Relationship Between Integrity of the Corpus Callosum and Bimanual Coordination in Children With Unilateral Spastic Cerebral Palsy

Spatiotemporal coordination in children with unilateral cerebral palsy: Insights from a bimanual goal-directed task

BACKGROUND

In children with unilateral cerebral palsy (uCP), bimanual assessments mostly focus on qualitative assessments of the impaired upper limb during bimanual tasks, which do not capture the spatiotemporal coordination between both hands. Hence, we aimed to advance our understandings in spatiotemporal coordination in children with uCP compared to typically developing children (TDC) using a bimanual, asymmetrical, goal-directed task.

PARTICIPANTS AND METHODOLOGY

In this observational study, thirty-seven children with uCP (11y8m±2y10m, 20 males, 16 right-sided uCP, Manual Ability Classification System level I = 23, II = 11, III = 3) and 37 age and sex-matched TDC opened a box with one hand and pressed a button inside using the opposite hand. Spatiotemporal bimanual (movement time, temporal coupling, movement overlap, goal synchronisation) and unimanual (movement time, path length and smoothness) parameters were extracted. Between groups comparisons were investigated using a two-way mixed ANCOVA with age as covariate (α < 0.05). Additionally, correlation coefficients between unimanual and bimanual parameters were calculated.

RESULTS

Compared to TDC, children with uCP were slower (p = 0.01, ηp2 = 0.13) and presented unimanual spatiotemporal deficits in both upper limbs (p < 0.03, ηp2>0.10), which worsened in children with lower manual abilities (p < 0.04, ηp2>0.19). However, they did not differ in bimanual coupling (p > 0.31, ηp2<0.03). Furthermore, slower movement time was related with increased unimanual spatiotemporal deficits bilaterally (r = 0.34-0.80, p = 0.001-0.04), suggesting that reduced performance at both upper limbs contributes to bimanual difficulties in children with uCP.

CONCLUSIONS

The bilateral reduced spatiotemporal performance, related to longer bimanual movement time, stresses the importance to assess and treat both upper limbs in children with uCP.

Robotic assessment of bilateral and unilateral upper limb functions in adults with cerebral palsy

BACKGROUND

Children with unilateral cerebral palsy (CP) exhibit motor impairments predominantly on one side of the body, while also having ipsilesional and bilateral impairments. These impairments are known to persist through adulthood, but their extent have not been described in adults with CP. This study's aim is to characterize bilateral and unilateral upper limbs impairments in adults with CP.

METHODS

Nineteen adults with CP (34.3 years old ± 11.5) performed three robotic assessments in the Kinarm Exoskeleton Lab, including two bilateral tasks (Object Hit [asymmetric independent goals task] and Ball on Bar [symmetric common goal task]) and one unilateral task (Visually Guided Reaching, performed with the more affected arm [MA] and less affected arm [LA]). Individual results were compared to sex, age and handedness matched normative data, describing the proportion of participants exhibiting impairments in each task-specific variable (e.g., Hand speed), each performance category (e.g., Feedforward control) and in global task performance. Associations were assessed using Spearman correlation coefficients between: 1: the results of the MA and LA of each limb in the unilateral task; and 2: the results of each limb in the unilateral vs. the bilateral tasks.

RESULTS

The majority of participants exhibited impairments in bilateral tasks (84%). The bilateral performance categories (i.e., Bimanual) identifying bilateral coordination impairments were impaired in the majority of participants (Object Hit: 57.8%; Ball on Bar: 31.6%). Most of the participants were impaired when performing a unilateral task with their MA arm (63%) and a smaller proportion with their LA arm (31%). The Feedforward control was the unilateral performance category showing the highest proportion of impaired participants while displaying the strongest relationship between the MA and LA arms impairments (rs = 0.93). Feedback control was the unilateral performance category most often associated with impairments in bilateral tasks (6 out of 8 performance categories).

CONCLUSIONS

Adults with CP experienced more impairment in bilateral tasks while still having substantial impairments in unilateral tasks. They frequently display Feedforward control impairments combined with a higher reliance on Feedback control during both bilateral and unilateral tasks, leading to poorer motor performance.

Bimanual Coordination in Children with Bilateral Cerebral Palsy: A Cross-Sectional Study

AIM

To compare bimanual coordination in children with bilateral cerebral palsy (BCP) with that of children with typical development (TD) and correlate bimanual coordination with clinical measures of hand function.

METHODS

3-D kinematic data were collected from 14 children with BCP (mean age 13 years 1 month; range 7.3-17.2 years, 5 females) and 14 age-matched children with TD (mean age 13 years 1 month, range 7.0-16.0 years, 7 females) as they opened a drawer with one hand and activated a switch inside it with the other hand at self-paced and as-fast-as-possible speeds. Hand roles varied in each condition. Participants' hand function levels were classified using the Manual Ability Classification System. Unimanual dexterity and bimanual performance were evaluated using the Box and Blocks Test and Both Hands Assessment respectively.

RESULTS

Participants with BCP performed the bimanual task more slowly (p < 0.001) and sequentially, as evidenced by greater time differences between the two hands achieving the end goal (p = 0.01). Faster speeds, particularly when the less affected hand opened the drawer, facilitated time-related measures of bimanual coordination (p < 0.05). Bimanual coordination correlated with all clinical measures of hand function (p < 0.05).

CONCLUSION

For children with BCP, speed and hand used for each subcomponent of the task influence bimanual coordination. Better bimanual coordination is associated with less impairment of both hands.

Corpus callosum long-term biometry in very preterm children related to cognitive and motor outcomes

BACKGROUND

The corpus callosum (CC) is suggested as an indirect biomarker of white matter volume, which is often affected in preterm birth. However, diagnosing mild white matter injury is challenging.

METHODS

We studied 124 children born preterm (mean age: 8.4 ± 1.1 years), using MRI to assess CC measurements and cognitive/motor outcomes based on the Wechsler Intelligence Scale for Children-V (WPPSI-V) and Movement Assessment Battery for Children-2 (MABC-2).

RESULTS

Children with normal outcomes exhibited greater height (10.2 ± 2.1 mm vs. 9.4 ± 2.3 mm; p = 0.01) and fractional anisotropy at splenium (895[680-1000] vs 860.5[342-1000]) and total CC length (69.1 ± 4.8 mm vs. 67.3 ± 5.1 mm; p = 0.02) compared to those with adverse outcomes. All measured CC areas were smaller in the adverse outcome group. Models incorporating posterior CC measurements demonstrated the highest specificity (83.3% Sp, AUC: 0.65) for predicting neurological outcomes. CC length and splenium height were the only linear measurements associated with manual dexterity and total MABC-2 score while both the latter and genu were related with Full-Scale Intelligence Quotient.

CONCLUSIONS

CC biometry in children born very preterm at school-age is associated with outcomes and exhibits a specific subregion alteration pattern. The posterior CC may serve as an important neurodevelopmental biomarker in very preterm infants.

IMPACT

The corpus callosum has the potential to serve as a reliable and easily measurable biomarker of white matter integrity in very preterm children. Estimating diffuse white matter injury in preterm infants using conventional MRI sequences is not always conclusive. The biometry of the posterior part of the corpus callosum is associated with cognitive and certain motor outcomes at school age in children born very preterm. Length and splenium measurements seem to serve as reliable biomarkers for assessing neurological outcomes in this population.

A systematic review of instrumented assessments for upper limb function in cerebral palsy: current limitations and future directions

INTRODUCTION

Recently, interest in quantifying upper limb function in cerebral palsy has grown. However, the lack of reference tasks and protocols, have hindered the development of quantified movement analysis in clinical practice. This study aimed to evaluate existing instrumented assessments of upper limb function in cerebral palsy, with a focus on their clinical applicability, to identify reasons for the lack of adoption and provide recommendations for improving clinical relevance and utility.

