Verbal Learning in Alzheimer’s disease and Mild Cognitive Impairment: neuroanatomic correlates of acquisition and consolidation performances

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.

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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

.

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Leeds Memory Group, University of Leeds, UK.

*Centre de la Mémoire, CHU de Liège. §Centre de

Recherches du Cyclotron, Université de Liège, Belgique.

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.

Objective: The aim of this study was to examine correlations

between impaired memory acquisition/consolidation and brain metabolism at rest in Alzheimer’s disease.

CYCLOTRON RESEARCH CENTRE

INTRODUCTION

METHODS

RESULTS

44 AD

31 MCI

T1

4-8 years follow-up

15 stables

(MCI_S)

16 AD

(MCI_AD)

12 CTRL

T2

DISCUSSION

Measures:

acquisition = mean proportion of gained access across the 5 study-test trials of the California Verbal Learning Test.

consolidation = total proportion of lost access across the 5 study-test trials of the California Verbal Learning Test.

18FDG-PET

Analyses:

Cognitive-metabolic correlations (SPM8): gained/lost access performances - metabolic TEP T1; covariates: age, MMSE;

statistic threshold: p uncorrected with a priori hypotheses <.001.

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

Cognitive-metabolic correlations

Consolidation (lost access performances) :

Behavioral results

p = .052

18FDG-TEP

CVLT:

GAINED ACCESS (acquisition)

LOST ACCESS (consolidation)

Cognitive-metabolic correlations: no significant correlation

44 AD

12 CTRL

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).