Longitudinal changes in cerebral metabolic rate of oxygen (CMRO2) in older adults without and with cognitive impairment

Motivation: Cerebral metabolic rate of oxygen (CMRO2) reflects the brain’s energy consumption and neural function. Longitudinal CMRO2 changes in the aging brain have not been fully characterized. Goal(s): Our goal was to study longitudinal CMRO2 changes in cognitively normal older adults and examine differences in CMRO2 between participants without and with cognitive impairment. Approach: CMRO2 was estimated from MRI measurements. Linear mixed effect (LME) models were employed to evaluate the relationship between CMRO2 and the related independent variables. Results: CMRO2 decreased with age cross-sectionally and increased with follow-up time longitudinally. CMRO2 was lower in cognitively impaired participants compared to cognitively normal participants. Impact: The present work revealed a bell-shaped trajectory of CMRO2 in aging. CMRO2 may also be a promising biomarker of neurogenerative diseases.