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.

De Novo VPS4A Mutations Cause Multisystem Disease with Abnormal Neurodevelopment.

The endosomal sorting complexes required for transport (ESCRTs) are essential for multiple membrane modeling and membrane-independent cellular processes. Here we describe six unrelated individuals with de novo missense variants affecting the ATPase domain of VPS4A, a critical enzyme regulating ESCRT function. Probands had structural brain abnormalities, severe neurodevelopmental delay, cataracts, growth impairment, and anemia. In cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A. Proband-derived fibroblasts had enlarged endosomal structures with abnormal accumulation of the ESCRT protein IST1 on the limiting membrane. VPS4A function was also required for normal endosomal morphology and IST1 localization in iPSC-derived human neurons. Mutations affected other ESCRT-dependent cellular processes, including regulation of centrosome number, primary cilium morphology, nuclear membrane morphology, chromosome segregation, mitotic spindle formation, and cell cycle progression. We thus characterize a distinct multisystem disorder caused by mutations affecting VPS4A and demonstrate that its normal function is required for multiple human developmental and cellular processes.

Long-Term Follow-Up of Pediatric Patients with Dyskinetic Cerebral Palsy and Deep Brain Stimulation.

BACKGROUND: Deep brain stimulation (DBS) has been increasingly used in the management of dyskinetic cerebral palsy (DCP). Data on long-term effects and the safety profile are rare. OBJECTIVES: We assessed the efficacy and safety of pallidal DBS in pediatric patients with DCP. METHODS: The STIM-CP trial was a prospective, single-arm, multicenter study in which patients from the parental trial agreed to be followed-up for up to 36 months. Assessments included motor and non-motor domains. RESULTS: Of the 16 patients included initially, 14 (mean inclusion age 14 years) were assessed. There was a significant change in the (blinded) ratings of the total Dyskinesia Impairment Scale at 36 months. Twelve serious adverse events (possibly) related to treatment were documented. CONCLUSION: DBS significantly improved dyskinesia, but other outcome parameters did not change significantly. Investigations of larger homogeneous cohorts are needed to further ascertain the impact of DBS and guide treatment decisions in DCP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Quality of Life After Deep Brain Stimulation of Pediatric Patients with Dyskinetic Cerebral Palsy: A Prospective, Single-Arm, Multicenter Study with a Subsequent Randomized Double-Blind Crossover (STIM-CP).

BACKGROUND: Patients with dyskinetic cerebral palsy are often severely impaired with limited treatment options. The effects of deep brain stimulation (DBS) are less pronounced than those in inherited dystonia but can be associated with favorable quality of life outcomes even in patients without changes in dystonia severity. OBJECTIVE: The aim is to assess DBS effects in pediatric patients with pharmacorefractory dyskinetic cerebral palsy with focus on quality of life. METHODS: The method used is a prospective, single-arm, multicenter study. The primary endpoint is improvement in quality of life (CPCHILD [Caregiver Priorities & Child Health Index of Life with Disabilities]) from baseline to 12 months under therapeutic stimulation. The main key secondary outcomes are changes in Burke-Fahn-Marsden Dystonia Rating Scale, Dyskinesia Impairment Scale, Gross Motor Function Measure-66, Canadian Occupational Performance Measure (COPM), and Short-Form (SF)-36. After 12 months, patients were randomly assigned to a blinded crossover to receive active or sham stimulation for 24 hours each. Severity of dystonia and chorea were blindly rated. Safety was assessed throughout. The trial was registered at ClinicalTrials.gov, number NCT02097693. RESULTS: Sixteen patients (age: 13.4 ± 2.9 years) were recruited by seven clinical sites. Primary outcome at 12-month follow-up is as follows: mean CPCHILD increased by 4.2 ± 10.4 points (95% CI [confidence interval] -1.3 to 9.7; P = 0.125); among secondary outcomes: improvement in COPM performance measure of 1.1 ± 1.5 points (95% CI 0.2 to 1.9; P = 0.02) and in the SF-36 physical health component by 5.1 ± 6.2 points (95% CI 0.7 to 9.6; P = 0.028). Otherwise, there are no significant changes. CONCLUSION: Evidence to recommend DBS as routine treatment to improve quality of life in pediatric patients with dyskinetic cerebral palsy is not yet sufficient. Extended follow-up in larger cohorts will determine the impact of DBS further to guide treatment decisions in these often severely disabled patients. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Highlighting the Dystonic Phenotype Related to GNAO1.

