title: Endoscopic laryngeal patterns in vagus nerve stimulation therapy for drug-resistant epilepsy.
abstract: In 30% of patients with epilepsy seizure control cannot be achieved with medications. When medical therapy is not effective, and epilepsy surgery cannot be performed, vagus nerve stimulator (VNS) implantation is a therapeutic option. Laryngeal patterns in vagus nerve stimulation have not been extensively studied yet. The objective was to evaluate laryngeal patterns in a cohort of patients affected by drug-resistant epilepsy after implantation and activation of a vagus nerve stimulation therapy device. 14 consecutive patients underwent a systematic otolaryngologic examination between 6 months and 5 years after implantation and activation of a vagus nerve stimulation therapy device. All patients underwent fiberoptic endoscopic evaluation, which was recorded on a portable device allowing a convenient slow-motion analysis of laryngeal patterns. All recordings were blindly evaluated by two of the authors. We observed three different laryngeal patterns. Four patients showed left vocal cord palsy at the baseline and during vagus nerve stimulation; seven showed left vocal cord palsy at the baseline and left vocal cord adduction during vagus nerve stimulation; and three patients showed a symmetric pattern at the baseline and constant left vocal cord adduction during vagus nerve stimulation. These laryngeal findings are here described for the first time in the literature and can be only partially explained by existing knowledge of laryngeal muscles and vagus nerve physiology. This might represent a new starting point for studies concerning laryngeal physiology and phonation, while the vagus nerve stimulation therapy could act as a new and ethical experimental model for human laryngeal physiology.
authors.affiliation: Otolaryngology Department, San Paolo Hospital, Università degli Studi di Milano, Via A. di Rudinì, 8, 20142, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Felisati
authors.forename: Elena
authors.initials: E
authors.lastname: Gardella
authors.forename: Paolo
authors.initials: P
authors.lastname: Schiavo
authors.forename: Alberto Maria
authors.initials: AM
authors.lastname: Saibene
authors.forename: Carlotta
authors.initials: C
authors.lastname: Pipolo
authors.forename: Manuela
authors.initials: M
authors.lastname: Bertazzoli
authors.forename: Valentina
authors.initials: V
authors.lastname: Chiesa
authors.forename: Alberto
authors.initials: A
authors.lastname: Maccari
authors.forename: Angelo
authors.initials: A
authors.lastname: Franzini
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Canevini
mesh_terms: D000328:Adult; D055154:Dysphonia / Q000503:physiopathology; D004724:Endoscopy; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006801:Humans; D007830:Larynx / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology; D055536:Vagus Nerve Stimulation; D014826:Vocal Cord Paralysis / Q000503:physiopathology*