title: Muscle-fiber conduction velocity and electromyography as diagnostic tools in patients with suspected inflammatory myopathy: a prospective study.
abstract: Combinations of different techniques can increase the diagnostic yield from neurophysiological examination of muscle. In 25 patients with suspected inflammatory myopathy, we prospectively performed needle electromyography (EMG) and measured muscle-fiber conduction velocity (MFCV) in a single muscle, using a technique with direct muscle-fiber stimulation and recording. Results of MFCV were compared with final diagnosis, EMG, and needle muscle biopsy. Diagnostic accuracy of combined MFCV and EMG studies was 72%, compared to 60% for EMG alone. This improvement was due to a gain in specificity. The MFCV did not prove useful in discriminating inflammatory myopathy from other myopathies. Furthermore, we found a correlation of 92% between variability of MFCV and myopathic changes in muscle biopsy. We conclude that the utility of electrodiagnostic examination can be increased if EMG examination is combined with MFCV studies.
authors.affiliation: Department of Clinical Neurophysiology, Institute of Neurology, University Medical Centre Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Blijham
authors.forename: Gerald J D
authors.initials: GJ
authors.lastname: Hengstman
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Ter Laak
authors.forename: Baziel G M
authors.initials: BG
authors.lastname: Van Engelen
authors.forename: Machiel J
authors.initials: MJ
authors.lastname: Zwarts
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D001707:Biopsy, Needle / Q000592:standards; D004558:Electric Stimulation; D004568:Electrodiagnosis / Q000379:methods; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology*; D009220:Myositis / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic