Cognitive Deficits in Alcoholism: Approaches to Theoretical Modeling.

Over the past 20 years, the field of cognitive neuroscience has progressed toward reaching its primary goal of defining what mechanisms in the brain underlie distinct domains of human cognitive functioning, such as components of memory and attention. Cognitive neuroscientific research has advanced understanding not only of how each domain operates uniquely from the others but also of how separate domains work together. Evidence from cognitive research shows that each of the complex cognitive functions is the product of several separate brain operations. Many studies focus on these operations, examining, for instance, the separate processes the brain may use to store different types of information in memory as opposed to the processes used to retrieve the memory later. Neurocognitive methods also are being used to search for the particular brain functions that are impaired and spared in alcoholism.(1) Studies are attempting to answer questions such as the following: What cognitive characteristics may place a person at risk for developing alcoholism? What are the cognitive aspects of addiction? What effects does alcohol have on the brain's neurophysiology? Cognitive neuroscience's research tools, measures, and approaches to the study of normal brain function also have much potential for helping to answer questions about alcohol-related impairments. In a reciprocal manner, and following a research tradition that hails from the mid-19th century, studies of impaired brain function undoubtedly will shed light on the workings of normal human cognition. Clinical studies of people with particular cognitive deficits--including those resulting from alcoholism--in whom other brain functions are spared have been used for over 100 years to help determine how brain functions may be differentiated. This article reviews the use of some of cognitive neuroscience's tools in studies of alcoholics, such as brain imaging, laboratory procedures for studying cognition (which allows functional analyses of cognitive operations), and drug challenge methods. It also examines the automatic-reflective operations model of cognitive organization that appears useful for defining alcoholics' impairments. (For further readings on the cognitive neuroscience perspective in research, see Gazzaniga 1988; Jacoby et al. 1992; Lister and Weingartner 1991; Posner 1989; and Schacter 1992.) A FOUNDATION: EXPERIMENTAL PSYCHOLOGY The field of experimental psychology has contributed to cognitive research on alcoholics and other impaired populations by focusing on functional analyses of patients' behavior without tying in aspects of biological science, such as neurochemistry. Experimental psychologists have systematically compared patterns of impaired functioning, such as those seen in alcoholism, with the cognitive profiles expressed by populations of neuropsychiatric disorder patients. These studies have advanced knowledge of cognitive functioning in alcoholics by examining questions such as the following: * To what extent do cognitive deficits apparent in the recently detoxified alcoholic disappear with continued abstinence? * Are the deficits apparent in alcoholics attributable to the same underlying causes as the profound amnesias associated with alcoholic Korsakoff's syndrome (for a definition of this and other terms in this article, see glossary, pp. 136-137). * Are the cognitive changes associated with alcoholism similar to or different from the cognitive changes associated with normal aging?(2) * Are alcoholics' cognitive impairments associated with changes seen in other neuropsychiatric syndromes, such as depression or anxiety? Experimental psychology research has formed a foundation for the more recent cognitive neuroscience approaches to studying these and other questions concerning alcoholism's effects on cognition. (For reviews of cognitive research in experimental psychology, see Brandt et al. …