Resting-State Electroencephalography and P300 Evidence: Age-Related Vestibular Loss as a Risk Factor Contributes to Cognitive Decline

Background: In recent years, there have been several meaningful advances in the understanding of the cognitive effects of vestibular loss. However, there has not yet been an investigation exploring the early biomarkers of preclinical cognitive decline in individuals with age-related vestibular loss. Objective: We aim to explore the "early biomarkers" of preclinical cognitive decline based on altered cortical activity (resting-state electroencephalography (EEG) and P300) with a multichannel EEG system in individuals with age-related vestibular loss. Method: This is a case-control study. A total of 21 patients with age-related vestibular loss (66.50 +/- 5.79 years, 13 [62%] females), 19 patients with cognitive decline (68.42 +/- 5.82 years, 13 [68%] females), and 21 age- and sex-matched healthy controls were recruited. All participants underwent a comprehensive battery of neuropsychological tests, audio-vestibular evaluations, resting-state EEG and P300 recordings. Results: Significant visuo-spatial, executive, and attention hypofunction were observed in the age-related vestibular group, reflected by decreased subscale scores. Reduced gamma functional connectivity between the right cuneus (Brodmann area 19, BA19) and the left superior parietal gyrus (BA7) was observed in both the age-related vestibular group and the cognitive impairment group. Smaller P300 amplitudes were observed in the age-related vestibular group (1.43 +/- 3.69 mu V) and cognitive impairment group (1.15 +/- 4.24 mu V) than in the healthy control group (3.97 +/- 2.38 mu V). Conclusion: Decreased P300 amplitude and functional connectivity between the right BA19 and the left BA7 were "early biomarkers" observed in individuals with age-related vestibular loss; these biomarkers may contribute to visuospatial, executive, and attention hypofunction.