Deformation-based morphometry of brain changes in alcohol dependence and abstinence

Abstract

Brain atrophy associated with chronic alcohol consumption is partially reversible after cessation of drinking. Recovering alcoholics (RA, 45+/-8 years) were studied with MRI within 1 week of entering treatment, with follow-up at 8 months. Light drinkers (LD) were studied with MRI twice 1 year apart. For each participant, deformation maps of baseline structure and longitudinal size changes between baseline and follow-up scans were created using nonlinear registration techniques. ANCOVA assessed group differences and regression methods examined relationships between deformation maps and measures of drinking severity or baseline atrophy. At baseline, RA showed significant atrophy in the frontal and temporal lobes. Longitudinally, abstainers recovered tissue volumes significantly faster than LD in parietal and frontal lobes. When comparing abstainers to relapsers, additional regions with significantly greater recovery in abstainers were temporal lobes, thalamus, brainstem, cerebellum, corpus callosum, anterior cingulate, insula, and subcortical white matter. Gray matter volume at baseline predicted volume recovery during abstinence better than white matter. Drinking severity was not significantly related to brain structural changes assessed with this method. Longitudinally, deformation-based morphometry confirmed tissue recovery in RAs who maintain long-term sobriety. Abstinence-associated tissue volume gains are significant in focal parts of the fronto-ponto-cerebellar circuit that is adversely affected by heavy drinking.

Figure 1

Maps of longitudinal tissue recovery in which 17 abstaining alcoholics are compared to 8 relapsing alcoholics; the T-statistic maps from this comparison are shown here overlaid on the spatially normalized average anatomy (N=33). Red/yellow indicates voxels where abstainers recovered tissue faster than relapsers. The contours encompass clusters of voxels that significantly differentiate abstainers from relapsers after correction for multiple comparisons; see Table III for the cluster numbers corresponding to the contour color key. The contour for cluster 6 is black.

Figure 2

Scatterplot of the average change in % tissue volume between scans, computed using all voxels within the ten significant clusters listed in Table 3.

Figure 3

The T-statistic map, showing the relationship between longitudinal tissue change in 25 recovering alcoholics and gray matter volume at 1 week of abstinence, is shown overlaid on the spatially normalized average anatomy. Red/yellow indicates voxels where smaller GM volumes at 1 week of abstinence were associated with faster tissue recovery. The contours encompass clusters of voxels with this negative association that are significant after correction for multiple comparisons; see Table IV for the cluster numbers corresponding to the contour color key.