Lower myelin content is associated with more rapid cognitive decline among cognitively unimpaired individuals
Zhaoyuan Gong, Murat Bilgel, Matthew Kiely, Curtis Triebswetter, Luigi Ferrucci, Susan M. Resnick, Richard G. Spencer, Mustapha Bouhrara
Abstract
Abstract Introduction The influence of myelination on longitudinal changes in cognitive performance remains unclear. Methods For each participant ( N = 123), longitudinal cognitive scores were calculated. Myelin content was probed using myelin water fraction (MWF) or longitudinal relaxation rate ( R 1 ); both are MRI measures sensitive to myelin, with MWF being specific. Results Lower MWF was associated with steeper declines in executive function ( p < .02 in all regions) and lower R 1 was associated with steeper declines in verbal fluency ( p < .03 in all regions). Additionally, lower R 1 was associated with steeper declines in executive function ( p < .02 in all regions) and memory ( p < .04 in occipital and cerebral white matter) but did not survive Bonferroni correction. Discussion We demonstrate significant relationships between myelin content and the rates of change in cognitive performance among cognitively normal individuals. These findings highlight the importance of myelin in cognitive functioning and suggest MWF and R 1 as imaging biomarkers to predict cognitive changes.