Ulnar neuropathy at the elbow: Reappraisal of the wrist-upper arm latency difference between ulnar and median nerves.

OBJECTIVES: To evaluate the sensitivity and specificity of the latency difference (DLat) between ulnar and median nerves of the arm after stimulation at the wrist; one of the easiest techniques proposed for recognizing ulnar neuropathy at the elbow (UNE). As latency difference is not a standardized technique, we set up a multicenter study to recruit large numbers of normal subjects and patients with UNE or generalized neuropathy. METHODS: Six centers participated in the study with data obtained from three groups of participants, controls (CTRLs), patients with UNE and patients with generalized neuropathy (GNP). We first verified the anatomical superposition of the ulnar and median nerves in cadaver examination. The optimal recording site for these two nerves was found to be 10 cm above the medial epicondyle. We then standardized the position of the arm with full extension of the elbow and stimulated first the median and then the ulnar nerves at the wrist. CTRLs were examined on both arms at two consecutive visits. RESULTS: We recorded 32 idiopathic UNE cases, 44 GNP patients and 62 controls. We demonstrated that a DLat cut-off value of 0.69 ms brings a sensitivity of 0.86 and specificity of 0.89 to discriminate CTRLs from UNE. We also validated that intra-examiner reproducibility was good. CONCLUSION: We report a lower normal value for DLat than reported in several non-standardized studies and CTRL and UNE groups have clearly separated DLat values. SIGNIFICANCE: Due to its high sensitivity, our standardized technique could be used as a first-line diagnostic tool when UNE is suspected.

[The mucisian's cramp. About the illness of Robert Schumann]. / La crampe du musicien. A propos de la maladie de Robert Schumann.

The musicians are seen in daily neurological practice facing various problems sometimes simple such as skeletal or tendon pain or even compression of a nerve trunk and sometimes more complicated such as focal dystonia. Dystonia often has a dramatic impact on the career of a musician given the complexity of the clinical and therapeutic approach and the results are often disappointing. The history of the German Romantic composer Robert Schumann illustrates this reality; through his story a discussion of both the different pathophysiological hypotheses responsible for focal dystonia, a disorder of brain plasticity, and of the multimodal therapeutic approaches, revisited in the light of neurophysiological findings will be described.

[Mutation of the aprataxin gene presenting with Charcot-Marie-Tooth-like neuropathy and cerebellar ataxia]. / Amyotrophie de type Charcot-Marie-Tooth associée à une ataxie cérébelleuse autosomique récessive révélatrice d'une mutation du gène de l'aprataxine.

BACKGROUND: Phenotype-genotype correlations, generally based on predominant associated signs, are being increasingly used to distinguish different types of autosomal recessive cerebellar ataxias (ARCA). CASE REPORTS: Two brothers developed signs of cerebellar ataxia with peripheral axonal motor and sensory neuropathy, distal muscular atrophy, pes cavus and steppage gait as seen in Charcot-Marie-Tooth neuropathy. The examination also showed oculomotor apraxia. Sural nerve biopsy revealed conspicuous reduction in the density of myelinated fibres but preservation of unmyelinated nerve fibres. Blood tests revealed low serum albumin and elevated cholesterol. A homozygous W279X truncating mutation was identified in exon 6 of the APTX gene, confirming the diagnosis of cerebellar ataxia with oculomotor apraxia type 1 (AOA1). CONCLUSIONS: These cases illustrate the presentation of AOA1 type of ARCA and discuss the role of peripheral neuropathy in the differential diagnostic of the ARCAs variants.

New mutations of SCN4A cause a potassium-sensitive normokalemic periodic paralysis.

