Auditory Event-Related Potentials in Older Adults with Subjective Memory Complaints

Background: Auditory event-related potentials (AERPs) have been suggested as possible biomarkers for the early diagnosis of Alzheimer's disease (AD). However, no study has investigated AERP measures in individuals with subjective memory complaints (SMCs), who have been suggested to be at a pre-clinical stage of AD. Objective: This study investigated whether AERPs in older adults with SMC can be used to objectively identify those at high risk of developing AD. Methods: AERPs were measured in older adults. Presence of SMC was determined using the Memory Assessment Clinics Questionnaire (MAC-Q). Hearing thresholds using pure-tone audiometry, neuropsychological data, levels of amyloid-beta burden and Apolipoprotein E (APOE) epsilon genotype were also obtained A classic two-tone discrimination (oddball) paradigm was used to elicit AERPs (i.e., P50, N100, P200, N200, and P300). Results: Sixty-two individuals (14 male, mean age 71.9 +/- 5.2 years) participated in this study, of which, 43 (11 male, mean age 72.4 +/- 5.5 years) were SMC and 19 (3 male, mean age 70.8 +/- 4.3 years) were non-SMC (controls). P50 latency was weakly but significantly correlated with MAC-Q scores. In addition, P50 latencies were significantly longer in A beta+ individuals compared to A beta- individuals. Conclusion: Results suggest that P50 latencies may be a useful tool to identify individuals at higher risk (i.e., participants with high A beta burden) of developing measurable cognitive decline. Further longitudinal and cross-sectional studies in a larger cohort on SMC individuals are warranted to determine if AERP measures could be of significance for the detection of pre-clinical AD.

Automated summary

This study investigated whether auditory event-related potentials (AERPs) can be used to objectively identify older adults with subjective memory complaints (SMCs) who are at high risk of developing Alzheimer's disease (AD). The results suggest that P50 latencies may be a useful tool for identifying individuals at higher risk of developing measurable cognitive decline.