Biomedical subjects

L O Bauer

Publications and source records attributed to L O Bauer.

At least 19 recordsLinked to original sources

PubMed2001

Antisocial personality disorder and cocaine dependence: their effects on behavioral and electroencephalographic measures of time estimation.

The present study examined time estimation performance and concurrently-recorded electroencephalographic activity among 57 residential treatment program patients previously dependent on either cocaine or cocaine and alcohol. The patients were assigned to one of two subgroups based upon the presence (n=20) versus absence (n=37) of a comorbid diagnosis of Antisocial Personality Disorder (APD). Twenty-six subjects, who had no history of substance abuse and no diagnosis of APD, were also examined. All subjects performed a psychomotor task in which they were asked to press a response key exactly 2 s after the onset of a visual cue. Analyses revealed that cocaine-dependent patients with APD were often premature in their behavioral estimates of time passage. The analysis of a slow EEG potential, viz. the Contingent Negative Variation, recorded over the 2 s time estimation interval, also suggested premature response preparation in the cocaine-dependent, APD-positive group. Correlational analyses revealed that the number of conduct problems reported prior to age 15 was a better predictor of both premature responding and CNV amplitude than either severity of cocaine dependence, alcohol use, or anxious or depressed mood. The potential relevance of these findings for studies of future time orientation and delay discounting behavior are discussed.

Adult↗

PubMed2001

CNS recovery from cocaine, cocaine and alcohol, or opioid dependence: a P300 study.

OBJECTIVES: The goal of the present study was to evaluate the relative effects of cocaine, cocaine and alcohol, or opioid dependence on P300 event-related potentials (ERPs). In addition, the effects of selected premorbid and comorbid factors were examined. METHODS: P300 ERPs were recorded from 72 residential treatment program patients, characterized by a history of either cocaine (n=25), or cocaine and alcohol (n=18), or opioid (n=29) dependence, and 14 non-drug-dependent community volunteers. The 86 subjects completed a visual continuous performance test formed by a series of 150 presentations of individual consonant letters. They were asked to press a key whenever a letter was presented twice in succession. RESULTS: Analyses of P300 ERPs obtained on target trials revealed a similar amplitude decrement in all the patient groups. Further analyses of P300 activity in the 3 drug-dependent patient groups revealed a negative correlation between P300 amplitude and the number of DSM-IIIR childhood conduct disorder criterion behaviors as well as a positive correlation between P300 amplitude and the duration of drug abstinence. CONCLUSIONS: P300 amplitude in drug-dependent patients is influenced by a complex interaction between CNS pathology that predates, and probably promotes, the onset of drug dependence and CNS pathology that resolves during the process of recovery from drug dependence.

Adult↗

PubMed2000

Genetics of event-related brain potentials in response to a semantic priming paradigm in families with a history of alcoholism.

Alcoholism↗

PubMed2000

The P300 brain potential is reduced in smokers.

RATIONALE: Tobacco smoking is the most prevalent type of substance abuse, yet its biobehavioral etiology is little understood. Identification of differences between smokers and non-smokers on basic characteristics of neurocognitive functioning may help to elucidate the mechanisms of tobacco dependence. OBJECTIVES: This study assessed the relationship between smoking status and the P300 component of event-related potential (ERP) while controlling for potential confounders such as alcoholism, drug abuse, and psychopathology. METHODS: The ERP responses elicited by a visual oddball task were measured at the mid-parietal site in 905 current smokers, 463 ex-smokers, and 979 never smokers. RESULTS: P300 amplitude was significantly lower in current cigarette smokers compared to never-smokers. Ex-smokers did not differ significantly from never-smokers. P300 reduction was also associated with alcoholism, drug dependence, and family density of alcoholism. However, after controlling for smoking, only family density of alcoholism remained a significant predictor of P300 amplitude. CONCLUSIONS: The results indicate a significant effect of smoking status on P300 amplitude which is additive to family history of alcoholism and suggest that either (1) long-term tobacco smoking may produce a reversible change in brain function, or (2) reduced P300 may be a marker of risk for nicotine dependence.

Adolescent↗

PubMed1999

Heritability of event-related brain potentials in families with a history of alcoholism.

Event-related brain potentials (ERPs) are altered in patients with a variety of psychiatric disorders and may represent quantitative correlates of disease liability that are more amenable to genetic analysis than disease status itself. Estimates of heritability are presented for amplitude and latency of the N1 and P3 components of the ERP measured at 19 scalp locations in response to visual and auditory stimuli for 604 individuals in 100 pedigrees ascertained as part of the Collaborative Study on the Genetics of Alcoholism. Significant heritabilities were found for visual P3 amplitude in response to all stimuli and for visual P3 latency in response to target and novel, but not non-target, stimuli. Heritability of visual N1 latencies was uniformly low, whereas heritability of visual N1 amplitude was significant for all electrodes in response to the non-target stimuli but only for posterior electrodes in the other two stimulus conditions. Heritabilities for auditory target P3 were similar to those of the visual stimuli, with auditory target P3 amplitudes and latencies both demonstrating significant heritability. For auditory P2 in response to non-target stimuli, peak amplitude was heritable, but latency was not. Auditory N1 amplitude and latency were significantly heritable for both target and non-target conditions and did not demonstrate the anterior/posterior patterning obtained for visual N1 amplitude. This study represents the first systematic assessment of heritability of these potential neurophysiological markers in families with a history of alcoholism and suggests that many of these ERP phenotypes have heritabilities strong enough to justify genomic screening for loci jointly influencing ERP abnormalities and liability to alcoholism.

Adolescent↗

PubMed1999

P300 decrements in teenagers with conduct problems: implications for substance abuse risk and brain development.

BACKGROUND: The purpose of this study was to evaluate the effects of conduct disorder problems, family history, gender, and age on P300 electroencephalographic potentials in teenagers. METHODS: The 257 subjects, aged 15 to 20 years, were assigned to one of twelve groups defined by the crossing of three between-subjects factors: 1) gender; 2) ranking below vs above the median number of conduct disorder problems for their gender; and 3) no family history of alcohol or drug dependence vs familial alcohol dependence vs familial heroin or cocaine dependence. RESULTS: P300 amplitude was smaller among subjects reporting a greater number of conduct problems prior to age 15 vs those reporting fewer problems of this type. No family history effects were detected. Another set of analyses examined the effects of age on conduct problem-related decrements in P300. Smaller P300 amplitudes within the posterior scalp region were associated with a greater number of conduct problems among subjects younger than 16.5 years. Among subjects greater than this median age, the effects of these behaviors were only apparent over the frontal scalp. CONCLUSIONS: It is concluded that P300 decrements previously attributed to familial alcohol/substance dependence might be the result of a coincident increase in the prevalence of conduct disorder problems. The analysis of age interactions suggests that P300 amplitude decrements observed at posterior scalp sites among subjects with more conduct problems disappear at approximately 16 to 17 years of age. After that age, decrements in frontal brain function may begin to emerge in the subset of conduct problem subjects who are at risk for developing adult antisocial personality disorder.

Adolescent↗

PubMed1999

Subtypes of family history and conduct disorder: effects on P300 during the stroop test.

The goal of the present study was to identify neurophysiological differences associated with a family history of substance dependence, and its subtypes (paternal alcohol, cocaine, or opiate dependence), and with conduct disorder, and its subtypes (aggression, deceitfulness/theft, and rules violations). P300 event-related brain potentials were recorded from 210 males and females, aged 15-20 years while they performed the Stroop color-word compatibility test. Analyses revealed no significant effects of familial substance dependence on P300. However, an elevated number of conduct disorder problems was associated with a statistically significant reduction in P300 amplitude. The P300 amplitude reduction was related to the severity of the "rules violation" subtype, but was unrelated to aggression or deceitfulness and theft. It is concluded that conduct disorder can explain many of the P300 findings previously attributed to a family history of alcohol dependence. Furthermore, it appears that conduct disorder may be a heterogenous classification comprised of neurophysiologically different subtypes.

Adolescent↗

PubMed1999

Verbal ability predicts abstinence from drugs and alcohol in a residential treatment population.

Measures of cognitive ability, depression, anxiety, antisocial personality, as well as length, type and severity of addiction were obtained from 122 substance abusers enrolled in residential treatment programs. Over a subsequent 6-mo. monitoring period, relapse to substance use was detected in 46 subjects. 17 subjects withdrew from treatment for other reasons and their relapse status was unknown. The remaining 59 maintained abstinence from alcohol or drug use throughout the monitoring period. The only variables to differentiate the groups significantly on outcome were IQ and the Verbal subtest from the Shipley Institute of Living Scale. Stepwise discriminant function analysis indicated that the Verbal component alone correctly identified 64.4% of patients who would successfully remain abstinent.

Adult↗

PubMed1998

Effects of chronic opioid dependence and HIV-1 infection on pattern shift visual evoked potentials.

The goal of the present study was to examine the effects of opioid dependence, alone and in combination with asymptomatic HIV-1 infection, on the pattern shift visual evoked potential (PSVEP). For this purpose, three groups of patients were evaluated, including patients characterized by: (1) a past history (2-4 months abstinent) of DSM-IIIR opioid dependence (i.e. in partial remission); (2) a recent history (7 days abstinent) of opioid dependence with ongoing methadone maintenance; and (3) a recent history of opioid dependence, ongoing methadone maintenance, and asymptomatic HIV-1 infection. A group of healthy, non-drug dependent volunteers was also evaluated. Analyses revealed no PSVEP differences between patients with a past history of opioid dependence and healthy volunteers. There were also no PSVEP differences between methadone-maintained patients with or without HIV-1 infection. Collectively, however, the two methadone maintenance groups exhibited significant delays in the N75 and P100 components of the PSVEP relative to the other two groups. The delay in N75 latency was strongly correlated with self-reported years of heroin abuse, but not with years of cocaine, alcohol, or other drug abuse. These results are interpreted as reflecting an adverse effect of chronic opioid dependence on neural transmission within primary visual areas of the brain.

Adult↗

PubMed1998

Quantitative trait loci analysis of human event-related brain potentials: P3 voltage.

The P3 event-related brain potential (ERP) is a positive-going voltage change of scalp-recorded electroencephalographic activity that occurs between 300-500 ms after stimulus onset. It is elicited when a stimulus is perceived, memory operations are engaged, and attentional resources are allocated toward its processing. Because this ERP component reflects fundamental cognitive processing, it has found wide utility as an assessment of human mental function in basic and clinical studies. In particular, P3 attributes are heritable and have demonstrated considerable promise as a means to identify individuals at genetic risk for alcoholism. We have conducted a quantitative linkage analysis on a large sample from families with a high density of affected individuals. The analyses suggest that several regions of the human genome contain genetic loci related to the generation of the P3 component of the ERP, which are possible candidate loci underlying the functional organization of human neuroelectric activity.

Alcoholism↗

PubMed1998

Neuropsychologic findings in cocaine-dependent outpatients.

1. Nineteen recently abstinent cocaine-dependent males were compared to 16 control subjects on a battery of neuropsychological tests. 2. The performance of cocaine-dependent subjects was inferior to the control group on tasks assessing higher level verbal skills, and on a task requiring logical sequencing of complex visual stimuli. 3. Cocaine users also performed poorly on a delayed visual memory task and on a verbal generation task, but performed better than the control group on a task assessing simple visual-motor speed. 4. Possible reasons for these findings are discussed, as are the treatment implications of these findings.

Adult↗

PubMed1998

Smooth pursuit eye movement dysfunction in substance-dependent patients: mediating effects of antisocial personality disorder.

Smooth pursuit eye movements were evaluated in 21 healthy volunteers and 126 patients meeting criteria for one of the following DSM-III-R dependence diagnoses: alcohol (n = 10), cocaine (n = 44), heroin (n = 34), or dual alcohol and cocaine (n = 38). A significant reduction in tracking accuracy was found in the heroin and the dually dependent groups relative to controls. Interestingly, the eye movement dysfunction in the drug-dependent groups was no longer detectable when the effects of antisocial personality disorder were statistically removed. The magnitude of the dysfunction also correlated with several antisocial personality-related features, including an increased number of criminal charges and months of incarceration, increased problems associated with drug abuse, and lower intellectual functioning. The relationship demonstrated presently between antisocial personality disorder and eye movement dysfunction may have implications beyond studies of substance dependence.

Adult↗

PubMed1998

Amplitude of visual P3 event-related potential as a phenotypic marker for a predisposition to alcoholism: preliminary results from the COGA Project. Collaborative Study on the Genetics of Alcoholism.

Recent data collected at six identical electrophysiological laboratories from the large national multisite Collaborative Study on the Genetics of Alcoholism provide evidence for considering the P3 amplitude of the event-related potential as a phenotypic marker for the risk of alcoholism. The distribution of P3 amplitude to target stimuli at the Pz electrode in individuals 16 years of age and over from 163 randomly ascertained control families (n = 687) was compared with those from 219 densely affected alcoholic families (n = 1276) in which three directly interviewed first-degree relatives met both DSM-III-R and Feighner criteria at the definite level for alcohol dependence (stage II). The control sample did not exclude individuals with psychiatric illness or alcoholism to obtain incidence rates of psychiatric disorders similar to those of the general population. P3 amplitude data from control families was converted to Z-scores, and a P3 amplitude beyond 2 SD's below the mean was considered an "abnormal trait." When age- and sex-matched distributions of P3 amplitude were compared, members of densely affected stage II families were more likely to manifest low P3 amplitudes (2 SD below the mean) than members of control families, comparing affected and unaffected offspring, and all individuals; all comparisons of these distributions between groups were significant (p < 0.00001). P3 amplitude means were also significantly lower in stage II family members, compared with control family members for all comparisons, namely probands, affected and unaffected individuals (p < 0.0001), and offspring (p < 0.01). Furthermore, affected individuals from stage II families, but not control families, had significantly lower P3 amplitudes than unaffected individuals (p < 0.001). Affected males from stage II families had significantly lower P3 amplitudes than affected females (p < 0.001). Recent linkage analyses indicate that visual P3 amplitude provides a biological phenotypic marker that has genetic underpinnings.

Adolescent↗

PubMed1997

Neuropsychological differences between alcohol-dependent and cocaine-dependent patients with or without problematic drinking.

The present study evaluated differences among three groups of substance abusers, abstinent for 1-5 months. One group was composed of 17 alcohol-dependent patients. The other two groups were composed of cocaine-dependent patients who scored below (n = 29) or above (n = 18) the median Michigan Alcoholism Screening Test (MAST) score for the cocaine-dependent group in total. The Shipley Institute of Living Scale was administered to all subjects. An ANOVA, with age as a covariate, revealed that the cocaine-dependent group with lower MAST scores exhibited statistically significant impairments on the Shipley abstraction subtest and on total IQ relative to the two other groups. There were no group differences on the verbal subtest. The abstraction and IQ deficits in the lower MAST score cocaine-dependent group could not be explained by decreased verbal abilities, a greater duration or frequency of cocaine use, or by a higher prevalence of Antisocial Personality Disorder. However, a chi 2 analysis revealed that this group contained more individuals who used cocaine in its 'freebase' or smoked form. Since the two cocaine-dependent groups were comparable in demographic and psychological characteristics, but had different levels of cocaine exposure, the results suggest that the decrements in abstraction scores reflect a cocaine-related effect.

Adult↗

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↗