Early diagnosis of ALS: the search for signs of denervation in clinically normal muscles.
OBJECTIVE
We prospectively investigated whether early diagnosis of amyotrophic lateral sclerosis (ALS) could be facilitated by demonstrating signs of denervation in a muscle of a clinical and electromyographical unaffected region. Muscle fibre conduction velocity (MFCV) was determined in 18 patients in whom the diagnosis ALS was considered but not established beyond a level of clinically possible ALS according to the revised El Escorial criteria. A muscle biopsy was obtained from the same muscle, to demonstrate neurogenic changes. The study followed the guidelines from the STARD initiative.


CONCLUSIONS
Results were analysed with respect to the final diagnosis. After a mean follow-up of 16 months, 9 patients developed probable or definite ALS. Sensitivity of abnormal MFCV for developing ALS was 89%. Muscle biopsy confirmed that denervation was the cause of abnormal MFCV. We concluded that MFCV can be used to detect denervation in muscles that show no clinical or electromyographical signs of lower motor neuron disease, and thus may contribute to early diagnosis of probable laboratory-supported ALS.
Blijham
Paul J
PJ
Department of Clinical Neurophysiology, Institute of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. p.blijham@neuro.umcn.nl
Schelhaas
H Jurgen
HJ
Ter Laak
Henk J
HJ
van Engelen
Baziel G M
BG
Zwarts
Machiel J
MJ
D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009121:Muscle Denervation / Q000379:methods*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity