In patients with Alzheimer’s disease, iVNS improved Alzheimer’s disease assessment scale-cognitive subscale and mini-mental state examination scores over 3 and 6 months, potentially enhancing cognitive functions and memory retention by decreasing tau protein accumulation and improving cerebral blood flow (Sjögren et al., 2002; Merrill et al., 2006). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.