METHODS

A systematic review was conducted by a multidisciplinary team of researchers and clinicians (Prospero CRD42023402382). PubMed and Web of Science databases were searched using relevant keywords and inclusion/exclusion criteria.

RESULTS

A total of 657 articles were initially identified, and after the selection process, 76 records were included for analysis comprising a total of 1293 patients with cerebral palsy. The quality assessment of the reviewed studies revealed a moderate overall quality, with deficiencies in sample size justification and participant information. Optoelectronic motion capture systems were predominantly used in the studies (N = 57/76). The population mainly consisted of individuals with spastic cerebral palsy (834/1293) with unilateral impairment (N = 1092/1293). Patients with severe functional impairment (MACS IV and V) were underrepresented with 3.4% of the 754 patients for whom the information was provided. Thirty-nine tasks were used across the articles. Most articles focused on unimanual activities (N = 66/76) and reach or reach and grasp (N = 51/76). Bimanual cooperative tasks only represented 3 tasks present in 4 articles. A total of 140 different parameters were identified across articles. Task duration was the most frequently used parameter and 23% of the parameters were used in only one article.

CONCLUSION

Further research is necessary before incorporating quantified motion analysis into clinical practice. Existing protocols focus on extensively studied populations and rely on costly equipment, limiting their practicality. Standardized unimanual tasks provide limited insights into everyday arm use. Balancing methodological requirements and performance evaluation flexibility is a challenge. Exploring the correlation between outcome parameters and therapeutic guidance could facilitate the integration of quantified movement assessment into treatment pathways.

Corpus Callosum Functional Activities in Children with Cerebral Palsy

Background

Since cerebral palsy (CP) is a corollary to brain damage, persistent treatment should accompany an alteration in brain functional activity in line with clinical improvements. In this regard, the corpus callosum (CC), as a connecting bridge between the two hemispheres, plays an essential role.

Objective

This study aimed to investigate the therapeutic effects of occupational therapy (OT) on CC functional activity and walking capacity in children with cerebral palsy.

Material and Methods

In this clinical trial study, 4 children with CP (8.25±1.71 years) received 45 min OT sessions 3 times weekly for 8 weeks. Functional magnetic resonance imaging (fMRI) was acquired while conducting passive motor tasks to quantify CC activation. The pre-post activation changes in CC following therapy were quantified in terms of activated voxels. Walking capacity was evaluated using the timed-up-and-go (TUG), 6-minute walk test (6 MWT), and 10-meter walk test (10 MWT) in pre-and post-treatment.

Results

The number of activated voxels in CC indicated significant improvement in participants. Post-treatment activated voxels substantially exceeded pre-treatment active voxels. Clinical measures, including TUG, 6 MWT, and 10 MWT are improved by 11.9%, 12.6%, and 25.4%, respectively.

Conclusion

Passive task-based fMRI can detect the effects of OT on CC functional activity in children with CP. According to the results, OT improves CC functional activity in addition to gait and balance performance.

In-depth quantification of bimanual coordination using the Kinarm exoskeleton robot in children with unilateral cerebral palsy

BACKGROUND

Robots have been proposed as tools to measure bimanual coordination in children with unilateral cerebral palsy (uCP). However, previous research only examined one task and clinical interpretation remains challenging due to the large amount of generated data. This cross-sectional study aims to examine bimanual coordination by using multiple bimanual robotics tasks in children with uCP, and their relation to task execution and unimanual performance.

METHODS

The Kinarm exoskeleton robot was used in 50 children with uCP (mean age: 11 years 11 months ± 2 years 10 months, Manual Ability Classification system (MACS-levels: l = 27, ll = 16, lll = 7)) and 50 individually matched typically developing children (TDC). All participants performed three tasks: object-hit (hit falling balls), ball-on-bar (balance a ball on a bar while moving to a target) and circuit task (move a cursor along a circuit by making horizontal and vertical motions with their right and left hand, respectively). Bimanual parameters provided information about bimanual coupling and interlimb differences. Differences between groups and MACS-levels were investigated using ANCOVA with age as covariate (α < 0.05, [Formula: see text]). Correlation analysis (r) linked bimanual coordination to task execution and unimanual parameters.

RESULTS

Children with uCP exhibited worse bimanual coordination compared to TDC in all tasks (p ≤ 0.05, [Formula: see text] = 0.05-0.34). The ball-on-bar task displayed high effect size differences between groups in both bimanual coupling and interlimb differences (p < 0.001, [Formula: see text] = 0.18-0.36), while the object-hit task exhibited variations in interlimb differences (p < 0.001, [Formula: see text] = 0.22-0.34) and the circuit task in bimanual coupling (p < 0.001, [Formula: see text] = 0.31). Mainly the performance of the ball-on-bar task (p < 0.05, [Formula: see text] = 0.18-0.51) was modulated by MACS-levels, showing that children with MACS-level lll had worse bimanual coordination compared to children with MACS-level l and/or II. Ball-on-bar outcomes were highly related to task execution (r = - 0.75-0.70), whereas more interlimb differences of the object-hit task were moderately associated with a worse performance of the non-dominant hand (r = - 0.69-(- 0.53)).

CONCLUSION

This study gained first insight in important robotic tasks and outcome measures to quantify bimanual coordination deficits in children with uCP. The ball-on-bar task showed the most discriminative ability for both bimanual coupling and interlimb differences, while the object-hit and circuit tasks are unique to interlimb differences and bimanual coupling, respectively.

Bimanual hand use in children and adolescents with unilateral spastic cerebral palsy: an exploratory study

BACKGROUND

Individuals with unilateral spastic cerebral palsy (USCP) often show difficulties using their hands during activities of daily living.

OBJECTIVE

To investigate the factors that interfere with hand use during bimanual activities in children and adolescents with USCP.

METHODS

We conducted a cross-sectional study with 102 children and adolescents with USCP, aged 6 to 18 years. We collected information with the caregivers about the classification of the child's manual ability, according to the Manual Ability Classification System (MACS); child's age; side of the involvement; Children's Hand-Use Experience Questionnaire- CHEQ2.0. Cluster analysis identified groups of children and adolescents who performed CHEQ activities with or without assistance. Multiple linear regression analyses identified the contribution of the factors: age, sex, MACS level, side of hemiparesis, and clusters of assistance, on the outcomes of efficacy, time, and feeling bothered.

RESULTS

MACS and clusters of assistance explained the variance in efficacy (p<0.05; R2=0.31) and time (p<0.05; R2=0.37). MACS explained 22% of the variance in feeling bothered.  Children and adolescents with increased difficulty to perform activities that involve hand use (i.e., MACS III) and who receive assistance during most bimanual activities showed less efficacy of use, were slower in their performance, and presented greater feeling of being bothered.

CONCLUSION

Assistance in bimanual activities and MACS level contributed to explain the efficacy of use, time, and feeling bothered in performing bimanual activities. Intervention strategies aimed at promoting the performance of bimanual activities in the daily routine of children with USCP should consider these outcomes.

Biological and environmental factors may affect children's executive function through motor and sensorimotor development: Preterm birth and cerebral palsy

Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.

Altered corpus callosum structure in adolescents with cerebral palsy: connection to gait and balance

