Early Event-Related Potential components as potential biomarkers for Alzheimer's Disease and their relationship with attentional capacity.

Abstract

Deficits in attentional capacity are a common symptom of Alzheimer's Disease (AD), however research focusing on attention deficits in AD is much less prevalent than research on memory. To remedy this, this study repurposed behavioural and event-related potentials (ERP) data from a cross modal associative memory test conducted on 135 adults (70 healthy older adults, 65 older adult patients with mild AD diagnosis). The aim was to understand differences in attentional capacity, measured by reaction time, alongside peak amplitude and latency of the early ERP components N1, N200 and P300, components related to attentional processing. A 2x3 factorial ANOVA of reaction time comprised of two groups (controls & patients) and three memory conditions (new, old/short & old/long stimuli) revealed that AD patients reacted significantly slower than control patients across all memory conditions. 2x3factorial ANOVA analysis of ERP data (group x memory condition) revealed a significant effect of group on N1 peak amplitudes, with control patients displaying lower peak amplitudes, and a significant effect of memory condition on N200 and P300 peak amplitudes, with patients displaying lower peak amplitudes in the N200 and higher peak amplitudes in the P300. Furthermore, there was a significant effect of group on peak latency in the N200 and P300 peak latencies for the AD group. There was also small correlations between sequential ERP components, particularly in AD patients, suggesting possible cascading effects. This data indicates that there are significant and objective differences in AD patients’ attentional capacity and ERP responses, and that attentional capacity and ERP amplitude and latency may have a relationship. Further research should be carried out to understand this potential relationship, and that early ERP components can serve as a valid biomarker for diagnosing early AD.