Associative memory and underlying brain correlates in older adults with mild cognitive impairment

This study investigated associative recognition memory by using unique features of the Chinese language and the underlying neuroanatomical correlates. The study participants were 22 Chinese speakers with mild cognitive impairment (MCI) and 25 cognitively normal (CN) Chinese speakers. The results revealed that the MCI group demonstrated impaired associative memory performance, despite exhibiting item memory performance comparable with that of the CN group, and that associative memory performance in older adults was associated with gray matter integrity in the medial temporal regions as well as executive function. An abnormal elevation was also observed in false-positive errors related to features unique to Chinese characters, namely orthographical errors, in addition to rearranged and semantic errors in the MCI group relative to the CN group, and the three error subtypes were differentially associated with gray matter integrity in the hippocampus or lateral prefrontal regions. Overall, these results demonstrate the value of evaluating associative memory in people with prodromal Alzheimer's disease (AD), and further elucidate the underlying neural substrates related to associative recognition memory in older adults.