Cerebral palsy (CP) is the most common motor disorder in childhood. Recent studies in children with CP have associated weakened sensorimotor performance with impairments in the major brain white-matter (WM) structure, corpus callosum (CC). However, the relationship between CC structure and lower extremity performance, specifically gait and balance, remains unknown. This study investigated the transcallosal WM structure and lower limb motor stability performance in adolescents aged 10-18 years with spastic hemiplegic (n = 18) or diplegic (n = 13) CP and in their age-matched controls (n = 34). The modern diffusion-weighted MRI analysis included the diffusivity properties of seven CC subparts and the transcallosal lower limb sensorimotor tract of the dominant hemisphere. Children with CP had comprehensive impairments in the cross-sectional area, fractional anisotropy, and mean diffusivity of the CC and sensorimotor tract. Additionally, the extent of WM alterations varied between hemiplegic and diplegic subgroups, which was seen especially in the fractional anisotropy values along the sensorimotor tract. The diffusion properties of transcallosal WM were further associated with static stability in all groups, and with dynamic stability in healthy controls. Our novel results clarify the mechanistic role of the corpus callosum in adolescents with and without CP offering valuable insight into the complex interplay between the brain's WM organization and motor performance. A better understanding of the brain basis of weakened stability performance could, in addition, improve the specificity of clinical diagnosis and targeted rehabilitation in CP.

The Challenge of Diffusion Magnetic Resonance Imaging in Cerebral Palsy: A Proposed Method to Identify White Matter Pathways

Cerebral palsy (CP), a neuromotor disorder characterized by prenatal brain lesions, leads to white matter alterations and sensorimotor deficits. However, the CP-related diffusion neuroimaging literature lacks rigorous and consensual methodology for preprocessing and analyzing data due to methodological challenges caused by the lesion extent. Advanced methods are available to reconstruct diffusion signals and can update current advances in CP. Our study demonstrates the feasibility of analyzing diffusion CP data using a standardized and open-source pipeline. Eight children with CP (8-12 years old) underwent a single diffusion magnetic resonance imaging (MRI) session on a 3T scanner (Achieva 3.0T (TX), Philips Healthcare Medical Systems, Best, The Netherlands). Exclusion criteria were contraindication to MRI and claustrophobia. Anatomical and diffusion images were acquired. Data were corrected and analyzed using Tractoflow 2.3.0 version, an open-source and robust tool. The tracts were extracted with customized procedures based on existing atlases and freely accessed standardized libraries (ANTs, Scilpy). DTI, CSD, and NODDI metrics were computed for each tract. Despite lesion heterogeneity and size, we successfully reconstructed major pathways, except for a participant with a larger lesion. Our results highlight the feasibility of identifying and quantifying subtle white matter pathways. Ultimately, this will increase our understanding of the clinical symptoms to provide precision medicine and optimize rehabilitation.

Corpus Callosal Microstructure Predicts Bimanual Motor Performance in Chronic Stroke Survivors: a Preliminary Cross-Sectional Study

BACKGROUND

Microstructural changes in the corpus callosum (CC) are associated with more severe motor impairment in the paretic hand, poor recovery, and general disability. The purpose of this study was to determine if CC microstructure predicts bimanual motor performance in chronic stroke survivors.

METHODS

We examined the relationship between the fractional anisotropy (FA) across the CC, in both the sensorimotor and non-sensorimotor regions, and movement times for two self-initiated and self-paced bimanual tasks in 41 chronic stroke survivors. Using publicly available control datasets (n = 52), matched closely for imaging acquisition parameters, we also explored the effect of stroke and age on callosal microstructure.

RESULTS

In mild-to-moderate chronic stroke survivors with relatively localized lesions to the motor areas, lower callosal FA values, suggestive of a more disorganized microstructure, were associated with slower bimanual performance. Associations were strongest for the primary motor fibers (b = -2.19 ± 1.03, p = .035), followed closely by premotor/supplementary motor (b = -2.07 ± 1.07, p = .041) and prefrontal (b = -1.92 ± 0.97, p = .05) fibers of the callosum. Secondary analysis revealed that compared to neurologically age-similar adults, chronic stroke survivors exhibited significantly lower mean FA in all regions of the CC, except the splenium.

CONCLUSION

Remote widespread changes in the callosal genu and body are associated with slower performance on cooperative bimanual tasks that require precise and interdependent coordination of the hands. Measures of callosal microstructure may prove to be a useful predictor of real-world bimanual performance in chronic stroke survivors.

