Cognitive Deficits in Chronic Alcoholics and Elderly Subjects Assessed by Evoked Brain Potentials

Abstract

It has been hypothesized that alcoholism accelerates the aging process. Most evidence for this hypothesis comes from the neuropsychological literature, where similarities in cognitive functioning between young alcoholics and old people have been reported (Fitzhugh et al. 1960, 1965, Williams et al. 1973, BJusewicz et al. 1977a. These neuropsychological studies indicate that alcoholic and geriatric subjects have in common global deficits in abstraction a d adaptive abilities, with both groups manifesting perseverative tendencies.However, these neuropsychological techniques must rely solely on behavioral indices. Although alcoholics may exhibit similar behavioral deficits to old p p l e , these behavioral deficits may well reflect the result of different neuronal pbllhology, or are general enough to be non-specific.The event-related potential (ERP) technique offers a unique approach for assessing level of brain functioning in that it combines cognition with electrophysiology. ERP's can be recorded to various sensory stimuli in conjunction with behavior (Begleiter 1979). Therefore, the ERP is an ideal technique for assessing similarities in brain functioning between alcoholics and old people. For the past several years in our laboratory, we have systematically examined electrophysiological aberrations in various patient populations with the use of event-related potential (ERP) techniques. These ERP techniques require the subject to be actively engaged in a task, usually an informationprocnsing task. We have been particularly interested in assessing brain &&unction in chronic alcoholics who have been abstinent from alcohol for lolLg periods of time. In one recent study (Porjesz & Begleiter 1979) we found that the ERP late component, Nl-P2, a component sensitive to the selection of =levant or irrelevant stimulus modality, was markedly reduced in alcoholics to &&stimuli regardless of task relevance. These results indicated that alcoholics have difficulty differentiating between relevant and irrelevant inputs.In the present study, we decided to use a particular event-related potential component that is most sensitive to certain aspects of information processing, namely the P3 or P300 component. The P300 component is a positive occurring deflection, so named because it occurs approximately 300 msecs after the stimulus. A P300 wave can only be elicited under rather specific conditions; namely:1. The subject (S) is actively attending to the stimulus sequence (discriminating targets from non-targets), and a different decision or response is required to the targets (Sutton et al. 1965, 1967).

An event-related potential evaluation of the cognitive performance of U. S. Navy alcoholics.

“…We support the Nl-P2 difference that has been previously documented Porjesz et al, 1982). Our findings also support the results of studies that have found reduced P300 amplitudes (Patterson et al, 1987), and more specifically, no difference in amplitude between rare and frequent tones for alcoholics (Porjesz et al, 1982).…”

“…14 N2-P3 Component Porjesz, Begleiter, and Sammuelly (1982) reported that the N2-P3 for alcoholics was significantly smaller, therefore the N2-P3 was compared between groups. No group main effects or interactions were found for the N2-P3 component amplitude.…”

“…ERP studies that have compared alcoholics and nonalcoholics have found significantly smaller P300 amplitudes and longer P300 latency differences in alcoholics (Patterson et al, 1987;Pfefferbaum, Horvath, Roth, Clifford, & Kopell, 1980;Porjesz & Regleiter, 1985;Porjesz, Begleiter, & Sammuelly, 1982;Skerchock & Cohen, 1984). Typically the experimenters used "chronic" alcoholics with a mean age of approximately 36 years and who had used alcohol in exce-sive quantities for at least seven continuous years (Ellis & Oscar-Berman, 1989).…”

Effects of Age on Event-Related Potentials in Chronic Alcoholics: A Multimodal Study

“…Such similari ties were not found in this study, both groups differing in all parameters except N2 latency, in keeping with differ ences found by neuropsychological tests [23,24], and late ERPs [25][26][27], Pfefferbaum et al [28] and Porjesz et al [29] have reported impaired sensory filtering mechanisms in alcoholics, which appear to function correctly in elderly people. Nevertheless, it should be pointed out that some specific similarities exist between ERPs of alcoholics and older healthy subjects.…”

An Event-Related Potential Evaluation of the Cognitive Performance of U. S. Navy Alcoholics

“…The Nl-P2 and N2-P3 values were determined by subtracting the negative from the positive component values. Porjesz, Begleiter, and Sammuelly (1982) found significantly smaller N2-P3 amplitudes in a group of alcoholics. (Barr, 1984).…”