University of Southern California Repeatable Episodic Memory Test.

The University of Southern California Repeatable Episodic Memory Test (USC-REMT) was developed to provide a brief assay of memory in clinical drug trials where the same subject is tested multiple times over days or weeks. Therefore, it had to be minimally affected by repeated testing. The test also provides a measure of subjective organization, a cognitive strategy that might be sensitive to frontal lobe dysfunction and HIV-related memory deficits. The USC-REMT has seven different lists, each composed of 15 semantically unrelated, high-frequency nouns. The words are presented in a different order on three study-test trials. After each study trial the subject recalls the words in any order. The test takes about 10 min to administer and score. The recall protocol can be scored for (a) global mnemonic efficiency, (b) primary and secondary memory, (c) subjective organization, (d) recall consistency and (e) recall as a function of serial position. We report initial data showing that the test is sensitive to memory decrements. Thirty-six HIV-1 seropositive men, at various stages of illness, recalled significantly fewer words and exhibited less subjective organization than 14 matched controls. The test had no significant practice effects over the first three administrations when separated by several days. The seven alternate lists are essentially equivalent. The USC-REMT appears to complement currently published verbal memory tasks.

P3 in young boys as a predictor of adolescent substance use.

Event-related potentials were recorded during a visual, continuous performance task from 36 boys before use of alcohol or other drugs began. The boys were sons of 13 recovering alcoholics who themselves had a family history of alcoholism, 11 nonalcoholics with a family history of alcoholism, and 12 nonalcoholics with no family history of alcoholism. Four years after electrophysiological assessment, a behavioral questionnaire was administered (mean age = 16.1 years). A Substance Use score was derived from reported use of alcohol and other drugs, and from highly correlated delinquent behavior scores. P3s of lowest amplitude were associated with the highest adolescent Substance Use. The combination of reduced amplitude and prolonged latency of both target and nontarget P3 significantly predicted adolescent Substance Use scores after correction for subjects' age. Although this is the first electrophysiological predictor of adolescent substance use we are aware of, the effect was small, indicating the utility of P3 as a vulnerability marker for substance abuse disorders is likely to depend on its joint use with other measures.

Event-related potentials in alcoholic fathers and their sons.

ERPs were recorded during a simple color discrimination and a more difficult visual continuous performance task (CPT) from three father-son (n = 15) pair groups: recovering alcoholics with a family history of alcoholism and their sons (A+), nonalcoholics with a family history of alcoholism and their sons (NA+), and nonalcoholics with no family history of alcoholism and their sons (NA-). The sons, aged 8 to 12, had not begun drinking or using other drugs. Groups were matched on age, education and socioeconomic status. There were two principal findings. Compared to nonalcoholic groups, both A+ sons and fathers exhibited increased latency and decreased amplitude of P3 for the difficult task, but not for the easy task. This result helps to explain previous inconsistencies in the literature, and strengthens the suggestion that one indication of a vulnerability to develop alcoholism is an abnormal P3, when elicited by an appropriate task. Additionally, A+ fathers had more negative amplitudes for a late slow wave in both tasks, suggesting electrophysiological consequences of long-term alcohol abuse.

Personality characteristics of alcoholic fathers and their sons.

Recovering alcoholic fathers with a positive family history of alcoholism and their 10-15 year-old sons were assessed on a variety of personality measures and compared to a matched group of nonalcoholic fathers with a negative family history of alcoholism, and their sons. Assessment instruments for the sons included the Personality Inventory for Children, High School Personality Questionnaire, Junior Eysenck Personality Inventory and the Tridimensional Personality Questionnaire. Comparable questionnaires were administered to the fathers: the MMPI, 16 Personality Factor Questionnaire, Eysenck Personality Inventory and the Tridimensional Personality Questionnaire. No psychopathology or extreme personality variants were observed in either fathers' or sons' groups. However, MANOVAS and linear discriminant functions revealed significant differences on several personality measures between fathers' and sons' groups. Compared to sons of nonalcoholics, sons of alcoholics were relatively more compulsive, insecure and fearful while being more subdued and detached. The recovering alcoholics were more impulsive and regimented than the nonalcoholics. An index resulting from the combination of the best personality discriminators was significantly correlated in father-son pairs. In addition, this index was significantly correlated with key neurocognitive variables from our previous study which assessed the same father-son pairs. This atypical CNS profile, encompassing altered electrophysiology, neuropsychological performance and personality traits, may be useful in identifying those at increased risk for developing alcoholism.

An atypical neurocognitive profile in alcoholic fathers and their sons.

Prepubescent boys and their recovering alcoholic fathers exhibited an Atypical Neurocognitive Profile consisting of (1) a reduction in amplitude of the late positive complex (LPC) of the event-related potential (ERP) during a complex visual discrimination task, and (2) reduced visuoperceptual performance evidenced by significantly lower scores on the Object Assembly, Block Design and Picture Completion subtests of the WISC-R and the Embedded Figures Test. Low LPC amplitudes were significantly correlated with poorer visuoperceptual performance. This Atypical Neurocognitive Profile may represent a marker for alcoholism.

Effects of spontaneous cortical slow potentials on semantic information processing.

Adult subjects were tested on a choice reaction time (RT) task for decisions of word pairs as synonyms or unrelated. For each trial the word stimuli were presented contingent upon computer-detection of a predetermined negative or positive EEG baseline shift, recorded from either parietal or frontal midline electrodes. With parietal slow potential (SP) shifts, RTs were significantly faster and less variable under negative than positive polarity conditions. No appreciable RT differences were found between negative and positive SP shifts from frontal electrodes or for control subjects. The parietal negative SP shifts are considered to reflect enhanced semantic processing. The present findings in combination with previous results (Born et al., 1982, Electroencephalogr. Clin. Neurophysiol., 54: 668-676) demonstrate a double dissociation between the functional properties of negative SP shifts from parietal and frontal cortical areas, with respective involvements in semantic processing and response selection and execution.

Spontaneous cortical slow-potential shifts and choice reaction time performance.

EEGs from Fz, Cz and Pz locations (reference--right mastoid) were obtained from 36 adults. For experimental trials the Fz slow potentials (SP) were determined for a pretask interval of: a 3 sec baseline, followed by a 2.5 sec SP shift, in either negative (3.5 microV) or positive (1.5 microV) direction, and maintenance at this level for another 2.5 sec. When this criterion was met the stimuli for a choice RT task were presented (potential-related event, PRE), which required a button-press response with the right or left hand for differing stimulus configurations. During subsequent control sessions subjects were tested without pretask criterion SP shifts, with yoked pretask intervals from the experimental sessions. For the experimental conditions the mean RTs were significantly faster and less variable with the negative than with the positive SP shift condition. For the control conditions mean RTs were somewhat faster for the positive than for the negative criterion, which might be attributed to the more variable pretask intervals during the latter polarity condition. For confirmation of the cortical localization of this effect, the experimental session was replicated with corresponding negative and positive SP shift criteria from Pz. No significant differences among means and standard deviations of RTs were found. SP shifts from criterion electrodes (Fz or Pz) were significantly greater in mean amplitude than the concomitant SP shifts from the other electrodes. The present findings demonstrate the feasibility of the PRE methodology for investigations of human brain functions.