A comparison of medial and lateral temporal lobe atrophy in dementia with Lewy bodies and Alzheimer's disease: magnetic resonance imaging volumetric study.
OBJECTIVE
To compare medial and lateral temporal lobe atrophy on magnetic resonance imaging (MRI) in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), and to examine the relationship between volumetric indices and cognitive and non-cognitive symptoms.


METHODS
T(1)-weighted 1.0-tesla MRI scans were acquired in elderly subjects with DLB (n = 26; mean age = 75.8 years) and AD (n = 22; 77.3 years) and normal controls (n = 26; 76.2 years). MRI-based volume measurements of the hippocampus, parahippocampus, fusiform gyrus, combined inferior and middle temporal gyri, and superior temporal gyrus were acquired.


RESULTS
Hippocampal and parahippocampal volumes were significantly larger in subjects with DLB compared to AD. Differences in hippocampal volumes between DLB and AD were observed across the entire length, and in all subjects with dementia there was a loss of hippocampal asymmetry compared to normal controls. Atrophy of temporal lobe structures correlated with memory impairment in both groups, and with age in DLB. There was no association between atrophy and psychotic symptoms in either group.


CONCLUSIONS
Subjects with DLB and AD have a different pattern of temporal lobe atrophy with the most striking differences relating to medial rather than lateral temporal lobe structures. These structural differences could explain the relative preservation of memory function in DLB compared to AD.
Barber
R
R
Institute for the Health of the Elderly, Newcastle General Hospital, Newcastle upon Tyne, UK. Robert.Barber@ncl.ac.uk
McKeith
I G
IG
Ballard
C
C
Gholkar
A
A
O'Brien
J T
JT
D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D001284:Atrophy / Q000473:pathology; D003072:Cognition Disorders / Q000175:diagnosis; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis* / Q000523:psychology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011618:Psychotic Disorders / Q000175:diagnosis / Q000209:etiology; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000473:pathology*