PubMed Health⌕ Search

Biomedical subjects

T Baldeweg

Publications and source records attributed to T Baldeweg.

34 records · Page 2Linked to original sources
PubMed1996

Prospective associations between lateralised brain function and immune status in HIV infection: analysis of EEG, cognition and mood over 30 months.

Prospective relations between individual differences in both lateralised neuro-psychophysiological functions and mood ratings with immune status (CD4 and CD8 counts) were examined in asymptomatic HIV-positive men (n = 27) over thirty months. They participated in a controlled study of zidovudine versus placebo (results published elsewhere). Measures included EEG spectra, neuropsychological tests and mood ratings. A model of reciprocal lateralised influences on the immune system was tested whereby patients with left superior to right hemispheric functions were predicted to show a less deleterious outcome than those with the opposite asymmetry pattern. Prospective relations with immune status were found in the EEG with lateralised theta, alpha and beta activity; among cognitive measures with word fluency, semantic processing, and lateralised motor and recognition memory (word/face) processes; with mood ratings including depression, confusion and the total mood score. The nature of the effects supported the laterality predictions. These unique data, showing that neuro-psychophysiological factors in HIV+ but otherwise healthy subjects predict immune competence and compromise present 2-3 years later, warrant replication in a larger cohort.

Adult↗
PubMed1995

Neurophysiological evaluation of zidovudine in asymptomatic HIV-1 infection: a longitudinal placebo-controlled study.

The effect of early antiretroviral medication with zidovudine on neurophysiological functions was evaluated in subjects with asymptomatic HIV-1 infection. Patients were recruited participants of a larger double-blind randomised placebo-controlled treatment trial with zidovudine (Concorde). The main outcome measures included: quantitative electroencephalography (QEEG), auditory event-related potentials (AEP) and pattern-reversal visual evoked potentials (PRVEP), as well as standard clinical, virological and immunological markers. No significant impairment and no difference between treatment groups was found in visual P100 latency and auditory long-latency P3 responses which is in agreement with the absence of neurological and neuropsychological impairment over the study period. Significant treatment effects were revealed by quantitative electroencephalography (QEEG). While the placebo group showed a significant increase in delta and theta slow frequency QEEG activity over the study period, slow wave amplitude remained unchanged in the zidovudine group after a mean follow-up period of 28 months. In summary, the data provide evidence for a low level neuropathological process in asymptomatic HIV-1 infection which can be effectively suppressed by antiretroviral medication.

Adult↗
PubMed1995

Long-term zidovudine reduces neurocognitive deficits in HIV-1 infection.

OBJECTIVE: To determine the efficacy of zidovudine (ZDV) in preventing decline of neurocognitive functions in HIV-1 infection. DESIGN: Retrospective evaluation of subjects enrolled in a natural history study. Two analyses were made to evaluate the effect of (1) current ZDV, irrespective of length of treatment and (2) long-term ZDV treatment for at least 1 year. SETTING: Subjects were recruited from HIV out-patient clinics. PATIENTS: HIV-1-seropositive subjects were assigned to one of three groups according to the Centers for Disease Control and Prevention classification: asymptomatic infection (n = 60), symptomatic infection but without AIDS (n = 51), and AIDS (n = 32). MAIN OUTCOME MEASURES: Standardized neuropsychological and neurophysiological measures [electroencephalogram (EEG) and long-latency evoked potentials]. RESULTS: Long-term ZDV use was associated with improved cognitive performance in subjects with early symptomatic HIV-1 infection and AIDS, compared to subjects in the same clinical stage but without previous ZDV treatment. This was corroborated by neurophysiological evidence of reduced slow-wave EEG amplitude in the ZDV-treated subjects. The advantage of ZDV treatment was evident despite lower immune status in most treated subjects. CONCLUSIONS: The findings in this natural history study indicate that long-term ZDV treatment may be an effective prophylactic to reduce neurocognitive deficits in symptomatic HIV-1 infection, thereby lowering the risk for developing HIV-1-associated dementia.

Acquired Immunodeficiency Syndrome↗
PubMed1994

A longitudinal study of the neuropsychiatric consequences of HIV-1 infection in gay men. I. Neuropsychological performance and neurological status at baseline and at 12-month follow-up.

