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IC‐P‐018: Pathologically proven Alzheimer's disease without medial temporal lobe atrophy: The importance of posterior cerebral atrophy
Author(s) -
Lehmann Manja,
Koedam Esther,
Barnes Josephine,
Jonathan Bartlett,
Pijnenburg Yolande,
Barkhof Frederik,
Wattjes Mike,
Scheltens Philip,
Fox Nick
Publication year - 2011
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.05.035
Subject(s) - atrophy , frontotemporal lobar degeneration , temporal lobe , receiver operating characteristic , medicine , psychology , alzheimer's disease , dementia , pathology , cardiology , audiology , disease , neuroscience , frontotemporal dementia , epilepsy
Background:Whilst the presence of medial temporal lobe atrophy (MTA) is an important hallmark of Alzheimer’s disease (AD), MTA is also present in frontotemporal lobar degeneration (FTLD), and normal aging. A growing number of studies emphasize the presence of posterior atrophy (PA) in AD, and has been suggested to be more prominent in earlyonset (EOAD) than late-onset AD (LOAD). Visual rating scales are a convenient way of assessing atrophy in a clinical setting. This study aimed to assess PA in pathologically-proven AD and FTLD, and to investigate the ability of PA and MTA ratings to distinguish AD from FTLD and normal aging. Methods: Visual ratings of MTA and PA were obtained in 50 healthy controls, 44 AD and 27 FTLD patients. The AD group was divided into EOAD (age at onset <65 years, N1⁄433), and LOAD (N1⁄411), and compared with age-matched younger (N1⁄433) and older controls (N1⁄414), respectively. MTA and PA ratings were dichotomized into normal and abnormal, with a mean score of >1 being considered abnormal. Discriminatory power was assessed using area under the receiver operating characteristic curve (AUC). Logistic regression was used to combine MTA and PA ratings in predicting group membership. Results: MTA ratings were greater in AD and FTLD compared with controls (p<0.0001). PA ratings were greater in AD compared with controls (p<0.001) and FTLD (p1⁄40.02). 32% of AD patients had PA in the absence of abnormal MTA, whereas 44% of the FTLD patients had MTA only (Figure). Combining MTA and PA ratings improved discrimination of AD from FTLD in the right hemisphere compared with MTA alone (AUC1⁄40.72, p1⁄40.02, Table). Whilst both EOAD and LOAD showed higher MTA scores compared with younger and older controls, respectively (p<0.01), only EOAD showed greater PA scores (p<0.0001). 33% of EOAD patients had PA only, whereas 46% of the LOAD patients had MTA only. Combining MTA and PA ratings improved the separation of EOAD from younger controls (AUC1⁄40.89, p<0.03, Table) compared to either scale alone. Conclusions: Marked PA was found in the absence of clear MTA in pathologically-proven AD. Visual ratings of PA may be useful for distinguishing AD from FTLD and normal aging. Table Areas under the ROC curve (AUC) for classification of controls, AD and FTLD, as well as younger and older controls, EOAD and LOAD. Shown are AUCs for MTA and PA separately and combined, as well as p values for added value of each scale. The addition of the PA to the MTA scale can be seen to havemost value in separating controls fromAD – especially in earlyonset patients.