Older adults with cognitive complaints show brain atrophy similar to that of amnestic MCI

TLDR

The study investigates whether older adults with subjective cognitive complaints but normal memory performance exhibit medial temporal lobe gray matter changes similar to those seen in Alzheimer disease and amnestic mild cognitive impairment. Using voxel‑based morphometry and hippocampal volume analysis, the authors compared MRI scans of 40 cognitively complaining older adults with 40 amnestic MCI patients and 40 healthy controls. Cognitive‑complaint older adults displayed medial temporal and frontotemporal gray‑matter loss comparable to amnestic MCI, with hippocampal volumes intermediate between MCI and healthy controls, suggesting that subjective complaints may signal early neurodegeneration and offer a pre‑MCI therapeutic window.

Abstract

To examine the neural basis of cognitive complaints in healthy older adults in the absence of memory impairment and to determine whether there are medial temporal lobe (MTL) gray matter (GM) changes as reported in Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI).Participants were 40 euthymic individuals with cognitive complaints (CCs) who had normal neuropsychological test performance. The authors compared their structural brain MRI scans to those of 40 patients with amnestic MCI and 40 healthy controls (HCs) using voxel-based morphometry and hippocampal volume analysis.The CC and MCI groups showed similar patterns of decreased GM relative to the HC group on whole brain analysis, with differences evident in the MTL, frontotemporal, and other neocortical regions. The degree of GM loss was associated with extent of both memory complaints and performance deficits. Manually segmented hippocampal volumes, adjusted for age and intracranial volume, were significantly reduced only in the MCI group, with the CC group showing an intermediate level.Cognitive complaints in older adults may indicate underlying neurodegenerative changes even when unaccompanied by deficits on formal testing. The cognitive complaint group may represent a pre-mild cognitive impairment stage and may provide an earlier therapeutic opportunity than mild cognitive impairment. MRI analysis approaches incorporating signal intensity may have greater sensitivity in early preclinical stages than volumetric methods.