Quality of Life and Memory after Vagus Nerve Stimulator Implantation for Epilepsy

Abstract

Implantation of a vagus nerve stimulator (VNS) to decrease seizure frequency and severity became available for commercial application in Europe in 1994 and in the US since 1997. 1 Randomized clinical trials have reported greater than 50% improvement in seizure control in 20 to 30 percent of patients experiencing therapeutic levels of stimulation. 2-4 Improved seizure control has been correlated with a longer follow-up ABSTRACT: Objective: This prospective, case control study evaluates quality of life (QOL), depressive affect, and memory outcomes of epilepsy patients implanted with a vagus nerve stimulator (VNS). Methods: Three groups of patients with epilepsy underwent assessment on two occasions: 1) patients with a VNS were tested before and 12 months after implantation (n = 16); 2) patients who underwent cerebral resective surgery were tested pre-and post-operatively (n = 10); and 3) patients under medical management (n = 9). Group means were compared on the QOLIE-89, Geriatric Depression Scale, Wechsler Memory Scale -III, and the Memory Observation Questionnaire. Secondary analyses calculated the reliable change index, providing information on change beyond measurement error and chance. Results: Mean ratings of QOL, depression, and memory complaints and objective memory scores remained stable or improved in all the groups. The QOL improved more after cerebral resective surgery than VNS or medication controls, but the VNS and medication control groups did not differ. In the VNS group, QOL was not related to seizure reduction. The percentage of cases showing real change in memory was equivalent across groups, except in one of eight indices (i.e., verbal recognition memory). Conclusions: This first case controlled design found that vagus nerve stimulation as an adjunctive therapy for seizure control did not change QOL, depressive affect, or objective memory scores over one-year more so than medical management alone. We point out the need for larger case control, non-industry funded investigations. RÉSUMÉ: Qualité de vie et mémoire après implantation d'un stimulateur du nerf vague pour traiter l'épilepsie.Objectif : Le but de cette étude prospective cas-témoin était d'évaluer la qualité de vie (QV), l'affect dépressif et la mémoire de patients épileptiques chez qui un stimulateur du nerf vague (SNV) a été implanté. Méthodes : Trois groupes de patients épileptiques ont été évalués à deux reprises : 1) des patients porteurs d'un SNV ont été évalués avant et 12 mois après son implantation (n = 16); des patients qui ont subi une résection cérébrale chirurgicale ont été évalués avant et après la chirurgie (n = 10); 3) des patients sous traitement médical (n = 9). Nous avons comparé les moyennes des groupes pour les tests suivants : QOLIE-89, Geriatric Depression Scale, Wechsler Memory Scale-III et Memory Observation Questionnaire. Nous avons également calculé le reliable change index, ce qui ajoute de l'information sur le changement qui n'est pas dû à l'erreur de mesure ou au hasard. Résultats : La moyenne des évalu...

Psychosocial difficulties in people with epilepsy: A systematic review of literature from 2005 until 2010

“…Three studies reported improvements of depression in the course of the disease due to antiepileptic drugs (oxcarbazepine and levetiracetam) [32][33][34], showing that better control over seizures led to a decrease in depressive symptoms. On the contrary, McGlone and colleagues [35] reported no change in depressive symptoms after antiepileptic pharmacotherapy. Other studies reported that surgery for epilepsy positively contributed to decreasing depressive symptoms [36,37], whereas Cankurtaran and colleagues showed no reduction in depressive symptoms after the surgery [38].…”

“…Severity of depressive symptoms was also associated with cognitive complaints [41], low quality of life [35], and lack of adherence to treatment [39].…”

Epilepsy, Consciousness and Neurostimulation

“…However, this does not seem to influence memory. A small case-control study did not find any significant differences in objective memory scores using Wechsler Memory Scale III and the Memory Observation Questionnaire in VNS patients (n = 16) compared to those under medical management over 12 months (n = 9) [49]. Another small study (n = 12) investigating short-term memory in epilepsy patients using Mismatch Negativity latencies and amplitudes did not show significant changes 12 months after VNS implantation [8].…”

Vagus Nerve Stimulation in the Treatment of Refractory Epilepsy

“…61 However, these findings have been contradicted by a recent case-control study that found no change in QOL over 12 months of VNS. 62 These results suggest that there is insufficient evidence at this time to make conclusive statements regarding the effects of VNS on QOL in adult epilepsy.…”