title: Dysmorphology and microstructural degradation of the corpus callosum: Interaction of age and alcoholism.
abstract: Chronic alcohol abuse is a ubiquitous health and societal problem, with a growing prevalence in the older population. Alcoholism is a source of substantial deterioration in brain tissue and has been consistently observed in vivo and postmortem in white matter. To quantify the potential compounded effect of age and alcoholism, we used conventional structural MRI and diffusion tensor imaging (DTI) to examine the macrostructural and microstructural integrity of the corpus callosum, one of the most prominent white matter structures of the brain, in 131 adults, age 27-75 years. Compared with the 74 controls, the 40 alcoholic men and 17 alcoholic women, who were abstinent from alcohol for an average of 3 months, showed similar patterns and extents of callosal shrinkage, which was greatest in the genu and body and less prominent in the splenium. Microstructural integrity was measured with DTI as fractional anisotropy, an index of intravoxel orientational coherence of white matter fibers, and bulk mean diffusivity, an index of the amount of intravoxel water motility. The macrostructural shrinkage was accompanied by abnormalities in anisotropy and diffusivity of the microstructural environment of these callosal regions, indicative of disruption of structural constituents of local brain white matter. Correlational analyses revealed an age-alcohol interaction, where older alcoholics had smaller genu and splenium and higher diffusivity in these regions than younger alcoholics. Significant correlations between regional MRI and DTI measures and performance on working memory, visuospatial ability, and gait and balance provided evidence for the functional ramifications of the callosal abnormalities in the alcoholics. Thus, despite abstinence from alcohol, the interaction of age and recent alcoholism history exerted a compounded untoward effect on callosal macrostructure and microstructure.
authors.affiliation: Neuroscience Program, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA. dolf@synapse.sri.com
authors.forename: Adolf
authors.initials: A
authors.lastname: Pfefferbaum
authors.forename: Elfar
authors.initials: E
authors.lastname: Adalsteinsson
authors.forename: Edith V
authors.initials: EV
authors.lastname: Sullivan
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000473:pathology*; D020268:Alcohol-Induced Disorders, Nervous System / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D000437:Alcoholism / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D016880:Anisotropy; D001834:Body Water / Q000187:drug effects / Q000502:physiology; D001931:Brain Mapping; D003337:Corpus Callosum / Q000187:drug effects* / Q000473:pathology* / Q000503:physiopathology; D004058:Diffusion / Q000187:drug effects; D038524:Diffusion Magnetic Resonance Imaging; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D009186:Myelin Sheath / Q000187:drug effects / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000473:pathology; D011237:Predictive Value of Tests; D014855:Wallerian Degeneration / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology
chemical_list: D000431:Ethanol