The aim of this study was to determine whether HIV infection is associated with neurological or neuropsychological impairment in the asymptomatic and early symptomatic stages of disease. Subjects included 61 gay men (41 HIV-, 20 HIV+) who were assessed at the time of requesting their first HIV test and again 12 months later. The assessments at baseline were conducted double-blind to HIV serostatus. Measures included a neuropsychological battery, neurological examination and full psychiatric assessment. There were no differences between the asymptomatic HIV+ and HIV- groups at baseline or at follow-up in terms of mean scores on neuropsychological tests. Mean scores were within the normal range for all neuropsychological tests for both groups. Multiple regression analysis was used to predict each individual's performance at follow-up on the basis of their baseline performance, psychiatric state, neurological history and drug use for each of the neuropsychological tests. HIV+ subjects were more likely than control subjects to perform at a significantly lower level at follow-up on one or more tests than predicted on the basis of their baseline performance.

AIDS Dementia Complex↗
PubMed1994

A longitudinal study of the neuropsychiatric consequences of HIV-1 infection in gay men. II. Psychological and health status at baseline and at 12-month follow-up.

The aim of this study was to determine whether HIV infection is associated with increased psychosocial distress in the asymptomatic and early symptomatic stages of disease and to determine the factors associated with reporting health symptoms. Subjects included 61 gay men (41 HIV--, 20 HIV+) who were assessed at the time of requesting their first HIV test and again 12 months later. Measures included a detailed standardized psychiatric interview (Present State Examination, PSE), a range of psychosocial self-report measures and a physical symptom checklist. There were no differences between the HIV+ and HIV-- groups in terms of self-reported symptoms. Multiple regression analysis showed that the symptom reporting was not associated with clinical or immunological markers of disease progression but was associated with measures of psychosocial distress. Although both groups showed elevated levels of psychosocial distress at the time of HIV testing, there were no differences between serostatus groups at follow-up. Multiple regression analysis indicated that the best predictors of PSE scores at follow-up were baseline PSE score and a history of psychiatric illness. Early HIV disease is not associated with increased psychosocial distress and symptom reporting is more closely related to psychological measures than to clinical or immunological markers of disease.

AIDS Dementia Complex↗
PubMed1993

Neuropsychiatric aspects of HIV-1 infection in gay men: controlled investigation of psychiatric, neuropsychological and neurological status.

The aim of this study was to determine whether HIV infection is associated with psychiatric morbidity or neuropsychological impairment in asymptomatic and early symptomatic stages of disease in gay men. The subjects were 100 gay men (68 HIV-ve, 32 HIV+ve, 6 being CDC IV). All subjects were recruited at the time of requesting their first HIV test and the assessment was double-blind to HIV serostatus. There were no differences in psychiatric status or neuropsychological performance between the HIV-ve and HIV+ve groups. Multiple regression analysis and logistic regression were used to identify factors associated with psychiatric morbidity, neuropsychological impairment and subjective reporting of memory problems and physical symptoms for all 100 subjects. Previous psychiatric history and current illegal (non-dependent) drug use were associated with psychiatric morbidity, poor education was associated with neuropsychological impairment and psychiatric status (score on HAD and PSE) was associated with subjective reporting of memory problems and physical symptoms.

AIDS Dementia Complex↗
PubMed1993

Detection of subclinical motor dysfunctions in early symptomatic HIV infection with topographical EEG.

Motor dysfunctions are amongst the earliest and most common signs of brain impairment caused by human immunodeficiency virus (HIV) infection. Topographical EEG was recorded in patients both with asymptomatic and early symptomatic infection (without acquired immunodeficiency syndrome (AIDS) defining illness), as well as in seronegative controls under resting and motor activation conditions. While patients' motor performance did not differ from control values, the EEG showed a consistent increase in rhythmic activity in Theta, Alpha and Beta frequency bands in Symptomatics. This amplitude increase was evident in different topographical regions during resting states as compared with motor activation, findings which suggest concurrent involvement of several motor areas possibly due to a functional impairment in subcortical integratory mechanisms. Comparing motor task and baseline both patient groups showed less consistent patterns of task-related EEG amplitude reduction than found in the control group. Here topographical EEG in connection with motor activation procedures was found to be more sensitive than behavioral measures of motor performance and offers a technique to assess treatment effects before the development of motor abnormalities in patients with HIV infection.

Adult↗
PubMed1993

Event-related brain potential correlates of self-reported hunger and satiety.

Perception of hunger and satiety was examined by means of event-related potential (ERP) recordings. On the basis of Helson's frame-of-reference theory, it was hypothesized that hunger is perceived with reference to an actual adaptation level. ERPs were recorded to adjectives (hungry, thirsty, tired) combined with one of five adverbs (very, almost, somewhat, hardly, not). Subjects indicated whether a particular adverb-adjective combination accurately described their actual feeling of hunger, thirst, or fatigue. They were tested after they had fasted for 16 hr and another time when they were satiated. Area of P300 of the ERP was smallest for adverb-adjective combinations agreeing with the subject's actual state of hunger (i.e., adaptation level), which was almost hungry in fasting subjects and hardly hungry in satiated subjects. These P300 minima were flanked by significantly enhanced (p < 0.001) P300 areas for the immediately adjacent adverbs combined with hungry. P300 areas for adverbs combined with thirsty and tired did not depend on the subject's state of hunger. The data suggest that perception of internal states, such as hunger, refers to an adaptation level that is sensitively indicated by P300 area.

