Chronic Stimulation of the Left Vagal Nerve in Children: Effect on Swallowing

Abstract

Summary:Purpose: To learn whether stimulation of the left vagal nerve would influence swallowing.Methods: Eight children receiving intermittent left vagal nerve stimulation (VNS) for their pharmacoresistant epilepsy underwent barium swallow studies with their generators off, on, and at maximally tolerated settings.Results: Laryngeal penetration of barium was present in three patients without stimulation, and was caused by VNS in one other patient. Aspiration never occurred.Conclusions: Stimulation of the left vagal nerve under conditions used to treat epilepsy does not cause aspiration. Key Words: Vagal nerve stimulation-Pediatric epilepsySwallowing.Intermittent left vagal nerve stimulation (VNS) has been associated with improved seizure control in some children with pharmacoresistant epilepsy (1,2). The approval by the Food and Drug Administration states: the NCP system is indicated for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents older than 12 years with partial onset seizures that are refractory to antiepileptic medications (AEDs).Some children with intractable epilepsies, candidates for this intervention, have severe neurologic deficits and impaired swallowing. As the left vagus nerve sends motor fibers to the larynx and pharynx, its long-term intermittent stimulation could provoke additional swallowing difficulties, including aspiration.The presence of aspiration was reported in one small series of children (3), but the relation to vagal stimulation is unclear. In our own series of 24 children whose epilepsy was treated >1 year with intermittent stimulation of the left vagal nerve (l), one underwent placement of a feeding gastrostomy after I0 months of stimulation. Whether or not this was related to VNS is also unclear. To help answer this important question, barium swallows were performed in eight patients receiving therapeutic left VNS for their epilepsy. METHODSFifteen patients undergoing long-term periodic stimulation of the left vagal nerve were solicited to perform barium swallows under fluoroscopy. The families of eight patients consented. None of these eight children had a history of aspiration pneumonia. The results are described in Table 1. Regarding the cognitive abilities of these patients, patient 1) was nonmobile, two (2 and 3) were mobile and moderately mentally retarded, and five (4-8) had only mild mental retardation. The most severely impaired, patient 1, received nutrition via a feeding gastrostomy.Fluoroscopic observation of vocal cord movement was performed in the erect anteroposterior (AP) projection and in the erect left lateral position. Several swallows of oral barium sulfate suspension (Liquid E-Z-Paque; E-ZEm, Inc. Westbury, NY, U.S.A.) were observed. Repeated ob$ervations were made with the vagal nerve stimulator off, with the stimulator at the patient's customary setting, and, when possible, with the milliamperes (mA) of current increased to the maximum tolerated. The duration of stimulation, normally 30 s, was increased to 3-4 rn...

Vagus Nerve Stimulation for Refractory Epilepsy: A Transatlantic Experience

“…In a minority of patients, occasional gagging occurred. This side effect has been previously reported in children (Lundgren et al, 1998;Schallert et al, 1998). If clinically significant swallowing problems occur (e.g., during meals), the stimulator can be temporarily put in the off-mode by temporarily attaching the magnet to the skin overlying the implanted generator.…”

Operative and Technical Complications of Vagus Nerve Stimulator Implantation

“…33,34 Hoarseness in patients with VNS is a common and well described side effect. [35][36][37] It was presumed to be a direct result of stimulation via both the superior and the inferior (recurrent) laryngeal nerves. 38 We observed a stimulationindependent recurrent palsy of the laryngeal nerve most likely caused by damage to the neural structure by placement of the electrode in 2 cases (Table 1).…”

Vagus nerve stimulation for intractable epilepsy in children

“…A multicenter study group recently presented their postmarketing experience 11 . Finally, two studies have assessed swallowing in children after implantation of the pulse generator 12,13 .…”

“…Schallert et al 12 tested the swallowing of eight children with barium swallows when VNS was off/on at routine clinical treatment stimulation parameters, and on with continuous stimulation for 3 to 4 minutes. Swallowing difficulties had not been reported before or after VNS therapy in these patients.…”