Somatosensory evoked potentials in the assessment of peripheral neuropathies: Commented results of a survey among French-speaking practitioners and recommendations for practice.

BACKGROUND: Somatosensory evoked potentials (SSEPs) are increasingly performed for the assessment of peripheral neuropathies, but no practical guidelines have yet been established in this specific application. STUDY AIM: To determine the relevant indication criteria and optimal technical parameters for SSEP recording in peripheral neuropathy investigation. METHODS: A survey was conducted among the French-speaking practitioners with experience of SSEP recording in the context of peripheral neuropathies. The results of the survey were analyzed and discussed to provide recommendations for practice. RESULTS: SSEPs appear to be a second-line test when electroneuromyographic investigation is not sufficiently conclusive, providing complementary and valuable information on central and proximal peripheral conduction in the somatosensory pathways. CONCLUSIONS: Guidelines for a standardized recording protocol, including the various parameters to be measured, are proposed. CLINICAL RELEVANCE: We hope that these proposals will help to recognize the value of this technique in peripheral neuropathy assessment in clinical practice.

Absence of the OPTN mutation in a patient with ALS and familial primary open angle glaucoma.

The optineurin (OPTN) gene, known to be implicated in primary open-angle glaucoma (POAG), is the more recent genetic factor linked to ALS. We report the case of a 75year-old man who developed ALS and whose medical history was dominated by a familial POAG. The absence of OPTN gene mutation in a patient who suffered from two conditions linked to mutations of this gene does not support involvement of OPTN in ALS.

Predictive value of motor evoked potentials in clinically isolated syndrome.

OBJECTIVES: To assess the predictive role of several measures obtained by transcranial magnetic stimulation (TMS) in patients with clinically isolated syndrome (CIS) for the risk of conversion to multiple sclerosis (MS) during the first 2 years. MATERIALS AND METHODS: We investigated 34 patients with CIS. After 2 years of follow-up and classification into two groups according to MS diagnosis, initial TMS measures were compared to determine their predictive values for conversion to MS. RESULTS: Sixteen patients developed MS. We observed a significant difference between the two groups for contralateral silent period and no significant difference for the central motor conduction time, amplitude ratio, motor threshold, ipsilateral silent period, and the transcallosal conduction time. CONCLUSIONS: Contralateral silent period (SP) seems to be a valuable parameter to early distinguish patients who will develop MS or not. This result about SP during CIS has never been described until now. An increased contralateral silent period would predict a conversion to MS with a positive predictive value of 75%, but this result needs to be confirmed in larger groups.

[Diabetic amyotrophy: favorable outcome following corticosteroid therapy?]. / Amyotrophie diabétique : intérêt de la corticothérapie ?

Diabetic amyotrophy or lombosacral radiculoplexus neuropathy is a rare complication associated with early-stage diabetes. Thigh pain, quadricipital amyotrophy, proximal weakness of lower limbs and weight loss are the main symptoms of the disease. As neurological damage is related to inflammatory microvasculitis, corticosteroid therapy may be considered as the first line therapy. We report a 54-year-old patient with type 2 diabetes affected with severe diabetic amyotrophy. Following intravenous corticosteroid therapy, the patient reported a rapid pain relief and gained muscle strength.

APOE ε4 allele is associated with an increased risk of bulbar-onset amyotrophic lateral sclerosis in men.

