the brain shrinkage associated with normal chronological aging. More recently, Pfefferbaum and colleagues (1992) used magnetic resonance imaging (MRI) techniques and found evidence of increased brain tissue loss in alcoholics, compared with nonalcoholics, even after their ages had been taken into account. Considered together, these findings provide evidence that alcoholics and aging nonalcoholics show atrophy of the cerebral cortex. As discussed below, however, studies revealing different patterns of cognitive impairment as a result of this brain atrophy have not always supported the premature aging hypothesis.
