Parietal and premotor cortex regions are serious contenders for bringing motor intentions and motor responses into awareness. We used electrical stimulation in seven patients undergoing awake brain ...surgery. Stimulating the right inferior parietal regions triggered a strong intention and desire to move the contralateral hand, arm, or foot, whereas stimulating the left inferior parietal region provoked the intention to move the lips and to talk. When stimulation intensity was increased in parietal areas, participants believed they had really performed these movements, although no electromyographic activity was detected. Stimulation of the premotor region triggered overt mouth and contralateral limb movements. Yet, patients firmly denied that they had moved. Conscious intention and motor awareness thus arise from increased parietal activity before movement execution.
Complex motor responses are often thought to result from the combination of elemental movements represented at different neural sites. However, in monkeys, evidence indicates that some behaviors with ...critical ethological value, such as self-feeding, are represented as motor primitives in the precentral gyrus (PrG). In humans, such primitives have not yet been described. This could reflect well-known interspecies differences in the organization of sensorimotor regions (including PrG) or the difficulty of identifying complex neural representations in peroperative settings. To settle this alternative, we focused on the neural bases of hand/mouth synergies, a prominent example of human behavior with high ethological value. By recording motor- and somatosensory-evoked potentials in the PrG of patients undergoing brain surgery (2–60 y), we show that two complex nested neural representations can mediate hand/mouth actions within this structure: (i) a motor representation, resembling self-feeding, where electrical stimulation causes the closing hand to approach the opening mouth, and (ii) a motor–sensory representation, likely associated with perioral exploration, where cross-signal integration is accomplished at a cortical site that generates hand/arm actions while receiving mouth sensory inputs. The first finding extends to humans’ previous observations in monkeys. The second provides evidence that complex neural representations also exist for perioral exploration, a finely tuned skill requiring the combination of motor and sensory signals within a common control loop. These representations likely underlie the ability of human children and newborns to accurately produce coordinated hand/mouth movements, in an otherwise general context of motor immaturity.
Inhibition is a central component of motor control. Although current models emphasize the involvement of frontal networks 1, 2, indirect evidence suggests a potential contribution of the posterior ...parietal cortex (PPC). This region is active during inhibition of upper-limb movements to undesired targets 3, and its stimulation with single magnetic pulses can depress motor-evoked potentials 4, 5. Also, it has been speculated that alien hand movements caused by focal parietal lesions reflect a release of inhibition from PPC to M1 6. Considering these observations, we instructed 16 patients undergoing awake brain surgery to perform continuous hand movements while electrical stimulation was applied over PPC. Within a restricted dorsoposterior area, we identified focal sites where stimulation prevented movement initiation and instantly inhibited ongoing responses (which restarted promptly at stimulation offset). Inhibition was selective of the instructed response. It did not affect speech, hand movements passively generated through muscle electrical stimulation, or the ability to initiate spontaneous actions with other body segments (e.g., the feet). When a patient inadvertently performed a bilateral movement, a bilateral inhibition was found. When asked to produce unilateral movements, this patient presented a contralesional but not ipsilateral inhibition. This selectivity contrasted sharply with the unspecific inhibitions reported by previous studies within frontal regions, where speech and all limbs are typically affected (as we here confirm in a subset of patients) 7–10. These results provide direct evidence that a specific area in the dorsoposterior parietal cortex can inhibit volitional upper-limb responses with high selectivity.
•The dorsoposterior parietal cortex was focally stimulated during brain surgeries•Stimulation inhibited execution and initiation of contralesional hand movements•Speech, ipsilateral hand movements, or lower-limb movements remained unaffected•This selectivity differs from the general inhibition evoked by frontal stimulations
Desmurget et al. show that electrical stimulation at focal cortical sites in the dorsoposterior parietal region (DPPr) blocks the execution of volitional hand movements. This blockage is highly selective. It does not disrupt speech or movements performed with other body parts (e.g., the foot). DPPr is a key element of the motor inhibition network.
Purpose
Thoracolumbar fractures are the most common kind of spine injury in children. Several types of spine injury can occur, and for this reason, treatment algorithms have been put in place for the ...management of these patients. At present, the thoracolumbar injury classification and severity score system (TLICS) and the thoracolumbar AOSpine injury score (AOSpine score) aimed at providing treatment recommendations. We aimed to assess the reliability, in children, of the TLICS scoring and AOSpine scoring systems, and to define the superiority of one of the methods of scoring, to spread its use in routine clinical management in the pediatric spine trauma.
Methods
A retrospective chart review of consecutive children admitted to a Level 1 trauma center for traumatic thoracolumbar fractures, between 2006 and 2019, was performed. We compared the management we performed in clinical practice in children with spine trauma, to the decisional algorithms based on the TLICS and AOSpine scores. According to these scores, surgical treatment should be performed when the TLICS score ≥ 5 and the AOSpine score > 5; and surgical or conservative treatment was considered reasonable when the TLICS score = 4 and the AOSpine score = 4 or 5. Surgical indications were based on the clinical status, the anatomy of the fracture, and the risk of sagittal imbalance of the growing spine.
Results
Fifty-four patients met the inclusion criteria. We demonstrated that both the AOSpine score and the TLICS scores had a significant correlation for surgical management decision of spine trauma (
p
< 0.0001). We found a high concordance between surgical decision making in the pediatric clinical practice and the TLICS score. In our pediatric cohort, there were significantly more patients with TLICS ≥ 5 (n = 47, 87%) than with AOSpine score > 5 (n = 26, 46%,
p
< 0.0001). There were significantly more patients with TLICS ≥ 4 (n = 53, 98%), than with AOSpine score ≥ 4 (n = 42, 77%,
p
= 0.001).
Conclusions
The TLICS score was significantly more appropriate than the AOSpine score, for the surgical treatment decision in children, especially when considering the future risk of sagittal imbalance.
Recent genomic studies have shed light on the biology and inter-tumoral heterogeneity underlying pineal parenchymal tumors, in particular pineoblastomas (PBs) and pineal parenchymal tumors of ...intermediate differentiation (PPTIDs). Previous reports, however, had modest sample sizes and lacked the power to integrate molecular and clinical findings. The different proposed molecular group structures also highlighted a need to reach consensus on a robust and relevant classification system. We performed a meta-analysis on 221 patients with molecularly characterized PBs and PPTIDs. DNA methylation profiles were analyzed through complementary bioinformatic approaches and molecular subgrouping was harmonized. Demographic, clinical, and genomic features of patients and samples from these pineal tumor groups were annotated. Four clinically and biologically relevant consensus PB groups were defined: PB-miRNA1 (
n
= 96), PB-miRNA2 (
n
= 23), PB-MYC/FOXR2 (
n
= 34), and PB-RB1 (
n
= 25). A final molecularly distinct group, designated PPTID (
n
= 43), comprised histological PPTID and PBs. Genomic and transcriptomic profiling allowed the characterization of oncogenic drivers for individual tumor groups, specifically, alterations in the microRNA processing pathway in PB-miRNA1/2,
MYC
amplification and
FOXR2
overexpression in PB-MYC/FOXR2,
RB1
alteration in PB-RB1, and
KBTBD4
insertion in PPTID. Age at diagnosis, sex predilection, and metastatic status varied significantly among tumor groups. While patients with PB-miRNA2 and PPTID had superior outcome, survival was intermediate for patients with PB-miRNA1, and dismal for those with PB-MYC/FOXR2 or PB-RB1. Reduced-dose CSI was adequate for patients with average-risk, PB-miRNA1/2 disease. We systematically interrogated the clinical and molecular heterogeneity within pineal parenchymal tumors and proposed a consensus nomenclature for disease groups, laying the groundwork for future studies as well as routine use in tumor diagnostic classification and clinical trial stratification.
Object
Though positional posterior plagiocephaly (PPP) is considered common in infants since the pediatric recommendations of “Back to Sleep”, several aspects of its natural history still remain ...unclear. The aim of this study is to understand the actual prevalence and severity of PPP in children and adolescents.
Methods
Head CT scans performed for head trauma during the period September 2016–September 2017 were retrospectively analyzed in a total of 165 children ranging from 0 to 18 years of age (101 boys).
Cranial vault asymmetry index (CVAI) was calculated at the level of the superior orbital rim. CVAI values greater 3.5% was considered index of asymmetry.
The results were analyzed according to different age groups: group I: 1 month to 1 year of age (37 children), group II: 2 to 4 years (32 children), group III: 5 to 8 years (36 children), group IV: 9 to 12 years (27 children), and group V: 13 to 18 years (33 children) and the severity of asymmetry according to CVAI values: mild group (CVAI range 3.5–7%), moderate group (CVAI range 7–12%), and severe group (CVAI > 12%).
Result
The total prevalence of PPP in the 165 children was 25%. While the prevalence in infants of group I was estimated to be 40.5%, it was 15.6% in group II, 30.5% in group III, 18.5% in group IV, and 12% in group V.
The mean and maximum degrees of deformation were 3.5% and 15.1%, respectively. Most children had a mild asymmetry. One child (group II) presented a severe asymmetry. The degree of the asymmetry varied according to the groups but moderate asymmetry could be found at all ages even in groups IV and V.
Conclusion
This study analyzing PPP in an unselected unbiased pediatric population shows that PPP has a high prevalence in adolescents. It confirms that the prevalence of deformational plagiocephaly is more common than usually reported and that PPP may persist at a late age.
The dorso-posterior parietal cortex (DPPC) is a major node of the grasp/manipulation control network. It is assumed to act as an optimal forward estimator that continuously integrates efferent ...outflows and afferent inflows to modulate the ongoing motor command. In agreement with this view, a recent per-operative study, in humans, identified functional sites within DPPC that: (i) instantly disrupt hand movements when electrically stimulated; (ii) receive short-latency somatosensory afferences from intrinsic hand muscles. Based on these results, it was speculated that DPPC is part of a rapid grasp control loop that receives direct inputs from the hand-territory of the primary somatosensory cortex (S1) and sends direct projections to the hand-territory of the primary motor cortex (M1). However, evidence supporting this hypothesis is weak and partial. To date, projections from DPPC to M1 grasp zone have been identified in monkeys and have been postulated to exist in humans based on clinical and transcranial magnetic studies. This work uses diffusion-MRI tractography in two samples of right- (n = 50) and left-handed (n = 25) subjects randomly selected from the Human Connectome Project. It aims to determine whether direct connections exist between DPPC and the hand control sectors of the primary sensorimotor regions. The parietal region of interest, related to hand control (hereafter designated DPPChand), was defined permissively as the 95% confidence area of the parietal sites that were found to disrupt hand movements in the previously evoked per-operative study. In both hemispheres, irrespective of handedness, we found dense ipsilateral connections between a restricted part of DPPChand and focal sectors within the pre and postcentral gyrus. These sectors, corresponding to the hand territories of M1 and S1, targeted the same parietal zone (spatial overlap > 92%). As a sensitivity control, we searched for potential connections between the angular gyrus (AG) and the pre and postcentral regions. No robust pathways were found. Streamline densities identified using AG as the starting seed represented less than 5 % of the streamline densities identified from DPPChand. Together, these results support the existence of a direct sensory-parietal-motor loop suited for fast manual control and more generally, for any task requiring rapid integration of distal sensorimotor signals.
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Introduction
The diagnosis of Chiari I malformation, its symptomatology, and the results of its surgical management are still discussed. We report a pediatric series of CMI without associated skull ...base malformations or cerebellar growth anomalies operated between 2001 and 2018.