The Role of the Corpus Callosum (Micro)Structure in Bimanual Coordination: A Literature Review Update

The characterization of callosal white matter is crucial for understanding the relationship between brain structure and bimanual motor function. An earlier literature review established this. With advancements in neuroimaging and data modeling, we aim to provide an update on the existing literature. Firstly, we highlight new CC parcellation approaches, such as functional MRI- and atlas-informed tractography and in vivo histology. Secondly, we elaborate on recent insights into the CC's role in bimanual coordination, drawing evidence from studies on healthy young and older adults, patients and training-related callosal plasticity. We also reflect on progress in the field and propose future perspectives to inspire research on the underlying mechanisms of structural-functional interactions.

Bimanual movements in children with cerebral palsy: a systematic review of instrumented assessments

BACKGROUND

Assessment of bimanual movements, which are frequently impaired in children with cerebral palsy, is highly challenging in clinical practice. Instrumented measures have been developed to evaluate and help to understand impaired upper limb movement during bimanual tasks in these children. The aim of this review was to report instrumented measurement tools (3D motion analysis, sensors, etc.) used for bimanual task movement analysis, and the metrological properties of the measures in children with cerebral palsy.

METHODS

A systematic review was conducted (Prospero CRD42022308517). PubMed, Web of Science, Cochrane and Scopus databases were searched with relevant keywords and inclusion/exclusion criteria. Article quality and biomechanical methods were evaluated with a customized scale and metrological properties with the COSMIN checklist.

RESULTS

In total, 452 children, mostly with unilateral cerebral palsy, mean age 10.9 (SD 3.2) years, underwent quantitative bimanual assessments in the 31 included studies (mean quality score 22/32 points [SD 4.7]). The tools used were 3D motion analysis (n = 26), accelerometers (n = 2), and other instruments (cube, digitizer, etc.) (n = 3). Children performed 1-5 bimanual tasks in laboratory settings, mostly activities of daily living or game scenarios. Analyses focused mostly on spatiotemporal variables, 6 of which were specifically developed for bilateral measures (task completion time, goal synchronization, movement overlap time, interlimb coupling, continuous relative phase and asynchrony). These instrumented measurements had moderate to good discriminant and convergent validity, but reliability and responsiveness assessments were lacking.

CONCLUSIONS

A large number of quantitative bimanual assessments involving different tools, bimanual tasks and specific variables developed to evaluate bimanual function were found. Development of other relevant variables and validation of these tools are needed to further determine their usefulness, both as research outcomes and to guide therapies in clinical practice. Future research, involving younger children and real-life assessments, will improve our understanding of bimanual function in children with cerebral palsy.

Bimanual motor impairments in older adults: an updated systematic review and meta-analysis

This updated systematic review and meta-analysis further examined potential effects of aging on bimanual movements. Forty-seven qualified studies that compared bimanual motor performances between elderly and younger adults were included in this meta-analysis. Moderator variable analyses additionally determined whether altered bimanual motor performances in older adults were different based on the task types (i.e., symmetry vs. asymmetry vs. complex) or outcome measures (i.e., accuracy vs. variability vs. movement time). The random effects model meta-analysis on 80 comparisons from 47 included studies revealed significant negative overall effects indicating more bimanual movement impairments in the elderly adults than younger adults. Moderator variable analyses found that older adults showed more deficits in asymmetrical bimanual movement tasks than symmetrical and complex tasks, and the bimanual movement impairments in the elderly adults included less accurate, more variable, and greater movement execution time than younger adults. These findings suggest that rehabilitation programs for improving motor actions in older adults are necessary to focus on functional recovery of interlimb motor control including advanced motor performances as well coordination.

