Turn/amplitude parameter changes during sustained effort.
Little is known about the effect of sustained effort on turn/amplitude parameters. Therefore, the turn/amplitude analysis was applied at contractions with 50 +/- 5% of the right biceps brachii muscle's maximum force to 31 healthy human subjects (19-67 years old), 15 patients with neuropathies (30-83 years old) and 15 patients with myopathies (16-66 years old). After 3 min of sustained contraction, turns/second (T/S) decreased by 50% in healthy human subjects and by 25% in patients with neuropathies and patients with myopathies. The amplitude/turn (A/T) increased by 25% in healthy human subjects and remained almost unchanged in pathological cases. Compared to its onset values, the ratio A/T:T/S increased by > 150% in healthy human subjects and by 50% in patients with myopathies. With decreasing T/S, the A/T increased in healthy human subjects, decreased in patients with neuropathies and stayed unchanged in patients with myopathies. With this method detection rates of 60% for patients with neuropathies and 67% for patients with myopathies were found. The most reliable turn/amplitude parameters for the identification of pathological cases were the T/S and the A/T. Evaluating these two parameters, the rate of false positive results was 3.2%. The study demonstrated changes during sustained effort to be different between sexes and between healthy human subjects and patients with neuromuscular disorders. It described turn/amplitude analysis during sustained effort as a supplemental electrophysiological device for the detection of patients with neuromuscular disorders. The method is objective, fast and reliable.
LBI for Research in Epilepsy and Neuromuscular Disorders, Vienna, Austria.
J
J
Finsterer
B
B
Mamoli
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001132:Arm / Q000502:physiology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D009468:Neuromuscular Diseases / Q000503:physiopathology*; D012016:Reference Values