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Updated: Nov 13, 2025
Vagus Nerve Stimulation As an Adjunctive Neurostimulation Tool in Treatment-resistant Depression
Published on: January 7, 2019
Cognitive outcomes following vagus nerve stimulation, responsive neurostimulation and deep brain stimulation for
Jordan Lam1, Marcus Williams2, Mark Ashla3
1Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, United States.
Background:
The cognitive impacts of resective surgery for epilepsy have been well-studied. While seizure outcomes for less invasive, neuromodulatory treatments are promising, there is a paucity of data for cognitive outcomes.
Methods:
Medline, EMBASE, and the Cochrane Library were searched on November 2019. Inclusion criteria were studies reporting cognitive outcomes following chronic (>6 months) vagus nerve stimulation (VNS), deep brain stimulation (DBS) and responsive neurostimulation (RNS) for epilepsy in at least five patients. Studies reporting acute on-off effects of stimulation were also included. Studies were screened, extracted of data, and assessed for bias using the Joanna Briggs Institute Critical Appraisal Tools by two independent reviewers. Prospero ID: CRD42020184432.
Results:
Of 8443 studies screened, 29 studies were included. Nineteen investigated the effects of chronic stimulation (11 VNS, 6 DBS, 2 RNS): 10 (53 %) reported no change compared to preoperative baseline; 8 (42 %) reported some improvement in one or more cognitive domain; 1 (5%) reported decline. Ten investigated the effects of acute stimulation (5 VNS, 5 DBS): 3 (30 %) reported no change; 4 reported improvement (40 %); 3 (30 %) reported decline. Eight (28 %) did not report statistical analysis.
Conclusions:
Long-term cognitive outcomes are at least stable following VNS, DBS and RNS. Acute effects of stimulation are less clear. However, data are limited by number, size, and quality. More robust evidence is needed to properly assess the cognitive effects of each of these treatments.
