Effect of Trans‐Auricular Vagal Nerve Stimulation on Cognitive Functions in Diabetic Polyneuropathy Patients

BACKGROUND AND PURPOSE: Diabetic polyneuropathy is associated with poor cognitive performance in executive function, memory and reaction time. Patients had a 50% greater risk of developing dementia. Trans-auricular vagal nerve stimulation (ta-VNS) is a new, safe and promising instrument for enhancing cognitive performance. This study aimed to investigate the effect of trans-auricular vagal nerve stimulation (ta-VNS) on cognitive functions and its impact on quality of life (QOL) in diabetic polyneuropathy patients. METHODS: Forty individuals with type II diabetic polyneuropathy participated in this study. They were randomly assigned to two equal parallel groups: study group (GI) and control group (GII). The study group received active trans-auricular vagal nerve stimulation (ta-VNS) in addition to a computer-based cognitive rehabilitation (CBCR) program, while the control group received the same program with sham (ta-VNS). Both groups underwent intervention three times per week for 3 weeks. Cognitive functions (attention-concentration, and figural memory) and quality of life were assessed at baseline and after 3 weeks using the RehaCom system and the World Health Organization's Quality of Life Brief Questionnaire, respectively. RESULTS: Post-treatment, there was a significant increase in the level of attention-concentration, as well as a significant increase in the quality-of-life score. Additionally, there was a significant decrease in the mean time for attention-concentration, as well as in figural memory acquisition time for both groups, with more improvement in favor of the study group (p < 0.05). Furthermore, there was a significant increase in the task performance and level of figural memory, along with a significant decrease in figural memory solution time only in the study group (p < 0.05). DISCUSSIONS: Adding trans-auricular vagal nerve stimulation (ta-VNS) to Computer-based cognitive rehabilitation (CBCR) program significantly enhancing cognitive functions and quality of life in diabetic polyneuropathy patients. TRIAL REGISTRATION: The study was registered at the ClinicalTrials.gov (NCT06048653).