Year: 2006
Type: article
Study design: Observational Study
Abstract: We previously reported that fMRI hippocampal activation is greater in subjects with mild cognitive impairment (MCI) who subsequently demonstrate further cognitive decline. We investigated whether fMRI hippocampal activation predicts the degree of subsequent cognitive decline in MCI, and whether or not it predicts this degree of decline even after controlling for clinical predictors. Subjects included 27 older participants (ages 65–86) in a longitudinal memory and aging study for whom an average of 4.5 years (S.D. 1.1) of follow–up clinical data were available after fMRI scanning. All subjects had MCI (defined here as CDR= 0.5) and a CDR Sum–of–Boxes (CDR–SB) between 0.5 and 3.5 at the time of scanning (baseline). During scanning, subjects performed a visual scene–encoding paradigm (Dickerson BC et al., Ann Neurol 2004). fMRI data were analyzed (SPM2) using an ROI approach in which a mask was created of hippocampal clusters showing differential activation in the Novel vs. Repeated (NvR) contrast at the group level. Clusters were included in the mask if voxels within the cluster were significant at p<.005 (uncorrected) and the cluster itself was significant at p<.05 (small–volume correction). Hippocampal activation was quantified by extracting the SPM parameter estimate of NvR from this mask from each individual's data. A linear regression model was created to predict degree of future cognitive decline (change in CDR–SB score after scanning) from baseline age, CDR–SB, and hippocampal activation. Partial correlations were run to examine the effect of each variable, controlling for the others. The decline in CDR–SB after scanning ranged from 0 to 4.5 points (mean 1.88, S.D. 1.45). The linear regression model predicted cognitive decline (p=.04), and partial correlation analyses revealed an effect of left hippocampal activation, controlling for the other predictors (r=0.53, p=.006). These results suggest that fMRI may be a useful tool for predicting subsequent cognitive decline in individuals with MCI. Within a group of individuals with MCI spanning a range of mild impairment in daily life, greater hippocampal activation at the time of scanning predicted a greater degree of future cognitive decline.
Source: Alzheimer s & Dementia
Authors: Saul L. Miller, Julie Bates, Deborah Blacker, Reisa Sperling, Bradford C. Dickerson
Institutions: Massachusetts General Hospital, Brigham and Women's Hospital
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W3022842001