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Alcoholism Heritability and Brain Waves

J. Polich, J.J. Wass

ALCOHOLISM AND BRAIN WAVES

A variety of evidence suggests that predisposition for alcoholism is biologically mediated and perhaps inherited. A child of alcoholic parents who is raised by nonalcoholic foster parents is at higher risk for alcoholism than is a biological child of nonalcoholic parents. Differences between abstinent alcoholics and control subjects in sensory evoked potentials and cognitive event-related potentials (ERPs) have been reported.

Because the P300 component of the ERP is smaller in long-term abstinent alcoholics than in control subjects, using these procedures to assess individuals at high risk for alcoholism was a natural progression of previous work. Moreover, studies in twins and in biologically related family members have shown significant correlations for ERP measures among family members, evidence of P300 heritability. Thus, if aberrant P300 ERPs are detected in persons at biological risk for alcoholism, this ERP component could be developed as a diagnostic marker for the likelihood of alcoholism and therefore could shed light on the etiology of this disease.

ALCOHOLISM AND THE P300 BRAIN POTENTIAL

A meta-analysis was done of ERP studies that used P300 amplitudes to compare high-risk sons of alcoholics with low-risk control subjects. Despite the general impression that P300 components differ between these 2 groups, only 40% of the studies actually report a statistically reliable difference between high- and low-risk subjects for P300 amplitude. In addition, analysis of "moderator variables" across studies indicated that the largest differences in P300 amplitude between groups of subjects originate from tasks that used visual stimuli with relatively difficult task conditions. These findings suggest that the type of stimulus and specific task conditions may be important variables when ERPs are used to assay the heritability of alcoholism.

P300 AND ALCOHOLISM HERITABILITY

Because of the outcome of the meta-analysis, it is important to establish whether the same visual task with varied perceptual difficulty will produce P300 components that systematically reflect alcoholism status among (1) unaffected control subjects, (2) adult children of alcoholic fathers, and (3) alcoholic adults. Visual stimuli were used to assess 20 men and 20 women in each of these 3 groups. Perceptual difficulty and task difficulty were varied by requiring subjects to press a button only when an infrequent (12%) target stimulus (a large "X") was presented and not to respond when either an infrequent (12%) nontarget stimulus ("novel" color forms that were different for each trial) or a frequent (76%) standard stimulus (a large "square") was presented. Young adult subjects (mean age for all groups, 20.5 years) from families whose background indicated no prevalence of alcoholism (unaffected controls) were compared with nonalcoholic subjects from families in which alcoholism was prevalent, as defined by the father's diagnosis of alcoholism. Both groups were compared with a sample of alcoholic adults from alcoholic families.

The results are illustrated in Figure 1. For the infrequently presented target and nontarget stimulus conditions, the P300 voltage level and area decreased as the degree of alcoholism increased: Unaffected controls evinced the largest and brightest P300 components, adult children of alcoholics had a somewhat diminished response pattern, and the alcoholic subjects produced the smallest and least amount of P300 voltage. These findings indicate that the P300 ERP systematically reflects the heritability of alcoholism. Studies are planned to assess whether different scalp topography patterns may be useful as predictors of subsequent alcoholism.

PUBLICATIONS

Alexander, J.E., Polich, J. Handedness and P300 from auditory stimuli. Brain Cogn. 35:259, 1997.

Begleiter, H., Porjesz, B., Reich, T., Edenberg, H.J., Goate, A., Blangero, J., Almasy, L., Foroud, T., Van Eerdewegh, P., Polich, J., Rohrbaugh, J., Kuperman, S., Bauer, L.O., O'Connor, S.J., Chorlian, D.B., Li, T.-K., Conneally, P.M., Hesselbrock, V., Rice, J.P., Schuckit, M.A., Cloninger, R., Nurnberger, J., Jr., Crowe, R., Bloom, F.E. Quantitative trait loci analysis of human event-related brain potentials: P3 voltage. Electroencephalogr. Clin. Neurophysiol. 108:244, 1998.

Comerchero, M.D., Polich, J. P3a and P3b from typical auditory and visual stimuli. Electroencephalogr. Clin. Neurophysiol., in press.

Comerchero, M.D., Polich, J. P3a, perceptual distinctiveness, and stimulus modality. Cogn. Brain Res., in press.

Hoffman, L.D., Friedmann, A., Saltman, P., Polich, J. Neuroelectric assessment of nutrient intake. Int. J. Psychophysiol., in press.

Hoffman, L.D., Polich, J. EEG, ERPs, and food consumption. Biol. Psychol., in press.

Hoffman, L.D., Polich, J. P300, handedness, and corpus callosal size: Gender, modality, and task. Int. J. Psychophysiol., in press.

Ilan, A.B., Polich, J. P300 and response time from a manual Stroop task. Electroencephalogr. Clin. Neurophysiol., in press.

Katayama, J., Polich, J. Stimulus context determines P3a and P3b. Psychophysiology 35:23, 1998.

Koziol, J., Alexander, J.E., Bauer, L., Kuperman, S., Morzorati, S., O'Connor, S.J., Rohrbaugh, J., Porjesz, B., Begleiter, H., Polich, J. A new method for displaying correlational arrays. Am. Statistician 51:301, 1997.

Mertens, R., Polich, J. P300 from a single stimulus: Modality and response effects. Electroencephalogr. Clin. Neurophysiol. 104:488, 1997.

Morgan, C.D., Geisler, M.W., Covington, J.W., Polich, J., Murphy, C. Olfactory P300 in young and older adults. Psychophysiology, in press.

Polich, J. Cognitive electrophysiology. In: Encyclopedia of Psychology. Kazdin, A.E. (Ed.). American Psychological Association, Washington, DC, in press.

Polich, J. P300 clinical utility and control of variability. J. Clin. Neurophysiol. 15:14, 1997.

Polich, J. P300 in clinical applications. In: Electroencephalography: Basic Principles, Clinical Applications and Related Fields. Niedermeyer, E., Lopes da Silva, F. (Eds.). Urban Schwarzenberg, Baltimore, in press.

Polich, J., Bloom, F.E. P300, alcoholism inheritability, and stimulus modality. Alcohol, in press.

Polich, J., Hoffman, L.D. Alzheimer's disease and P300: Evaluation of modality and task difficulty. In: Koga, Y., Nagata, K., Hirata, K. (Eds.). Brain Topography Today. Elsevier Science, New York, 1998, p. 527.

Polich, J., Hoffman, L.D. P300 and handedness: Possible corpus callosal contributions to ERPs. Psychophysiology 35:1, 1998.

Polich, J., Lardon, M.T. P300 and long-term physical exercise. Electroencephalogr. Clin. Neurophysiol. 103:493, 1997.

Polich, J., Pitzer, A. P300 in early Alzheimer's disease: Oddball task difficulty and modality effects. Clin. Neurophysiol., in press.

Ravden, D., Polich, J. Habituation of P300 from visual stimuli. Int. J. Psychophysiol., in press.

Spencer, K., Polich, J. Spectral analysis of P300: Attention, task, and probability. Psychophysiology, in press.

Rodríguez-Holguín, S., Porjesz, B., Chorlian, D.B., Polich, J., Begleiter, H. Visual P3a in male alcoholics and controls. Electroencephalogr. Clin. Neurophysiol., in press.