Vagus nerve stimulation therapy in patients with autism spectrum disorder and intractable epilepsy: results from the vagus nerve stimulation therapy patient outcome registry

Abstract

Object The purpose of this study was to determine the effectiveness of vagus nerve stimulation (VNS) therapy on quality-of-life (QOL) variables among patients with both autism spectrum disorder (ASD) and persistent or recurrent intractable epilepsy. Methods Data were obtained from the VNS therapy patient outcome registry, which was established after US FDA approval of the VNS device in 1997 as a means of capturing open-label clinical data outside of protocol. The integrity of the systems for collecting and processing registry data was authenticated by an independent auditing agency. The effect of potential selection bias, however, remains uncertain. Results Two cohorts were compared: 1) patients with epilepsy but without ASD (non-ASD [NASD] Group, 315 patients) who were being tracked in the registry (this cohort, which was controlled for age, included patients 20 years of age or younger); and 2) patients with a diagnosis of ASD who underwent implantation of the VNS device (ASD Group, 77 patients). Differences between the ASD and NASD groups were noted in the following categories: sex (male preponderance in ASD); normal imaging results (MR imaging results normal in ASD); depression (less common in ASD); behavioral problems (more common in ASD); neurological deficit (more common in ASD); mental retardation (more common in ASD); and developmental delay. The only QOL difference between the ASD and NASD groups was noted in mood at 12 months postimplant (mood was improved in ASD) (p = 0.04). There were no other differences in the QOL variables. Conclusions Patients with ASD and intractable epilepsy respond as favorably as all other patients receiving VNS therapy. In addition, they may experience a number of QOL improvements, some of which exceed those classically observed following placement of a VNS device.