Determination of peak-ratio by digital turns-amplitude analysis on line.
In a previous study the peak-ratio of turns to mean amplitude of the EMG interference pattern obtained from tape recordings identified 80% of patients with myopathy. In order to obtain the peak-ratio during the examination using the mean amplitude as an indication of force a digital turns-amplitude computer with a TMS 320/10 digital signal processor was developed. The EMG was analysed with a 12 bit resolution and a sampling rate of 100 kHz. In 492 samples from the brachial biceps muscle of controls, patients with myopathy and neuropathy, the digital method gave about the same turns-amplitude values as the analogue analyser. Control material for on line analysis of the peak-ratio was obtained in the brachial biceps, the abductor pollicis brevis, the medial vastus and the anterior tibial muscles of 20 subjects.
Liguori
R
R
Department of Clinical Neurophysiology, Hvidovre Hospital, University of Copenhagen, Denmark.
Dahl
K
K
Vingtoft
S
S
Fuglsang-Frederiksen
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000703:Analog-Digital Conversion; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D009135:Muscular Diseases / Q000503:physiopathology; D009422:Nervous System Diseases / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted