Biomedical subjects

L O Bauer

Publications and source records attributed to L O Bauer.

At least 37 records · Page 2Linked to original sources

PubMed1997

Beneficial effects of thiamine on recognition memory and P300 in abstinent cocaine-dependent patients.

The present study evaluated the effects of thiamine vs. placebo on memory task performance and event-related electroencephalographic potentials in eight abstinent cocaine-dependent patients. Patients orally ingested 5 g of thiamine and 5 g of a lactose placebo on two separate days scheduled approximately 1 week apart. The order of administration was randomized. Double-blind procedures were followed. Approximately 3 h after ingesting the capsules, patients completed Sternberg's (1975) memory scanning task during which performance and event-related potentials (P300) were recorded simultaneously. Thiamine was found to significantly improve recognition accuracy and P300 amplitude, at the midline parietal (Pz) electrode. The improvement was most reliable under conditions of increased memory load. These preliminary findings justify a further examination of the relation between thiamine's hypothesized effects on central nervous system cholinergic function, and the direct and indirect effects of cocaine abuse.

Adult↗

PubMed1997

Frontal P300 decrements, childhood conduct disorder, family history, and the prediction of relapse among abstinent cocaine abusers.

P300 event related brain potentials were studied in 49 cocaine dependent patients, abstinent for 1-5 months, and 20 healthy, non-drug-dependent controls. Patients were assigned to one of two subgroups based on the presence/absence of a DSM-IIIR diagnosis of antisocial personality disorder (ASPD). Analyses of P300s recorded during a visual selective attention task revealed reduced amplitudes at frontal electrode sites among patients with ASPD, relative to the ASPD negative patient and control groups. The frontal P300 decrement was significantly correlated with the number of childhood conduct disorder symptoms, but not with the presence/absence of a family history of alcoholism. A secondary analysis examined the relationship between P300 amplitude among cocaine dependent patients and their future behavior, i.e., relapse versus continued abstinence. Discriminant function analysis revealed that P300 amplitude alone accurately identified 70.6% of the patients who later relapsed, and 53.3% of the patients who did not.

Adult↗

PubMed1997

P300 topography of amplitude/latency correlations.

The correlational association from 19 electrode sites between peak amplitude and latency for the P3(00) event-related brain potential (ERP) for n = 80 homogeneous subjects was assessed using a simple auditory discrimination task. The correlation strength varied systematically across scalp topography in different ways for the various ERP components. For the target stimuli, P3 amplitude and latency were negatively correlated and most tightly coupled over the frontal-central and right medial/lateral recording sites. In contrast, the N1 produced negative correlations that were strongest over the left and right central/lateral locations; P2 demonstrated a positive correlation that was strongest frontally and centrally; N2 demonstrated a positive correlations that was strongest over the central and parietal sites. ERPs from the standard stimuli produced generally similar patterns for the P3 and P2 components, with only weak or no reliable effects observed for the N1 and N2 potentials. Taken together, the findings suggest that analysis of amplitude/latency correlational relationships can provide information about ERP component generation. Theoretical implications are discussed.

Adult↗

PubMed1997

Chronic alcohol abuse and the acute sedative and neurophysiologic effects of midazolam.

The aim of the present investigation was to examine benzodiazepine sensitivity in abstinent alcoholics. For this purpose, two escalating doses of the benzodiazepine midazolam were i.v. administered to nine alcohol-dependent patients after 2-3 weeks of abstinence and 12 healthy, non-alcoholic volunteers. A variety of dependent measures were examined, including the power spectrum of the resting electroencephalogram (EEG) and evoked EEG responses, saccadic eye movements, self-reported sedation, and vigilance task performance. Analyses revealed a significant association between plasma midazolam levels and changes in EEG beta power, pattern shift visual evoked potential amplitude, heart rate, and saccade amplitude and velocity. The patient and control groups differed significantly in the onset latencies of their saccadic eye movements, and marginally in EEG beta power, both before and after midazolam. However, no differences were detected between the groups in the dose of midazolam required to produce sedation or in midazolam's neurophysiological effects.

Adult↗

PubMed1997

Slow brain potentials in a visual-spatial memory task: topographic distribution and inter-laboratory consistency.

Slow brain electrical potentials (SPs) were investigated in a visual-spatialmemory task. Two issues were addressed: (1) the nature and topographic distribution of the potentials obtained under such conditions; and (2) the consistency of the SPs when recorded in six identically configured laboratories. Fifteen young male subjects were studied at each laboratory (total n = 90). The paradigm entailed presentations of paired-visual patterns (S1 and S2), to which subjects responded with a choice reaction time response indicating whether or not the two patterns matched. A biphasic contingent negative variation (CNV) was produced which consisted of an early symmetric component with bilateral foci at posterior temporal sites and a subsequent mid-parietal dominant wave later in the retention interval. Although the CNVs from all laboratories were similar in waveform and in topographic distribution, there were significant inter-laboratory differences in amplitude of the slow potential components. The topographic distributions of the components and the possible role of sampling effects are discussed.

Adult↗

PubMed1997

Effects of naltrexone on cue-elicited craving for alcohol and cocaine.

This study examined the effects of naltrexone (50 mg/day) on mood and self-reported desire for alcohol and cocaine in 26 patients with comorbid alcohol and cocaine abuse/dependence. Two laboratory sessions were conducted, separated by 1 week. During the sessions, subjects viewed 5-min films containing either cocaine, alcohol, or neutral cues. The first session occurred prior to random assignment to medication group and the second session was held after 1 week of double-blind treatment with either naltrexone or placebo. The cocaine-related film induced a greater desire to use cocaine than the desire for alcohol that was induced by the alcohol-related film. This finding was observed using both a simple, one-item analog scale administered during the films and more complex craving questionnaires administered immediately after the films. Collectively, the alcohol and cocaine-related films evoked greater levels of self-reported anxiety and elation, and lower levels of concentration, than the neutral film. Naltrexone did not differ from placebo in reducing the desire to use either cocaine or alcohol.

Adolescent↗

PubMed1997

Alcohol cue reactivity, negative-mood reactivity, and relapse in treated alcoholic men.

Relapsed alcoholic individuals frequently report that negative emotional states trigger their return to drinking. A parametric laboratory study was conducted to assess the separate and combined effects of exposure to alcohol-related stimuli and induced negative moods in abstinent alcoholic persons. The authors also sought to determine if reactivity to alcohol cues or reactivity to negative mood induction predicted relapse soon after treatment. Men with alcoholism (N = 50) undergoing inpatient treatment participated in a guided imagery procedure designed to induce negative moods and were then exposed to either their favorite alcoholic beverage or to spring water. Results indicated that both alcoholic beverage presentation and negative affect imagery led to increased subjective reporting of desire to drink. These effects were additive but not multiplicative (i.e., the interaction of mood state with beverage type was not significant). Reported urge to drink during the trial that combined negative mood imagery with alcoholic beverage exposure predicted time to relapse after inpatient discharge.

Adult↗

PubMed1997

Smooth pursuit eye movement dysfunction in abstinent cocaine abusers: effects of a paternal history of alcoholism.

The present study evaluated smooth pursuit eye movement (SPEM) function in 36 cocaine-dependent patients, with or without a paternal history of alcoholism, and 12 nondrug-dependent normal volunteers. None of the subjects in either group met DSM-III-R diagnostic criteria for schizophrenia, or delusional, major affective, or schizotypal personality disorders. None possessed a history of seizures, significant head injury, HIV-1 infection, or regular medication use. SPEMs were elicited by a pendulum, oscillated at 0.5 Hz, and recorded using electro-oculographic techniques. Tracking accuracy was estimated by the power of the horizontal electro-oculograph at the stimulus oscillation frequency. Analyses revealed that the SPEM tracking accuracy of cocaine-dependent patients without a paternal history of alcoholism was superior to that of the normal control group. SPEM tracking in these patients correlated positively with years of cocaine and polysubstance abuse. In contrast, patients with a paternal history of alcoholism exhibited subnormal SPEM tracking performance. These differences could not be explained by other family history, demographic, or drug use variables.

Adult↗

PubMed1996

Neuropsychological correlates of urine toxicology results.

1. The present study evaluated neuropsychological differences among 4 groups of men and women, aged 15 to 61 years. The groups were defined on the basis of urine toxicology screens indicating recent cocaine (n = 12), cannabis (n = 14), or multiple drug (n = 7) use, or no such use (n = 21). 2. The Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Trail Making Tests, and the Porteus Maze Test were administered to all subjects. 3. Analyses revealed no significant differences between the groups in age, gender composition, or in the proportion of group members with personal histories of alcohol/drug abuse or dependence, or Anti-Social Personality Disorder. 4. The cocaine positive group exhibited statistically significant impairments in Verbal IQ, as well as on Information, Vocabulary, Comprehension, Picture Completion, and Trails B subtests. The other experimental groups did not differ from the urine negative group.

Adolescent↗

PubMed1996

Pattern shift visual evoked potentials in abstinent cocaine-dependent, alcohol-dependent, and cross-dependent patients.

The present study evaluated pattern shift visual evoked potential (VEP) amplitudes and latencies in four groups of adult subjects, characterized by the presence/absence of a recent history of alcohol dependence factorially crossed with the presence/absence of a recent history of cocaine dependence. All of the subjects were healthy and uncomplicated by histories of serious head injury, seizures (including drug-related seizures), and major medical, neurological, or psychiatric disorders. The subjects comprising the three patient groups were evaluated after 1 - 5 months of verified abstinence. Analyses of VEPs evoked by checkerboard reversal indicated a main effect of previous cocaine dependence on P100 latency. No main effect of previous alcohol dependence and no alcohol by cocaine dependence interaction were detected. The increased P100 latencies detected in abstinent, cocaine-dependent subjects are most likely related to cerebrovascular and neurological effects of chronic cocaine use.

Adult↗

PubMed1996

Differential effects of cocaine, alcohol, and nicotine dependence on olfactory evoked potentials.

Olfactory evoked potentials (OEP) were elicited by odorous and nonodorous stimuli in 50 adult subjects: 26 subjects with histories of either cocaine (n = 19) or alcohol (n = 7) dependence, 10 with histories of nicotine but no other drug dependence, 2 with clinical anosmia of peripheral origin, and 12 subjects without drug or olfactory disorders. The presentation of nonodorous stimuli (i.e. a nasal air puff) did not elicit OEP component amplitude and latency differences among the groups. However, the presentation of odorous stimuli elicited a significantly smaller P1 component in the cocaine-dependent and alcohol-dependent groups than in the normal control and nicotine-dependent groups. The P1 amplitude deficit in the cocaine-dependent group is consistent with case report data associating cocaine use with lesions of the peripheral and/or central olfactory apparatus.

Adult↗

PubMed1996

Resting hand tremor in abstinent cocaine-dependent, alcohol-dependent, and polydrug-dependent patients.

Laboratory studies of cocaine-exposed rodents, and positron emission tomographic studies of human cocaine abusers have suggested that chronic cocaine abuse downregulates dopaminergic function in the basal ganglia. The present study sought to provide behavioral evidence for this phenomenon by demonstrating enhanced levels of resting hand tremor among patients with previous histories of cocaine dependence. to determine the specificity of the phenomenon, patients with previous histories of alcohol dependence, cocaine/alcohol codependence, and cocaine/opiate codependence were also evaluated. Patients were assigned to one of four groups according to DSM-IIIR diagnostic criteria: (1) cocaine dependent (n = 19); (2) cocaine and alcohol dependent (n = 12); (3) cocaine and opiate dependent (n = 7); (4) alcohol dependent (n = 9). All were abstinent from their primary drug of abuse for a period of 1 to 5 months. The three patient groups with histories of cocaine dependence exhibited significantly more resting hand tremor than the alcohol-dependent and normal control groups. Furthermore, hand tremor in the former three groups was positively related to the number of self-reported uses of cocaine and negatively related to the number of months of cocaine abstinence.

Alcoholism↗

PubMed1996

Psychomotor and electroencephalographic sequelae of cocaine dependence.

In conclusion, there appears to be strong evidence from these studies supporting the existence of a postcocaine abuse syndrome. The general hypothesis stated that cocaine-dependent patients would exhibit impaired performance on tests of motor system functioning. It was further hypothesized that these impairments would be more severe and persistent than impairments in other areas. These hypotheses were confirmed. Cocaine-dependent, patients were found to exhibit a statistically significant resting hand tremor, which did not remit despite 3 months of verified abstinence. In contrast, alcohol-dependent patients exhibited an enhanced action tremor and enhanced body sway that remitted after 1 week. Cocaine-dependent, but not alcohol-dependent, patients also exhibited slower reaction times than controls during a protracted vigilance tasks and during simpler tasks requiring visual or auditory divided attention. The reaction time slowing was substantial (approximately 50 to 75 ms), task independent, and, like resting tremor, did not remit after 3 months of abstinence. The demonstration of smooth pursuit eye movement irregularities in the cocaine-dependent group further reinforced the motor system hypothesis. During visual tracking of an oscillating pendulum, the tracking accuracy of cocaine-dependent patients was superior to that of controls at all three time points. Studies that have administered acute amphetamine to normal, nondrug-dependent individuals have reported a similar finding. Collectively, these findings suggest that chronic cocaine use may induce a hyperexcitability of the smooth pursuit eye movement control system, which persists into abstinence. Evidence for EEG abnormalities among recovering cocaine-dependent patients was provided by a variety of experiments. In a new and ongoing experiment, cocaine-dependent patients exhibit reduced P300b ERPs to rare stimuli, which they must acknowledge with a motor response. Evidence for a nonmotor CNS dysfunction was provided by examining EEG responses to a simple flickering light. However, the nature of the dysfunction was complex. EEG responses to square wave modulated light revealed diminished reactivity among both cocaine-dependent and alcohol-dependent patients at all three time points. In contrast, EEG responses to sine wave modulated light revealed enhanced reactivity among the cocaine-dependent patients only. The coexistence of diminished or enhanced EEG reactivity and diminished or enhanced motor system functioning implies that cocaine dependence can simultaneously depress and enhance different aspects of brain function in the same individual. The diversity of cocaine's EEG and psychomotor effects may have an analog in demonstrations of the simultaneous development of sensitization and tolerance among animals chronically exposed to cocaine.

Animals↗

PubMed1995

Carbamazepine treatment of cocaine dependence: a placebo-controlled trial.

Cocaine-induced kindling, which has been hypothesized to underlie cocaine-induced craving, is reversed by carbamazepine treatment. Though preliminary studies showed carbamazepine to be useful for relapse prevention in cocaine-dependent subjects, more recent studies have failed to replicate those findings. We conducted a randomized, double-blind, placebo-controlled trial of carbamazepine 600 mg/day in 40 cocaine-dependent males. During active treatment there were no significant effects of carbamazepine on cocaine use, alcohol consumption, anxiety or depressive symptoms. At three months post-treatment carbamazepine-treated subjects reported fewer drinking days. We conclude that carbamazepine at this dose level is probably not efficacious for treatment of cocaine dependence.

Adolescent↗

PubMed1995

Carbamazepine and cocaine-cue reactivity.

Subjective and electroencephalographic reactions to cocaine cues were evaluated in 33 cocaine-dependent out-patients and 17 non-cocaine-dependent controls. Subjective, EEG, and autonomic reactions to three 5-min videos (cocaine-associated, erotic, neutral) were evaluated twice with an interpolated 1-week interval. Between evaluations, cocaine-dependent patients received carbamazepine 400 mg daily or matching placebo in double-blind fashion. In all three groups the cocaine-associated and erotic videos produced a comparable increase in the self-rated desire for cocaine and reduction in total EG power. Carbamazepine treatment increased EEG fast alpha power and self-rated fatigue, and decreased self-rated concentration and vigor. However, it had no specific effect on subjective or physiological reactivity to either the cocaine-associated or erotic videos. This negative finding is consistent with recent clinical trials of carbamazepine for cocaine dependence.

Adolescent↗

PubMed1995

P300 hemispheric amplitude asymmetries from a visual oddball task.

The P3(00) event-related potential (ERP) was elicited in 80 normal, right-handed male subjects using a simple visual discrimination task, with electroencephalographic (EEG) activity recorded at 19 electrodes. P3 amplitude was larger over the right than over the left hemisphere electrode sites primarily at anteromedial locations (F3/4, C3/4) for target, novel, and standard stimuli. The N1, P2, and N2 components also demonstrated hemispheric asymmetries. The strongest P3 hemispheric asymmetries for all stimuli were observed at anterior locations, suggesting a frontal right hemisphere localization for initial stimulus processing, although target stimuli produced larger P3 amplitudes at parietal locations that did novel stimuli. The relationships of hemispheric asymmetries to anatomical variables, background EEG activity, and neurocognitive factors are discussed.

Adult↗

PubMed1994

Electroencephalographic activity and mood in cocaine-dependent outpatients: effects of cocaine cue exposure.

Electroencephalographic (EEG) and subjective reactions to cocaine cues were evaluated in 18 cocaine-dependent outpatients, after 14 or fewer days of abstinence, and 16 noncocaine-dependent controls. EEG activity and desire for cocaine were recorded while subjects viewed three 5-min films that featured either cocaine-associated, erotic, or neutral stimuli. Other measures of mood state and cocaine craving, derived from the Mood Adjective Checklist and the Cocaine Craving Questionnaire, respectively, were recorded immediately after each film. Analyses of absolute EEG power within six frequency bands (delta, theta, slow and fast alpha, slow and fast beta) revealed no EEG abnormalities in the cocaine-dependent group under any condition. In both subject groups, the cocaine-associated and erotic films produced a similar reduction in total EEG power. The cocaine-associated and erotic films also produced a similar increase in the self-rated desire for cocaine, but this change only occurred in the cocaine-dependent group.

Adolescent↗

PubMed1994

P300 from an auditory oddball task: inter-laboratory consistency.

Event-related potentials (ERPs) were recorded from normal subjects for the purpose of evaluating measurement consistency among six laboratories located in different cities within the United States. At each laboratory location 15 male subjects were tested using a simple auditory stimulus discrimination task and identical electrophysiological equipment and recording methods. Assessment of the N1, P2, N2, and P3(00) potentials from both the target and standard stimuli resulted in no reliable differences among laboratories for component amplitudes, latencies, and scalp distributions. Quantitative evaluation of overall waveform and specific component morphology yielded good to excellent agreement across laboratories. The findings suggest that large-scale inter-laboratory human electrophysiological studies are feasible and may prove of value when using ERPs to evaluate cognitive function in humans.

Adult↗