Material and methods
Ninety-one children out of 146 surgically treated cases have been included in the study. Age at surgery ranged from 5 months to 17 years clinical data, and complementary examinations leading to the surgical indication have been analyzed together with the surgical outcomes. The average follow-up duration was of 4 years. The occipito-cervical decompression with duraplasty without opening the arachnoid was the procedure of election. Three quarters of patients presented with headaches, 12% with cerebellar syndrome, 13% with vertigo, 26% with nausea or vomiting, 24% with sensorimotor deficits, 11% with cranial nerve deficits, and 29% with other symptoms. Eighteen percent of patients suffered from scoliosis, 47% had an associated syrinx and 16% a ventricular dilation.
Results
After the treatment, the clinical symptomatology improved in about three-quarters of the patients: headache (69.4%), nausea or vomiting (66.7%), sensorimotor deficits (55.6%), and other symptoms (78.3%). Syringomyelic cavities diminished partially in size or disappeared in 58.3% of patients, remained stable in 29.2%, and worsened in 12.5%. Only one-third of children with preoperative scoliosis benefited from the surgical treatment. No clinical signs or symptoms were found to be reliable predictors of surgical success, neither the extent of the cerebellar tonsil descent.
Conclusion
Occipito-cervical decompression allows to improve the clinical condition in the majority of children with symptomatic CMI in the absence of associated cervico-spinal junction alterations, craniosynostosis, or cerebellar growth anomalies. No clinical signs or symptoms neither radiological criterion appear to be a specific finding for the surgical indication.
Introduction
Split cord malformation (SCM) is a rare congenital spinal abnormality. Clinical presentation varies. Other congenital defects can be associated. Management is surgical.
Material and ...methods
We retrospectively reviewed all our SCM cases and reported our experience for its management. From 1990 to 2014, 37 patients were operated. Five situations lead to the diagnosis (orthopedic disorders (
n
= 8), orthopedic and neurological disorders (
n
= 16), pure neurological disorders (
n
= 5), no symptoms except cutaneous signs (
n
= 7), antenatal diagnosis (
n
= 1)). Scoliosis was the most common associated condition. The level of the spur was always under T7 except in one case. There were more type I (
n
= 22) than type II (
n
= 15) SCM.
Results
Patients with preoperative neurological symptoms (
n
= 21) were improved in 71.4%. Five out of nine patients that had preoperative bladder dysfunction were improved. Eleven patients needed surgical correction of the scoliosis.
Conclusions
For us, the surgical procedure is mandatory even in case of asymptomatic discovery in order to avoid late clinical deterioration. In any case, the filum terminale need to be cut in order to untether completely the spinal cord. In case a surgical correction of a spinal deformity is needed, we recommend a two-stage surgery, for both SCM type. The SCM surgery can stop the evolution of the scoliosis and it may just need an orthopedic treatment with a brace.
Background Primary leptomeningeal melanomatosis (PLM) is a rare and aggressive form of nonmetastatic invasion of leptomeninges by malignant melanocytic cells. Clinical presentation includes ...nonspecific meningism with various forms of cerebrospinal fluid circulation or absorption disorders leading to hydrocephalus. Case Description A 5-year-old child with PLM without neurocutaneous melanosis presented with cystic enlargement of the brainstem surrounding cisterns and hydrocephalus requiring occipitoaxial decompression and endoscopic cystostomy. Initial cerebrospinal fluid cytology screening and frontal meningeal and brain biopsy specimens showed negative results. The diagnosis of unpigmented (amelanotic) malignant melanocytic cells was made after a biopsy specimen of the bulbar leptomeninges was obtained. Despite continuous management of hydrocephalus and chemotherapy, the disease progressed, and the patient died 11 months after diagnosis. Conclusions To the best of our knowledge, this is the first report of an amelanotic form of PLM without association of neurocutaneous melanosis in a child. This case report illustrates the difficulty of diagnosis in the absence of cutaneous lesions and lack of melanin.
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