Perceptual Learning in Detoxified Alcoholic Men: Contributions From Explicit Memory, Executive Function, and Age

Authors

  • Rosemary Fama,

    1. Neuroscience Program, SRI International, Menlo Park, California
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  • Adolf Pfefferbaum,

    1. Neuroscience Program, SRI International, Menlo Park, California
    2. Department of Psychiatry and Behavioral Sciences and Neuroscience Program, Stanford University School of Medicine, Stanford, California.
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  • Edith V. Sullivan

    Corresponding author
    1. Department of Psychiatry and Behavioral Sciences and Neuroscience Program, Stanford University School of Medicine, Stanford, California.
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  • Supported by Grants AA10723, AA05965, and AG17919.

  • Presented in part at the International Neuropsychological Society conference, February 2004, Baltimore, Maryland.

Reprint requests: Edith V. Sullivan, PhD, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine (MC5723), 401 Quarry Rd., Stanford, CA 94305-5723; Fax: 650-859-2743; E-mail: edie@stanford.edu.

Abstract

Background: Visuospatial and visuoperceptual deficits have consistently been observed in detoxified alcoholics; however, the severity of impairment varies with test and task type. Identifying the component processes and factors that underlie a particular deficit may reveal why some visuospatial and visuoperceptual tasks are more compromised than others and may lead to the specification of neural systems that are particularly vulnerable in alcoholism.

Methods: We examined visuoperception and perceptual learning with a picture fragment identification task in 51 recently detoxified nonamnesic alcoholic men (aged 29–66 years) compared with 63 normal control men (aged 21–70 years). Executive function and explicit declarative memory were also assessed.

Results: Despite deficits in the primary components of visuoperception and explicit memory for visuospatial stimuli, the alcoholics showed normal perceptual learning. Although the alcoholics and controls performed at comparable levels on the perceptual learning task, multiple regression analyses indicated that the factors accounting for perceptual learning variance differed between and within groups. Visuoperceptual abilities consistently predicted perceptual learning in the control subjects but not the alcoholic subjects. Explicit memory contributed to perceptual learning performance in both the alcoholic and control groups. Frontal executive ability consistently predicted perceptual learning in the alcoholic subjects, but it had predictive ability only in the control subjects as time elapsed. Age was significantly correlated with perceptual learning performance in both groups. Lifetime alcohol consumption, but not alcoholism duration, was an independent predictor of 1-hr perceptual learning.

Conclusions: These correlational analyses suggest that controls invoke basic visuospatial processes to perform a perceptual learning task, whereas alcoholics invoke higher-order cognitive processes (i.e., frontal executive systems) to perform the same task at normal levels. Use of more demanding cognitive systems by the alcoholics may be less efficient and more costly to processing capacity than those invoked by controls.

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