Cortical generators of somatosensory evoked potentials to median nerve stirnulation

Dudley S. Dinner, Hans Lüders, Ronald P. Lesser, Harold H. Morris

Research output: Contribution to journalArticlepeer-review

Abstract

In 12 patients with intractable partial seizures, chronically implanted subdural electrodes were used to define the relationship of the epileptogenic focus to cortical functional areas. Cortical somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded from these electrodes. The initial cortical positivity, postrolandic primary cortical potential (PCP), was recorded in all 12 patients with a mean latency of 22.3 ± 1.6 msec. A potential of opposite polarity, prerolandic PCP, was defined in nine patients with a mean latency of 24.1 ± 2.7 msec. The latency of the postrolandic PCP was 1.61 ± 1.59 msec shorter than the prerolandic PCP (p < 0.01, paired t test). The maximum amplitude postrolandic PCP was 2.1 times larger than the maximum prerolandic PCP (p < 0.02, paired t test). The phase reversal of the SEPs was compared with the position of the rolandic fissure (RF) defined by electrical stimulation. This study shows that (1) the latency and amplitude characteristics of post- and prerolandic PCPs are significantly different and give support to the concept that they are produced by different generators; and (2) cortical SEPs are helpful in locating the RF.

Original languageEnglish (US)
Pages (from-to)1141-1145
Number of pages5
JournalNeurology
Volume37
Issue number7
DOIs
StatePublished - Jul 1987
Externally publishedYes

ASJC Scopus subject areas

  • Clinical Neurology

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