Poor working memory performance in healthy elderly adults with electroencephalographic risk of cognitive decline affects syntactic processing

Abstract

ObjectiveTo examine the effects of working memory (WM) load and gender agreement on sentence processing as a function of the electroencephalographic risk (i.e., abnormally high values of theta absolute power) of cognitive decline in older adults. MethodsEvent-related potentials (ERPs) were collected from Spanish speakers (22 older adults belonged to the Risk group, mean age = 67.7 years; 22 older adults belonged to the Control group, mean age = 65.2 years) while reading sentences to detect grammatical errors. Sentences varied with regard to (1) the gender agreement of the noun and adjective, where gender of the adjective either agreed or disagreed with the noun, and (2) WM load (i.e., the number of words between the noun and adjective in the sentence). ResultsThe Risk group showed a lower percentage of correct answers and longer reaction times than the Control group. The Risk group also showed a different pattern of ERP components, which was characterized by smaller amplitude and longer latency of the P600a component under high WM load conditions. ConclusionThe findings suggest that the Risk group shows difficulties integrating information associated with the previous sentence context. SignificanceThe electroencephalographic risk factor of cognitive decline might be not only a predictor of but also an indicator of current decline.