Diagnostic Value of Electromyography and Muscle Biopsy in Arthrogryposis Multiplex Congenita

Peter B. Kang, Hart G.W. Lidov, William S. David, Alcy Torres, Douglas C. Anthony, H. Royden Jones, Basil T. Darras

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Arthrogryposis multiplex congenita (AMC), a clinical syndrome characterized by multiple congenital joint contractures, frequently is caused by lesions in the peripheral nervous system. Two standard tests for the evaluation of the motor unit are nerve conduction studies/electromyography (NCS/EMG) and muscle biopsy. We reviewed the diagnostic value of these two studies in the evaluation of AMC over a 23-year period, analyzing 38 patients with AMC who had NCS/EMG, muscle biopsy, or both. Final diagnoses were classified as neurogenic (8 patients), myopathic (10 patients), "other" (12 patients), or unknown (8 patients). Neither test alone had consistently high sensitivities, positive predictive values, or specificities. However, when NCS/EMG and muscle biopsy were concordant for neurogenic or myopathic findings, they were more accurate than either test alone, especially for neurogenic diseases. Test results were most commonly discordant in patients with "other" or unknown diagnoses. These findings suggest that when the clinical evaluation indicates a specific syndromic, developmental, or exogenous cause, NCS/EMG and muscle biopsy are not helpful and may not need to be performed. When the history, examination, and genetic evaluation are unrevealing, NCS/EMG and muscle biopsy together provide valuable diagnostic information.

Original languageEnglish (US)
Pages (from-to)790-795
Number of pages6
JournalAnnals of Neurology
Issue number6
StatePublished - Dec 2003
Externally publishedYes


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