From Hemispheric Asymmetry through Sensorimotor Experiences to Cognitive Outcomes in Children with Cerebral Palsy

Recent neuroimaging studies allowed us to explore abnormal brain structures and interhemispheric connectivity in children with cerebral palsy (CP). Behavioral researchers have long reported that children with CP exhibit suboptimal performance in different cognitive domains (e.g., receptive and expressive language skills, reading, mental imagery, spatial processing, subitizing, math, and executive functions). However, there has been very limited cross-domain research involving these two areas of scientific inquiry. To stimulate such research, this perspective paper proposes some possible neurological mechanisms involved in the cognitive delays and impairments in children with CP. Additionally, the paper examines the ways motor and sensorimotor experience during the development of these neural substrates could enable more optimal development for children with CP. Understanding these developmental mechanisms could guide more effective interventions to promote the development of both sensorimotor and cognitive skills in children with CP.

Upper Limb Motor Planning in Individuals with Cerebral Palsy Aged between 3 and 21 Years Old: A Systematic Review

Individuals with cerebral palsy have difficulties performing activities of daily living. Beyond motor execution impairments, they exhibit motor planning deficits contributing to their difficulties. The objective of this review is to synthesize the behavioral evidence of motor planning deficits during an upper limb motor task in children, adolescents and young adults with cerebral palsy aged between 3 and 21 years. Methods: The inclusion criteria were: (1) including individuals with cerebral palsy from 3 to 21 years old; (2) assessing upper limb motor planning. Six databases were screened. The quality assessment of the studies was performed. Results: Forty-six studies and 686 participants were included. Five articles have been identified as very high quality, 12 as high, 20 as moderate, six as low, three as very low. Force planning studies reported a deficit for the more affected hand but adequate performances for the less affected hand. Object-manipulation studies reported hand posture planning deficits irrespectively of the hand assessed. Conclusions: Motor planning deficits has been shown in the more affected hand for force scaling, while the results for other variables showed overall deficits. Hence, variables affected by motor planning deficits in both hands should be considered in children with cerebral palsy to optimize intervention.

Impact of Sensory Deficits on Upper Limb Motor Performance in Individuals with Cerebral Palsy: A Systematic Review

People living with cerebral palsy (CP) exhibit motor and sensory impairments that affect unimanual and bimanual functions. The importance of sensory functions for motor control is well known, but the association between motor and sensory functions remains unclear in people living with CP. The objective of this systematic review was to characterize the relationship between sensory deficits and upper limb motor function in individuals living with CP.

METHODS

Five databases were screened. The inclusion criteria were: (1) including people living with CP, (2) reporting measurements of upper limb motor and sensory functions. A qualitative analysis of the studies' level of evidence was done.

RESULTS

Thirty-three articles were included. Twenty-five articles evaluated tactile functions, 10 proprioceptive functions and 7 visual functions; 31 of the articles reported on unimanual functions and 17 of them reported on bimanual functions. Tactile functions showed a moderate to high association; it was not possible to reach definitive conclusions for proprioceptive and visual functions.

CONCLUSIONS

The heterogeneity of the results limits the ability to draw definitive conclusions. Further studies should aim to perform more comprehensive assessments of motor and sensory functions, to determine the relative contribution of various sensory modalities to simple and more complex motor functions.

Corpus Callosum Integrity Relates to Improvement of Upper-Extremity Function Following Intensive Rehabilitation in Children With Unilateral Spastic Cerebral Palsy

BACKGROUND

The corpus callosum (CC) plays an important role in upper extremity (UE) function. The impact on UE function in children with unilateral spastic cerebral palsy (USCP) and improvements following intensive interventions remain unknown.

OBJECTIVES

To examine the (1) relationship between UE function and CC integrity and (2) relationship between CC integrity and changes in UE function following intensive interventions.

METHODS

We retrospectively analyzed clinical and neuroimaging data from a sample of convenience of 44 participants (age 9.40 ± 3.10 years) from 2 larger trials. Participants received 90 hours of Hand-Arm Bimanual Intensive Therapy (HABIT) or Constraint-Induced Movement Therapy (CIMT). Unimanual dexterity (Jebsen-Taylor Test of Hand Function [JTTHF]) and bimanual performance (Assisting Hand Assessment [AHA]) were assessed preintervention and postintervention. CC tractography was reconstructed with diffusion tensor imaging (DTI) and segmented into 3 regions (genu, midbody, splenium). Pearson correlations and regression were used to assess the relationship between outcomes and DTI parameters (ie, fractional anisotropy [FA], number of streamlines, and mean, radial, and axial diffusivity).

