The effect of Vagus nerve stimulation (VNS) on seizure control, cognitive function, and quality of life in individuals with drug-resistant epilepsy: A systematic review article

Objectives

To evaluate the effect of vagus nerve stimulation (VNS) on seizure control, cognitive functions, and quality of life in individuals with drug-resistant epilepsy.

Methods

An extensive search of electronic databases was carried out in order to carry out this systematic review. The databases Google Scholar, Embase, PubMed, and the Cochrane Library were searched first to carryout gray literature. To reduce the quantity of pointless studies in the advanced search, the search is limited to “human studies” and “English language” publications only. Combining keywords and Medical Subject Headings (MeSH) terms like (“Vagus Nerve Stimulation” OR “VNS”) AND (“Epilepsy” OR “Seizure Control”) AND (“Cognitive Function” OR “Quality of Life”). Studies that have been published up to November 30/2023 were included.

Results

The search strategy yielded a total of 392 relevant studies. The mean age of participant's ranges from 11 years to 33 years. The duration of follow-up ranging from 6 to 36 months. Eleven studies were included in the review. The mean≥50% response rate after VNS therapy was 56.94% ranged from 48.90% to 83.00%. Four and three studies provided information about Quality of Life in Epilepsy Inventory (QOLIE-31) and The Liverpool Seizure Severity Scale (LSSS) questionnaires respectively.

Significance

Epilepsy is a chronic disease characterized by sudden abnormal discharge of brain neurons, which leads to transient brain dysfunction and the presence of spontaneous recurrent seizures. Vagus nerve stimulation has recently been proposed as a potential tool in the treatment of seizure, depressive symptoms, and cognitive impairments. There has been variation in the effects of VNS treatment on seizure control, cognitive functions, and quality of life among patients with drug-resistant epilepsy. So, a comprehensive review of exciting literature is important to see the pooled effect. Previous systematic review and meta-analysis papers were mostly randomized control trial type with specific diseases. The use of a wider variety of study designs than only randomized controlled trials is important. So, we included retrospective and prospective cohort studies in addition to randomized control trials. This enables a more thorough assessment of the connection between quality of life, cognitive function, and vagus nerve stimulation. In addition, the paper looks at a wide range of disease kinds and patterns. We have established a uniform and comprehensive approach throughout the selected studies by mandating the inclusion of all three crucial parameters: vagus nerve stimulation, cognitive function, and quality of life.

Plain Language Summary

This systematic review examined 392 relevant studies on vagus nerve stimulation (VNS) therapy, with participants ranging from 11 to 33 years old and follow-up durations of 6–36 months. Eleven studies were included, and the mean response rate after VNS therapy was 56.94%, ranging from 48.90% to 83.00%. The review also reported on quality of life and cognitive function, and seizure severity frequency result from several studies.