Inter-individual variability in resting-state cerebral metabolism in normal aging: Cognitive reserve as a potential mediator

Conference (2011)

Episodic autobiographical memory in amnestic mild cognitive impairment: a FDG-PET study

Conference (2011)

Recollection and familiarity processes in probable Alzheimer's disease: an fMRI study

in Proceedings of the 5th International Conference on Memory (2011)

Cerebral activity associated with recollection and familiarity in 28 patients with Alzheimer’s disease (AD) and 17 healthy controls was directly measured in an event-related fMRI experiment during ... [more ▼]

Cerebral activity associated with recollection and familiarity in 28 patients with Alzheimer’s disease (AD) and 17 healthy controls was directly measured in an event-related fMRI experiment during performance of a recognition memory task with the process dissociation procedure. Brain regions associated to recollection were evidenced by contrasting activations for inclusion and exclusion conditions whereas brain regions related to familiarity were explored with the mean effect of the two conditions (at P < .05 corrected). Twelve patients had null recollection estimates (AD-), whereas 16 patients did experience some recollection although significantly less than controls (AD+). In AD+ and controls, recollection activated the posterior cingulate cortex (PCC). In contrast, familiarity estimates were equivalent in the 3 groups and were associated with brain activations around the intraparietal sulcus (IPS). Thus, in AD, impaired recollection is related to damage of the PCC whereas preserved familiarity is supported by the IPS. [less ▲]

Controlled Memory Processes in Questionable Alzheimer's Disease: A View from Neuroimaging Research

in Journal of Alzheimer's Disease [=JAD] (2010), 20(2), 547-560

Alzheimer's disease (AD) is characterized by a progressive loss of controlled cognitive processes, and neuroimaging studies at early stages of AD provide an opportunity to tease out the neural correlates ... [more ▼]

Alzheimer's disease (AD) is characterized by a progressive loss of controlled cognitive processes, and neuroimaging studies at early stages of AD provide an opportunity to tease out the neural correlates of controlled processes. Accordingly, controlled and automatic memory performance was assessed with the Process Dissociation Procedure in 50 patients diagnosed with questionable Alzheimer's disease (QAD). The patients' brain glucose metabolism was measured using FDG-PET. After a follow-up period of 36 months, 27 patients had converted to AD, while 23 remained stable. Both groups showed a similar decrease in controlled memory processes but preserved automatic processes at entry into the study. Voxel-based cognitive and metabolic correlations showed that a decrease in controlled memory processes was preferentially correlated with lower activity in the dorsomedial prefrontal and posterior cingulate cortices in very early AD patients. In stable QAD patients, reduced controlled performance in verbal memory correlated with impaired activity in the left anterior hippocampal structure. The results demonstrated the central role of a medial frontal-posterior cingulate network for controlled processing of episodic memory in the early stages of AD. [less ▲]

Consciousness of memory functioning in Alzheimer’s disease

Poster (2010, May 28)

Metamemory is a multi-faceted concept which deals with the individual’s knowledge and control of memory functioning. Previous studies that have examined the ability of Alzheimer’s disease (AD) patients to ... [more ▼]

Metamemory is a multi-faceted concept which deals with the individual’s knowledge and control of memory functioning. Previous studies that have examined the ability of Alzheimer’s disease (AD) patients to monitor efficiently their memory processes provided contradictory results. These discrepancies between studies could be the result of two factors: the kind of memory task used (episodic, semantic) and the kind of memory process on which memory monitoring is assessed (encoding, maintenance, retrieval). In the present study, different aspects of memory monitoring in 21 AD patients and 21 healthy elderly participants were explored with two tasks : a semantic memory task assessing the feeling-of-knowing (FOK) accuracy for general knowledge and an episodic memory task assessing judgment-of-learning (JOL) and FOK accuracy for information associated to a specific spatiotemporal encoding context By comparison to healthy participants, AD patients exhibit impaired performance on episodic FOK accuracy but not on semantic FOK accuracy. Moreover, no difference was observed between the two groups on the JOL post-encoding accuracy. These results confirm that not all aspects of memory monitoring are impaired in AD. Indeed, although there exists an impairment of episodic FOK performance, semantic FOK and JOL post-encoding appear preserved. The dissociation between the two FOK performance could be due to recruitment of more automatic processes for metacognitive judgment on general knowledge (semantic FOK) than for metacognitive judgment based on specific recent experience (episodic FOK). Similarly, a global prediction during maintenance (JOL) could be based on more automatic processes than an item-by-item judgment during retrieval. [less ▲]

Les corrélats cérébraux de la recollection et de la familiarité dans la maladie d'Alzheimer

Conference (2010)

Controlled and automatic prospective memory processes in Alzheimer's disease: Behavioral data

Conference (2010)

Neural substrates of recollection and familiarity in Alzheimer’s disease

in Proceedings of the 16th annual meeting of the Organization for Human Brain Mapping (2010)

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

in Proceedings of the Annual Meeting of the Belgian Association for Psychological Sciences (2010)

The aim of this study was to examine correlations between impaired memory acquisition/consolidation and brain metabolism at rest in Alzheimer’s disease. 44 confirmed Alzheimer patients (AD), 16 patients ... [more ▼]

The aim of this study was to examine correlations between impaired memory acquisition/consolidation and brain metabolism at rest in Alzheimer’s disease. 44 confirmed Alzheimer patients (AD), 16 patients with mild cognitive impairment (MCI) who converted to AD (MCI-C) (4-8 years of follow-up), 15 MCI patients who remained stable and 12 healthy elderly controls were administered the California Verbal Learning Task (CVLT) at entry. Acquisition and consolidation memory scores were calculated respectively as mean gained and total lost access across the 5 study-test trials (p = 0.05). Brain metabolism was measured by 18FDG-PET. Cognitive-metabolic correlations were performed with SPM8 (p<0.05 uncorrected). Mean gained access was significantly lower in the AD group than in the control and MCI-S group and was significantly lower in the MCI-C group than in the control group. Mean gained access was significantly correlated to metabolism in the left precentral gyrus and IPS fondus in the control group, in the left and right inferior parietal lobules in the MCI-S group and in the left hippocampus in the AD group. Total lost access was greater in AD patients compared to control participants. No significant correlation between total lost access and brain metabolism was found. The acquisition process is impaired in AD patients at a very early stage of the disease (MCI-C). This deficit is linked to metabolic changes in a frontoparieto-hippocampal learning network. In addition, consolidation process is specifically impaired in confirmed AD patients, while this deficit was not significantly correlated to brain metabolism in our participant groups. [less ▲]

L’anosognosie dans la maladie d’Alzheimer est-elle observée pour les modifications de comportement et de personnalité?

in Proceedings du XIème Colloque International sur le Vieillissement Cognitif (2010)