クロカワ　カツミ   Katsumi Kurokawa   黒川　勝己    所属   川崎医科大学  医学部 臨床医学　総合内科学１    職種   教授
言語種別	英語
発表タイトル	Far-Field Potentials (FFPs) Contaminating Ulnar CMAPs: Investigation from the 2L/IO Method
会議名	2009 Asian and Oceanian Congress of Clinical Neurophysiology
学会区分	国際学会及び海外の学会
発表形式	口頭
講演区分	一般
発表者・共同発表者	◎Kurokawa Katsumi, Sonoo Masahiro, Higashihara Mana, Kurono Hiroko, Hatanaka Yuki, Shimizu Teruo
発表年月日	2009/04/16
開催地 （都市, 国名）	Seoul, Korea
学会抄録	Clinical Neurophysiology 120(Suppl.),S24 2009
概要	Background We’ve investigated the far-field potential (FFP) components contaminating median, ulnar and radial compound muscle action potential (CMAP). The waveforms of FFPs were quite different among nerves and their generating mechanism is still unclear. In the present study, we aimed to elucidate the generating mechanism of FFPs in ulnar and median CMAPs by investigating the 2L-IO method (2nd lumbricalis and 1st palmar interosseous recording; Preston’s method). Materials and Methods Subjects were five healthy volunteers. We placed electrodes over the bellies of the 2L/IOP1, ADM, IOD1 and APB muscles, and at the tip of the digits II, V and I. The common proximal reference was placed at the forearm. We recorded the CMAPs following supramaximal stmulation of the median and ulnar nerves at the wrist. We also obtained routine CMAPs of each muscle. Results Ulnar nerve stimulation elicited large FFPs with negative-positive-negative three phases at the tip of the index finger, even larger than those over the little finger, whereas those following median nerve stimulation were small. The onset latencies of both the negative FFPs over the finger tips and the CMAPs of IOP1 and IOD1 by the belly-proximal recordings following ulnar nerve stimulation were similar, and were earlier than those of routine IOP1 and IOD1 CMAPs with distal references. Conclusions The present and other studies of ours have suggested that at least the initial negative phase of the ulnar FFPs is generated by the interosseous muscles. The early onset of these negative FFPs indicates that they were generated by the commencement of the action potentials at these muscles, instead of their termination.