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Pain-Related Somatosensory Evoked Potentials

Kakigi, Ryusuke; Watanabe, Shoko; Yamasaki, Hiroshi

Journal of Clinical Neurophysiology: May 2000 - Volume 17 - Issue 3 - p 295-308
Review Articles
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Summary The authors reviewed basic and clinical reports of pain-related somatosensory evoked potentials (SSEP) after high-intensity electrical stimulation [pain SSEP(E)] and painful laser stimulation [pain SSEP(L)]. The conduction velocity of peripheral nerves for both pain SSEP(E) and pain SSEP(L) is approximately 10 to 15 m/second, in a range of Aδ fibers. The generator sources are considered to be the secondary somatosensory cortex and insula, and the limbic system, including the cingulate cortex, amygdala, or hippocampus of the bilateral hemispheres. The latencies and amplitudes are clearly affected by vigilance, attention–distraction, and various kinds of stimulation applied simultaneously with pain. Abnormalities of pain SSEP(L) reflect an impairment of pain–temperature sensation, probably relating to dysfunction of Aδ fibers of the peripheral nerve and spinothalamic tract. In contrast, conventional SSEP after nonpainful electrical stimulation reflects an impairment of tactile, vibratory, and deep sensation, probably relating to dysfunction of Aα or Aβ fibers of the peripheral nerve and dorsal column. Therefore, combining the study of pain SSEP(L) and conventional SSEP is useful to detect physiologic abnormalities, and sometimes subclinical abnormalities, of patients with peripheral and central nervous system lesions.

Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan

Address correspondence and reprint requests to Dr. Ryusuke Kakigi, Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, 444-8585, Japan; e-mail: kakigi@nips.ac.jp

Copyright © 2000 American Clinical Neurophysiology Society