries in diplegic children, and thus provides a more comprehensive assessment of gait pathology in children with CP. The findings suggest that spatiotemporal asymmetry assessments during BW might reflect an impaired state and/or descending control of the spinal locomotor circuitry and can be used for diagnostic purposes and as complementary markers of gait recovery. NEW & NOTEWORTHY Early injuries to developing motor regions of the brain affect both forward progression and other forms of gait. In particular, backward walking highlights prominent gait asymmetries in children with hemiplegia and diplegia from cerebral palsy and can give a more comprehensive assessment of gait pathology. The observed spatiotemporal asymmetry assessments may reflect both impaired supraspinal control and impaired state of the spinal circuitry.

Coaction of individual and environmental factors: a review of intensive therapy paradigms for children with unilateral spastic cerebral palsy

Evidence-based treatment approaches for children with unilateral spastic cerebral palsy are expanding and being modified to fit the constraints of families and the child receiving treatment. In this review, we first provide an overview of a theoretical framework that considers the intricate interactions between the individual child and the environment in which treatment is provided. Next, we describe intensive interventions that have strong support for their efficacy. We also highlight the heterogeneity with which children respond to these approaches. Individual characteristics that might affect responsiveness are summarized. We propose that a one-size-fits-all approach may not be as efficacious as approaches based on the specific brain damage and resulting development of the corticospinal tract. Finally, we review evidence suggesting that the environment can be structured to promote opportunities for intensive practice and self-generated movement-two important aspects of efficacious treatments. Emphasis is placed on intensive home programs delivered by caregivers.

WHAT THIS PAPER ADDS

Considerable variability exists in how children with unilateral spastic cerebral palsy respond to intensive upper extremity therapies. Individual and environmental factors interact to shape responsiveness.

Task-Specific and Functional Effects of Speed-Focused Elliptical or Motor-Assisted Cycle Training in Children With Bilateral Cerebral Palsy: Randomized Clinical Trial

BACKGROUND

Locomotor training using treadmills or robotic devices is commonly utilized to improve gait in cerebral palsy (CP); however, effects are inconsistent and fail to exceed those of equally intense alternatives. Possible limitations of existing devices include fixed nonvariable rhythm and too much limb or body weight assistance.

OBJECTIVE

To quantify and compare effectiveness of a motor-assisted cycle and a novel alternative, an elliptical, in CP to improve interlimb reciprocal coordination through intensive speed-focused leg training.

METHODS

A total of 27 children with bilateral CP, 5 to 17 years old, were randomized to 12 weeks of 20 minutes, 5 days per week home-based training (elliptical = 14; cycle = 13) at a minimum of 40 revolutions per minute, with resistance added when speed target was achieved. Primary outcomes were self-selected and fastest voluntary cadence on the devices and gait speed. Secondary outcomes included knee muscle strength, and selective control and functional mobility measures.

RESULTS

Cadence on trained but not nontrained devices increased, demonstrating task specificity of training and increased exercise capability. Mean gait speed did not increase in either group, nor did parent-reported functional mobility. Knee extensor strength increased in both. An interaction between group and time was seen in selective control with scores slightly increasing for the elliptical and decreasing for the cycle, possibly related to tighter limb coupling with cycling.

CONCLUSIONS

Task-specific effects were similarly positive across groups, but no transfer was seen to gait or function. Training dose was low (≤20 hours) compared with intensive upper-limb training recommendations and may be insufficient to produce appreciable clinical change.

Life course health development of individuals with neurodevelopmental conditions

The life course health development (LCHD) model by Halfon et al. conceptualizes health development occurring through person-environment transactions that enable well-being and participation in desired social roles throughout life, areas that have not received adequate attention in healthcare. The aim of this 'perspectives' paper is to apply the six core tenets of the LCHD model and the concept of health development trajectories to individuals with lifelong neurodevelopmental conditions. We share the perspective that modifiable aspects of the environment often restrict health development; we then advocate that children, beginning at a young age, should engage in 'real-world' experiences that prepare them for current and future social roles. LCHD encourages future planning from the outset, continuity of care between pediatric and adult systems, and coordination of services and supports. We believe LCHD can be transformative in enabling healthy living of individuals with neurodevelopmental conditions.

A critical period of corticomuscular and EMG-EMG coherence detection in healthy infants aged 9-25 weeks

KEY POINTS

The early postnatal development of functional corticospinal connections in human infants is not fully clarified. Corticospinal drive to upper and lower limb muscle shows developmental changes with an increased functional coupling in infants between 9 and 25 weeks in the beta frequency band. The changes in functional coupling coincide with the developmental period where fidgety movements are present in healthy infants. Data support a possible sensitive period where functional connections between corticospinal tract fibres and spinal motoneurones undergo activity-dependent reorganization.

ABSTRACT

The early postnatal development of functional corticospinal connections in human infants is not fully clarified. We used EEG and EMG to investigate the development of corticomuscular and intramuscular coherence as indicators of functional corticospinal connectivity in healthy infants aged 1-66 weeks. EEG was recorded over leg and hand area of motor cortex. EMG recordings were made from right ankle dorsiflexor and right wrist extensor muscles. Quantification of the amount of corticomuscular coherence in the 20-40 Hz frequency band showed a significantly larger coherence for infants aged 9-25 weeks compared to younger and older infants. Coherence between paired EMG recordings from tibialis anterior muscle in the 20-40 Hz frequency band was also significantly larger for the 9-25 week age group. A low-amplitude, broad-duration (40-50 ms) central peak of EMG-EMG synchronization was observed for infants younger than 9 weeks, whereas a short-lasting (10-20 ms) central peak was observed for EMG-EMG synchronization in older infants. This peak was largest for infants aged 9-25 weeks. These data suggest that the corticospinal drive to lower and upper limb muscles shows significant developmental changes with an increase in functional coupling in infants aged 9-25 weeks, a period which coincides partly with the developmental period of normal fidgety movements. We propose that these neurophysiological findings may reflect the existence of a sensitive period where the functional connections between corticospinal tract fibres and spinal motoneurones undergo activity-dependent reorganization. This may be relevant for the timing of early therapy interventions in infants with pre- and perinatal brain injury.

Non cell-autonomous role of DCC in the guidance of the corticospinal tract at the midline

DCC, a NETRIN-1 receptor, is considered as a cell-autonomous regulator for midline guidance of many commissural populations in the central nervous system. The corticospinal tract (CST), the principal motor pathway for voluntary movements, crosses the anatomic midline at the pyramidal decussation. CST fails to cross the midline in Kanga mice expressing a truncated DCC protein. Humans with heterozygous DCC mutations have congenital mirror movements (CMM). As CMM has been associated, in some cases, with malformations of the pyramidal decussation, DCC might also be involved in this process in human. Here, we investigated the role of DCC in CST midline crossing both in human and mice. First, we demonstrate by multimodal approaches, that patients with CMM due to DCC mutations have an increased proportion of ipsilateral CST projections. Second, we show that in contrast to Kanga mice, the anatomy of the CST is not altered in mice with a deletion of DCC in the CST. Altogether, these results indicate that DCC controls CST midline crossing in both humans and mice, and that this process is non cell-autonomous in mice. Our data unravel a new level of complexity in the role of DCC in CST guidance at the midline.

Unimanual versus bimanual therapy in children with unilateral cerebral palsy: Same, same, but different

BACKGROUND

There is high-level evidence supporting constraint-induced movement therapy (CIMT) and bimanual therapy for children with unilateral cerebral palsy. Evidence-based intervention includes time-limited, goal-directed, skills-based, intensive blocks of practice based on motor learning theory.

AIM AND METHODS

Using supporting literature and clinical insight, we provide a theoretical rationale to highlight previously unreported differences between CIMT and bimanual therapy.

DISCUSSION

The current emphasis on total dosage of practice for achieving positive outcomes fails to recognise the influence of other critical concepts within motor learning. Limitations exist in the application of motor learning principles using CIMT due to its unimanual nature. CIMT is effective for development of unimanual actions brought about by implicit learning, however it is difficult to target explicit learning that is required for learning how to use two hands together. Using bimanual therapy, object properties can be adapted to trigger goal-related perceptual and cognitive processes required for children to learn to recognise when two hands are required for task completion.

CONCLUSION

CIMT and bimanual should be viewed as complementary. CIMT could be used to target unimanual actions. Once these actions are established, bimanual therapy could be used for children to learn how to use these actions for bimanual skill development.

Cerebral plasticity: Windows of opportunity in the developing brain

BACKGROUND

Neuroplasticity refers to the inherently dynamic biological capacity of the central nervous system (CNS) to undergo maturation, change structurally and functionally in response to experience and to adapt following injury. This malleability is achieved by modulating subsets of genetic, molecular and cellular mechanisms that influence the dynamics of synaptic connections and neural circuitry formation culminating in gain or loss of behavior or function. Neuroplasticity in the healthy developing brain exhibits a heterochronus cortex-specific developmental profile and is heightened during "critical and sensitive periods" of pre and postnatal brain development that enable the construction and consolidation of experience-dependent structural and functional brain connections.

PURPOSE

In this review, our primary goal is to highlight the essential role of neuroplasticity in brain development, and to draw attention to the complex relationship between different levels of the developing nervous system that are subjected to plasticity in health and disease. Another goal of this review is to explore the relationship between plasticity responses of the developing brain and how they are influenced by critical and sensitive periods of brain development. Finally, we aim to motivate researchers in the pediatric neuromodulation field to build on the current knowledge of normal and abnormal neuroplasticity, especially synaptic plasticity, and their dependence on "critical or sensitive periods" of neural development to inform the design, timing and sequencing of neuromodulatory interventions in order to enhance and optimize their translational applications in childhood disorders of the brain.

METHODS

literature review.

RESULTS

We discuss in details five patterns of neuroplasticity expressed by the developing brain: 1) developmental plasticity which is further classified into normal and impaired developmental plasticity as seen in syndromic autism spectrum disorders, 2) adaptive (experience-dependent) plasticity following intense motor skill training, 3) reactive plasticity to pre and post natal CNS injury or sensory deprivation, 4) excessive plasticity (loss of homeostatic regulation) as seen in dystonia and refractory epilepsy, 6) and finally, plasticity as the brain's "Achilles tendon" which induces brain vulnerability under certain conditions such as hypoxic ischemic encephalopathy and epileptic encephalopathy syndromes. We then explore the unique feature of "time-sensitive heightened plasticity responses" in the developing brain in the in the context of neuromodulation.

CONCLUSION

The different patterns of neuroplasticity and the unique feature of heightened plasticity during critical and sensitive periods are important concepts for researchers and clinicians in the field of pediatric neurology and neurodevelopmental disabilities. These concepts need to be examined systematically in the context of pediatric neuromodulation. We propose that critical and sensitive periods of brain development in health and disease can create "windows of opportunity" for neuromodulatory interventions that are not commonly seen in adult brain and probably augment plasticity responses and improve clinical outcomes.

Immature Spinal Locomotor Output in Children with Cerebral Palsy

Detailed descriptions of gait impairments have been reported in cerebral palsy (CP), but it is still unclear how maturation of the spinal motoneuron output is affected. Spatiotemporal alpha-motoneuron activation during walking can be assessed by mapping the electromyographic activity profiles from several, simultaneously recorded muscles onto the anatomical rostrocaudal location of the motoneuron pools in the spinal cord, and by means of factor analysis of the muscle activity profiles. Here, we analyzed gait kinematics and EMG activity of 11 pairs of bilateral muscles with lumbosacral innervation in 35 children with CP (19 diplegic, 16 hemiplegic, 2-12 years) and 33 typically developing (TD) children (1-12 years). TD children showed a progressive reduction of EMG burst durations and a gradual reorganization of the spatiotemporal motoneuron output with increasing age. By contrast, children with CP showed very limited age-related changes of EMG durations and motoneuron output, as well as of limb intersegmental coordination and foot trajectory control (on both sides for diplegic children and the affected side for hemiplegic children). Factorization of the EMG signals revealed a comparable structure of the motor output in children with CP and TD children, but significantly wider temporal activation patterns in children with CP, resembling the patterns of much younger TD infants. A similar picture emerged when considering the spatiotemporal maps of alpha-motoneuron activation. Overall, the results are consistent with the idea that early injuries to developing motor regions of the brain substantially affect the maturation of the spinal locomotor output and consequently the future locomotor behavior.

