Combined low-rate nerve stimulation and maximal voluntary contraction in the detection of compound muscle action potential facilitation in Lambert-Eaton myasthenic syndrome

1997 ◽  
Vol 20 (9) ◽  
pp. 1207-1208 ◽  
Author(s):  
Mauro LoMonaco ◽  
Margherita Milone ◽  
Luca Padua ◽  
Pietro Tonali
Keyword(s):  
Action Potential ◽  
Nerve Stimulation ◽  
Maximal Voluntary Contraction ◽  
Compound Muscle Action Potential ◽  
Voluntary Contraction ◽  
Muscle Action ◽  
Muscle Action Potential ◽  
Myasthenic Syndrome ◽  
Low Rate

Congenital Myasthenic Syndrome: Presentation, Electrodiagnosis, and Muscle Biopsy

2004 ◽  
Vol 19 (3) ◽  
pp. 175-182 ◽  
Author(s):  
Christina A. Gurnett ◽  
Judy A. Bodnar ◽  
Jeffrey Neil ◽  
Anne M. Connolly
Keyword(s):  
Action Potential ◽  
Nerve Stimulation ◽  
Compound Muscle Action Potential ◽  
Muscle Action ◽  
Repetitive Nerve Stimulation ◽  
Poor Growth ◽  
Congenital Myasthenic Syndromes ◽  
Feeding Difficulties ◽  
Muscle Action Potential ◽  
Myasthenic Syndromes

We report 10 children with congenital myasthenic syndromes diagnosed by clinical features, electrodiagnostic studies, and response to acetylcholinesterase inhibitors. Age at diagnosis (mean = 4.4 years; range 0.2–10 years) correlated with age fatigue was recognized. Symptoms at presentation included mild gross motor development delay (7/10), speech articulation difficulty (5/10), and respiratory and feeding difficulties resulting in poor growth in 7 of 10 children. None of the five children with possible presynaptic abnormalities had decremental compound muscle action potential responses to 2 Hz repetitive nerve stimulation. Instead, electrodiagnostic studies showed a more than 100% increment of compound muscle action potential amplitude during 50 Hz repetitive nerve stimulation in two children and sustained compound muscle action potential decrement to 2 Hz repetitive nerve stimulation after depletion (10 Hz stimulation for 10 min) in four children. Muscle biopsies ( n = 7) showed mild to severe variation in fiber size. Our experience suggests that many children with congenital myasthenic syndromes might be undiagnosed because of atypical presentation and because additional electrophysiologic studies are required.

Sign in / Sign up

Export Citation Format

Share Document