Verbal Learning in Alzheimer’s disease and Mild
Cognitive Impairment: neuroanatomic correlates of
acquisition and consolidation performances.
S.
§
Genon ,
F.
§
Collette ,
C.
#
Moulin ,
F.
*
Lekeu ,
E.
*§
Salmon ,
C.
§
Bastin .
# Leeds Memory Group, University of Leeds, UK. *Centre de la Mémoire, CHU de Liège. §Centre de
Recherches du Cyclotron, Université de Liège, Belgique.
INTRODUCTION
RESULTS
Objective: The aim of this study was to examine correlations
between impaired memory acquisition/consolidation and brain
metabolism at rest in Alzheimer’s disease.
METHODS
Acquisition (gained access performances) :
Behavioral results
ANCOVA : F(3,80) = 9.08 ; P < .00005
POST-HOC (HSD different N):
*P < 0.005, **P < 0.001, P*** <. 0.0005
70
Mean gained access (%)
Episodic memory impairment is a key feature of cognitive
decline in Alzheimer’s disease (AD). Indeed, episodic memory
is generally the first cognitive function to be altered even at
Mild Cognitive Impairment (MCI) stage.
Moulin et al. (2004) have shown that acquisition and
consolidation deficits can account for episodic impairment in
AD patients and in patients with MCI. However, little is known
about cerebral alterations associated with these particular
deficits.
***
**
60
*
50
40
30
20
10
0
AD
T1
T2
Brain examination +
cognitive assessment
CYCLOTRON
RESEARCH
CENTRE
MCI-AD
Groups
MCI-S
Control
Cognitive-metabolic correlations
Analysis of cognitivemetabolic correlations
44 AD
44 AD
16 AD
(MCI_AD)
31 MCI
4-8 years follow-up
15 stables
(MCI_S)
12 CTRL
12 CTRL
18FDG-TEP
CVLT:
GAINED ACCESS (acquisition)
LOST ACCESS (consolidation)
Consolidation (lost access performances) :
Behavioral results
ANCOVA : F(3,80) = 4.04 ; P < .01
POST-HOC (HSD different N):
1,4
acquisition = mean proportion of gained access across the 5
study-test trials of the California Verbal Learning Test.
1,2
consolidation = total proportion of lost access across the 5
study-test trials of the California Verbal Learning Test.
18FDG-PET
Analyses:
Total lost access (%)
Measures:
p = .052
1
0,8
0,6
0,4
0,2
0
Cognitive-metabolic correlations (SPM8): gained/lost access
performances - metabolic TEP T1; covariates: age, MMSE;
statistic threshold: p uncorrected with a priori hypotheses <.001.
AD
MCI-AD
Groups
MCI-S
Control
Cognitive-metabolic correlations: no significant correlation
DISCUSSION
The acquisition process is impaired in AD patients even at a very early stage of the disease (MCI_AD). This deficit is linked to metabolic changes in the
hippocampal formation. In contrast, variations of relatively intact performances of controls and participants with stable MCI are related to metabolic
variations in a fronto-parietal attentional network. The consolidation process is specifically impaired in AD patients at the dementia stage of the disease.
However, this deficit was not significantly correlated to brain metabolism in our participant groups at the selected statistical threshold.
This work was supported by grants from the Foundation for Research on Alzheimer’s disease (SAO-FRMA); from the Inter-University Attraction
Pole (PAI) and from the Belgian National Funds for Scientific Research (FNRS).