Reliability of functional magnetic resonance imaging associative encoding memory paradigms in non-demented elderly adults

Deepti Putcha, Kelly O'Keefe, Pete LaViolette, Jackie O'Brien, Doug Greve, Dorene M. Rentz, Joseph Locascio, Alireza Atri, Reisa Sperling
2011 Human Brain Mapping  
Functional MRI holds significant potential to aid in the development of early interventions to improve memory function, and to assess longitudinal change in memory systems in aging and early Alzheimer's disease. However, the test-retest reliability of hippocampal activation and of "beneficial" deactivation in the precuneus has yet to be fully established during memory encoding tasks in older subjects. Using a mixed block and event-related face-name associative encoding paradigm, the reliability
more » ... of hippocampal activation and default network deactivation was assessed over a four-to-six week inter-scan interval in 27 older individuals who were cognitively normal (Clinical Dementia Rating Scale= 0; n=18) or very mildly impaired (CDR=0.5; n=9). Reliability was assessed in whole brain maps and regions-of-interest using both a full task paradigm of six functional runs as well as an abbreviated paradigm of the first two functional runs, which would be advantageous for use in clinical trials. We found reliable hippocampal signal response across both block and event-related designs in the right hippocampus. Comparable reliability in hippocampal activation was found in the full and the abbreviated paradigm. Similar reliability in hippocampal activation was observed across both CDR groups overall, but the CDR 0.5 group was more variable in left hippocampal activity. Task-related deactivation in the precuneus demonstrated much greater variability than hippocampal activation in all analyses. Overall, these results are encouraging for the utility of fMRI in "Proof of Concept" clinical trials investigating the efficacy of potentially therapeutic agents for treatment of age-related memory changes, cognitive impairment, and early Alzheimer's disease.
doi:10.1002/hbm.21166 pmid:21259385 pmcid:PMC3551453 fatcat:vpougjc5mzag7ap45mszzlofdy