Evaluating P300 Latency as a Physiological Marker for Asymptomatic and Prodromal Alzheimer’s Disease

Background Alzheimer's disease (AD) is a progressive neurodegenerative disorder that poses significant challenges in terms of early diagnosis and intervention. While various biomarkers have been explored, few studies have utilized electroencephalography (EEG) with a focus on P300 peak latency to distinguish between the preclinical stages of AD, specifically Asymptomatic AD (AAD) and Prodromal AD (PAD). Methods In this study, we investigated P300 latency during an oddball task. EEG data was collected from a total of 117 participants with 39 Healthy Controls (HCs) (mean age = 72.08 ± 4.08 years), 39 AAD (mean age = 73.08 ± 4.75 years), and 39 PAD (mean age = 74.95 ± 4.29 years). Statistical analyses involved ANOVA tests to assess group differences in neurophysiological and neuropsychological data. With a focus on regional differences across the left, middle, and right brain hemispheres, a mixed-design ANOVA examined P300 peak latency, followed by post-hoc tests and ROC analysis to evaluate classification performance at the individual level. Results Our results showed that P300 peak latency can effectively differentiate HC from both AAD and PAD, with the left hemisphere providing the most significant distinction between HC and AAD, with a sensitivity of 74.3% and specificity of 55.6%. P300 latency from the middle region demonstrated a sensitivity of 77.4% and specificity of 72.2% for distinguishing HC from PAD, while the right region showed the highest sensitivity (80%) but lower specificity (63.9%) for HC vs PAD. However, no clear distinction was observed between AAD and PAD, except for a borderline significance in the middle region. Conclusions These results suggest that P300 latency from the left hemisphere is capable of differentiating HCs from AAD, and latency in any brain region distinguishes HCs from PAD. Accordingly, we concluded that P300 latency could serve as a useful biomarker for the early detection and classification of AD, particularly in its preclinical stages.