OBJECTIVE: Several association studies have identified possible susceptibility factors for sporadic amyotrophic lateral sclerosis (SALS). Studies on the APOE gene provided conflicting results, especially about the effect on bulbar onset. We assessed the possible role of APOE gene in a large cohort of patients with ALS and matched controls. METHODS: The APOE alleles were determined in 1482 patients with SALS and 955 controls and analysed by univariate and multivariate statistics, taking into account gender, site-of-onset and age-at-onset. RESULTS: Patients with bulbar onset were more likely to be women [odds ratio (OR)=2.17; 95% CI: 1.74-2.72] and to be older (OR=3.47; 95% CI: 2.58-4.67). The ε4-carriers were more frequent in the bulbar-onset group than in the limb-onset group (OR=1.39 bulbar onset versus limb onset; 95% CI: 1.08-1.80) but this association was observed amongst men (OR=1.78; 95% CI: 1.25-2.53) and not women (OR=1.09; 95% CI: 0.75-1.59). CONCLUSION: Our study provides evidence for a contribution of the ε4 allele in the occurrence of bulbar-onset ALS amongst men. We propose that men are normally protected by androgens against bulbar onset and that the ε4 allele inhibits this protection, perhaps by interfering with the androgen pathway.

[Chronic demyelinating polyneuropathy and B6 hypervitaminosis]. / Polyneuropathie chronique démyélinisante et hypervitaminose B6.

We report a 62-year-old patient who presented with a several month history of a peripheral sensory neuropathy with ataxia that was attributed to a chronic immune demyelinating polyneuropathy but was resistant to corticosteroid therapy. Diagnostic workup finally showed a high serum level of pyridoxin related to a chronic intake of oral vitamin medication for several years. We discuss the link between the clinical and electrophysiological manifestations of the chronic polyneuropathy, based on similar reported observations in the literature. This observation highlights the possibility of important long-term deleterious effects of vitamin oral supplementations, particularly pyridoxin.

[Progressive anarthria: an individual entity]. / Anarthrie progressive: une entité propre.

INTRODUCTION: First described 15 years ago, primary progressive anarthria is a focal cortical atrophy defined as a rare progressive impairment of speech associated with orofacial apraxia and leading to mutism with a frontal lobe syndrome. The aim of this study was to analyze clinical and neuropsychological data and results of complementary tests in a series of patients presented with primary progressive anarthria. MATERIAL AND METHODS: We, retrospectively, studied five patients with primary progressive anarthria. We particularly analyzed the following parameters: age at onset, age at the diagnostic, disease time from onset to first consultation, the initial orientation, the neuropsychological and clinical data at the first visit, electromyography, brain MRI, and single photon emission computed tomography (SPECT) findings. Clinical and neuropsychological data were used to monitor disease course. RESULTS: The mean age at onset of symptoms was 75.2+/-5.8 years. Patients were primarily referred to a specialist in memory disease (n=3) or a specialist in motor neuron disease (n=2). The time from onset to first consultation was 11.2+/-3 months. Anarthria was associated with dysexecutive syndrome and sometimes, with impaired comprehension. Electromyography was always normal. Cranial MRI showed temporal or left frontal atrophy (n=3). Spect revealed decreased cerebral blood flow predominating in the left frontal or temporal region (n=4). CONCLUSION: Long delay for specialist consultation and inadequate initial orientation retard disease diagnosis, leading to severe incapacity. Complementary studies are required to confirm diagnostic and to rule out lateral amyotrophic sclerosis. During the early stages, involvement of the premotor cortex may be considered due to the speech apraxia. Secondary motor orofacial disturbances suggest an extension to the motor cortex. Primary progressive anarthria is a distinct individual entity within the spectrum of focal cortical atrophies.

[Genetics of motor neuron disorders]. / Génétique des maladies du motoneurone.

Motor neuron disorders (MND) form a heterogeneous group of neurodegenerative affections: phenotypic description is based on selective injury to the upper motor neuron or lower motor neuron or both. Phenotypic heterogeneity is also present concerning genetic features: genetic factors involved in MND may be causative or susceptibility factors. Consequences of genetic abnormalities lead to metabolic or functional cellular disturbances that are apparently specific for motor neuron disorder. Genetics greatly contribute to our understanding of the pathophysiological mechanisms of motor neuron degeneration. Genetic studies provide pathological hypotheses considering the function of protein encoded. Moreover, when a gene mutation is identified, animal models can be developed to search for modifications induced by the mutation. We propose to detail causative and susceptibility genetic factors involved in MND and to discuss pathological mechanisms that may explain motor neuron death.

