TY - JOUR
T1 - Stationary potentials after median nerve stimulation
T2 - changes with arm position
AU - Kameyama, Shigeki
AU - Yamada, Thoru
AU - Matsuoka, Hiroo
AU - Fuchigami, Yasunori
AU - Nakazumi, Yuji
AU - Suh, Chung kyu
AU - Kimura, Jun
PY - 1988
Y1 - 1988
N2 - We previously reported the presence of stationary negative potentials (N3, N6, N9) over the arm ipsilateral to the side of median nerve stimulation. In this study, we examined the effect of different arm positions upon these stationary peaks in 12 normal subjects. When arm position was changed from elbow extended to elbow flexed 90°, we recorded a new negative peak, N4. The peak latency of N4 corresponded to the traveling impulse reaching the distal biceps brachii. With the elbow flexed, N3, N6 and N9 peak latencies significantly shortened compared to those recorded with the arm in the usual elbow extended position. In contrast, with the arm abducted at the shoulder, N6 and N9 latencies were significantly prolonged while N3 remained unchanged. Corresponding latency shifts were also observed in the bipolarly recorded traveling impulse. We consider 2 possible factors for N4 enhancement by elbow flexion. One is the change in conducting volume surrounding the nerve, i.e., increased muscle bulk of biceps brachii. The other is the change in axial orientation of the propagating nerve impulse by 90°. We also propose that the latency shifts of the stationary potential as well as of a travelling wave can be attributed primarily to relaxation or stretching of the nerve trunk with change in arm position.
AB - We previously reported the presence of stationary negative potentials (N3, N6, N9) over the arm ipsilateral to the side of median nerve stimulation. In this study, we examined the effect of different arm positions upon these stationary peaks in 12 normal subjects. When arm position was changed from elbow extended to elbow flexed 90°, we recorded a new negative peak, N4. The peak latency of N4 corresponded to the traveling impulse reaching the distal biceps brachii. With the elbow flexed, N3, N6 and N9 peak latencies significantly shortened compared to those recorded with the arm in the usual elbow extended position. In contrast, with the arm abducted at the shoulder, N6 and N9 latencies were significantly prolonged while N3 remained unchanged. Corresponding latency shifts were also observed in the bipolarly recorded traveling impulse. We consider 2 possible factors for N4 enhancement by elbow flexion. One is the change in conducting volume surrounding the nerve, i.e., increased muscle bulk of biceps brachii. The other is the change in axial orientation of the propagating nerve impulse by 90°. We also propose that the latency shifts of the stationary potential as well as of a travelling wave can be attributed primarily to relaxation or stretching of the nerve trunk with change in arm position.
KW - Far-field potential
KW - Somatosensory evoked potential
KW - Stationary potentials
KW - Traveling wave
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U2 - 10.1016/0168-5597(88)90037-8
DO - 10.1016/0168-5597(88)90037-8
M3 - Article
C2 - 2457486
AN - SCOPUS:0023686478
VL - 71
SP - 348
EP - 356
JO - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
JF - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
SN - 0168-5597
IS - 5
ER -