BACKGROUND: Most reported patients carrying GNAO1 mutations showed a severe phenotype characterized by early-onset epileptic encephalopathy and/or chorea. OBJECTIVE: The aim was to characterize the clinical and genetic features of patients with mild GNAO1-related phenotype with prominent movement disorders. METHODS: We included patients diagnosed with GNAO1-related movement disorders of delayed onset (>2 years). Patients experiencing either severe or profound intellectual disability or early-onset epileptic encephalopathy were excluded. RESULTS: Twenty-four patients and 1 asymptomatic subject were included. All patients showed dystonia as prominent movement disorder. Dystonia was focal in 1, segmental in 6, multifocal in 4, and generalized in 13. Six patients showed adolescence or adulthood-onset dystonia. Seven patients presented with parkinsonism and 3 with myoclonus. Dysarthria was observed in 19 patients. Mild and moderate ID were present in 10 and 2 patients, respectively. CONCLUSION: We highlighted a mild GNAO1-related phenotype, including adolescent-onset dystonia, broadening the clinical spectrum of this condition. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Genetic Panel Reveals Coexisting Neuromuscular Disorders in Patients With Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy is a genetically based neuromuscular disorder characterized by progressive physical impairment and cardiomyopathy in children, leading to fatal cardiac or respiratory failure. Duchenne muscular dystrophy shares some overlapping clinical features with other disorders, complicating clinical differentiation. We hypothesized that some Duchenne muscular dystrophy patients may have a secondary neuromuscular disorders that could negatively skew data during pharmaceutical clinical trials and lead to incomplete treatment plans. Consecutive genetic panels on 353 patients were reviewed. Thirty-two (32; 9.1%) patients with Duchenne muscular dystrophy were identified. Three (3; 9.4%) were found to have at least 1 genetically confirmed secondary neuromuscular disorder. Overlooking these coexisting disorders could lead to unexpected treatment failures, potentially affecting medication efficacy in trials or commercial use. Secondary neuromuscular disorders should be considered in Duchenne muscular dystrophy patients before clinical trial enrollment or treatment planning, with expanded genetic testing, such as whole exome sequencing or whole genome sequencing, likely to reveal even more secondary disorders.

Effects of deep brain stimulation in dyskinetic cerebral palsy: a meta-analysis.

Secondary dystonia encompasses a heterogeneous group with different etiologies. Cerebral palsy is the most common cause. Pharmacological treatment is often unsatisfactory. There are only limited data on the therapeutic outcomes of deep brain stimulation in dyskinetic cerebral palsy. The published literature regarding deep brain stimulation and secondary dystonia was reviewed in a meta-analysis to reevaluate the effect on cerebral palsy. The Burke-Fahn-Marsden Dystonia Rating Scale movement score was chosen as the primary outcome measure. Outcome over time was evaluated and summarized by mixed-model repeated-measures analysis, paired Student t test, and Pearson's correlation coefficient. Twenty articles comprising 68 patients with cerebral palsy undergoing deep brain stimulation assessed by the Burke-Fahn-Marsden Dystonia Rating Scale were identified. Most articles were case reports reflecting great variability in the score and duration of follow-up. The mean Burke-Fahn-Marsden Dystonia Rating Scale movement score was 64.94 ± 25.40 preoperatively and dropped to 50.5 ± 26.77 postoperatively, with a mean improvement of 23.6% (P < .001) at a median follow-up of 12 months. The mean Burke-Fahn-Marsden Dystonia Rating Scale disability score was 18.54 ± 6.15 preoperatively and 16.83 ± 6.42 postoperatively, with a mean improvement of 9.2% (P < .001). There was a significant negative correlation between severity of dystonia and clinical outcome (P < .05). Deep brain stimulation can be an effective treatment option for dyskinetic cerebral palsy. In view of the heterogeneous data, a prospective study with a large cohort of patients in a standardized setting with a multidisciplinary approach would be helpful in further evaluating the role of deep brain stimulation in cerebral palsy. © 2013 Movement Disorder Society.

