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.

[Vasculitis confined to the peripheral nervous system: atypical clinical presentation]. / Vascularite restreinte au système nerveux périphérique: présentation clinique atypique.

INTRODUCTION: Peripheral neuropathy is a common feature of many vasculitic syndromes. In some patients, the neuropathy may be the sole manifestation of vasculitis. EXEGESIS: A 74-year-old lady complained of pain and weakness of the lower limbs. In her history, we noted right optic neuritis, monoclonal gammopathy and dyslipidemia treated by fenofibrate. Clinical examination showed proximal muscle strength deficit of lower limbs, with quadriceps femoral muscles atrophy. Muscle stretch reflexes were absent. There was no deficit in light touch and pain sensation, but proprioception was impaired. There was electromyographic evidence of myopathic impairment with abnormal spontaneous activity. Amplitude of the sensory action potentials was mildly reduced. Laboratory tests were normal. Fenofibrate was stopped, but the clinical symptoms increased. Four months later, another electrophysiological study showed a very reduced amplitude of sensory action potentials. Myopathic impairment was less severe. Nerve biopsy showed inflammation and necrosis of nerve arteries, which lead to the diagnosis of necrotizing vasculitis. A corticosteroid treatment was done. Six months later, clinical and electrophysiological improvement clearly appeared. CONCLUSION: Histological lesions of vasculitis confined to the peripheral nervous system are those of classic polyarteritis nodosas. There is no systemic involvement nor biological abnormalities, which strengthens the role of nerve and muscle biopsy. The prognosis is good after corticosteroid treatment, which is not the case with systemic vasculitis.

[The value of motor evoked potentials in the localization of radicular lesions. 2 cases of herniated cervical disc]. / Intérêt des potentiels évoqués moteurs pour la localisation des lésions radiculaires. Deux cas de hernie discale cervicale.

Cervical electrical stimulation evokes a potential in the muscle innervated by the cervical and brachial plexuses. We present 2 cases of herniated cervical intervertebral disc which illustrate the usefulness of motor stimulation to localize a motor radicular lesion. The simultaneous recording of several muscles innervated by different radicular levels has enabled us to demonstrate the exact level and side of the lesion. Cervical motor tract stimulation is a good means of diagnosing a radicular lesion when peripheral nerve conduction velocities are normal.