Alteration of glucose neurometabolism and brain morphology in mild behavioral impairment: a neuroimaging study on cognitively healthy individuals.

INTRODUCTION

Regional brain enlargement and increased glucose neurometabolism do not normally indicate neurodegeneration. Mild behavioral impairment (MBI) occurring in cognitively healthy individuals, however, might be significantly affected by these processes.

METHODS

Three hundred forty-one cognitively normal individuals were analyzed using partial least squares (PLS) regression to determine neurometabolic and brain volumetric determinants of MBI scores. Radiolabeled glucose non-displaceable binding potential and volumes of Schaefer homooxygenation parcels were screened as regressors. PLS models were evaluated with cross-validation, scrambling, and bootstrapping.

RESULTS

Hypermetabolism in the left entorhinal cortex and hypertrophy in the left dorsal attention network B contribute substantially to the MBI total score. Significant morpho-functional interactions were observed between the right middle temporal cortex and the right salience-ventral attention B network.

DISCUSSION: MBI might depend on cerebral bioenergetic processes and morpho-functional interactions. Relative hypermetabolism and hypertrophy could be considered specific biomarkers of MBI indicating a prodromal maladaptive neural response.