Muscle MRI STIR signal intensity and atrophy are correlated to focal lower limb neuropathy severity.

OBJECTIVES: The objective is to determine if muscle MRI is useful for assessing neuropathy severity. METHODS: Clinical, MRI and electromyography (EMG) examinations were performed in 17 patients with focal lower limb neuropathies. MRI Short Tau Inversion Recovery (STIR) signal intensity, amyotrophy, and muscle fatty infiltration measured after T1-weighted image acquisition, EMG spontaneous activity (SA), and maximal voluntary contraction (MVC) were graded using semiquantitative scores and quantitative scores for STIR signal intensity and were correlated to the Medical Research Council (MRC) score for testing muscle strength. Within this population, subgroups were selected according to severity (mild versus severe), duration (subacute versus chronic), and topography (distal versus proximal) of the neuropathy. RESULTS: EMG SA and MVC MRI amyotrophy and quantitative scoring of muscle STIR intensity were correlated with the MRC score. Moreover, MRI amyotrophy was significantly increased in severe, chronic, and proximal neuropathies along with fatty infiltration in chronic lesions. CONCLUSIONS: Muscle MRI atrophy and quantitative evaluation of signal intensity were correlated to MRC score in our study. Semiquantitative evaluation of muscle STIR signal was sensitive enough for detection of topography of the nerve lesion but was not suitable to assess severity. Muscle MRI could support EMG in chronic and proximal neuropathy, which showed poor sensitivity in these patients.

[Cerebral plasticity: from bench to bedside in stroke treatment]. / Plasticité cérébrale : de la théorie à la pratique dans le traitement de l'accident vasculaire cérébral.

It has long been believed that cerebral lesions were irreversible in the adult human brain. However, the spontaneous improvement in functional outcome observed in the following weeks after cerebral ischemia suggests plasticity phenomenons involving postischemic neuronal network reorganization. Regarding the large prevalence of stroke in industrialized countries, and the few available treatments, the understanding of cerebral plasticity has become an important issue but also a potential source of new therapeutic approaches in stroke. Thus, "constraint induced therapy" and repetitive transcranial magnetic stimulation (rTMS) are based on the concept of local but also remote consequences of the ischemic focal lesion. Cell-therapy is based on the capacity of stem cells to respond to hypoxic signals and adapt their phenotype to the host organ, but above all to release cytokines locally and boost endogeneous repair mechanisms. We could consider to perform in the future a sequential treatment with fibrinolysis, stem cell therapy, repetitive transcranial magnetic stimulation and constraint-induced therapy in the same patient.

[Nerve and muscle imaging in peripheral neuropathy associated to electroneuromyography: the ideal couple?]. / L'imagerie du nerf et du muscle dans les atteintes nerveuses périphériques associée à l'électroneuromyographie : le couple idéal ?

Electroneuromyography (ENMG) is the gold standard tool in evaluating peripheral neuropathies, and it is essential to the diagnosis and the location of the involvement, as well as the assessment of the severity and the prognosis of the lesion. However, it has also limitations. It is highly examiner dependant and because it is unpleasant, the assessment of some nerves and muscles is limited. The evaluation of proximal nerve and deep muscles is difficult to perform. Magnetic resonance imaging and echography represent a fast growing field in demyelinating and motor neuropathy assessment, while these imaging procedures are now well validated in myopathies. In this article, we discuss sensitivity, specificity and prognostic data brought up by these new imaging tools compared to ENMG and the significant future prospects they offer.

[Vogt-Koyanagi-Harada syndrome]. / Le syndrome de Vogt-Koyanagi-Harada.

INTRODUCTION: Vogt-Koyanagi-Harada syndrome is a rare, inflammatory disease with manifestations affecting the ocular, central nervous, audito-vestibular, and integumentary systems. Vogt-Koyanagi-Harada syndrome is more frequent in Asia but is also described in Europe. We report three new non asiatic cases of this syndrome. OBSERVATIONS: The three patients had bilateral panuveitis and hypoacusia. Two of them had peripheral facial palsy, two of them had vestibular syndrome and one of them lymphocytic meningitis. In each case we found characteristic HLA II typing and in one case we discovered the simultaneous presence of three auto-antibodies: anti-retina (anti-Arrestin type), anti-choroid and anti-cochlea. These patients were treated by corticosteroids but required an additional treatment by cyclophosphamide (0.8g/m2). The clinical course was favorable with visual sequelae for two and auditory one for one. DISCUSSION: These biological and therapeutic elements and a review of the recent literature are in favor of an autoimmune origin of this syndrome.