Troubles neurologiques

The left and right hemispheres of the brain in most individuals are structurally and functionally specialized, but a significant minority displays an atypical variation in brain laterality specialization. Determining the biological basis of laterality specialization is essential for understanding the etiology of schizophrenia and bipolar disorder because they are often more prevalent in individuals with atypical brain laterality. These disorders are thought to be caused by contributions from hundreds of genes with small effects combined with environmental factors. However, lacking convincing evidence, the precise etiology of psychosis remains unknown. We have argued that chromosome 11 translocations associated with psychosis found in three families provide the only convincing evidence for the genetic etiology of psychosis. The paradoxes we try to resolve here concern the fact that the translocation breakpoints for chromosome 11 lie far apart, covering 40% length of the q arm, and the translocation associated psychoses is only 50% penetrant in each family. The selective chromatid segregation model has been proposed as a mechanism for the asymmetric cell division that initiates a cascade of gene regulation events in offspring cells to develop brain laterality in embryogenesis. The translocations we propose might cause random segregation of its sister chromatids to explain the result of 50% penetrance. We submit that errors in this system may explain the unique condition of these families. Here we review studies of model organisms that provide support to the model to explain brain laterality and psychosis development. We suggest that atypical brain laterality genetics predisposes carriers to develop general cases of psychoses due to developmental errors

In recent years the Critical Period Hypothesis of language acquisition has come under close scrutiny. The premise that native-like language proficiency can only be attained if the language is learned early in life seems difficult to maintain, as neuroimaging data have revealed a greater plasticity of the human brain to master new languages than has previously been assumed. The field of non-pathological first language (L1) attrition has not contributed much to this debate. Adding attrition perspectives, however, can inform the field of language learning and the critical period in general: learning a language early in life should leave long-lasting traces in the neural circuit. But investigations of this nature would also directly benefit the field of L1 attrition itself. Attrition theories have largely built on behavioral paradigms, and two pivotal questions remain unanswered but could be addressed using neuroimaging techniques: 1) Is the cause of L1 attrition mainly L1 non-use or rather the introduction and mastery of a second language (L2)? 2) is L1 attrition an irreversible, permanent phenomenon or does it merely reflect a temporary inaccessibility of the L1 system? This paper aims to review the scantly available evidence for functional and/or anatomical brain changes as a function of non-pathological L1 attrition, specifically focusing on the two outstanding questions above. Building on previous insights, this paper theorizes about L1 attrition-induced neurological changes that have not been addressed in previous work and formulates goals and avenues for future studies.

Objective: Spatial dissemination of focal white matter brain lesions, highly suggestive of multiple sclerosis (MS) in subjects without clinical neurological symptoms, is referred to as radiological isolated syndrome (RIS).

The aim of this study was to demonstrate that kinematic parameters are able to measure motor performance and to identify subtle symptoms undetectable with the clinical examination.

Methods: We investigated the clinical, kinematic motor performance in 6 subjects following conventional brain MRI (1.5-T). Subjects had a negative neurological examination and fulfilled the diagnostic criteria for RIS proposed by Okuda.

Results: Subjects were 4 females and 2 males with a mean age of 39.5 years. 2 subjects performed all kinematic parameters in the range of HC/M, 1 subject resulted with one parameter above the range of HC/M group, 3 subjects had more than 2 kinematic parameters above the range of HC/M. The mean nine-hole peg test (9HPT) score was 18 seconds ± 1. 2 subjects had spinal cervical cord lesions and oligoclonal bands were detected in other 2 patients. VEP were negative in all subjects. No case showed dissemination in time (no new T2 lesions at the 6 month MRI). Of the kinematic parameters used, the integral of the norm of the third derivative-jerk-of the hand path was the most sensitive parameter (four of six subjects), Remarkably the technique appears to be able to detect subtle differences between some subjects with RIS and control subjects.

Conclusion: We believe that this type of instrumental assessment can help in identifying subjects with RIS with a high risk for developing MS

Emerging evidence indicates that neuroimmunological changes in the brain can modify intrinsic brain processes that are involved in regulating neuroplasticity. Increasing evidence suggests that in some forms of motor neuron injury, many neurons do not die, but reside in an atrophic state for an extended period of time. In mice, facial motor neurons in the brain undergo a protracted period of degeneration or atrophy following resection of their peripheral axons. Reinjuring the proximal nerve stump of the chronically resected facial nerve stimulates a robust reversal of motor neuron atrophy which results in marked increases in both the number and size of injured motor neurons in the facial motor nucleus. In this brief review, we describe research from our lab which indicates that the reversal of atrophy in this injury model is dependent on normal cellular immunity. The role of T cells in this unique form of neuroplasticity following injury and in brain aging, are discussed. The potential role of yet undiscover intrinsic actions of recombination activating genes in the brain are considered. Further research using the facial nerve reinjury model could identify molecular signals involved in neuroplasticity, and lead to new ways to stimulate neuroregenerative processes in neurotrauma and other forms of brain insult and disease.

Some neurological disorders that cannot be managed with medication can alternatively be directly treated either at the sensory and/or motor nerve(s). In particular, chronic pain and/or muscle spasticity are a couple types of symptoms that can potentially be treated at the associated nerve. Various chemicals and medical devices are currently being employed in the clinic to treat peripheral nerves. Treatment of sensory nerves is typically used to attenuate chronic pain symptoms, while motor nerves are targeted for spasticity symptoms. A majority of treatment methods currently used in the field involve nerve injury and denervation of the target tissue through different mechanisms of action. Depending on the type and severity of the treatment, the nerve may or may not fully regenerate to a normal state. This article will review the various types of clinical methods used to treat neurological disorders and discuss the possible outcomes of nerve regeneration.

Background: This study was aimed to explore whether the free radical scavenger, edaravone, can reduce the inflammatory response providing better outcome along with not only conventional therapy but also recombinant tissue plasminogen activator (rt-PA) thrombolytic therapy.

Results: Acute ischemic stroke patients were enrolled (n=64, average 73.3 year-old) for measuring interleukin-6 (IL-6), tumor necrosis factor (TNFα) and malondialdehyde-modified LDL (MDA-LDL) as inflammatory biomarkers at 3 time points: before medication, 5 hrs and 24hs following medication. All patients were classified into four groups depending on the medication: conventional therapy without edaravone (n=15), conventional therapy with edaravone (n=34), rt-PA thrombolytic therapy without edaravone (n=4) and rt-PA thrombolytic therapy with edaravone (n=11). Neurological alteration was assessed by NIH Stroke Scale on admission and at 1 month. As the results, the inflammatory markers were reduced in the edaravone treated group, although it was not significant. While, IL-6 was significantly increased at 24 hrs in the thrombolytic group than the conventional group. Patients treated with rt-PA and edaravone exhibited better outcome than only rt-PA treated patients, although there was no difference of the recanalization rate.

Conclusion: Edaravone may be able to decrease the amplified inflammatory response following brain infarction, providing better outcome.

Posterior cortical atrophy (PCA) is a rare neurodegenerative syndrome characterized by insidious onset and selective, gradual decline in visuospatial and visuoperceptual skills.

We report a typical case of a patient with posterior cortical atrophy who presented initially with visuospatial deficit and apraxia. The aim of this report is to present this rare dementia subtype as a relevant differential diagnosis in respect to other neurodegenerative syndromes

Stroke is one of the leading causes of morbidity and mortality in the world and in recent years a lot of emphasis has been given to the role of newer drugs in stroke which increase neuroprotection. Citicholine (CDP-Choline; or Cytidine 5’-Diphosphocholine) has been shown to possess efficacy in the management of cognitive impairment in stroke as well as in Alzheimer’s disease. It has been demonstrated to be a neuroprotective as well as a neuroregenerative agent in patients of acute stroke. A large number of animal studies and clinical trials exist to support the efficacy of this drug in ischemic stroke and Alzheimer’s disease. Few studies have also shown its efficacy in hemorrhagic stroke and Traumatic Brain Injury (TBI). The main effects of citicholine are due to the modification of lipid metabolism in neuronal membranes. It regenerates the levels of phosphatidylcholine in the brain and improves neuronal functions. The drug is relatively safe with a very few side-effects

This study reports seizures as an adverse event (AE) in children with neurological diseases treated with autologous bone marrow mononuclear cells (BMMNCs) intrathecal transplantation. It also assesses the effectiveness of antiepileptic prophylactic regimen to reduce the incidence of seizures as an AE. Seizures were considered as an AE if there were increased pre-existing seizures or new onset seizures. In part I; seizures as an AE was analyzed in detail. Seizures occurred as an AE in 8/131 (6%) in part I. Out of these 8, one patient’s EEG was not available, but showed increased preexisting seizures and 7 had a pre-existing epileptogenic focus on EEG. Out of these 7, 3 developed new onset seizures and 4 had increased pre-existing seizures. Based on this analysis an antiepileptic prophylactic regimen was designed. In Part II effect of this regimen was studied and a significant decrease in the incidence of seizures as an AE was observed along with no new onset seizures. Though small proportions of patients show seizures as an AE of cellular therapy, it definitely requires attention and is preventable. Pre-existing epileptogenic focus is an independent predictor for seizures as an AE. Future clinical trials of cellular therapy in pediatric population may consider these findings.

Carcinomatous meningitis (CM) results from spread of malignant cells from solid tumors to leptomeninges and subarachnoid space. CM occurs in the late stage of cancer in the setting of widespread metastases. We report a patient presenting with intracranial hypertension, lower cranial nerve palsies and reactive CSF. His post contrast MRI brain and skull base was normal. Cerebrospinal fluid (CSF) was cellular but did not show malignant cells. Repeat CSF cytology the third time finally demonstrated carcinoma cells. A pulmonary mass was subsequently detected on high resolution computed tomogram (CT) of chest. CT guided biopsy was suggestive of adenocarcinoma.

High frequency oscillations (ripples 80-250 Hz and fast ripples 250-600 Hz) have been widely studied in the last decade for their potential role as a more precise biomarker of the seizure onset zone, in particular fast ripples. The hippocampus is the best described brain topology as well as its association with this activity. However, in recent years; several groups have analyzed the association of high frequency activity with extra-temporal epilepsies, which could eventually influence the decision making process in the pre-surgical evaluation ensuring a better outcome in patients suffering from different forms of intractable epilepsy. In this review, the brain topology of fast ripples and several human pre-surgical studies were analyzed using fast ripple activity as an epileptogenic biomarker, also it was reviewed the preferred methods of recording for detecting high frequency oscillations in every case.

Clonus is one of the important clinical sign elicited in neurology. It is the rhythmic muscle contraction which usually occurs in patients with lesions involving descending motor pathways. Repetition of this sequence of events induces rhythmic oscillation of some joints, the frequency of which is generally between 5 and 8 Hz. Clonus usually elicited at ankle and knee. Jaw clonus is rarely reported. We report here jaw clonus in a patient who presented with vascular dementia and Parkinsonism.