Hippocampal volumes predict risk of dementia with Lewy bodies in mild cognitive impairment.
OBJECTIVE
To predict the risk of probable dementia with Lewy bodies (DLB) competing with Alzheimer disease (AD) dementia by hippocampal volume (HV) in patients with mild cognitive impairment (MCI) with impairments in amnestic or nonamnestic cognitive domains.


METHODS
Patients with MCI (n = 160) from the Mayo Clinic Alzheimer's Disease Research Center, who participated in an MRI study at baseline from 2005 to 2014, were followed with approximately annual clinical evaluations. HVs were analyzed from 3T MRIs using FreeSurfer (5.3). Hippocampal atrophy was determined from the most normal 10th percentile of the measurement distributions in a separate cohort of clinically diagnosed patients with AD dementia. The subdistribution hazard ratios for progression to probable DLB and AD dementia were estimated by taking into account the competing risks.


RESULTS
During a median (range) follow-up of 2.0 (0.7-8.1) years, 20 (13%) patients with MCI progressed to probable DLB, and 61 (38%) progressed to AD dementia. The estimated subdistribution hazard ratio (95% confidence interval) for normal HV relative to hippocampal atrophy for progression to AD dementia was 0.56 (0.34-0.91; p = 0.02) after taking into account the competing risks. The estimated hazard ratio for normal HV relative to hippocampal atrophy for progression to probable DLB was 4.22 (1.42-12.6; p = 0.01) after adjusting for age and after including the MCI subtype in the model.


CONCLUSIONS
Preserved hippocampal volumes are associated with increased risk of probable DLB competing with AD dementia in patients with MCI. Preservation of HV may support prodromal DLB over AD, particularly in patients with MCI with nonamnestic features.
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville. kantarci.kejal@mayo.edu.
Kejal
K
Kantarci
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Timothy
T
Lesnick
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Tanis J
TJ
Ferman
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Scott A
SA
Przybelski
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Bradley F
BF
Boeve
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Glenn E
GE
Smith
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Walter K
WK
Kremers
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
David S
DS
Knopman
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Clifford R
CR
Jack
From the Departments of Radiology (K.K., C.R.J.), Health Sciences Research (T.L., S.A.P., W.K.K.), and Neurology (B.F.B., D.S.K., R.C.P.), Mayo Clinic, Rochester, MN; Department of Psychology and Psychiatry (T.J.F.), Mayo Clinic Jacksonville; and Department of Psychology (G.E.S.), University of Florida, Gainesville.
Ronald C
RC
Petersen
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging; D001284:Atrophy; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D015994:Incidence; D020961:Lewy Body Disease / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009929:Organ Size; D011379:Prognosis; D016016:Proportional Hazards Models; D012306:Risk