Variability in Sensory Event-Related Potential as an Early Marker of Cognitive Impairment

Mild cognitive impairment (MCI) is a precursor to dementia and poses significant health and economic challenges. Early detection of MCI can slow disease progression and ease the burden on patients and caregivers. This study aimed to explore sensory-perception deficits and fluctuations in MCI using auditory event-related potentials (ERPs) from a prefrontal two-channel electroencephalogram (EEG) device. The study involved 573 MCI patients and 1,295 cognitively normal (CN) individuals, with cognitive decline assessed through the Seoul neuropsychological screening battery (SNSB) and the mini-mental state examination (MMSE). This study analyzed ERPs and trial-to-trial variability using the response variance curve (RVC) in neural responses to eight auditory sounds. While no significant differences were observed in ERP amplitudes and area under the curves (AUCs) for sensory (N1) and perception (P2) processing between MCI and CN groups, MCI patients showed notable differences in trial-to-trial variability, particularly in those aged 70 to 79 years. This variability remained significant even after adjusting for factors such as age, sex, years of education, and MMSE scores. The study suggests that MCI is associated with instability in preattentive auditory detection and higher-order perceptual processing. The findings highlight that people in their 70s may be in a transitional phase associating these sensory-perceptual variabilities with cognitive impairment. Given the large sample size and limitations of current neuropsychological tests, the study underscores the potential of sensory ERP measures as a supplementary tool for MCI screening.