Myalgic Becker Muscular Dystrophy Due to an Exon 15 Point Mutation: Case Series and Literature Review.

ABSTRACT: Dystrophinopathies result from mutations to the DMD gene. We report 5 boys in 3 families with heterogenous phenotypes due to a point mutation in the DMD gene: a hemizygous tyrosine-to-cysteine change in exon 15 (c.1724T>C) resulting in an amino acid substitution of leucine to proline at codon 575. This mutation has been reported before, with at least 3 prior patients presenting with similar clinical findings of myalgia, myoglobinuria, and occasional muscle cramping. The mutation on DMD c.1724T>C (p.Leu575Pro) is listed in the Clinvar database as a variant of unknown significance. Our report provides contributing evidence that this alteration should be classified as pathogenic.

Dystonia due to cerebral palsy responds to deep brain stimulation of the globus pallidus internus.

BACKGROUND: Cerebral palsy is the most common cause of pediatric-onset dystonia. Deep brain stimulation is gaining acceptance for treating dystonias in children. There is minimal reported experience regarding the efficacy of deep brain stimulation in cerebral palsy. METHODS: Fourteen patients, including 8 younger than 16 years, received bilateral implants (13 patients) or a unilateral implant (1 patient) of the internal globus pallidus and were observed in a noncontrolled, nonblinded study for at least 6 months. Motor function was assessed using the Burke-Fahn-Marsden Dystonia Movement and Disability scales and the Barry Albright Dystonia Scale. RESULTS: By 6 months, significant improvement was observed in the Burke-Fahn-Marsden Dystonia Movement scale (P=.004), the Burke-Fahn-Marsden Dystonia Disability scale (P=.027), and the Barry Albright Dystonia Scale (P=.029) for the whole cohort (n=14) and in the patients treated before skeletal maturity (group 1; n=8): Burke-Fahn-Marsden Dystonia Movement scale, P=.012; Burke-Fahn-Marsden Dystonia Disability scale, P=.020; and Barry Albright Dystonia Scale, P=.027. CONCLUSIONS: Deep brain stimulation may offer an effective treatment option for cerebral palsy-related dystonia, especially in those treated before skeletal maturity.

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.

A Randomized, Double-Blind, Placebo-Controlled, Global Phase 3 Study of Edasalonexent in Pediatric Patients with Duchenne Muscular Dystrophy: Results of the PolarisDMD Trial.

BACKGROUND: Edasalonexent (CAT-1004) is an orally-administered novel small molecule drug designed to inhibit NF-κB and potentially reduce inflammation and fibrosis to improve muscle function and thereby slow disease progression and muscle decline in Duchenne muscular dystrophy (DMD). OBJECTIVE: This international, randomized 2 : 1, placebo-controlled, phase 3 study in patients ≥4 - < 8 years old with DMD due to any dystrophin mutation examined the effect of edasalonexent (100 mg/kg/day) compared to placebo over 52 weeks. METHODS: Endpoints were changes in the North Star Ambulatory Assessment (NSAA; primary) and timed function tests (TFTs; secondary). Assessment of health-related function used the Pediatric Outcomes Data Collection tool (PODCI). RESULTS: One hundred thirty one patients received edasalonexent (n = 88) and placebo (n = 43). At week 52, differences between edasalonexent and placebo for NSAA total score and TFTs were not statistically significant, although there were consistently less functional declines in the edasalonexent group. A pre-specified analysis by age demonstrated that younger patients (≤6.0 years) showed more robust and statistically significant differences between edasalonexent and placebo for some assessments. Treatment was well-tolerated and the majority of adverse events were mild, and most commonly involved the gastrointestinal system (primarily diarrhea). CONCLUSIONS: Edasalonexent was generally well-tolerated with a manageable safety profile at the dose of 100 mg/kg/day. Although edasalonexent did not achieve statistical significance for improvement in primary and secondary functional endpoints for assessment of DMD, subgroup analysis suggested that edasalonexent may slow disease progression if initiated before 6 years of age. (NCT03703882).

