Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study
Hyperactivation, which is defined as a higher level of activation in patients compared to cognitively unimpaired older adults (controls; CTL), might represent an early signature of Alzheimer's Disease (AD). The goal of this study was to assess the presence and location of hyperactivation in ind...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2019-01-01
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| Series: | NeuroImage: Clinical |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213158219303080 |
| _version_ | 1818150688268484608 |
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| author | Nick Corriveau-Lecavalier Samira Mellah Francis Clément Sylvie Belleville |
| author_facet | Nick Corriveau-Lecavalier Samira Mellah Francis Clément Sylvie Belleville |
| author_sort | Nick Corriveau-Lecavalier |
| collection | DOAJ |
| description | Hyperactivation, which is defined as a higher level of activation in patients compared to cognitively unimpaired older adults (controls; CTL), might represent an early signature of Alzheimer's Disease (AD). The goal of this study was to assess the presence and location of hyperactivation in individuals with mild cognitive impairment (MCI) who were later diagnosed with dementia, examine how hyperactivation changes longitudinally, and whether it is related to time before dementia. Forty participants, 26 with MCI and 14 CTL were enrolled in the study. Magnetic resonance imaging was used to measure functional activation while participants encoded word-pairs as well as cortical thickness and regional brain volume at study entry (Y0) and two years later (Y2). Clinical follow-up was completed every two years following study entry to identify progressors (pMCI), that is, individuals who later received a diagnosis of dementia. Task-related activation was assessed in pMCI in both hippocampi and in regions showing greater cortical thinning from Y0 to Y2 compared to CTLs. Hyperactivation was found in pMCI individuals in the right supramarginal gyrus. Persons with pMCI also showed hypoactivation in the left hippocampus and left pars opercularis. Both hyper- and hypoactivation were present at Y0 and Y2 and did not change longitudinally. Activation was not associated with time before dementia diagnosis. Smaller volume and thinner cortical thickness were associated with shorter time to diagnosis in the left hippocampus and left pars opercularis. In conclusion, hyperactivation was found in individuals who later progressed to dementia, confirming that it might represent an early biomarker to identify individuals in the prodromal phase of AD and that its understanding could contribute to elucidate the key brain mechanisms that precede dementia. Keywords: Mild cognitive impairment, Alzheimer's disease, Task-related hyperactivation, Longitudinal fMRI, Episodic memory |
| first_indexed | 2024-12-11T13:26:54Z |
| format | Article |
| id | doaj.art-a4b6669b96e3441da47f785413bcc03f |
| institution | Directory Open Access Journal |
| issn | 2213-1582 |
| language | English |
| last_indexed | 2024-12-11T13:26:54Z |
| publishDate | 2019-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | NeuroImage: Clinical |
| spelling | doaj.art-a4b6669b96e3441da47f785413bcc03f2022-12-22T01:05:30ZengElsevierNeuroImage: Clinical2213-15822019-01-0124Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI studyNick Corriveau-Lecavalier0Samira Mellah1Francis Clément2Sylvie Belleville3Research Centre, Institut universitaire de gériatrie de Montréal, Canada; Department of Psychology, University of Montreal, Montreal, CanadaResearch Centre, Institut universitaire de gériatrie de Montréal, CanadaResearch Centre, Institut universitaire de gériatrie de Montréal, Canada; Department of Psychology, University of Montreal, Montreal, CanadaResearch Centre, Institut universitaire de gériatrie de Montréal, Canada; Department of Psychology, University of Montreal, Montreal, Canada; Corresponding author at: Research Centre, Institut universitaire de gériatrie de Montréal, 4565, Queen-Mary, Montreal, Québec H3W 1W5, Canada.Hyperactivation, which is defined as a higher level of activation in patients compared to cognitively unimpaired older adults (controls; CTL), might represent an early signature of Alzheimer's Disease (AD). The goal of this study was to assess the presence and location of hyperactivation in individuals with mild cognitive impairment (MCI) who were later diagnosed with dementia, examine how hyperactivation changes longitudinally, and whether it is related to time before dementia. Forty participants, 26 with MCI and 14 CTL were enrolled in the study. Magnetic resonance imaging was used to measure functional activation while participants encoded word-pairs as well as cortical thickness and regional brain volume at study entry (Y0) and two years later (Y2). Clinical follow-up was completed every two years following study entry to identify progressors (pMCI), that is, individuals who later received a diagnosis of dementia. Task-related activation was assessed in pMCI in both hippocampi and in regions showing greater cortical thinning from Y0 to Y2 compared to CTLs. Hyperactivation was found in pMCI individuals in the right supramarginal gyrus. Persons with pMCI also showed hypoactivation in the left hippocampus and left pars opercularis. Both hyper- and hypoactivation were present at Y0 and Y2 and did not change longitudinally. Activation was not associated with time before dementia diagnosis. Smaller volume and thinner cortical thickness were associated with shorter time to diagnosis in the left hippocampus and left pars opercularis. In conclusion, hyperactivation was found in individuals who later progressed to dementia, confirming that it might represent an early biomarker to identify individuals in the prodromal phase of AD and that its understanding could contribute to elucidate the key brain mechanisms that precede dementia. Keywords: Mild cognitive impairment, Alzheimer's disease, Task-related hyperactivation, Longitudinal fMRI, Episodic memoryhttp://www.sciencedirect.com/science/article/pii/S2213158219303080 |
| spellingShingle | Nick Corriveau-Lecavalier Samira Mellah Francis Clément Sylvie Belleville Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study NeuroImage: Clinical |
| title | Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study |
| title_full | Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study |
| title_fullStr | Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study |
| title_full_unstemmed | Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study |
| title_short | Evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia: A longitudinal fMRI study |
| title_sort | evidence of parietal hyperactivation in individuals with mild cognitive impairment who progressed to dementia a longitudinal fmri study |
| url | http://www.sciencedirect.com/science/article/pii/S2213158219303080 |
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