The corticospinal tract: Evolution, development, and human disorders

The corticospinal tract (CST) plays a major role in cortical control of spinal cord activity. In particular, it is the principal motor pathway for voluntary movements. Here, we discuss: (i) the anatomic evolution and development of the CST across mammalian species, focusing on its role in motor functions; (ii) the molecular mechanisms regulating corticospinal tract formation and guidance during mouse development; and (iii) human disorders associated with abnormal CST development. A comparison of CST anatomy and development across mammalian species first highlights important similarities. In particular, most CST axons cross the anatomical midline at the junction between the brainstem and spinal cord, forming the pyramidal decussation. Reorganization of the pattern of CST projections to the spinal cord during evolution led to improved motor skills. Studies of the molecular mechanisms involved in CST formation and guidance in mice have identified several factors that act synergistically to ensure proper formation of the CST at each step of development. Human CST developmental disorders can result in a reduction of the CST, or in guidance defects associated with abnormal CST anatomy. These latter disorders result in altered midline crossing at the pyramidal decussation or in the spinal cord, but spare the rest of the CST. Careful appraisal of clinical manifestations associated with CST malformations highlights the critical role of the CST in the lateralization of motor control. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 810-829, 2017.

Neural network remodeling underlying motor map reorganization induced by rehabilitative training after ischemic stroke

Motor map reorganization is believed to be one mechanism underlying rehabilitation-induced functional recovery. Although the ipsilesional secondary motor area has been known to reorganize motor maps and contribute to rehabilitation-induced functional recovery, it is unknown how the secondary motor area is reorganized by rehabilitative training. In the present study, using skilled forelimb reaching tasks, we investigated neural network remodeling in the rat rostral forelimb area (RFA) of the secondary motor area during 4weeks of rehabilitative training. Following photothrombotic stroke in the caudal forelimb area (CFA), rehabilitative training led to task-specific recovery and motor map reorganization in the RFA. A second injury to the RFA resulted in reappearance of motor deficits. Further, when both the CFA and RFA were destroyed simultaneously, rehabilitative training no longer improved task-specific recovery. In neural tracer studies, although rehabilitative training did not alter neural projection to the RFA from other brain areas, rehabilitative training increased neural projection from the RFA to the lower spinal cord, which innervates the muscles in the forelimb. Double retrograde tracer studies revealed that rehabilitative training increased the neurons projecting from the RFA to both the upper cervical cord, which innervates the muscles in the neck, trunk, and part of the proximal forelimb, and the lower cervical cord. These results suggest that neurons projecting to the upper cervical cord provide new connections to the denervated forelimb area of the spinal cord, and these new connections may contribute to rehabilitation-induced task-specific recovery and motor map reorganization in the secondary motor area.

Motor Experience Reprograms Development of a Genetically-Altered Bilateral Corticospinal Motor Circuit

Evidence suggests that motor experience plays a role in shaping development of the corticospinal system and voluntary motor control, which is a key motor function of the system. Here we used a mouse model with conditional forebrain deletion of the gene for EphA4 (Emx1-Cre:EphA4^tm2Kldr), which regulates development of the laterality of corticospinal tract (CST). We combined study of Emx1-Cre:EphA4^tm2Kldr with unilateral forelimb constraint during development to expand our understanding of experience-dependent CST development from both basic and translational perspectives. This mouse develops dense ipsilateral CST projections, a bilateral motor cortex motor representation, and bilateral motor phenotypes. Together these phenotypes can be used as readouts of corticospinal system organization and function and the changes brought about by experience. The Emx1-Cre:EphA4^tm2Kldr mouse shares features with the common developmental disorder cerebral palsy: bilateral voluntary motor impairments and bilateral CST miswiring. Emx1-Cre:EphA4^tm2Kldr mice with typical motor experiences during development display the bilateral phenotype of “mirror” reaching, because of a strongly bilateral motor cortex motor representation and a bilateral CST. By contrast, Emx1-Cre:EphA4^tm2Kldr mice that experienced unilateral forelimb constraint from P1 to P30 and tested at maturity had a more contralateral motor cortex motor representation in each hemisphere; more lateralized CST projections; and substantially more lateralized/independent reaching movements. Changes in CST organization and function in this model can be explained by reduced synaptic competition of the CST from the side without developmental forelimb motor experiences. Using this model we show that unilateral constraint largely abrogated the effects of the genetic mutation on CST projections and thus demonstrates how robust and persistent experience-dependent development can be for the establishment of corticospinal system connections and voluntary control. Further, our findings inform the mechanisms of and strategies for developing behavioral therapies to treat bilateral movement impairments and CST miswiring in cerebral palsy.