PEDiDBS: The pediatric international deep brain stimulation registry project.

BACKGROUND: Interactive neuromodulation represents the evolving frontier in surgical treatment of a variety of disorders involving the sensory organs and nervous system. Building on the advances of pioneering neurologists and neurosurgeons, progress has been made since the introduction of deep brain stimulation (DBS). Microelectrode recording has greatly aided our understanding of the underlying pathogenesis of movement disorders and the effects of electrical stimulation. The introduction of image - guided systems to provide targeted, controlled neuro-stimulation to specific brain areas is an emerging technique for implantation and may have special appeal for pediatric patients. RATIONALE/AIM: DBS is generally accepted as a treatment for some forms of childhood dystonia. Its potential role in other pediatric movement disorders is less well established. This is important, as most forms of dystonia begin in childhood or adolescence and many are inadequately responsive to current pharmacotherapy and other interventions. Nonetheless, many aspects of deep brain stimulation need clarification. CONCLUSION: This can only be accomplished through an organized platform for data sharing that will allow questions to be asked and hopefully answered, with the ultimate goal of developing evidence based practice based guidelines elucidating the role of DBS in pediatric patients.

Advances in management of movement disorders in children.

Movement disorders in children are causally and clinically heterogeneous and present in a challenging developmental context. Treatment options are broad ranging, from pharmacotherapy to invasive neuromodulation and experimental gene and stem cell therapies. The clinical effects of these therapies are variable and often poorly sustained, and only a few of the management strategies used in paediatric populations have been tested in randomised controlled studies with age-appropriate cohorts. Identification of the most appropriate treatment is uniquely challenging in children because of the incomplete knowledge about the pathophysiology of movement disorders and their influence on normal motor development; thus, effective therapeutic options for these children remain an unmet need. It is vital to transfer the expanding knowledge of the movement disorders into the development of novel symptomatic or, ideally, disease-modifying treatments, and to assess these therapeutic strategies in appropriately designed and well done trials.

De novo truncating variants in the AHDC1 gene encoding the AT-hook DNA-binding motif-containing protein 1 are associated with intellectual disability and developmental delay.

Whole-exome sequencing (WES) represents a significant breakthrough in clinical genetics, and identifies a genetic etiology in up to 30% of cases of intellectual disability (ID). Using WES, we identified seven unrelated patients with a similar clinical phenotype of severe intellectual disability or neurodevelopmental delay who were all heterozygous for de novo truncating variants in the AT-hook DNA-binding motif-containing protein 1 (AHDC1). The patients were all minimally verbal or nonverbal and had variable neurological problems including spastic quadriplegia, ataxia, nystagmus, seizures, autism, and self-injurious behaviors. Additional common clinical features include dysmorphic facial features and feeding difficulties associated with failure to thrive and short stature. The AHDC1 gene has only one coding exon, and the protein contains conserved regions including AT-hook motifs and a PDZ binding domain. We postulate that all seven variants detected in these patients result in a truncated protein missing critical functional domains, disrupting interactions with other proteins important for brain development. Our study demonstrates that truncating variants in AHDC1 are associated with ID and are primarily associated with a neurodevelopmental phenotype.

Epilepsy: habilitation and rehabilitation.

