RESUMO
We examined the effects of chronic left vagal electrostimulation on afferent and efferent gastrointestinal vagal function in eight patients. Afferent function was assessed using cortical evoked responses to electrical stimulation of the esophagus and to direct vagal stimulation using the implanted left vagal electrode. Efferent gastrointestinal vagal function was measured by examining the basal, maximal, and sham fed stimulated gastric acid output prior to and with chronic left vagal electrostimulation. Esophageal electrostimulation produced a cortical evoked response consisting of three negative and three positive peaks within 400 msec after stimulation. Prior to vagal electrostimulation the mean conduction velocity of the afferent signal was measured at 8.72 +/- 3.39 m/sec, compatible with A-delta fibers involvement. Basal, maximal, and sham fed acid output were 1.11, 21.87, and 9.37 mmol/hour, respectively. The evoked response to esophageal electrical stimulation was not changed with chronic left vagal electrostimulation. Direct vagal stimulation also produced evoked potentials that were comparable to those obtained with esophageal stimulation. The mean conduction velocity was 6.26 +/- 2.72 m/sec (NS) so that there was no evidence of loss of myelinated fibers with chronic stimulation. No differences were detected in basal (1.29 mmol/h), maximal (21.64 mmol/h), or sham fed stimulated (8.03 mmol/h) acid output, showing that vagal electrostimulation has no effect on either total or vagally mediated acid output, an efferent vagal function. In conclusion, chronic left vagal electrostimulation has no significant adverse effect on gastrointestinal vagal function.
Assuntos
Terapia por Estimulação Elétrica/instrumentação , Epilepsia Parcial Complexa/terapia , Ácido Gástrico/metabolismo , Próteses e Implantes , Nervo Vago/fisiologia , Adulto , Vias Aferentes/fisiologia , Vias Eferentes/fisiologia , Eletroencefalografia , Esôfago/inervação , Potenciais Evocados/fisiologia , Feminino , Alimentos , Humanos , Masculino , Condução Nervosa/fisiologiaAssuntos
Terapia por Estimulação Elétrica , Epilepsia do Lobo Temporal/terapia , Nervo Vago/fisiologia , Adulto , Terapia por Estimulação Elétrica/instrumentação , Eletrocardiografia , Eletroencefalografia , Esôfago/fisiologia , Potenciais Evocados , Humanos , Masculino , Neurofisiologia , Tempo de ReaçãoRESUMO
Balance and cognition were assessed in two patients with uncontrolled complex partial seizures. The patients were on anticonvulsant medications and were treated with left vagal stimulation. Balance and cognition were assessed before and after vagal stimulation, and the results were compared with age matched controls and older patients with Parkinson's disease. Severe impairments of function were found in the epileptic patients, and such negative effects of medication make vagal stimulation a potentially practical alternative treatment for uncontrolled epilepsy.