Distinct profiles of brain and cognitive changes in the very old with Alzheimer disease

• Published in: Neurology Vol. 77; no. 8; pp. 713 - 721
• Main Authors: STRICKER, N. H, CHANG, Y.-L, FENNEMA-NOTESTINE, C, DELANO-WOOD, L, SALMON, D. P, BONDI, M. W, DALE, A. M
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 23-08-2011
• Subjects: Age Factors; Aged; Aged, 80 and over; Alzheimer Disease - complications; Alzheimer Disease - pathology; Biological and medical sciences; Brain - pathology; Case-Control Studies; Cognition Disorders - etiology; Cognition Disorders - pathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Humans; Magnetic Resonance Imaging - methods; Male; Medical sciences; Middle Aged; Multivariate Analysis; Neurology; Neuropsychological Tests; Retrospective Studies; Nervous system diseases; Alzheimer disease; Central nervous system disease; Central nervous system; Degenerative disease; Cerebral disorder; Encephalon
• ISSN: 0028-3878; 1526-632X
• DOI: 10.1212/WNL.0b013e31822b0004

To determine whether age-standardized brain morphometric and cognitive profiles differ in young-old (aged 60-75 years) and very-old (aged 80-91 years) patients with Alzheimer disease (AD).
Using a case-control retrospective design, we compared hippocampal volume and cortical gray matter thickness in areas known to be affected by AD in 105 patients with AD and 125 healthy control (HC) participants divided into young-old and very-old subgroups. Brain morphometric and cognitive scores of the AD groups were standardized to their respective age-appropriate HC subgroup and then compared.
Several cognitive domains (executive function, immediate memory, and attention/processing speed) were less abnormal in the very old with AD than in the young old with AD. Similarly, the very old with AD showed less severe cortical thinning than the young old with AD in the left posterior cingulate cortex, right lateral temporal cortex, and bilateral parietal cortex and in overall cortical thickness. This effect is partially explained by an age-related decrease in cortical thickness in these brain regions in the HC participants.
The typical pattern of AD-related cognitive and morphometric changes seen in the young old appear to be less salient in the very old. Thus, mild cases of AD in the very old may go undetected if one expects to see the prototypical pattern and severity of cognitive or brain changes that occur in the young old with AD. These results underscore the importance of interpreting neuropsychological test performance and morphometric brain measures in reference to the individual's age.