Rehabilitation represents not only a distinct field of medicine, but also a philosophical and practical treatment approach that can be applied to a variety of chronic disorders. Neurology encompasses many chronic disorders, making it ideal for the application of rehabilitation principles in daily practice. Epilepsy offers a unique opportunity to incorporate rehabilitation principles into the management of a complex medical disorder. Epilepsy is an evolving disease process that changes with the maturation of the central nervous system. The rehabilitative model provides the framework for a dynamic treatment plan to meet the changing needs of the child with epilepsy through the social and developmental changes of childhood, adolescence, and adulthood. The development of epilepsy may complicate the recovery from many acute and chronic conditions that affect the central nervous system. The rehabilitation process must address these many aspects of the disease process and its sequelae. This makes neurologists uniquely qualified to manage the rehabilitation team. The impact of the therapeutic milieu on the recovery process may be as important as any specific medical or surgical intervention.

Pallidal stimulation in children: comparison between cerebral palsy and DYT1 dystonia.

The authors compared the outcomes of 17 children aged 7 to 15 years with DYT1 dystonia or cerebral palsy following deep brain stimulation. While patients with cerebral palsy presented with significantly greater motor disability than the DYT1 cohort at baseline, both groups demonstrated improvement at 1 year (cerebral palsy = 24%; DYT1 = 6%). The group as a whole demonstrated significant improvement on the Barry-Albright Dystonia Scale across time. Gains in motor function were apparent in both axial and appendicular distributions involving both upper and lower extremities. Gains achieved by 6 months were sustained in the cerebral palsy group, whereas the DYT1 group demonstrated continued improvement with ongoing pallidal stimulation beyond 18 months. Young patients with dystonia due to cerebral palsy responded comparably to patients with DYT1 dystonia. The severity of motor impairment in patients with cerebral palsy at baseline and follow-up raises the issue of even earlier intervention with neuromodulation in this population to limit long-term motor impairments due to dystonia.

Dystrophinopathy in girls with limb girdle muscular dystrophy phenotype.

OBJECTIVES: Limb girdle muscular dystrophy (LGMD) is a diverse group of myopathic disorders characterized by proximal muscle weakness and hyperCKemia. Mutations encoding sarcoglycans and numerous other proteins have been shown to be responsible for most cases. We report a series of girls with a negative family history for boys with Duchenne muscular dystrophy, demonstrating an LGMD phenotype associated with dystrophinopathy. METHODS: A retrospective chart review of all girls presenting with the LGMD phenotype to our clinic between January 2001 and September 2007 was conducted. Patients 18 years old or younger with dystrophinopathy proven by muscle biopsy and/or gene mutations and a negative family history for affected boys were included in the review. RESULTS: Five patients, 4 to 10 years of age at presentation, were included in the series. Four had an LGMD phenotype at presentation. All five patients had hyperCKemia, all five patients had gene mutations, and four patients had muscle biopsy consistent with dystrophinopathy. CONCLUSION: Dystrophinopathy is an important cause of LGMD phenotype in girls and should be considered in the differential diagnosis.

Deep brain stimulation for pediatric movement disorders.

Deep brain stimulation (DBS) has been used for the treatment of tremor and dystonia in adults since 1997. With more than 50,000 treated adults, it has become part of the standard care for pharmacoresistant tremor, Parkinson disease, and dystonias. Dystonias are a heterogeneous group of disorders with intrinsic (genetic) and extrinsic etiologic factors. In children and adults, DBS has been used for the treatment of both primary and secondary dystonias. Pediatric use has been more limited, with only a few experienced centers worldwide. Awake surgery can be safely performed with a dedicated multidisciplinary team approach to help ensure appropriate lead placement. It is incumbent upon us, as physicians, to advise patients and payers on the appropriate use of this technology. Neuromodulation of other disorders, including epilepsy, Tourette syndrome, obsessive-compulsive disorder, and depression, by DBS is under active investigation. Pediatric DBS is still in its early stages; experience will help us refine the indications and techniques for applying this complex technology to our most vulnerable patients, which should lead to our common goal of improving quality of life for our patients and their families. We review the role of DBS and our experience with establishing a dedicated pediatric DBS program.