Laryngeal Muscle-Evoked Potential Recording as an Indicator of Vagal Nerve Fiber Activation.
Neuromodulation
; 25(3): 461-470, 2022 Apr.
Article
em En
| MEDLINE
| ID: mdl-35177376
ABSTRACT
BACKGROUND:
Vagus nerve stimulation (VNS) is an adjunctive therapy for drug-resistant epilepsy. Noninvasive evoked potential recordings in laryngeal muscles (LMEPs) innervated by vagal branches may provide a marker to assess effective vagal nerve fiber activation. We investigated VNS-induced LMEPs in patients with epilepsy in acute and chronic settings. MATERIALS ANDMETHODS:
A total of 17 of 25 patients underwent LMEP recordings at initiation of therapy (acute group); 15 of 25 patients after one year of VNS (chronic group); and 7 of 25 patients were tested at both time points (acute + chronic group). VNS-induced LMEPs were recorded following different pulse widths and output currents using six surface laryngeal EMG electrodes to calculate input/output curves and estimate LMEP latency, threshold current for minimal (Ithreshold), half-maximal (I50), and 95% of maximal (I95) response induction and amplitude of maximal response (Vmax). These were compared with the acute + chronic group and between responders and nonresponders in the acute and chronic group.RESULTS:
VNS-induced LMEPs were present in all patients. Ithreshold and I95 values ranged from 0.25 to 1.00 mA and from 0.42 to 1.77 mA, respectively. Estimated mean LMEP latencies were 10 ± 0.1 milliseconds. No significant differences between responders and nonresponders were observed. In the acute + chronic group, Ithreshold values remained stable over time. However, at the individual level in this group, Vmax was lower in all patients after one year compared with baseline.CONCLUSIONS:
Noninvasive VNS-induced LMEP recording is feasible both at initiation of VNS therapy and after one year. Low output currents (0.25-1.00 mA) may be sufficient to activate vagal Aα-motor fibers. Maximal LMEP amplitudes seemed to decrease after chronic VNS therapy in patients.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Epilepsia
/
Estimulação do Nervo Vago
Limite:
Humans
Idioma:
En
Revista:
Neuromodulation
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Bélgica