BACKGROUND: Periodic paralysis is classified into hypokalemic (hypoPP) and hyperkalemic (hyperPP) periodic paralysis according to variations of blood potassium levels during attacks. OBJECTIVE: To describe new mutations in the muscle sodium channel gene SCN4A that cause periodic paralysis. METHODS: A thorough clinical, electrophysiologic, and molecular study was performed of four unrelated families who presented with periodic paralysis. RESULTS: The nine affected members had episodes of muscle weakness reminiscent of both hyperPP and hypoPP. A provocative test with potassium chloride was positive in two patients. However, repeated and carefully performed tests of blood potassium levels during attacks resulted in normal potassium levels. Remarkably, two patients experienced hypokalemic episodes of paralysis related to peculiar provocative factors (corticosteroids and thyrotoxicosis). Similarly to hyperPP, electromyography in nine patients revealed increased compound muscle action potentials after short exercise and a delayed decline during rest after long exercise as well as myotonic discharges in one patient. With use of molecular genetic analysis of the gene SCN4A, three new mutations were found affecting codon 675. They resulted in an amino acid substitution of a highly conserved arginine (R) to either a glycine (G), a glutamine (Q), or a tryptophan (W). Interestingly, hypoPP is caused by both mutations affecting nearby codons as well as the change of an arginine into another amino acid. CONCLUSION: A potassium-sensitive and normokalemic type of periodic paralysis caused by new SCN4A mutations at codon 675 is reported.

[Microtraumatic peripheral neuropathies in sports]. / Pathologies nerveuses microtraumatiques du sportif.

The microtraumatic peripheral neuropathies encountered during athletic activities are not related to a specific sport, and are induced by overuse or forced constraints as seen in scapular syndromes, in distal neuropathies of upper and lower limbs, and in the foot. These neuropathies are less frequently seen than those following direct traumatic conditions. The constant increase in sport activities in the general population implies that each neurologist should ask for athletic habits of his patient in order not to miss the repetitive activities that can induce an atypical nerve injury. Electrodiagnostic (ENMG) studies in the background of sporting activities are performed in similar ways as in a general setting, but the synthesis may be more complex in relation to frequent associated orthopaedic disorders. ENMG studies are useful in the diagnosis of pain syndromes with or without paresthesia in sports-related nerve injuries.

[Current indications for the treatment with botulin toxin]. / Les indications actuelles du traitement par la toxine botulique.

Botulinum toxin is more and more frequently used as a therapeutic agent. The toxin blocks selectively and reversibly the neuromuscular junction, causing a muscle relaxation. Indications are mainly muscular hypercontraction, such as dystonia, blepharospasm, focal spasticity, strabismus or tics. The range of action extend to focal hyperhydrosis, palmar, axillary or plantar. It seems now that some painful syndrome such as migraine or tension headache may benefit from toxin injections. Esthetic indications constitute an extension to the pure medical indications.

[Carpal tunnel syndrome with an unusual cause: a malignant nerve sheath tumor of the median nerve]. / Syndrome du canal carpien de cause rare: une tumeur maligne des gaines nerveuses du nerf médian.

We report on the follow-up of a patient who developed symptoms suggestive of carpal tunnel syndrome. Symptoms were however atypical with involvement of the nondominant hand and with selective, fascicular, electroneurographic changes. During the surgical decompression of the median nerve at the wrist a tumor was found, corresponding to an isolated malignant peripheral nerve sheath tumor (MPNST) of mild type. A course of local radiation therapy was completed, with no sign of recurrence, and a normalization of the serum level of neurone specific enolase.

Exercise test in muscle channelopathies and other muscle disorders.

We studied the percentage change in compound muscle action potential (CMAP) amplitude and area during and after a 5-min maximal contraction of the muscle. The exercise test (ET) was performed on 64 patients with different muscle disorders and on 46 normal controls. The range of normal ET values was defined as the mean + 2 SD of the control values. The mean sensitivity of the test was 63% in the whole group with ion channel muscle disorders, the highest sensitivity being seen in primary periodic paralysis (81%) and the lowest in chloride channelopathies (17%). In thyrotoxic periodic paralysis, the ET was abnormal in the three of the four patients studied. In patients with myotonic dystrophy, a smaller than normal increase in CMAP amplitude occurred during and after exercise, whereas in proximal myotonic myopathy a normal initial increase in CMAP amplitude was followed by an abnormal decrement. We conclude that the ET can be of use in confirming abnormal muscle membrane excitability in patients with calcium and sodium channelopathies and thyrotoxic periodic paralysis. In chloride channelopathy, the test may also be abnormal, but shows no, or only a small, increase in amplitude or area in the immediate postexercise period. The test may also be abnormal in proximal myotonic myopathy, but is normal in myotonic dystrophy.

