Widespread Effects of Alcohol on White Matter Microstructure

Abstract

Background Evidence suggests that chronic misuse of alcohol may preferentially affect the integrity of frontal white matter tracts, which can impact executive functions important to achieve and maintain abstinence. Methods Global and regional white matter (WM) microstructure was assessed using diffusion magnetic resonance (MR) measures of fractional anisotropy (FA) for 31 abstinent alcoholics with an average of 25 years of abuse and approximately 5 years of sobriety and 20 nonalcoholic control participants. Data processing was conducted with FreeSurfer and FSL processing streams. Voxelwise processing of the FA data was carried out using TBSS (Tract-Based Spatial Statistics). Clusters of significance were created to provide a quantitative summary of highly significant regions within the voxel wise analysis. Results Widespread, bilateral reductions in FA were observed in abstinent alcoholics as compared to nonalcoholic control participants in multiple frontal, temporal, parietal, and cerebellar WM tracts. FA in the left inferior frontal gyrus was associated with drinking severity. Conclusions The present study found widespread reductions in WM integrity in a group of abstinent alcoholics compared to nonalcoholic control participants, with most pronounced effects in frontal and superior tracts. Decreased FA throughout the frontostriatal circuits that mediate inhibitory control may result in impulsive behavior and inability to maintain sobriety.