MRI-Based Volumetry Correlates of Autobiographical Memory in Alzheimer's Disease

Abstract

The aim of the present volumetric study was to explore the neuro-anatomical correlates of autobiographical memory loss in Alzheimer's patients and healthy elderly, in terms of the delay of retention, with a particular interest in the medial temporal lobe structures. Fifteen patients in early stages of the disease and 11 matched control subjects were included in the study. To assess autobiographical memory and the effect of the retention delay, a modified version of the Crovitz test was used according to five periods of life. Autobiographical memory deficits were correlated to local atrophy via structural MRI using Voxel Based Morphometry. We used a ‘lateralized index’ to compare the relative contribution of hippocampal sub-regions (anterior vs posterior, left vs right) according to the different periods of life. Our results confirm the involvement of the hippocampus proper in autobiographical memory retrieval for both recent and very remote encoding periods, with larger aspect for the very remote period on the left side. Contrary to the prominent left-sided involvement for the young adulthood period, the implication of the right hippocampus prevails for the more recent periods and decreases with the remotness of the memories, which might be associated with the visuo-spatial processing of the memories. Finally, we suggest the existence of a rostrocaudal gradient depending on the retention duration, with left anterior aspects specifically related to retrieval deficits of remote memories from the young adulthood period, whereas posterior aspects would result of simultaneous encoding and/or consolidation and retrieval deficit of more recent memories.

Autobiographical memory decline in Alzheimer’s disease, a theoretical and clinical overview

“…Interestingly, a study has found associations between hippocampal volume and episodic autobiographical memory in AD for both recent and remote memories (Philippi et al, 2012). In contrast, a functional MRI study has demonstrated that retrieval of recent memories in AD participants was more associated with right prefrontal activation whereas retrieval of remote memories was more associated with left prefrontal activation, regardless of hippocampal activation (Eustache et al, 2004).…”

A quasi-experimental study of a reminiscence program focused on autobiographical memory in institutionalized older adults with cognitive impairment

“…Studies about autobiographical memory in cognitive impairment are consensual on the fact that the progression of dementia involves decline in autobiographical memory (Addis & Tippett, 2004;El Haj, Postal, Le Gall, & Allain, 2011;Irish et al, 2011;Martinelli, Anssens, Sperduti, & Piolino, 2013;Muller et al, 2012;Philippi et al, 2012) and that these changes can be observed from early stages (Lalanne, Gallarda, & Piolino, 2014;Lemos, Hazin, & Falcão, 2012), resulting in a loss of personal identity (Lalanne et al, 2014). Some particularities are nevertheless to be highlighted in this process.…”

“…Some particularities are nevertheless to be highlighted in this process. Firstly, studies observed a phenomenon entitled "positive temporal gradient" (a decrease in autobiographical memories for the recent past events), associated to a characteristic of Alzheimer's disease: the presence of retrograde amnesia (Muller et al, 2012;Philippi et al, 2012;Seidl, Lueken, Thomann, Geider, & Schröder, 2011). Secondly, research has pointed to the presence of overgeneralization of the autobiographical memory (Fromholt et al, 2003;Irish et al, 2011;Lemos et al, 2012;Martinelli et al, 2013), a phenomenon also observed in other psychopathological conditions as depression and suicidal attempts (e.g.…”

Retrieval of Recent Autobiographical Memories is Associated with Slow-Wave Sleep in Early AD

“…In contrast, deficits of personal semantics were related to the atrophy of anterior and posterior lateral temporal areas bilaterally, more pronounced on the left, as well as right frontal degeneration. More recently, Philippi et al (2012) reported positive correlations between hippocampal volume and episodic autobiographical memory for both recent and remote periods of life. Using the TEMPau task exploring autobiographical memory from three time periods (the last 5 years, middle age, teenage/childhood) and resting-state FDG-PET imaging, Eustache et al (2004) reported a temporal gradient of recalls in favor of remote past and that right hippocampal metabolism correlated uniquely with recent memories.…”