RESULTS

Both groups improved in bimanual performance (P < .01). The CIMT group improved in unimanual dexterity (P < .01). Baseline unimanual dexterity and bimanual performance correlated with FA and number of streamlines for most CC regions (P < .05). Following CIMT, pre-post changes in JTTHF were negatively correlated with axial and radial diffusivity of the CC, and AHA with splenium and number of streamlines for the CC, midbody, and splenium (all P < .05). Following HABIT, midbody FA was positively correlated with pre-post AHA changes (r = 0.417; P = .042).

CONCLUSIONS

CC integrity is important for UE function in children with USCP.

Neurodevelopment of Posture-movement Coordination from Late Childhood to Adulthood as Assessed From Bimanual Load-lifting Task: An Event-related Potential Study

In a bimanual task, proprioception provides information about position and movement of upper arms. Developmental studies showed improvement of proprioceptive accuracy and timing adjustments of muscular events from childhood to adulthood in bimanual tasks. However, the cortical maturational changes related to bimanual coordination is not fully understood. The aim of this study was to investigate cortical correlates underlying motor planning and upper limb stabilization performance at left (C3) and right (C4) sensorimotor cortices using event-related potential (ERP) analyses. We recruited 46 participants divided into four groups (12 children: 8-10 years, 13 early adolescents: 11-13 years, 11 late adolescents: 14-16 years and 10 young adults: 20-35 years). Participants performed a bimanual load-lifting task, where the left postural arm supported the load and the right motor arm lifted the load. Maximal amplitude of elbow rotation (MA%) of the postural arm, reaction time (RT) and EMG activity of biceps brachii bilaterally were computed. Laplacian-transformed ERPs of the electroencephalographic (EEG) signal response-locked to motor arm biceps EMG activity onset were analyzed over C3 and C4. We found a developmental effect for behavioral and EEG data denoted by significant decrease of MA% and RT with age, earlier inhibition of the biceps brachii of the postural arm in adults and earlier EEG activation/inhibition onset at C3/C4. Amplitude of the negative wave at C4 was higher in children and early adolescents compared to the other groups. In conclusion, we found a maturational process in cortical correlates related to motor planning and upper limb stabilization performance with interhemispheric lateralization appearing during adolescence. Findings may serve documenting bimanual performance in children with neurodevelopmental disorders.

A perspective on the development of hemispheric specialization, infant handedness, and cerebral palsy

Cerebral Palsy (CP), a common form of neurological pediatric disability, results from pre- or perinatal brain injury. Although there is growing evidence of the efficacy of motor learning-based therapies, several factors interact to produce variability in impairment and limit the effectiveness of these therapies. The variability of hand function present in children with CP indicates that a range of developmental pathways must contribute to the manifestation of individually unique characteristics of impairment. Despite two decades of progress using therapies derived from understanding the mechanisms controlling hand function, very little is known about the sensorimotor experiences occurring during development that likely shape later functional problems for children with CP. In this "perspective" paper, we propose that the study of the development of motor skills in typically developing infants may reveal experiential factors potentially important for creating remedial therapies for children with CP. Specifically, we use the development of infant handedness, a model of hemispheric specialization of function, as an example of how self-generated experiences and sensorimotor feedback can shape the development of limb control and hemispheric specialization. We illustrate how early sensorimotor asymmetries concatenate into pronounced differences in skill between the two hands. We suggest that this model of infant handedness provides a framework for studying the individual differences manifested in children with CP. These differences likely arise from aberrant sensorimotor experiences created by sensorimotor circuits disrupted by the early brain injury. We conclude that knowledge of the developmental events, including subtle motor behaviors, that shape sensorimotor pathways, can improve treatment options for children with CP.