Reorganization of the somatosensory cortex in hemiplegic cerebral palsy associated with impaired sensory tracts

Somatosensory modulation of affective pictures' processing in adults with cerebral palsy and healthy controls: a case-control study

BACKGROUND

Brain processing of both somatosensation and emotion is altered in individuals with cerebral palsy. This paper aims at further exploring the interaction between the somatosensory system and affective processing in individuals with cerebral palsy.

METHODS

Somatosensory thresholds and emotion knowledge were assessed in 18 adults with cerebral palsy and compared with 15 age and sex-matched controls. EEG event-related potentials elicited by viewing affective pictures were recorded. During event-related potentials acquisition, a continuous cutaneous electrical stimulus was applied either at supra- or sub-threshold intensity.

RESULTS

Adults with CP had higher pain sensitivity and increased emotion difficulties, as well as lower event related potential amplitudes than controls. Moreover, the modulatory effects of the somatosensory stimuli on the brain processing of affective pictures differed between adults with CP and controls. Sex was an important factor affecting somatosensory modulation in affective picture brain processing.

CONCLUSIONS

In adults with CP the interaction of abnormal processing of somatosensory and emotional inputs may give rise to a more basic interpretation of emotional cues in complex contexts. Pain sensitivity and sex appear as relevant factors that influence the processing of emotions in CP and should be taken into account in research and clinical settings.

The amplitude of low frequency fluctuation and spontaneous brain activity alterations in age-related macular degeneration

Background

Wet age-related macular degeneration (wAMD) is a vision-threatening eye disease worldwide. The amplitude of low-frequency fluctuation (ALFF) method was used to observe changes in spontaneous brain activity, which may help to investigate the underlying pathological mechanism of AMD.

Methods

Eighteen patients with wAMD and 18 age- and gender-matched healthy controls (HCs) were recruited. The ALFF method was used on each subject and mean ALFF values were compared between groups. The receiver operating characteristic (ROC) curve was used to compare the two groups.

Results

ALFF values in the temporal lobe and limbic lobe/parahippocampal gyrus were significantly higher than controls, while values in the postcentral gyrus were significantly lower. The under the curve of the ROC (AUC) of the three regions shows high accuracy of the diagnosis.

Conclusion

The abnormal spontaneous brain activity of patients with AMD suggests scope for the use of ALFF in the diagnosis or prognosis in AMD.

Psychometric properties of Child Sensory Profile-2 (CSP-2) among children with spastic cerebral palsy

Cerebral palsy (CP) is not just caused by neuromuscular abnormalities; it is also a result of an impaired sensory system. Since there is not a standardized measure to evaluate sensory processing of children with spastic CP, therefore an in-depth assessment of sensory processing deficits in children with spastic CP would require an understanding of the validity and reliability of the Child Sensory Profile-2 (CSP-2) in children with spastic CP. The sample of this study included 230 children with spastic CP aged 3 to 14 years who referred to different paediatric rehabilitation centres of Delhi-NCR from April 2021 and September 2023 by using the snowball sampling procedure. To collect the data, the CSP-2 caregiver questionnaire was used. For validity, face and content validity were determined. For reliability, internal consistency of all the responses was examined using Cronbach's alpha reliability coefficient. For validity, experts involved in the study reported that the organization and design of the questionnaire would be appropriate for the children with spastic CP. All the items of the CSP-2 questionnaire were simple and easy to understand. Internal consistency was also calculated for total items (N = 86) and found to be 0.898 which indicates that all items of the questionnaire are internally consistent and reliable.

CONCLUSION

According to the findings of our study, the CSP-2 is a valid and reliable measure for evaluating sensory processing in children with spastic CP. Additionally, it may be an appropriate tool for accurately assessing this population's sensory processing deficits.

WHAT IS KNOWN

• Sensory processing deficits commonly concur with motor deficit in children with CP. Overall prevelance of sensory processing deficit was 83% in children with CP.

WHAT IS NEW

• Child Sensory Profile-2 is a reliable and valid tool for measuring sensory processing abilities in children with CP.

Tractography of sensorimotor pathways in dyskinetic cerebral palsy: Association with motor function

OBJECTIVES

Neuroimaging studies of dyskinetic cerebral palsy (CP) are scarce and the neuropathological underpinnings are not fully understood. We delineated the corticospinal tract (CST) and cortico-striatal-thalamocortical (CSTC) pathways with probabilistic tractography to assess their (1) integrity and (2) association with motor functioning in people with dyskinetic CP.

METHODS

Diffusion weighted magnetic resonance images were obtained for 33 individuals with dyskinetic CP and 33 controls. Fractional anisotropy (FA) and mean diffusivity (MD) for the CST and the CSTC pathways were compared between groups. Correlation analyses were performed between tensor metric values and motor function scores of participants with dyskinetic CP as assessed by the Gross Motor Function Classification System (GMFCS), the Bimanual Fine Motor Function (BFMF), and the Manual Ability Classification System (MACS).

RESULTS

White matter integrity in both the CST and the CSTC pathways was reduced in people with dyskinetic CP. The GMFCS, MACS and, less commonly, the BFMF were associated with FA and, particularly, MD in most portions of these pathways.

INTERPRETATION

The present study advances our understanding of the involvement of white matter microstructure in sensorimotor pathways and its relationship with motor impairment in people with dyskinetic CP. Our results are consistent with well-described relationships between upper limb function and white matter integrity in the CST and CSTC pathways in other forms of CP. This knowledge may ultimately help prognosis and therapeutic programmes.

The Impact of Cerebral Visual Impairment on Social Skills and Sensory Processing

Limited evidence exists on the impact of cerebral visual impairment (CVI) on developmental domains in toddlers. This study investigated whether CVI influences social skills and sensory processing in toddlers with cerebral palsy (CP). The study included toddlers with CP, with or without CVI, and typically developing (TD) toddlers. All parents completed the demographic information form. Social skills were assessed by the Brief Infant-Toddler Social and Emotional Assessment (BITSEA). Sensory processing was evaluated by the Infant/Toddler Sensory Profile (ITSP). Analysis of covariance was employed to assess the disparity in BITSEA and ITSP scores. Toddlers with CP and CVI group demonstrated lower social competence than the other groups (p < .05). Having CVI did not cause a statistically significant difference in sensory processing among toddlers with CP (p > .05). CVI significantly affects social competence in toddlers with CP but does not affect sensory processing.

Proprioception, Emotion and Social Responsiveness in Children with Developmental Disorders: An Exploratory Study in Autism Spectrum Disorder, Cerebral Palsy and Different Neurodevelopmental Situations

Proprioception has long been linked with emotional dysregulation in neurotypical adults. Neuropediatric disorders such as autism spectrum disorder (ASD) and cerebral palsy (CP) are distinct entities and yet both present with deficits and challenges in sensory processing and the regulation of emotions. This study aimed to explore the relationship between proprioception and emotional-social performance in children and to compare proprioception and emotional-social performance in different underlying neurodevelopmental conditions. For this purpose, this cross-sectional study included 42 children with ASD, 34 children with CP and 50 typically developing peers. Proprioceptive acuity, proprioceptive reactive behavior as well as emotion regulation and social responsiveness were assessed. The results show a significant correlation between proprioceptive deficits and emotional difficulties in this pediatric sample, with distinct proprioceptive impairment patterns according to the underlying neurological disorder. Children with CP showed significant emotional knowledge deficits, while children with ASD predominantly showed challenges in social responsiveness. These data thus suggest a differentiated impact of proprioception on emotional-social performance in neurodevelopmental disorders and highlight proprioception as a potential therapeutic target for balancing emotion regulation in children with neurodevelopmental conditions.

Spatiotemporal dynamics of cortical somatosensory network in typically developing children

Sense of touch is essential for our interactions with external objects and fine control of hand actions. Despite extensive research on human somatosensory processing, it is still elusive how involved brain regions interact as a dynamic network in processing tactile information. Few studies probed temporal dynamics of somatosensory information flow and reported inconsistent results. Here, we examined cortical somatosensory processing through magnetic source imaging and cortico-cortical coupling dynamics. We recorded magnetoencephalography signals from typically developing children during unilateral pneumatic stimulation. Neural activities underlying somatosensory evoked fields were mapped with dynamic statistical parametric mapping, assessed with spatiotemporal activation analysis, and modeled by Granger causality. Unilateral pneumatic stimulation evoked prominent and consistent activations in the contralateral primary and secondary somatosensory areas but weaker and less consistent activations in the ipsilateral primary and secondary somatosensory areas. Activations in the contralateral primary motor cortex and supramarginal gyrus were also consistently observed. Spatiotemporal activation and Granger causality analysis revealed initial serial information flow from contralateral primary to supramarginal gyrus, contralateral primary motor cortex, and contralateral secondary and later dynamic and parallel information flows between the consistently activated contralateral cortical areas. Our study reveals the spatiotemporal dynamics of cortical somatosensory processing in the normal developing brain.