Bilateral hand amyotrophy with PMP-22 gene deletion.

Hereditary neuropathy with liability to pressure palsies (HNPP) phenotypes are heterogeneous. We report the case of a 52-year-old woman without medical history, who complained of bilateral hand weakness suggestive first of a motor neuron disorder. The presence of a diffuse predominant distal demyelinating neuropathy suggested a deletion of PMP-22 gene, which was confirmed by genetic analysis. This case report underlines a novel phenotype related to the deletion of PMP-22 gene.

[Psychiatric comorbidity in patients with pseudoseizures: retrospective study conducted in a video-EEG center]. / Comorbidité psychiatrique au cours des événements non épileptiques: étude rétrospective dans un centre de vidéo-EEG.

INTRODUCTION: Pseudoseizures involve a group of paroxysmal behavioral symptoms mimicking an epileptic seizure, but without modifications of cerebral electrical activity. PATIENTS AND METHOD: In this retrospective study focusing on mental disorders, 37 patients with pseudoseizures were recorded during video-EEG procedure. RESULTS: According to DSM-IV criteria, 70 percent of the patients had at least one mental disorder when evaluated. Diagnoses were, in decreasing order of frequency: post-traumatic stress disorders, other anxious disorders, somatoform disorders, dissociative disorders, and mood disorders. CONCLUSION: The strong association between pseudoseizures and post-traumatic stress disorders is discussed. Our results argue in favor of a systematic evaluation of psychiatric comorbidity.

[Emergency EEG: actual indications and results]. / EEG d'urgence: indications réelles et résultats.

PURPOSE: The indications of emergency electroencephalogram (eEEG) were defined by a French consensus conference in May 1996. We retrospectively confronted the recommendations with the actual requests for emergency EEG in our University hospital, in order to determine the contribution of the eEEG in the most frequent clinical situations encountered. MATERIAL AND METHOD: Three hundred and twenty nine consecutive eEEGs over a 6-months period were retrospectively analyzed. RESULTS AND CONCLUSION: The most frequent indications were presumption of brain death (13%), convulsive status epilepticus after treatment (12.1%), and suspicion of nonconvulsive epilepticus status (10.6%). More than one third of the requests (38.6%) were not in conformity with the recommendations of the consensus conference. The contribution of the EEG is much improved by the application of the consensual criteria. Thus, the EEG remains essential for the management of convulsive status epilepticus after treatment, to seek a subtle epilepticus status or a nonconvulsive epilepticus status. Conversely, the EEG did not prove useful in emergency after a transient loss or alteration of consciousness or a focal, non-febrile, neurological transient or permanent deficit.

[Image-guided epidural blood patch as effective treatment of intracranial hypotension. A case report]. / Le blood-patch épidural thoracique radioguidé: un traitement efficace du syndrome d'hypotension intracrânienne.

We report the case of a patient with postural headache. A CT scan revealed bilateral subdural hygroma. Brain MRI showed diffuse pachymeningeal enhancement. A diagnosis of intracranial hypotension was therefore made. Thoracic cerebrospinal fluid leak was proved by radionuclide cisternography and contrast myelography. Conservative medical treatment was ineffective. Two thoracic epidural blood patches with radiographic control were made. We think the blood patch is the most important element for success.

[Hemimegalencephaly: a misleading EEG tracing]. / L'hémimégalencéphalie: un aspect EEG trompeur.

Hemimegalencephaly is a rare cerebral malformation that usually presents with mental retardation, controlateral hemiparesis and intractable seizures. We report a case of hemimegalencephaly diagnosed in adulthood based on MRI findings. The electroencephalogram initially suggested partial status epilepticus. The diagnosis of this cerebral malformation has been made easier thanks to recent progress in cerebral imagery with MRI. We describe and discuss the relevant encephalographic aspects.