The ERP correlate of episodic recollection is a neurocognitive determinant of subjective memory complaints: Implications on their predictive validity.

Abstract

Objective: Subjective memory complaints (SMCs) seem to be a promising marker of cognitive decline and progressing dementia in healthy older adults. However, SMCs have not been invariably related to memory performance, probably because objective tests do not always target the specific neurocognitive processes that underlie SMCs. This study disentangles the neurocognitive basis of memory-specific SMCs by investigating their dependence on episodic recollection which relies on the hippocampal relational memory system as well as their predictive value for memory tests that target such processes. Method: In 29 healthy participants, aged 52-70 years, we assessed SMCs, using the Memory Assessment Clinics Self-Rating Scale (MAC-S), episodic recollection and associated event-related potentials (ERPs), the Verbal Learning and Memory Test (VLMT), which assesses hippocampal functions, as well as depressive symptomology, using Beck Depression Inventory II (BDI). We used correlational and regression models to estimate the association of SMCs with recollection and VLMT performance, independent of age, depressive symptomology, and the P300, an ERP correlate of attentional processes. Results: The ERP correlate of source-recollection significantly accounted for 9% unique variance in SMCs. Moreover, SMCs explained unique proportions of variance in several VLMT measures (ΔR 2 ranging from .07 to .17). Conclusions: SMCs are partially determined by malfunctioning of the hippocampal relational memory system. In line with this, SMCs predict performance in objective memory tests if they also target hippocampally dependent processes. The study emphasizes the prognostic relevance of SMCs as episodic memory decline is an important preclinical marker for the development of Alzheimer's Disease (AD). (PsycInfo Database Record (c) 2021 APA, all rights reserved).