Cardiorespiratory variables and sensation during stimulation of the left vagus in patients with epilepsy

R. B. Banzett, A. Guz, D. Paydarfar, Steven Shea, S. C. Schachter, R. W. Lansing

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

We studied physiological and sensory effects of left cervical vagal stimulation in six adult patients receiving this stimulation as adjunctive therapy for intractable epilepsy. Stimulus strength varied among subjects from 0.1 to 2.1 μCoulomb (μC) per pulse, delivered in trains of 30 45 s at frequencies from 20 to 30 Hz; these stimulation parameters were standard in a North American study. The stimulation produced no systematic changes in ECG, arterial pressure, breathing frequency tidal volume or end-expiratory volume. Five subjects experienced hoarseness during stimulation. Three subjects with high stimulus strength (0.9 2.1 μC) recalled shortness of breath during stimulation when exercising; these sensations were seldom present during stimulation at rest. No subjects reported the thoracic burning sensation or cough previously reported with chemical stimulation of pulmonary C fibers. Four of six subjects (all those receiving stimuli at or above 0.6 μC) experienced a substantial reduction in monthly seizure occurrence at the settings used in our studies. Although animal models of epilepsy suggest that C fibers are the most important fibers mediating the anti-seizure effect of vagal stimulation, our present findings suggest that the therapeutic stimulus activated A fibers (evidenced by laryngeal effects) but was not strong enough to activate B or C fibers.

Original languageEnglish (US)
Pages (from-to)1-11
Number of pages11
JournalEpilepsy Research
Volume35
Issue number1
DOIs
Publication statusPublished - May 1999
Externally publishedYes

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Keywords

  • Autonomic nervous system
  • Dyspnea
  • ECG
  • Epilepsy
  • Respiratory control
  • Vagus nerve

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Neurology

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