Regional cerebral glucose metabolism and gait speed in healthy community-dwelling older women

Abstract

Background: The objective of this study was to investigate the relationship between normalized regional cerebral metabolic rates of glucose (normalized-rCMRglc) and gait function in physically and mentally high-functioning older women.

Methods: One hundred eighty-two community-dwelling older women (mean age [SD], 69.4 [6.6] years) without disability in instrumental activities of daily living and without mobility limitations underwent positron emission tomography with 18F-fluorodeoxyglucose at rest to assess brain activity associated with gait function. We measured normalized-rCMRglc in 16 regions of interest. Within 6 months of the positron emission tomography with 18F-fluorodeoxyglucose scan, gait speed, step length, and step frequency both at comfortable and maximum paces were measured as indices of gait function. Associations between normalized-rCMRglc and gait indices were examined with multiple linear regression analyses adjusted for demographic characteristics, including age, height, body weight, blood pressure, past illness, and education.

Results: Slower maximum gait speed even in the range of individual difference was associated with lower normalized-rCMRglc in the prefrontal, posterior cingulate, and parietal cortices. Lower step frequency at the maximum pace was also associated with lower normalized-rCMRglc in these regions. However, there was no significant association between step length at the maximum pace and normalized-rCMRglc or between all gait variables at a comfortable pace and normalized-rCMRglc.

Conclusions: The normalized-rCMRglc values in specific regions were associated with individual differences in gait function, even in healthy older women. These regions of the cerebrum could play an important role in gait control. Understanding the cerebral glucose metabolism in these brain regions may enable early detection of mobility limitation.

Keywords: Brain aging; Cerebral metabolic activity; FDG-PET; Gait speed; Older adults..