[Scapular pain and supra-scapular neuropathy in sports medicine]. / Scapulalgie et neuropathie sus-scapulaire en pathologie sportive.

Eight patients with shoulder pain are reported with a history of athletic activities. On examination, performed with a delay of several months, all patients had painful paresis and atrophy of spinati fossa. Electroneuromyography was carried out in all cases and showed a suprascapular nerve axonal loss from the spinati muscles or infraspinatus muscle, signs of denervation-reinnervation in spinati or infraspinatus muscles, normal examination of other scapular girdle muscles, and a coordinate spinati contraction with shoulder displacement excluding rotator cuff tears. All patients had conservative treatment and only two improved. Six patients underwent surgical decompression of the suprascapular nerve; in three, motor function clearly improved, and in three others pain improved. The factors leading to entrapment include stretch mechanisms associated with shoulder movements, leading to suprascapular nerve liability to mechanical lesions. In patients with shoulder pain, the authors recommend an early electrophysiological work-up to recognize an isolated suprascapular neuropathy. The surgical decompression of the nerve should be based on persistent shoulder pain after conservative treatment.

[Myositis, polysynovitis and pulmonary fibrosis: anti-Jo-1 syndrome]. / Myosite, polysynovite et fibrose pulmonaire: le syndrome anti-Jo-1.

Polymyositis/dermatomyositis are rare autoimmune diseases. Classification is usually performed according to the criteria of Bohan and Peter. The occurrence of myositis-specific autoantibodies has recently been described in inflammatory myopathies. Approximately half of the patients can now be classified by these specific autoantibodies. Several of these autoantibodies (anti-aminoacyl-tRNA synthetases, anti-SRP, anti-Mi2) are strongly associated with the clinical presentation. We may expect that in the future different subsets of these diseases will be increasingly identified by serum antibodies. We report on a patient with myopathy, pulmonary fibrosis and polysynovitis, a typical clinical presentation of the anti-Jo1 syndrome (anti-synthetase syndrome).

[Meningoencephalo-myeloradiculitis due to Flavivirus: bi-brachial paralysis and respiratory insufficiency]. / Méningo-encéphalo-myélo-radiculite à flavivirus: parésie bi-brachiale et insuffisance respiratoire.

3 patients developed rapid onset of fever and nuchal stiffness. Paresis of brachial muscles occurred within 4 days and all patients had respiratory failure that needed mechanical ventilation. At the peak of the disease there were bilateral asymmetrical severe atrophy of brachial, shoulder and neck muscles, cranial nerve pareses and absent or weak deep reflexes in the upper extremities. CSF analyses showed sterile lymphocytic pleocytosis. In 2 cases the patients suffered a tick bite in Switzerland and the third was probably bitten by an insect while opening a package received from Indonesia. Patients had rapid defervescence and serological tests were found to be highly positive for IgM and then IgG ELISA FSME (Frühsommer-Meningoenzephalitis). The patients were ventilated for 2 to 5 weeks before a progressive improvement was seen. However, on follow-up at 12, 18 and 30 months respectively, proximal muscles were still atrophied and quite weak. Our cases underline that: (1) FSME-ELISA results may cross-react with the Japanese and Central European encephalitis virus species; (2) Flaviviruses do induce unusual and preferential long-term paralysis of the upper extremities simulating poliomyelitis; (3) in the 2 patients studied electrophysiologically, there were signs of axonal reinnervation not seen in lower motor neuron syndrome which were important for reinnervation to permit progressive, but late, motor improvement; (4) there is no evidence of extension of the endemic foci of tick-borne encephalitis in Switzerland.

