title: Quantification of concentric-needle-induced insertional activity by turn/amplitude analysis.
abstract: Quantification of needle-induced insertional activity (IA) by means of the turn/amplitude analysis (TAA) has not been attempted so far. IA was recorded from the right brachial biceps and right anterior tibial muscle of 29 healthy subjects, 17 woman, 12 men, aged 24-79 years and 51 patients with neuromuscular disorders (29 neuropathies and 22 myopathies), 24 woman, 27 men, aged 17-81 years. IA was analyzed with regard to IA duration (IAD), turns/second (T/S), amplitude/turn (A/T), T/S:IAD and A/T:IAD. IAD was not significantly different between healthy and diseased subjects in either of the two investigated muscles. On the contrary, T/S, A/T, T/S:IAD and A/T:IAD were significantly increased in the brachial biceps and anterior tibial muscle of patients with neuropathies. In myopathies T/S were increased in both muscles and the T/S:IAD in the anterior tibial muscle. Quantification of IA by TAA increases the sensitivity of conventional EMG from 38 to 69% in neuropathies and from 41 to 73% in myopathies. It is concluded that quantification of IA by TAA is of diagnostic support in the detection of neuromuscular disorders. The most useful parameter in this respect is the T/S, which, contrary to IAD, is increased in patients with neuropathies as well as patients with myopathies.
authors.affiliation: Neurological Hospital Rosenhügel, Postfach 348, 1180 Vienna, Austria. duarte@jet2web.cc
authors.forename: Josef
authors.initials: J
authors.lastname: Finsterer
authors.forename: Anders
authors.initials: A
authors.lastname: Fuglsang-Frederiksen
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D001132:Arm / Q000502:physiology; D003627:Data Interpretation, Statistical; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009339:Needles; D009468:Neuromuscular Diseases / Q000175:diagnosis / Q000503:physiopathology*