Adults with cerebral palsy exhibit uncharacteristic cortical oscillations during an adaptive sensorimotor control task

Prior research has shown that the sensorimotor cortical oscillations are uncharacteristic in persons with cerebral palsy (CP); however, it is unknown if these altered cortical oscillations have an impact on adaptive sensorimotor control. This investigation evaluated the cortical dynamics when the motor action needs to be changed "on-the-fly". Adults with CP and neurotypical controls completed a sensorimotor task that required either proactive or reactive control while undergoing magnetoencephalography (MEG). When compared with the controls, the adults with CP had a weaker beta (18-24 Hz) event-related desynchronization (ERD), post-movement beta rebound (PMBR, 16-20 Hz) and theta (4-6 Hz) event-related synchronization (ERS) in the sensorimotor cortices. In agreement with normative work, the controls exhibited differences in the strength of the sensorimotor gamma (66-84 Hz) ERS during proactive compared to reactive trials, but similar condition-wise changes were not seen in adults with CP. Lastly, the adults with CP who had a stronger theta ERS tended to have better hand dexterity, as indicated by the Box and Blocks Test and Purdue Pegboard Test. These results may suggest that alterations in the theta and gamma cortical oscillations play a role in the altered hand dexterity and uncharacteristic adaptive sensorimotor control noted in adults with CP.

Reduced brainstem volume is associated with mobility impairments in youth with cerebral palsy

BACKGROUND

Persons with cerebral palsy (CP) have impaired mobility that has been attributed to changes in structure and function within the nervous system. The brainstem is a region that plays a critical role in mobility by connecting the cortex and cerebellum to the spinal cord, yet this region has been largely unstudied in persons with CP.

RESEARCH QUESTION

We used high-resolution structural MRI and biomechanical analyses to examine whether the volume of the whole brainstem and its constituent elements are altered in CP and if these alterations relate to the mobility impairments within this population.

METHODS

A cohort study was conducted to assess the volume of the whole brainstem, pons, midbrain, medulla, and superior cerebellar peduncle in a cohort of persons with CP (N = 26; Age = 16.3 ± 1.0 years; GMFCS levels I-IV, Females = 12) and a cohort of neurotypical (NT) controls (N = 38; Age = 14.3 ± 0.4 years, Females = 14) using structural MR imaging of the brainstem. Outside the scanner, a digital mat was used to quantify the spatiotemporal gait biomechanics of these individuals.

RESULTS

We found a significant decrease in volume of the total brainstem, midbrain, and pons in persons with CP in comparison to the NT controls. Furthermore, we found that the altered volumes were related to reduced gait velocity and step length.

SIGNIFICANCE

The structural changes in the brainstems of persons with CP may contribute to the mobility impairments that are ubiquitous within this population.

Reduced evoked cortical beta and gamma activity and neuronal synchronization in succinic semialdehyde dehydrogenase deficiency, a disorder of γ-aminobutyric acid metabolism

Succinic semialdehyde dehydrogenase deficiency is a rare autosomal recessively inherited metabolic disorder of γ-aminobutyric acid catabolism manifested by intellectual disability, expressive aphasia, movement disorders, psychiatric ailments and epilepsy. Subjects with succinic semialdehyde dehydrogenase deficiency are characterized by elevated γ-aminobutyric acid and related metabolites, such as γ-guanidinobutyric acid, and an age-dependent downregulation of cerebral γ-aminobutyric acid receptors. These findings indicate impaired γ-aminobutyric acid and γ-aminobutyric acid sub-type A (GABAA) receptor signalling as major factors underlying the pathophysiology of this neurometabolic disorder. We studied the cortical oscillation patterns and their relationship with γ-aminobutyric acid metabolism in 18 children affected by this condition and 10 healthy controls. Using high-density EEG, we recorded somatosensory cortical responses and resting-state activity. Using electrical source imaging, we estimated the relative power changes (compared with baseline) in both stimulus-evoked and stimulus-induced responses for physiologically relevant frequency bands and resting-state power. Stimulus-evoked oscillations are phase locked to the stimulus, whereas induced oscillations are not. Power changes for both evoked and induced responses as well as resting-state power were correlated with plasma γ-aminobutyric acid and γ-guanidinobutyric acid concentrations and with cortical γ-aminobutyric acid measured by proton magnetic resonance spectroscopy. Plasma γ-aminobutyric acid, γ-guanidinobutyric acid and cortical γ-aminobutyric acid were higher in patients than in controls (P < 0.001 for both). Beta and gamma relative power were suppressed for evoked responses in patients versus controls (P < 0.01). No group differences were observed for induced activity (P > 0.05). The mean gamma frequency of evoked responses was lower in patients versus controls (P = 0.002). Resting-state activity was suppressed in patients for theta (P = 0.011) and gamma (P < 0.001) bands. Evoked power changes were inversely correlated with plasma γ-aminobutyric acid and with γ-guanidinobutyric acid for beta (P < 0.001) and gamma (P < 0.001) bands. Similar relationships were observed between the evoked power changes and cortical γ-aminobutyric acid for all tested areas in the beta band (P < 0.001) and for the posterior cingulate gyrus in the gamma band (P < 0.001). We also observed a negative correlation between resting-state activity and plasma γ-aminobutyric acid and γ-guanidinobutyric acid for theta (P < 0.001; P = 0.003), alpha (P = 0.003; P = 0.02) and gamma (P = 0.02; P = 0.01) bands. Our findings indicate that increased γ-aminobutyric acid concentration is associated with reduced sensory-evoked beta and gamma activity and impaired neuronal synchronization in patients with succinic semialdehyde dehydrogenase deficiency. This further elucidates the pathophysiology of this neurometabolic disorder and serves as a potential biomarker for therapeutic trials.

Investigation of the Relationship between Sensory-Processing Skills and Motor Functions in Children with Cerebral Palsy

The main purpose of this study is to examine the relationship between sensory-processing skills and gross motor functions, bimanual motor functions, and balance in children with cerebral palsy (CP). A total of 47 patients between the ages of 3 and 10, diagnosed with CP, who received or applied for treatment in our physical therapy and rehabilitation unit were included in the study. Sensory profiling (SP), assisting hand assessment (AHA), the Gross Motor Function Measure-66 (GMFM-66), and the Pediatric Berg Balance Scale (PBBS) were used in the evaluation of the children with CP who participated in the study. The Gross Motor Function Classification System (GMFCS) was used to classify the children based on functional abilities and limitations, and the Manual Ability Classification System (MACS) was used to classify the children based on manual dexterity. The SP parameters were compared with AHA, GMFM-66, and PBBS results, and with GMFCS and MACS levels. Statistically significant relationships were found between AHA and SP, PBBS, and SP and between GMFM-66 and SP (p < 0.05). Our study shows that there are some disorders in sensory processing in children with CP. We think that sensory evaluations should be included in the CP rehabilitation program.

Somatosensation and motor performance in the less-affected and more-affected hand of unilateral cerebral palsy children: a cross-sectional study

PURPOSE

This study aimed to examine motor performance and somatosensory processing of unilateral cerebral palsy (UCP) children in both the less-affected hand and the more-affected hand. This study is also aimed at analysing the somatosensory proccessing in the more-affected hand in relation to age and damaged hemisphere.

MATERIALS AND METHODS

Forty-seven children aged from 6 to 15 years (UCP = 23; TD = 24) were recruited. Grip strength, pinch strength, Box and Block Test and Jebsen Taylor Hand Function Test were used to analyse motor performance. A comprehensive somatosensory assessment battery was included: tactile registration, unilateral, bilateral and spatio-temporal perception, haptic recognition, texture perception, proprioception, pressure pain threshold and functional sensitivity.

RESULTS

UCP children exhibited lower performance in all aspects of motor performance measured in both the less-affected hand and the more-affected hand, except grip strength in the less-affected hand. Significant differences were found for all tests included in the somatosensory assessment in both the less-affected hand and the more-affected hand, except unilateral perception tests in the less-affected hand.

CONCLUSIONS

UCP children present difficulties in motor performance and somatosensory processing not only in the more-affected hand, but also in the less-affected hand. Somatosensation may be a critical driver of functional performance.Implications for rehabilitationThe less-affected hand of children with unilateral cerebral palsy should be included in both assessment and intervention programmes.Somatosensory processing should be assessed through a comprehensive battery, both in the less-affected hand and in the more-affected hand of unilateral cerebral palsy children.Somatosensory treatment must be taken into account if functional performance in the activities of daily living of unilateral cerebral palsy children is to be improved.

Limb-specific thalamocortical tracts are impaired differently in hemiplegic and diplegic subtypes of cerebral palsy

Thalamocortical pathways are considered crucial in the sensorimotor functioning of children with cerebral palsy (CP). However, previous research has been limited by non-specific tractography seeding and the lack of comparison between different CP subtypes. We compared limb-specific thalamocortical tracts between children with hemiplegic (HP, N = 15) or diplegic (DP, N = 10) CP and typically developed peers (N = 19). The cortical seed-points for the upper and lower extremities were selected (i) manually based on anatomical landmarks or (ii) using functional magnetic resonance imaging (fMRI) activations following proprioceptive-limb stimulation. Correlations were investigated between tract structure (mean diffusivity, MD; fractional anisotropy, FA; apparent fiber density, AFD) and sensorimotor performance (hand skill and postural stability). Compared to controls, our results revealed increased MD in both upper and lower limb thalamocortical tracts in the non-dominant hemisphere in HP and bilaterally in DP subgroup. MD was strongly lateralized in participants with hemiplegia, while AFD seemed lateralized only in controls. fMRI-based tractography results were comparable. The correlation analysis indicated an association between the white matter structure and sensorimotor performance. These findings suggest distinct impairment of functionally relevant thalamocortical pathways in HP and DP subtypes. Thus, the organization of thalamocortical white matter tracts may offer valuable guidance for targeted, life-long rehabilitation in children with CP.

Brain structural and functional connectivity and network organization in cerebral palsy: A scoping review

AIM

To explore altered structural and functional connectivity and network organization in cerebral palsy (CP), by clinical CP subtype (unilateral spastic, bilateral spastic, dyskinetic, and ataxic CP).

METHOD

PubMed and Embase databases were systematically searched. Extracted data included clinical characteristics, analyses, outcome measures, and results.

RESULTS

Sixty-five studies were included, of which 50 investigated structural connectivity, and 20 investigated functional connectivity using functional magnetic resonance imaging (14 studies) or electroencephalography (six studies). Five of the 50 studies of structural connectivity and one of 14 of functional connectivity investigated whole-brain network organization. Most studies included patients with unilateral spastic CP; none included ataxic CP.

INTERPRETATION

Differences in structural and functional connectivity were observed between investigated clinical CP subtypes and typically developing individuals on a wide variety of measures, including efferent, afferent, interhemispheric, and intrahemispheric connections. Directions for future research include extending knowledge in underrepresented CP subtypes and methodologies, evaluating the prognostic potential of specific connectivity and network measures in neonates, and understanding therapeutic effects on brain connectivity.

Neural Correlates of Impaired Grasp Function in Children with Unilateral Spastic Cerebral Palsy

Unilateral spastic cerebral palsy (USCP) is caused by damage to the developing brain and affects motor function, mainly lateralized to one side of the body. Children with USCP have difficulties grasping objects, which can affect their ability to perform daily activities. Although cerebral palsy is typically classified according to motor function, sensory abnormalities are often present as well and may contribute to motor impairments, including grasping. In this review, we show that the integrity and connectivity pattern of the corticospinal tract (CST) is related to execution and anticipatory control of grasping. However, as this may not explain all the variance of impairments in grasping function, we also describe the potential roles of sensory and sensorimotor integration deficits that contribute to grasp impairments. We highlight studies measuring fingertip forces during object manipulation tasks, as this approach allows for the dissection of the close association of sensory and motor function and can detect the discriminant use of sensory information during a complex, functional task (i.e., grasping). In addition, we discuss the importance of examining the interactions of the sensory and motor systems together, rather than in isolation. Finally, we suggest future directions for research to understand the underlying mechanisms of grasp impairments.

Lower extremity proprioception and its association with activity and participation in children with unilateral spastic cerebral palsy

OBJECTIVE

This cross-sectional study aimed to assess lower extremity proprioception and investigate its relationship to activity and participation levels in children with unilateral spastic cerebral palsy (USCP).

METHODS

A total of 22 children with USCP between the ages of 5 and 16 years participated in this study. Lower extremity proprioception was evaluated with a protocol that consisted of verbal and location identification, unilateral and contralateral limb matching, and static and dynamic balance tests performed with the impaired and less impaired lower extremities under eyes-open and eyes-closed conditions. Furthermore, the Functional Independence Measure (WeeFIM) and Pediatric Outcomes Data Collection Instrument (PODCI) were used to evaluate the independence levels in daily living activities and participation levels.

RESULTS

Children demonstrated proprioceptive loss, as evidenced by an increase in matching errors under the eyes-closed condition compared to the eyes-open condition (p<0.05). Also, the impaired extremity had greater proprioceptive loss than the less impaired extremity (p<0.05). The 5-6-year age group experienced greater proprioceptive deficits than did the 7-11 and 12-16 age groups (p<0.05). Children's lower extremity proprioceptive deficit was moderately associated with their activity and participation levels (p<0.05).

CONCLUSIONS

Our findings suggest that treatment programs based on comprehensive assessments, including proprioception, may be more effective in these children.

Youth with Cerebral Palsy Display Abnormal Somatosensory Cortical Activity During a Haptic Exploration Task

There are numerous clinical reports that youth with cerebral palsy (CP) have proprioceptive, stereognosis and tactile discrimination deficits. The growing consensus is that the altered perceptions in this population are attributable to aberrant somatosensory cortical activity seen during stimulus processing. It has been inferred from these results that youth with CP likely do not adequately process ongoing sensory feedback during motor performance. However, this conjecture has not been tested. Herein, we address this knowledge gap using magnetoencephalographic (MEG) brain imaging by applying electrical stimulation to the median nerve of youth with CP (N = 15, Age = 15.8 ± 0.83 yrs, Males = 12, MACS levels I-III) and neurotypical (NT) controls (N = 18, Age = 14.1 ± 2.4 yrs, Males = 9) while at rest (i.e., passive) and during a haptic exploration task. The results illustrated that the somatosensory cortical activity was reduced in the group with CP compared to controls during the passive and haptic conditions. Furthermore, the strength of the somatosensory cortical responses during the passive condition were positively associated with the strength of somatosensory cortical responses during the haptic condition (r = 0.75, P = 0.004). This indicates that the aberrant somatosensory cortical responses seen in youth with CP during rest are a good predictor of the extent of somatosensory cortical dysfunction during the performance of motor actions. These data provide novel evidence that aberrations in somatosensory cortical function in youth with CP likely contribute to the difficulties in sensorimotor integration and the ability to effectively plan and execute motor actions.

Neuro-imaging characteristics of sensory impairment in cerebral palsy; a systematic review

Background

Objective: To identify and examine neural reorganization of the sensory network in terms of lesion type, somatotopic organization of the primary somatosensory area, and functional connectivity in relation to sensory function in children and young adults with cerebral palsy (CP).

Methods

Design: systematic review, Prospero registration ID 342570. Data sources: PubMed; Cochrane; Web of Science; Embase; CINAHL and PEDro from inception to March 13, 2021. Eligibility criteria: All types of original studies, concerning sensory connectivity in relation to sensory outcome in patients with spastic CP, &lt;30 years of age. No publication status or date restrictions were applied. Data extraction and synthesis: Two authors independently determined the eligibility of studies. Quality assessment was performed by a third author. Neuro-imaging/neurophysiological techniques, sensory outcomes and patient characteristics were extracted.

Results

Children and young adults with periventricular leucomalacia (PVL) lesions have significantly better hand function and sensation scores than patients with cortical-subcortical/middle cerebral artery (MCA) lesions. Ipsilesional reorganization of the S1 (primary somatosensory cortex) area appears to be the primary compensation mechanism after a unilateral early brain lesion, regardless of the timing of the lesion. Interhemispheric reorganization of the sensory system after early brain lesions is rare and, when it occurs, poorly effective. Diffusion tractography shows a positive correlation between the ascending sensory tract (AST) diffusivity metrics of the more affected hemisphere and sensory test outcomes.

Discussion and conclusions

Because of the large variability in study design, patient characteristics, neuroimaging/neurophysiological techniques and parameters as well as sensory assessment methods used, it is difficult to draw definite inferences on the relationship between the reorganization of the sensory network following early brain damage and sensory function in children and young adults with CP. In general, sensory function seems to be worse in cortical as opposed to white matter tract (PVL) lesions. International consensus on a clinically relevant sensory test battery is needed to enhance understanding of the intriguing compensatory mechanisms of sensory network following early brain damage and potential consequences for rehabilitation strategies.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/.

Reduced Brainstem Volume is Associated with Mobility Impairments in Youth with Cerebral Palsy

Persons with cerebral palsy (CP) have impaired mobility that has been attributed to changes in structure and function within the nervous system. The brainstem is a region that plays a critical role in locomotion by connecting the cortex and cerebellum to the spinal cord, yet this region has been largely unstudied in persons with CP. The objective of this investigation was to use high-resolution structural MRI and biomechanical analyses to examine whether the volume of the whole brainstem and its constituent elements are altered in CP, and if these alterations relate to the mobility impairments within this population. We assessed the volume of the pons, midbrain, medulla, and superior cerebellar peduncle (SCP) in a cohort of persons with CP (N = 26; Age = 16.3 ± 1.0 yrs; GMFCS levels I-IV, Females = 12) and a cohort of neurotypical (NT) controls (N = 38; Age = 14.3 ± 0.4 yrs, Females = 14) using structural MR imaging of the brainstem. Outside the scanner, a digital mat was used to quantify the spatiotemporal gait biomechanics of these individuals. Our MRI results revealed that there was a significant decrease in volume of the total brainstem, midbrain, and pons in persons with CP in comparison to the NT controls. Furthermore, we found that the altered volumes were related to reduced gait velocity and step length. These results suggest that there are structural changes in the brainstems of persons with CP that may contribute to the mobility impairments that are ubiquitous within this population.

Implementation of an Early Communication Intervention for Young Children with Cerebral Palsy Using Single-Subject Research Design

The implementation of an intervention protocol aimed at increasing vocal complexity in three pre-linguistic children with cerebral palsy (two males, starting age 15 months, and one female, starting age 16 months) was evaluated utilising a repeated ABA case series design. The study progressed until the children were 36 months of age. Weekly probes with trained and untrained items were administered across each of three intervention blocks. Successive blocks targeted more advanced protophone production and speech movement patterns, individualised for each participant. Positive treatment effects were seen for all participants in terms of a greater rate of achievement of target protophone categories and speech movement patterns. Tau coefficients for trained items demonstrated overall moderate to large AB phase contrast effect sizes, with limited evidence of generalisation to untrained items. Control items featuring protophones and speech movements not targeted for intervention showed no change across phases for any participant. Our data suggest that emerging speech-production skills in prelinguistic infants with CP can be positively influenced through a multimodal intervention focused on capitalising on early periods of plasticity when language learning is most sensitive.

A Val66Met polymorphism is associated with weaker somatosensory cortical activity in individuals with cerebral palsy

Background

The brain-derived neurotrophic factor (BDNF) protein plays a prominent role in the capacity for neuroplastic change. However, a single nucleotide polymorphism at codon 66 of the BDNF gene results in significant reductions in neuroplastic change. Potentially, this polymorphism also contributes to the weaker somatosensory cortical activity that has been extensively reported in the neuroimaging literature on cerebral palsy (CP).

Aims

The primary objective of this study was to use magnetoencephalography (MEG) to probe if BDNF genotype affects the strength of the somatosensory-evoked cortical activity seen within individuals with CP.

Methods and procedures

and Procedures: Twenty individuals with CP and eighteen neurotypical controls participated. Standardized low resolution brain electromagnetic tomography (sLORETA) was used to image the somatosensory cortical activity evoked by stimulation of the tibial nerve. BDNF genotypes were determined from saliva samples.

Outcomes and results

The somatosensory cortical activity was weaker in individuals with CP compared to healthy controls (P = 0.04). The individuals with a Val66Met or Met66Met BDNF polymorphism also showed a reduced response compared to the individuals without the polymorphism (P = 0.03), had higher GMFCS levels (P = 0.04), and decreased walking velocity (P = 0.05).

Conclusions and implications

These results convey that BDNF genotype influences the strength of the somatosensory activity and mobility in individuals with CP.

What this paper adds

Previous literature has extensively documented altered sensorimotor cortical activity in individuals with CP, which ultimately contributes to the clinical deficits in sensorimotor processing documented in this population. While some individuals with CP see vast improvements in their sensorimotor functioning following therapeutic intervention, others are clear non-responders. The underlying basis for this discrepancy is not well understood. Our study is the first to identify that a polymorphism at the gene that codes for brain derived neurotrophic factor (BDNF), a protein well-known to be involved in the capacity for neuroplastic change, may influence the altered sensorimotor cortical activity within this population. Potentially, individuals with CP that have a polymorphism at the BDNF gene may reflect those that have difficulties in achieving beneficial outcomes following intervention. Thus, these individuals may require different therapeutic approaches in order to stimulate neuroplastic change and get similar benefits from therapy as their neurotypical peers.

Power training alters somatosensory cortical activity of youth with cerebral palsy

OBJECTIVE

Our prior magnetoencephalographic (MEG) investigations demonstrate that persons with cerebral palsy (CP) have weaker somatosensory cortical activity than neurotypical (NT) controls, which is associated with reduced muscular strength and mobility. Power training can improve lower extremity isokinetic strength, muscular power, and walking performance of youth with CP. Potentially, these clinically relevant improvements are partially driven by changes in somatosensory processing. The objective of this investigation was to determine if power training has complementary changes in muscular function and somatosensory cortical activity in youth with CP.

METHODS

A cohort of youth with CP (N = 11; age = 15.90 ± 1.1 years) and NT controls (N = 10; Age = 15.93 ± 2.48 years) participated in this investigation. Youth with CP underwent 24 power training sessions. Pre-post bilateral leg press 1-repetition maximum (1RM), peak power production, 10-m walking speed, and distance walked 1-min were used as outcome measures. MEG neuroimaging assessed the changes in somatosensory cortical activity while at rest. NT controls only underwent a baseline MEG assessment.

RESULTS

Youth with CP had a 56% increase in 1RM (p < 0.001), a 33% increase in peak power production (p = 0.019), and a 4% improvement in 1-min walk (p = 0.029). Notably, there was a 46% increase in somatosensory cortical activity (p = 0.02).

INTERPRETATION

These results are the first to show that power training is associated with improvements in muscular function, walking performance, and the resting somatosensory cortical activity in individuals with CP. This treatment approach might be advantageous due to the potential to promote cortical and muscular plasticity, which appear to have carryover effects for improved walking performance.

Altered spontaneous cortical activity predicts pain perception in individuals with cerebral palsy

Cerebral palsy is the most common paediatric neurological disorder and results in extensive impairment to the sensorimotor system. However, these individuals also experience increased pain perception, resulting in decreased quality of life. In the present study, we utilized magnetoencephalographic brain imaging to examine whether alterations in spontaneous neural activity predict the level of pain experienced in a cohort of 38 individuals with spastic diplegic cerebral palsy and 67 neurotypical controls. Participants completed 5 min of an eyes closed resting-state paradigm while undergoing a magnetoencephalography recording. The magnetoencephalographic data were then source imaged, and the power within the delta (2–4 Hz), theta (5–7 Hz), alpha (8–12 Hz), beta (15–29 Hz), low gamma (30–59 Hz) and high gamma (60–90 Hz) frequency bands were computed. The resulting power spectral density maps were analysed vertex-wise to identify differences in spontaneous activity between groups. Our findings indicated that spontaneous cortical activity was altered in the participants with cerebral palsy in the delta, alpha, beta, low gamma and high gamma bands across the occipital, frontal and secondary somatosensory cortical areas (all p_FWE < 0.05). Furthermore, we also found that the altered beta band spontaneous activity in the secondary somatosensory cortices predicted heightened pain perception in the individuals with cerebral palsy (P = 0.039). Overall, these results demonstrate that spontaneous cortical activity within individuals with cerebral palsy is altered in comparison to their neurotypical peers and may predict increased pain perception in this patient population. Potentially, changes in spontaneous resting-state activity may be utilized to measure the effectiveness of current treatment approaches that are directed at reducing the pain experienced by individuals with cerebral palsy.

Spinal cord microstructural changes are connected with the aberrant sensorimotor cortical oscillatory activity in adults with cerebral palsy

Previous animal models have illustrated that reduced cortical activity in the developing brain has cascading activity-dependent effects on the microstructural organization of the spinal cord. A limited number of studies have attempted to translate these findings to humans with cerebral palsy (CP). Essentially, the aberrations in sensorimotor cortical activity in those with CP could have an adverse effect on the spinal cord microstructure. To investigate this knowledge gap, we utilized magnetoencephalographic (MEG) brain imaging to quantify motor-related oscillatory activity in fourteen adults with CP and sixteen neurotypical (NT) controls. A subset of these participants also underwent cervical-thoracic spinal cord MRI. Our results showed that the strength of the peri-movement beta desynchronization and the post-movement beta rebound were each weaker in the adults with CP relative to the controls, and these weakened responses were associated with poorer task performance. Additionally, our results showed that the strength of the peri-movement beta response was associated with the total cross-sectional area of the spinal cord and the white matter cross-sectional area. Altogether these results suggest that the altered sensorimotor cortical activity seen in CP may result in activity-dependent plastic changes within the spinal cord microstructure, which could ultimately contribute to the sensorimotor deficits seen in this population.

Imaging somatosensory cortex responses measured by OPM-MEG: Variational free energy-based spatial smoothing estimation approach

In recent years, optically pumped magnetometer (OPM)-based magnetoencephalography (MEG) has shown potential for analyzing brain activity. It has a flexible sensor configuration and comparable sensitivity to conventional SQUID-MEG. We constructed a 32-channel OPM-MEG system and used it to measure cortical responses to median and ulnar nerve stimulations. Traditional magnetic source imaging methods tend to blur the spatial extent of sources. Accurate estimation of the spatial size of the source is important for studying the organization of brain somatotopy and for pre-surgical functional mapping. We proposed a new method called variational free energy-based spatial smoothing estimation (FESSE) to enhance the accuracy of mapping somatosensory cortex responses. A series of computer simulations based on the OPM-MEG showed better performance than the three types of competing methods under different levels of signal-to-noise ratios, source patch sizes, and co-registration errors. FESSE was then applied to the source imaging of the OPM-MEG experimental data.

Stronger proprioceptive BOLD-responses in the somatosensory cortices reflect worse sensorimotor function in adolescents with and without cerebral palsy

Cerebral palsy (CP) is a motor disorder where the motor defects are partly due to impaired proprioception. We studied cortical proprioceptive responses and sensorimotor performance in adolescents with CP and their typically-developed (TD) peers. Passive joint movements were used to stimulate proprioceptors during functional magnetic resonance imaging (fMRI) session to quantify the proprioceptive responses whose associations to behavioral sensorimotor performance were also examined. Twenty-three TD (15 females, age: mean ± standard deviation 14.2 ± 2.4 years) and 18 CP (12 females, age: mean ± standard deviation, 13.8 ± 2.3 years; 12 hemiplegic, 6 diplegic) participants were included in this study. Participants' index fingers and ankles were separately stimulated at 3 Hz and 1 Hz respectively with pneumatic movement actuators. Regions-of-interest were used to quantify BOLD-responses from the primary sensorimotor (SM1) and secondary (SII) somatosensory cortices and were compared across the groups. Associations between responses strengths and sensorimotor performance measures were also examined. Proprioceptive responses were stronger for the individuals with CP compared to their TD peers in SM1 (p < 0.001) and SII (p < 0.05) cortices contralateral to their more affected index finger. The ankle responses yielded no significant differences between the groups. The CP group had worse sensorimotor performance for hands and feet (p < 0.001). Stronger responses to finger stimulation in the dominant SM1 (p < 0.001) and both dominant and non-dominant SII (p < 0.01, p < 0.001) cortices were associated with the worse hand sensorimotor performance across all participants. Worse hand function was associated with stronger cortical activation to the proprioceptive stimulation. This association was evident both in adolescents with CP and their typically-developed controls, thus it likely reflects both clinical factors and normal variation in the sensorimotor function. The specific mechanisms need to be clarified in future studies.

Identification of Proprioceptive Thalamocortical Tracts in Children: Comparison of fMRI, MEG, and Manual Seeding of Probabilistic Tractography

Studying white matter connections with tractography is a promising approach to understand the development of different brain processes, such as proprioception. An emerging method is to use functional brain imaging to select the cortical seed points for tractography, which is considered to improve the functional relevance and validity of the studied connections. However, it is unknown whether different functional seeding methods affect the spatial and microstructural properties of the given white matter connection. Here, we compared functional magnetic resonance imaging, magnetoencephalography, and manual seeding of thalamocortical proprioceptive tracts for finger and ankle joints separately. We showed that all three seeding approaches resulted in robust thalamocortical tracts, even though there were significant differences in localization of the respective proprioceptive seed areas in the sensorimotor cortex, and in the microstructural properties of the obtained tracts. Our study shows that the selected functional or manual seeding approach might cause systematic biases to the studied thalamocortical tracts. This result may indicate that the obtained tracts represent different portions and features of the somatosensory system. Our findings highlight the challenges of studying proprioception in the developing brain and illustrate the need for using multimodal imaging to obtain a comprehensive view of the studied brain process.

Assessing spino-cortical proprioceptive processing in childhood unilateral cerebral palsy with corticokinematic coherence

OBJECTIVE

To develop an electrophysiological marker of proprioceptive spino-cortical tracts integrity based on corticokinematic coherence (CKC) in young children with unilateral cerebral palsy (UCP), in whom behavioral measures are not applicable.

METHODS

Electroencephalography (EEG) signals from 12 children with UCP aged 19 to 57 months were recorded using 128-channel EEG caps while their fingers were moved at 2 Hz by an experimenter, in separate sessions for the affected and non-affected hands. The coherence between movement kinematics and EEG signals (i.e., CKC) was computed at the sensor and source (using a realistic head model) levels. Peaks of CKC obtained for the affected and non-affected hands were compared for location and strength. The relation between CKC strength on the lesion-side, the lesion-type (cortico-subcortical vs. subcortical) and the level of manual ability were studied with 2-way repeated-measures ANOVA.

RESULTS

At the individual level, a significant CKC peak at the central area contralateral to the moved hand was found in all young children with their non-affected hand and in 8 out of 12 children with their affected hand. At the group level, CKC to the affected hand movements was weaker than CKC to the non-affected hand movements. This difference was influenced by the type of lesion, the effect being predominant in the subgroup (n = 5) with cortico-subcortical lesions.

CONCLUSION

CKC is measurable with EEG in young children with UCP and provides electrophysiological evidence for altered proprioceptive spino-cortical tracts on the lesioned brain hemisphere, particularly in children with cortico-subcortical lesions.

Somatosensory Plasticity in Hemiplegic Cerebral Palsy Following Constraint Induced Movement Therapy

BACKGROUND

Children with hemiplegic cerebral palsy (HCP) experience upper limb somatosensory and motor deficits. Although constraint-induced movement therapy (CIMT) improves motor function, its impact on somatosensory function remains underinvestigated.

OBJECTIVE

The objective of this study was to evaluate somatosensory perception and related brain responses in children with HCP, before and after a somatosensory enhanced CIMT protocol, as measured using clinical sensory and motor assessments and magnetoencephalography.

METHODS

Children with HCP attended a somatosensory enhanced CIMT camp. Clinical somatosensory (tactile registration, 2-point discrimination, stereognosis, proprioception, kinesthesia) and motor outcomes (Quality of Upper Extremity Skills [QUEST] Total/Grasp, Jebsen-Taylor Hand Function Test, grip strength, Assisting Hand Assessment), as well as latency and amplitude of magnetoencephalography somatosensory evoked fields (SEF), were assessed before and after the CIMT camp with paired sample t-tests or Wilcoxon signed-rank tests.

RESULTS

Twelve children with HCP (mean age: 7.5 years, standard deviation: 2.4) participated. Significant improvements in tactile registration for the affected (hemiplegic) hand (Z = 2.39, P = 0.02) were observed in addition to statistically and clinically significant improvements in QUEST total (t = 3.24, P = 0.007), QUEST grasp (t = 3.24, P = 0.007), Assisting Hand Assessment (Z = 2.25, P = 0.03), and Jebsen-Taylor Hand Function Test (t = -2.62, P = 0.03). A significant increase in the SEF peak amplitude was also found in the affected hand 100 ms after stimulus onset (t = -2.22, P = 0.04).

CONCLUSIONS

Improvements in somatosensory clinical function and neural processing in the affected primary somatosensory cortex in children with HCP were observed after a somatosensory enhanced CIMT program. Further investigation is warranted to continue to evaluate the effectiveness of a sensory enhanced CIMT program in larger samples and controlled study designs.

Hand function development of children with hemiplegic cerebral palsy: A scoping review

PURPOSE

Hemiplegic cerebral palsy (hCP) typically impacts sensorimotor control of the hand, but comprehensive assessments of the hands of children with hCP are relatively rare. This scoping review summarizes the development of hand function for children with hCP.

METHODS

This scoping review focused on the development of hand function in children with hCP. Electronic databases (PubMed, PEDro, Web of Science, CINAHL, and SpringerLink) were searched to identify studies assessing hand function in children with hCP. The search was performed using keywords (e.g., "hemiplegia"). An iterative approach verified by two authors was used to select the studies. Articles which reported quantitative data for children with hCP on any items of a specified set of hand evaluations were included. Measures were sorted into three categories: quantitative neuromechanics, clinical assessments, and clinical functional evaluations.

RESULTS

Initial searches returned 1536 articles, 131 of which were included in the final review. Trends between assessment scores and age were examined for both hands.

CONCLUSION

While several studies have evaluated hand function in children with hCP, the majority relied on clinical scales, assessments, or qualitative descriptions. Further assessments of kinematics, kinetics, and muscle activation patterns are needed to identify the underlying impairment mechanisms that should be targeted for treatment.

Somatosensory deficits and neural correlates in cerebral palsy: a scoping review

AIM

To synthetize studies assessing somatosensory deficits and alterations in cerebral responses evoked by somatosensory stimulation in individuals with cerebral palsy (CP) compared to typically developing individuals.

METHOD

A scoping review of the literature was performed in the MEDLINE, Embase, PsycInfo, CINAHL, Evidence-Based Medicine Reviews, and Web of Science databases (last search carried out on 6th and 7th August 2020) with a combination of keywords related to CP and somatosensory functions. Somatosensory deficits were measured with clinical tests and alterations in cerebral responses were measured with functional magnetic resonance imaging, electroencephalography, and magnetoencephalography.

RESULTS

Forty-eight articles were included. Overall, 1463 participants with CP (mean [SD] age 13y 1mo [4y 11mo], range 1-55y; 416 males, 319 females, sex not identified for the remaining participants) and 1478 controls (mean [SD] age 13y 1mo [5y 8mo], range 1-42y; 362 males, 334 females, sex not identified for the remaining participants) were included in the scoping review. For tactile function, most studies reported registration (8 out of 13) or perception (21 out of 21) deficits in participants with CP. For proprioception, most studies also reported registration (6 out of 8) or perception (10 out of 15) deficits. Pain function has not been studied as much, but most studies reported registration (2 out of 3) or perception (3 out of 3) alterations. Neuroimaging findings (18 studies) showed alterations in the somatotopy, morphology, latency, or amplitude of cortical responses evoked by somatosensory stimuli.

INTERPRETATION

Despite the heterogeneity in the methods employed, most studies reported somatosensory deficits. The focus has been mainly on tactile and proprioceptive function, whereas pain has received little attention. Future research should rigorously define the methods employed and include a sample that is more representative of the population with CP. What this paper adds Most of the papers reviewed found tactile registration and perception deficits in the upper limbs. Proprioceptive deficits were generally observed in cerebral palsy but results were heterogeneous. Pain has received little attention compared to tactile and proprioceptive functions. Neuroimaging studies supported behavioral observations. Alterations were observed for both the most and least affected limb.

Rehabilitation of motor function in children with cerebral palsy based on motor imagery

To promote the rehabilitation of motor function in children with cerebral palsy (CP), we developed motor imagery (MI) based training system to assist their motor rehabilitation. Eighteen CP children, ten in short- and eight in long-term rehabilitation, participated in our study. In short-term rehabilitation, every 2 days, the MI datasets were collected; whereas the duration of two adjacency MI experiments was ten days in the long-term protocol. Meanwhile, within two adjacency experiments, CP children were requested to daily rehabilitate the motor function based on our system for 30 min. In both strategies, the promoted motor information processing was observed. In terms of the relative signal power spectra, a main effect of time was revealed, as the promoted power spectra were found for the last time of MI recording, compared to that of the first one, which first validated the effectiveness of our intervention. Moreover, as for network efficiency related to the motor information processing, compared to the first MI, the increased network properties were found for the last MI, especially in long-term rehabilitation in which CP children experienced a more obvious efficiency promotion. These findings did validate that our MI-based rehabilitation system has the potential for CP children to assist their motor rehabilitation.

Population Receptive Field Characteristics in the between- and Within-Digit Dimensions of the Undominant Hand in the Primary Somatosensory Cortex

Somatotopy is an important guiding principle for sensory fiber organization in the primary somatosensory cortex (S1), which reflects tactile information processing and is associated with disease-related reorganization. However, it is difficult to measure the neuronal encoding scheme in S1 in vivo in normal participants. Here, we investigated the somatotopic map of the undominant hand using a Bayesian population receptive field (pRF) model. The model was established in hand space with between- and within-digit dimensions. In the between-digit dimension, orderly representation was found, which had low variability across participants. The pRF shape tended to be elliptical for digits with high spatial acuity, for which the long axis was along the within-digit dimension. In addition, the pRF width showed different change trends in the 2 dimensions across digits. These results provide new insights into the neural mechanisms in S1, allowing for in-depth investigation of somatosensory information processing and disease-related reorganization.

Aberrant somatosensory phase synchronization in children with hemiplegic cerebral palsy

Children with hemiplegic cerebral palsy (HCP) often show disturbances of somatosensation. Despite extensive evidence of somatosensory deficits, neurophysiological alterations associated with somatosensory deficits in children with HCP have not been elucidated. Here, we aim to assess phase synchrony within and between contralateral primary (S1) and secondary (S2) somatosensory areas in children with HCP. Intra-regional and inter-regional phase synchronizations within and between S1 and S2 were estimated from somatosensory evoked fields (SEFs) in response to passive pneumatic stimulation of contralateral upper extremities and recorded with pediatric magnetoencephalography (MEG) in children with HCP and typically developing (TD) children. We found aberrant phase synchronizations within S1 and between S1 and S2 in both hemispheres in children with HCP. Specifically, the less-affected (LA) hemisphere demonstrated diminished phase synchronizations after the stimulus onset up to ~120 ms compared to the more-affected (MA) hemisphere and the dominant hemisphere of TD children, while the MA hemisphere showed enhanced phase synchronizations after ~100 ms compared to the LA hemisphere and the TD dominant hemisphere. Our findings indicate abnormal somatosensory functional connectivity in both hemispheres of children with HCP.

Brain-Computer Interfaces for Children With Complex Communication Needs and Limited Mobility: A Systematic Review

Brain-computer interfaces (BCIs) represent a new frontier in the effort to maximize the ability of individuals with profound motor impairments to interact and communicate. While much literature points to BCIs' promise as an alternative access pathway, there have historically been few applications involving children and young adults with severe physical disabilities. As research is emerging in this sphere, this article aims to evaluate the current state of translating BCIs to the pediatric population. A systematic review was conducted using the Scopus, PubMed, and Ovid Medline databases. Studies of children and adolescents that reported BCI performance published in English in peer-reviewed journals between 2008 and May 2020 were included. Twelve publications were identified, providing strong evidence for continued research in pediatric BCIs. Research evidence was generally at multiple case study or exploratory study level, with modest sample sizes. Seven studies focused on BCIs for communication and five on mobility. Articles were categorized and grouped based on type of measurement (i.e., non-invasive and invasive), and the type of brain signal (i.e., sensory evoked potentials or movement-related potentials). Strengths and limitations of studies were identified and used to provide requirements for clinical translation of pediatric BCIs. This systematic review presents the state-of-the-art of pediatric BCIs focused on developing advanced technology to support children and youth with communication disabilities or limited manual ability. Despite a few research studies addressing the application of BCIs for communication and mobility in children, results are encouraging and future works should focus on customizable pediatric access technologies based on brain activity.

Association between sensory processing and activity performance in children with cerebral palsy levels I-II on the gross motor function classification system

BACKGROUND

Investigating the influence of sensory processing disorders on the level of function of children with cerebral palsy (CP) may help therapists identify specific impairments that impact activity and participation in these children. This may provide direction on selection of interventions to improve function and quality of life.

OBJECTIVES

To investigate if sensory processing disorders in children with CP levels I and II on the Gross Motor Function Classification System (GMFCS) are associated with activity performance.

METHODS

Sensory processing and activity performance of 28 children with CP between 5 and 15 years (mean ± standard deviation; 9.9 ± 3.2 years) were evaluated using the Sensory Profile (SP) and Pediatric Evaluation of Disability Inventory (PEDI), respectively. Associations between the components of the SP and PEDI were assessed with Spearman correlation coefficients. Multiple linear regression analysis using backward stepwise method was used to determine the variables of sensory processing that are associated with activity performance on the PEDI.

RESULTS

The category of Behavioral Outcomes of Sensory Processing was the only variable associated with Functional Abilities in self-care and social function (r2 = 0.30 and r2 = 0.39, respectively) and Caregiver Assistance (r2 = 0.36 and r2 = 0.37, respectively), (p < 0.05).

CONCLUSION

Sensory processing in children with CP levels I-II on the GMFCS is associated with their ability to perform daily living activities and in their social interaction with the environment.

The somatosensory cortical activity in individuals with cerebral palsy displays an aberrant developmental trajectory

KEY POINTS

Individuals with cerebral palsy (CP) have a reduced somatosensory cortical response Somatosensory cortical response strength decreases from adolescence to early adulthood Somatosensory cortical responses in youth with CP are similar to adult controls Individuals with CP may have aberrant maturation of the somatosensory system ABSTRACT: Numerous studies have documented tactile and proprioceptive deficits in children with cerebral palsy (CP) and linked these with weaker somatosensory cortical activity. However, whether such aberrations in somatosensory processing extend and/or progress into adulthood remains poorly understood. In the current study, we used magnetoencephalography (MEG) to investigate the primary somatosensory responses in a sample of individuals with CP (N = 42; age = 9-28 years) and a cohort of healthy controls (N = 23; age range = 11-23 years). Briefly, transient electrical stimulation was applied to the right tibial nerve, and standardized low-resolution brain electromagnetic tomography (sLORETA) was used to image the dynamic somatosensory cortical response. We found that the strength of somatosensory cortical activity within the 112-252 ms time window was significantly reduced in the individuals with CP compared with the healthy controls (HC = 286.53 ± 30.51, 95% CI [226.74, 346.32]; CP = 208.30 ± 19.66,CI [169.77, 246.83], P = 0.0126). These results corroborate previous findings of aberrant somatosensory cortical activity in individuals with CP. Our results also suggest that the somatosensory cortical activity tends to become weaker with age, with a similar rate of neurophysiological change in individuals with CP and healthy controls (P = 0.8790). Visualization of regression models fitted to the data imply that youth with CP may have somatosensory cortical activity similar to adult controls. These findings suggest that some individuals with CP exhibit an aberrant developmental trajectory of their somatosensory system.

Body maps in the infant brain: implications for neurodevelopmental disabilities

This review and synthesis discusses recent work that has utilized brain imaging methods, such as the electroencephalogram (EEG) and magnetoencephalogram, to provide insights into the ways that the body is represented in the infant brain. One aspect of body representation concerns somatotopic maps of the body surface in somatosensory cortex. A good deal is known about the properties of these maps in adults, but there has been relatively little developmental work. Recent studies have provided new insights into the organization of infant neural body maps and have laid the foundations for examining their plasticity in relation to behavioral development. Other work has suggested that neural body maps may be involved in the registration of correspondences between self and other, with implications for early social development. Here, body representations are discussed in the context of preterm birth and autism spectrum disorder, providing novel perspectives relevant to developmental medicine and child neurology. WHAT THIS PAPER ADDS: ●Somatotopic body maps develop prenatally through intrinsic and activity-dependent mechanisms. ●There is increasing interest in understanding postnatal plasticity in body maps. ●Body representations may be involved in the registration of preverbal, interpersonal relationships.

Pediatric Magnetoencephalography in Clinical Practice and Research

Magnetoencephalography (MEG) is a noninvasive neuroimaging technique that measures the electromagnetic fields generated by the human brain. This article highlights the benefits that pediatric MEG has to offer to clinical practice and pediatric research, particularly for infants and young children; reviews the existing literature on adult MEG systems for pediatric use; briefly describes the few pediatric MEG systems currently extant; and draws attention to future directions of research, with focus on the clinical use of MEG for patients with drug-resistant epilepsy.

Foot and Ankle Somatosensory Deficits Affect Balance and Motor Function in Children With Cerebral Palsy

Sensory dysfunction is prevalent in cerebral palsy (CP). Evidence suggests that sensory deficits can contribute to manual ability impairments in children with CP, yet it is still unclear how they contribute to balance and motor performance. Therefore, the objective of this study was to investigate the relationship between lower extremity (LE) somatosensation and functional performance in children with CP. Ten participants with spastic diplegia (Gross Motor Function Classification Scale: I-III) and who were able to stand independently completed the study. Threshold of light touch pressure, two-point discriminatory ability of the plantar side of the foot, duration of cutaneous vibration sensation, and error in the joint position sense of the ankle were assessed to quantify somatosensory function. The balance was tested by the Balance Evaluation System Test (BESTest) and postural sway measures during a standing task. Motor performance was evaluated by using a battery of clinical assessments: (1) Gross Motor Function Measure (GMFM-66-IS) to test gross motor ability; (2) spatiotemporal gait characteristics (velocity, step length) to evaluate walking ability; (3) Timed Up and Go (TUG) and 6 Min Walk (6MWT) tests to assess functional mobility; and (4) an isokinetic dynamometer was used to test the Maximum Volitional Isometric Contraction (MVIC) of the plantar flexor muscles. The results showed that the light touch pressure measure was strongly associated only with the 6MWT. Vibration and two-point discrimination were strongly related to balance performance. Further, the vibration sensation of the first metatarsal head demonstrated a significantly strong relationship with motor performance as measured by GMFM-66-IS, spatiotemporal gait parameters, TUG, and ankle plantar flexors strength test. The joint position sense of the ankle was only related to one subdomain of the BESTest (Postural Responses). This study provides preliminary evidence that LE sensory deficits can possibly contribute to the pronounced balance and motor impairments in CP. The findings emphasize the importance of developing a thorough LE sensory test battery that can guide traditional treatment protocols toward a more holistic therapeutic approach by combining both motor and sensory rehabilitative strategies to improve motor function in CP.

Cerebral Palsy: Current Opinions on Definition, Epidemiology, Risk Factors, Classification and Treatment Options

Cerebral palsy (CP) is one of the most frequent causes of motor disability in children. According to the up-to-date definition, CP is a group of permanent disorders of the development of movement and posture, causing activity limitations that are attributed to non-progressive disturbances that occurred in the developing foetal or infant brain. The CP definition has evolved over time; the problem is aetiologically and clinically very heterogeneous. According to European data, the average frequency of CP is 2.08 per 1000 live births, but in the group of children born with a body weight below 1500 g, the frequency is 70 times higher when compared with the group of children with a body weight over 2500 g at birth. The risk factors for CP can be divided into pre-conception, prenatal, perinatal and postnatal ones. CP commonly co-exists with epilepsy, in particular drug-resistant epilepsy, but also with mental retardation, visual and hearing impairment, as well as feeding and behavioral disorders. The degree of motor problem varies from mild to very severe making the child totally dependent on caregivers. Cerebral palsy is divided into forms depending on the type of motor disorders which dominate the clinical presentation; the traditional classifications by Ingram and Hagberg have now been replaced by the Surveillance of Cerebral Palsy in Europe classification which divides CP into spastic, dyskinetic and ataxic forms. Although cerebral palsy is a clinical diagnosis, modern diagnostic imaging provides information that allows the division of the results of magnetic resonance imaging in children with cerebral palsy into five groups according to the magnetic resonance imaging classification system. Just as the clinical presentation and the factors predisposing for CP are very diverse, treatment is also a very complex problem. Modern treatment of spasticity includes both botulinum toxin therapies and surgical techniques, eg, rhizotomy. The authors present current views on definitions, risk factors, diagnostics and treatment of CP as well as comorbid problems, eg, drug-resistant epilepsy.

