Hippocampal atrophy on MRI in frontotemporal lobar degeneration and Alzheimer's disease.
BACKGROUND
Hippocampal atrophy on magnetic resonance imaging (MRI) is an early characteristic of Alzheimer's disease. However, hippocampal atrophy may also occur in other dementias, such as frontotemporal lobar degeneration (FTLD).


OBJECTIVE
To investigate hippocampal atrophy on MRI in FTLD and its three clinical subtypes, in comparison with Alzheimer's disease, using volumetry and a visual rating scale.


METHODS
42 patients with FTLD (17 frontotemporal dementia, 13 semantic dementia, and 12 progressive non-fluent aphasia), 103 patients with Alzheimer's disease, and 73 controls were included. Hippocampal volumetry and the easily applicable medial temporal lobe atrophy (MTA) rating scale were applied to assess hippocampal atrophy.


RESULTS
Multivariate analysis of variance for repeated measures showed an effect of diagnostic group on hippocampal volume. There was a significant diagnosis by side (left v right) interaction. Both FTLD and Alzheimer's disease showed hippocampal atrophy compared with controls. Results of the visual MTA rating scale confirmed these findings. Within the FTLD subtypes there were marked differences in hippocampal atrophy. Frontotemporal dementia and semantic dementia showed bilateral hippocampal atrophy, and in semantic dementia the left hippocampus was smaller than in Alzheimer's disease. No significant hippocampal atrophy was detected in non-fluent progressive aphasia.


CONCLUSIONS
Hippocampal atrophy is not only a characteristic of Alzheimer's disease but also occurs in FTLD. The three clinical subtypes of FTLD show different patterns of hippocampal atrophy.
van de Pol
L A
LA
VUMC, Department of Neurology, PO Box 7057, 1007 MB Amsterdam, The Netherlands. L.vandepol@vumc.nl
Hensel
A
A
van der Flier
W M
WM
Visser
P-J
PJ
Pijnenburg
Y A L
YA
Barkhof
F
F
Gertz
H Josef
HJ
Scheltens
P
P
D000368:Aged; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis*; D001284:Atrophy / Q000150:complications / Q000473:pathology; D003704:Dementia / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male