Cerebral palsy

Cerebral palsy is the most common cause of childhood-onset, lifelong physical disability in most countries, affecting about 1 in 500 neonates with an estimated prevalence of 17 million people worldwide. Cerebral palsy is not a disease entity in the traditional sense but a clinical description of children who share features of a non-progressive brain injury or lesion acquired during the antenatal, perinatal or early postnatal period. The clinical manifestations of cerebral palsy vary greatly in the type of movement disorder, the degree of functional ability and limitation and the affected parts of the body. There is currently no cure, but progress is being made in both the prevention and the amelioration of the brain injury. For example, administration of magnesium sulfate during premature labour and cooling of high-risk infants can reduce the rate and severity of cerebral palsy. Although the disorder affects individuals throughout their lifetime, most cerebral palsy research efforts and management strategies currently focus on the needs of children. Clinical management of children with cerebral palsy is directed towards maximizing function and participation in activities and minimizing the effects of the factors that can make the condition worse, such as epilepsy, feeding challenges, hip dislocation and scoliosis. These management strategies include enhancing neurological function during early development; managing medical co-morbidities, weakness and hypertonia; using rehabilitation technologies to enhance motor function; and preventing secondary musculoskeletal problems. Meeting the needs of people with cerebral palsy in resource-poor settings is particularly challenging.

Motor Cortex Activity Organizes the Developing Rubrospinal System

The corticospinal and rubrospinal systems function in skilled movement control. A key question is how do these systems develop the capacity to coordinate their motor functions and, in turn, if the red nucleus/rubrospinal tract (RN/RST) compensates for developmental corticospinal injury? We used the cat to investigate whether the developing rubrospinal system is shaped by activity-dependent interactions with the developing corticospinal system. We unilaterally inactivated M1 by muscimol microinfusion between postnatal weeks 5 and 7 to examine activity-dependent interactions and whether the RN/RST compensates for corticospinal tract (CST) developmental motor impairments and CST misprojections after M1 inactivation. We examined the RN motor map and RST cervical projections at 7 weeks of age, while the corticospinal system was inactivated, and at 14 weeks, after activity returned. During M1 inactivation, the RN on the same side showed normal RST projections and reduced motor thresholds, suggestive of precocious development. By contrast, the RN on the untreated/active M1 side showed sparse RST projections and an immature motor map. After M1 activity returned later in adolescent cat development, RN on the active M1/CST side continued to show a substantial loss of spinal terminations and an impaired motor map. RN/RST on the inactivated side regressed to a smaller map and fewer axons. Our findings suggest that the developing rubrospinal system is under activity-dependent regulation by the corticospinal system for establishing mature RST connections and RN motor map. The lack of RS compensation on the non-inactivated side can be explained by development of ipsilateral misprojections from the active M1 that outcompete the RST. Significance statement: Skilled movements reflect the activity of multiple descending motor systems and their interactions with spinal motor circuits. Currently, there is little insight into whether motor systems interact during development to coordinate their emerging functions and, if so, the mechanisms underlying this process. This study examined activity-dependent interactions between the developing corticospinal and rubrospinal systems, two key systems for skilled limb movements. We show that the developing rubrospinal system competes with the corticospinal system in establishing the red nucleus motor map and rubrospinal tract connections. This is the first demonstration of one motor system steering development, and ultimately function, of another. Knowledge of activity-dependent competition between these two systems helps predict the response of the rubrospinal system following corticospinal system developmental injury.

One hand clapping: lateralization of motor control

Lateralization of motor control refers to the ability to produce pure unilateral or asymmetric movements. It is required for a variety of coordinated activities, including skilled bimanual tasks and locomotion. Here we discuss the neuroanatomical substrates and pathophysiological underpinnings of lateralized motor outputs. Significant breakthroughs have been made in the past few years by studying the two known conditions characterized by the inability to properly produce unilateral or asymmetric movements, namely human patients with congenital “mirror movements” and model rodents with a “hopping gait”. Whereas mirror movements are associated with altered interhemispheric connectivity and abnormal corticospinal projections, abnormal spinal cord interneurons trajectory is responsible for the “hopping gait”. Proper commissural axon guidance is a critical requirement for these mechanisms. Interestingly, the analysis of these two conditions reveals that the production of asymmetric movements involves similar anatomical and functional requirements but in two different structures: (i) lateralized activation of the brain or spinal cord through contralateral silencing by cross-midline inhibition; and (ii) unilateral transmission of this activation, resulting in lateralized motor output.