Hand Motor Actions of Children With Cerebral Palsy Are Associated With Abnormal Sensorimotor Cortical Oscillations

Background. The neuroimaging literature on cerebral palsy (CP) has predominantly focused on identifying the structural aberrations (eg, fiber track integrity), with very few studies examining neural activity within the key networks that serve the production of hand movements. Objective. We aimed to start to fill this knowledge gap by using magnetoencephalographic brain imaging to quantify the temporal dynamics of the sensorimotor oscillations during a hand motor action. Methods: Children with CP (n = 12; MACS [Manual Abilities Classification System] levels I-III) and typically developing (TD) children (n = 26) performed an arrow-based version of the Eriksen flanker task where a button press was performed with either the second or third digit of the right hand depending on the arrow's direction. Results: Overall, the children with CP were less accurate and had slower reaction times compared with the TD children. These behavioral differences were closely linked with aberrant sensorimotor cortical oscillations seen in the children with CP. Compared with the TD children, the children with CP had a weaker gamma (68-82 Hz) response during motor execution and a weaker post-movement beta rebound (PMBR; 14-26 Hz) response on movement termination. Moreover, we observed a significant correlation between the amplitude of the gamma and PMBR with reaction time, with weaker gamma and PMBR responses being linked with slower reaction times. Conclusions: Overall, these results suggest that aberrations in motor-related gamma and beta cortical oscillations are associated with the impaired hand motor actions seen in children with CP.

Nutritive sucking abnormalities and brain microstructural abnormalities in infants with established brain injury: a pilot study

OBJECTIVE

To determine the relationship between nutritive sucking and microstructural integrity of sensorimotor tracts in newborns with brain injury.

STUDY DESIGN

Diffusion imaging was performed in ten newborns with brain injury. Nutritive sucking was assessed using Nfant®. The motor, sensory, and corpus callosum tracts were reconstructed via tractography. Fractional anisotropy, radial, axial, and mean diffusivity were estimated for these tracts. Multiple regression models were developed to test the association between sucking features and diffusion parameters.

RESULTS

Low-sucking smoothness correlated with low-fractional anisotropy of motor tracts (p = 0.0096). High-sucking irregularity correlated with high-mean diffusivity of motor (p = 0.030) and corpus callosum tracts (p = 0.032). For sensory tracts, high-sucking irregularity (p = 0.018) and low-smoothness variability (p = 0.002) correlated with high-mean diffusivity.

INTERPRETATION

We show a correlation between neuroimaging-demonstrated microstructural brain abnormalities and variations in sucking patterns of newborns. The consistency of this relationship should be shown on larger cohorts.

Abnormal Gray Matter Structural Covariance Networks in Children With Bilateral Cerebral Palsy

Bilateral cerebral palsy (BCP) is a common movement disorder in children, which often results in lifelong motor disability. One main symptom of BCP is the limitation of hand function in everyday activities. However, the neuroanatomical basis of this prominent hand impairment is yet to discover. Recent advances mainly focus on the lesions of BCP, but the views on the atypical development of cortical parcellations are extremely lacking. Here, in our study, neuroimaging with network analysis was employed to evaluate the changes of structural covariance networks (SCNs) in BCP children. We aimed to elucidate the alteration of SCNs based on cortical thickness (CT), and to reveal the relationship of CT and hand function in the participants with BCP. SCNs were constructed using covariance between regional CT, which was acquired from T1-weighted images of 19 children with BCP and 19 demographically matched healthy controls (HCs). Compared with HCs, BCP children showed increased CT in several regions involving the bilateral areas (lateral occipital, lingual, and fusiform) and right areas (cuneus, pericalcarine, inferior temporal, middle temporal, superior temporal, and insula). Decreased CT was found in the left superior temporal and right superior parietal cortices. Global network analyses revealed significantly decreased normalized clustering and small-worldness in the BCP network. The area under the curve (AUC) of global network measures varied slightly between the BCP and HC networks. The resistance of the both SCNs to the target and random attack showed no significant difference. Also, the BCP foci (right superior temporal and subtemporal cortex) showed a significantly negative correlation between the CT and manual ability. In this work, we identified the CT-based SCNs changes in children with BCP. The abnormal topological organization of SCNs was revealed, indicating abnormal CT, incongruous development of structural wiring, destructive nodal profiles of betweenness, and moved hub distribution in BCP children. This may provide a neuroanatomical hallmark of BCP in the developing brain. Therefore, our results may not only reflect neurodevelopmental aberrations but also compensatory mechanisms.

Functional and structural asymmetry in primary motor cortex in Asperger syndrome: a navigated TMS and imaging study

Motor functions are frequently impaired in Asperger syndrome (AS). In this study, we examined the motor cortex structure and function using navigated transcranial magnetic stimulation (nTMS) and voxel-based morphometry (VBM) and correlated the results with the box and block test (BBT) of manual dexterity and physical activity in eight boys with AS, aged 8–11 years, and their matched controls. With nTMS, we found less focused cortical representation areas of distinct hand muscles in AS. There was hemispheric asymmetry in the motor maps, silent period duration and active MEP latency in the AS group, but not in controls. Exploratory VBM analysis revealed less gray matter in the left postcentral gyrus, especially in the face area, and less white matter in the precentral area in AS as compared to controls. On the contrary, in the right leg area, subjects with AS displayed an increased density of gray matter. The structural findings of the left hemisphere correlated negatively with BBT score in controls, whereas the structure of the right hemisphere in the AS group correlated positively with motor function as assessed by BBT. These preliminary functional (neurophysiological and behavioral) findings are indicative of asymmetry, and co-existing structural alterations may reflect the motor impairments causing the deteriorations in manual dexterity and other motor functions commonly encountered in children with AS.

Altered White Matter Connectivity Associated with Intergyral Brain Disorganization in Hemiplegic Cerebral Palsy

Despite extensive literature showing damages in the sensorimotor projection fibers of children with hemiplegic cerebral palsy (HCP), little is known about how these damages affect the global brain network. In this study, we assess the relationship between the structural integrity of sensorimotor projection fibers and the integrity of intergyral association white matter connections in children with HCP. Diffusion tensor imaging was performed in 10 children with HCP and 16 typically developing children. We estimated the regional and global white-matter connectivity using a region-of-interest (ROI)-based approach and a whole-brain gyrus-based parcellation method. Using the ROI-based approach, we tracked the spinothalamic (STh), thalamocortical (ThC), corticospinal (CST), and sensorimotor U- (SMU) fibers. Using the whole-brain parcellation method, we tracked the short-, middle-, and long-range association fibers. We observed for the more affected hemisphere of children with HCP: (i) an increase in axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) for the STh and ThC fibers; (ii) a decrease in fractional anisotropy (FA) and an increase in MD and RD for the CST and SMU fibers; in (iii) a decrease in FA and an increase in AD, MD, and RD for the middle- and long-range association fibers; and (iv) an association between the integrity of sensorimotor projection and intergyral association fibers. Our findings indicate that altered structural integrity of the sensorimotor projection fibers disorganizes the intergyral association white matter connections among local and distant regions in children with HCP.

Mapping the human brain during a specific Vojta's tactile input: the ipsilateral putamen's role

A century of research in human brain parcellation has demonstrated that different brain areas are associated with functional tasks. New neuroscientist perspectives to achieve the parcellation of the human brain have been developed to know the brain areas activation and its relationship with different stimuli. This descriptive study aimed to compare brain regions activation by specific tactile input (STI) stimuli according to the Vojta protocol (STI-group) to a non-STI stimulation (non-STI-group). An exploratory functional magnetic resonance imaging (fMRI) study was performed. The 2 groups of participants were passively stimulated by an expert physical therapist using the same paradigm structure, although differing in the place of stimulation. The stimulation was presented to participants using a block design in all cases. A sample of 16 healthy participants, 5 men and 11 women, with mean age 31.31 ± 8.13 years was recruited. Indeed, 12 participants were allocated in the STI-group and 4 participants in the non-STI-group. fMRI was used to map the human brain in vivo while these tactile stimuli were being applied. Data were analyzed using a general linear model in SPM12 implemented in MATLAB. Differences between groups showed a greater activation in the right cortical areas (temporal and frontal lobes), subcortical regions (thalamus, brainstem, and basal nuclei), and in the cerebellum (anterior lobe). STI-group had specific difference brain activation areas, such as the ipsilateral putamen. Future studies should study clinical implications in neurorehabilitation patients.