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Introduction: Brody myopathy (BM) is a recessive condition caused by mutations in the ATP2A1 gene and usually induces impaired muscle relaxation during and after exercise. Diagnosis relies on needle electromyography showing electrical silence, muscle biopsy with decreased sarcoplasmic reticulum calcium adenosine triphosphatase activity, and genetic analysis. Electrodiagnostic functional analyses are useful in the diagnosis of channelopathies, and thus may be impaired in BM.Methods: We performed exercise tests and repetitive nerve stimulation (RNS; 10 supramaximal stimuli at 3 Hz) in 10 patients with BM.Results: All participants showed incremental responses on RNS. Compound muscle action potential amplitude was increased and duration was decreased, especially in the ulnar nerve (+30.2 ± 7.1% and - 30.3 ± 2.8%, respectively; both P < .001).Discussion: Easily accessible, this sign, referred to as the Arzel sign, could prove to be a very useful tool in BM diagnosis and in broadening its phenotype. [ABSTRACT FROM AUTHOR]

Key Clinical Message Guillain-Barré syndrome (GBS) may present as distal acute inflammatory demyelinating polyradiculoneuropathy (AIDP), with severe distal demyelination of the peripheral nerves in the absence of radiculitis. Clinical course is benign, and prognosis seems favorable, but nerve conduction studies (NCS) findings at nadir may resemble some chronic forms of polyneuropathy, so close follow-up during recovery is needed. [ABSTRACT FROM AUTHOR]

Introduction: Generally, spinal muscular atrophy (SMA) is believed to be a pure motor neuron disease. We retrospectively evaluated our electrodiagnostic findings in SMA type 1 patients to demonstrate co-existence of sensorimotor neuropathies. Methods: Electroneuromyographic (ENMG) studies in 15 patients (11 boys, 4 girls) were reviewed independently by 2 neurophysiologists. Upper extremity findings were compared with normal right arm controls. Results: Patient ages ranged from 1.5 to 26 months. Four SMA patients (26.7%) had decreased sensory nerve action potentials (SNAPs) or sensory nerve conduction velocities. Of them, median SNAPs could not be elicited in 3, and sural SNAPs could not be elicited in 2. Compound muscle action potential amplitudes were severely decreased in 14 (93.3%) and normal in 1. Conclusions: Survival motor neuron 1 ( SMN1) gene analysis should be considered if clinical features are consistent with SMA, even if pathological or electrophysiological findings demonstrate peripheral sensorimotor polyneuropathies. Muscle Nerve, 2013 [ABSTRACT FROM AUTHOR]