Quantitative EMG analysis and longitudinal nerve conduction studies in a Refsum's disease patient.

A patient with aosmia and night blindness had repeated clinical and electrophysiological examinations during a 21-year period. Within the first 11 years, he experienced two subacute episodes of numbness with weakness and ataxia. Over the 10 ensuing years, no additional functional disability appeared. We looked retrospectively for a correlation between repeated manual muscle scoring and different nerve conduction parameters. Further studies were done in order to estimate reinnervation in proximal and distal muscles and to assess autonomic functions. A direct relationship was found between the magnitude of muscle weakness and the amplitude of compound muscle action potentials, whereas nerve conduction velocities were inhomogeneously reduced but almost unchanged over time. Parasympathetic tests were normal but sympathetic skin responses were absent. As estimated by macro-EMG and turns-amplitude analysis the compensatory reinnervation was very high. We conclude that, in Refsum's disease, recurrent segmental demyelination of a significant portion of the motor units can occur in parallel with exacerbations of weakness, and that a considerable degree of progressive motor and sudoromotor axonal loss can be found although there is an apparent long-term clinical stabilization of the neuropathy.

[Carpal tunnel syndrome. Clinical and electrophysiologic aspects]. / Le syndrome du tunnel carpien. Aspect clinique et électrophysiologique.

After a short pathophysiological review of what is known about the compression of the median nerve in the carpal tunnel, the symptoms and clinical features of carpal tunnel syndrome (CTS) are discussed. Causes and disorders associated with CTS are then reviewed. The usefulness of electrophysiological tests and procedures are discussed in a comprehensive overview and a strategy for the electrodiagnosis of CTS is proposed in mild or atypical cases.

[Efficacy and tolerance of cyclosporin A in the treatment of multiple sclerosis]. / Efficacité et tolérance de la cyclosporine A dans le traitement de la sclérose en plaques.

The use and tolerance of cyclosporine A (Cy A) and azathioprine (AZA) are compared as long-term immunosuppression treatment for multiple sclerosis. 38 patients with multiple sclerosis were randomized and received either Cy A (5 mg/kg/d) or AZA (2 mg/kg/d) during 24 months. These patients were assessed clinically and with different biological parameters. The Cy A blood level was controlled, and Cy A was well tolerated without side effects forcing to stop the treatment. However, its benefits were limited when the different clinical scores are compared.

Cyclosporine versus azathioprine in the treatment of multiple sclerosis: 12-month clinical and immunological evaluation.

The aim of this trial was to compare the efficacy and tolerance of cyclosporine A (CYA) and azathioprine (AZA) as long-term immunosuppressive treatment for patients with multiple sclerosis. 31 randomly assigned patients completed a 12-month treatment with either CYA (5 mg/kg/day) or AZA (2 mg/kg/day). Evaluation included serial quantitative clinical assessments and circulating T cell markers. The CYA treatment group improved in only one of three scoring systems (p less than 0.05), while no difference was observed in the AZA group. CYA and AZA did not influence CD4+/CD8+ ratio of circulating T cells but affected HNK-1+ cells. The overall frequency of abnormal laboratory values were comparable in both groups. We conclude that CYA given in a low dose is relatively well tolerated but its benefits appear to be of limited value.

[EEG recordings in 19 cases of AIDS with encephalic involvement]. / EEG dans 19 cas de SIDA avec atteinte de l'encéphale.

Between 1983 and 1987, 19 patients presenting with encephalic involvement of AIDS had an EEG recording during the early neurological examination. In 8 patients, EEGs were repeated 1 to 11 times during the course of the disease. All recordings were abnormal. A good EEG correlation existed with clinical, virological and bacteriological (SF), radiological, and histological data (10 cases). EEG recordings are useful to study the encephalic pathology of AIDS, not only for its secondary, but even more for its primary involvement.