Anosognosia for memory deficits in mild cognitive impairment: Insight into the neural mechanism using functional and molecular imaging
Year: 2017
Type: article
Study design: Observational Study
Abstract: Anosognosia, or loss of insight of memory deficits, is a common and striking symptom in Alzheimer's disease (AD). Previous findings in AD dementia patients suggest that anosognosia is due to both functional metabolic changes within cortical midline structures involved in self-referential processes, as well as functional disconnection between these regions. The present study aims to extend these findings by investigating the neural correlates of anosognosia in the prodromal stage of AD. Here, we used regional brain metabolism (resting state 18-F fluorodeoxyglucose positron emission tomography (FDG-PET)) to unravel the metabolic correlates of anosognosia in subjects with amnestic mild cognitive impairment (aMCI) and subsequently resting state functional magnetic resonance imaging (rs-fMRI) to investigate the intrinsic connectivity disruption between brain regions. Thirty-one subjects (mean age: 74.1; Clinical Dementia Rating (CDR) global score: 0.5) with aMCI, and 251 cognitively normal (CN) older adults (mean age: 73.3; CDR: 0) were included as a reference group for behavioral and FDG data. An anosognosia index was obtained by calculating a discrepancy score between subjective and objective memory scores. All subjects underwent FDG-PET for glucose metabolism measurement, and aMCI subjects underwent additional rs-fMRI for intrinsic connectivity measurement. Voxel-wise correlations between anosognosia and neuroimaging data were conducted in the aMCI subjects. Subjects with aMCI had significantly decreased memory awareness as compared to the CN older adults. Greater anosognosia in aMCI subjects was associated with reduced glucose metabolism in the posterior cingulate (PCC) cortices and hippocampus. Intrinsic connectivity analyses revealed a significant association between anosognosia and attenuated functional connectivity between the PCC seed region and orbitofrontal cortex (OFC) as well as bilateral inferior parietal lobes (IPL). These findings provide further evidence that implicates cortical midline structures and hippocampus in the awareness of memory deficits. Investigating neuroimaging changes that co-vary with memory awareness may improve our ability to identify the cause of anosognosia and ultimately increase our chances for its treatment.
Source: NeuroImage Clinical
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,490
Funders: Alzheimer's Association, Bristol-Myers Squibb, Eli Lilly and Company, Pfizer, Massachusetts General Hospital, Biogen, Harvard University, Harvard Catalyst, Eisai, Centre d'Imagerie BioMédicale, H. Lundbeck A/S, Grifols, National Institutes of Health, Avid Radiopharmaceuticals, Pfizer Pharmaceuticals, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, National Institute on Aging, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Institute of Biomedical Imaging and Bioengineering, National Center for Research Resources, National Center for Advancing Translational Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development
Awards: G104586243, G1129981694, G1161633587, G1185609304, G1298807586, G1360098495, G1609492295, G1778344677, G1852383229, G1880935189, G1898657284, G1966481800, G2080581370, G2298519484, G2496518617, Cortical connectivity, physiology, and response to stimulation in human epilepsy, Vascular Dysfunction in Cerebral Amyloid Angiopathy, Role of functional brain connectivity on efficacy of TMS for depression, G3131374986, G3146424788, G3171611343, G3189672611, G3401643927, Harvard Clinical and Translational Science Center (UL1), G3553156159, G3652633055, G3710456697, G3740841103, The Role of Alzheimer's-associated Abeta in POD and POCD, Mentoring Imaging Research in Early AD, G43180419, G453267231, G46759241, Functional and pathological correlates of memory self-awareness in aging and AD, G4745712227, G5026486270, G5103963307, G5110839, G5207404921, G5209990037, G5234771832, G5389965057, Alzheimer's Disease Neuroimaging Initiative, Evolution of memory related fMRI activation over the course of MCI and AD, G6210868510, Optimizing measures of subjective and objective decline in preclinical AD, Cortical plasticity in type II diabetes mellitus, G635533866, G6371410416, Characterizing the Evolution of Amyloid Deposition in Normal Elderly, Transcranial Direct Current Stimulation and Robotic Training in Chronic Stroke, G6899163935, G6957926738, Cortical Plasticity in Autism Spectrum Disorders, MR-assisted PET data optimization for neuroimaging studies, G7560863178, Massachusetts Alzheimer's Disease Research Center, G7799614282, G781725486, Center for Functional Imaging Technologies, G7855923974, Alzheimer's Disease Cooperative Study, Transcranial Stimulation in Spino-Cerebellar Ataxia, Dominantly Inherited Alzheimer Network, PIB binding, hypometabolism, apathy and executive dysfunction in MCI and AD, Fetal Hormonal Programming of Sex Differences in Aging of the Memory Circuitry, G881697893, Neural Processes Underlying Cognitive Aging, G885938762, G9000039018, G9000072272, G9000098334, G9000106143, G9000121663, G9000122335, G9000208643, G9000239186, Impact of Amyloid and Tau on the Aging Brain: The Harvard Aging Brain Study, G920654007
OpenAlex ID: W2619223814