Differential Atrophy of Hippocampal Subfields: A Comparative Study of Dementia with Lewy Bodies and Alzheimer Disease.
OBJECTIVE
Dementia with Lewy bodies (DLB) is characterized by relative preservation of the medial temporal lobe compared with Alzheimer disease (AD). The differential involvement of the hippocampal subfields in both diseases has not been clearly established, however. We aim to investigate hippocampal subfield differences in vivo in a clinical cohort of DLB and AD subjects.


METHODS
104 participants (35 DLBs, 36 ADs, and 35 healthy comparison [HC] subjects) underwent clinical assessment and 3T T1-weighted imaging. A Bayesian model implemented in Freesurfer was used to automatically segment the hippocampus and its subfields. We also examined associations between hippocampal subfields and tests of memory function.


RESULTS
Both the AD and DLB groups demonstrated significant atrophy of the total hippocampus relative to HC but the DLB group was characterized by preservation of the cornu ammonis 1 (CA1), fimbria, and fissure. In contrast, all the hippocampal subfields except the fissure were significantly atrophied in AD compared with both DLB and HC groups. Among DLB subjects, CA1 was correlated with the Recent Memory score of the CAMCOG and Delayed Recall subscores of the HVLT.


CONCLUSIONS
DLB is characterized by milder hippocampal atrophy that was accompanied by preservation of the CA1. The CA1 was also associated with memory function in DLB. Our findings highlight the promising role of hippocampal subfield volumetry, particularly that of the CA1, as a biomarker for the distinction between AD and DLB.
Department of Psychiatry, School of Clinical Medicine, Addenbrooke University of Cambridge, UK.
Elijah
E
Mak
Department of Psychiatry, School of Clinical Medicine, Addenbrooke University of Cambridge, UK.
Li
L
Su
Wolfson Brain Imaging Centre, University of Cambridge, UK.
Guy B
GB
Williams
Department of Aged Care, The Royal Melbourne Hospital, Melbourne, Australia; Institute of Neuroscience, Newcastle University, Newcastle, UK; The Florey Institute of Neuroscience and the Department of Medicine, The University of Melbourne, Parkville, Australia.
Rosie
R
Watson
Institute of Neuroscience, Newcastle University, Newcastle, UK.
Michael
M
Firbank
Institute of Cellular Medicine and Newcastle Magnetic Resonance Centre, Newcastle, UK.
Andrew
A
Blamire
Department of Psychiatry, School of Clinical Medicine, Addenbrooke University of Cambridge, UK. Electronic address: john.obrien@medschl.cam.ac.uk.
John
J
O'Brien
D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D001284:Atrophy; D001499:Bayes Theorem; D015415:Biomarkers; D016022:Case-Control Studies; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D020961:Lewy Body Disease / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D013702:Temporal Lobe / Q000473:pathology*
D015415:Biomarkers
Alzheimer disease; Lewy bodies; MRI; hippocampus; neuroimaging