Adult↗
PubMed1993

The psychosocial impact of HIV infection in gay men, drug users and heterosexuals. Controlled investigation.

The aim of this study was to establish the prevalence of current and past psychiatric morbidity in HIV seropositive asymptomatic subjects belonging to three transmission categories (gay men, intravenous drug users, and heterosexuals) compared with that found in HIV seronegative controls from the same groups. A cross-sectional, controlled study including 279 seropositive subjects belonging to groups II and III defined by the Center for Disease Control (94 gay men, 157 intravenous drug users, and 28 heterosexuals) and 159 seronegative subjects (38 gay men, 91 intravenous drug users, and 30 heterosexuals) is reported. Outcome measures included standardised, self-report questionnaires and a semistructured interview to assess current psychopathological status and past psychiatric history. In addition, a psychiatric diagnosis according to DSM-III-R criteria Axis I and II was made in the seropositive subjects. Results showed that these subjects differed very little from the controls and that overall levels of psychiatric disturbances in both groups were low and similar to those found in other life-threatening illnesses. Furthermore, intravenous drug users, regardless of HIV serological status, had the highest levels of psychological morbidity. Psychosocial distress was associated with previous and current lifestyle, independently of HIV status.

Adult↗
PubMed1992

Risk of deliberate self-harm and factors associated with suicidal behaviour among asymptomatic individuals with human immunodeficiency virus infection.

The study was aimed at evaluating the risk of deliberate self-harm (DSH) and factors associated with suicidal behaviour in 213 asymptomatic individuals with human immunodeficiency virus (HIV) infection in 3 transmission categories (68 gay men, 123 intravenous drug users and 22 heterosexuals). The results showed that 12 HIV-seropositive (HIV+) subjects were involved in DSH after the notification of a positive HIV test result, of which 8 occurred within 6 months and 4 between 6 months and 3 years. HIV+ subjects with a past psychiatric history showed a 7.7-fold increase in the relative risk of DSH, and HIV+ subjects with a history of DSH showed a 5-fold increase in the relative risk of DSH compared with HIV+ individuals without a past psychiatric history and a history of DSH. Professionals involved in the care of HIV+ individuals need to be aware of this risk, especially in the first few months after notification of HIV status and also at later stages of acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Auditory and visual event-related potentials in a controlled investigation of HIV infection.

Auditory and visual event-related brain potentials (ERPs) were used to complement neuropsychological and medical assessment in neurologically healthy subjects with asymptomatic and symptomatic human immunodeficiency virus type 1 (HIV-1) infection. Auditory and visual ERPs, recorded using standard oddball paradigms, disclosed delays in late waves (N2 and P3) in symptomatic subjects (CDC stage IV) when compared with matched controls. Abnormally delayed P3 waves in at least one modality were recorded in 41% of symptomatics and this was associated with deficits in neuropsychological performance, particularly psychomotor slowing. However, no differences in late wave latencies between asymptomatic and control subjects were found, though asymptomatics showed delays in auditory N1 and P2 latencies. The number of morphological abnormalities, such as indiscernible late waves as well as topographical variability of the P3 wave, was increased in both HIV seropositive groups and possibly indicates a distinct mechanism of impairment, different from latency delay. Whilst P3 delay in symptomatics was not associated with changes in immune function (T4 cells) there was, however, a link with anaemia and subclinical hepatic dysfunction.

Adult↗
PubMedDate not supplied

Recall and recognition confabulation in psychotic and bipolar disorders: evidence for two different types without unitary mechanisms.

Several forms of confabulation have been identified recently in schizophrenic patients, but it has not yet been investigated whether these forms are specific to schizophrenia. Furthermore, the origin of confabulation is unclear. The present study investigated recall and recognition confabulation and their relations with symptomatology, cognitive domains (abstraction and flexibility, verbal fluency, verbal memory, motor activity, and visual-motor processing/attention), computed tomographic (CT) measures (ventricular, cerebral, and Sylvian fissure size), and auditory event-related potentials (amplitudes and latencies of peak components in oddball paradigms) in 33 schizophrenic patients, 35 bipolar I patients, eight schizoaffective patients, and seven patients with other psychotic disorders. We found that neither type of confabulation was specific of any diagnostic group. Recall confabulation was mainly predicted by the predominance of positive symptoms, while recognition confabulation was predicted by a delay in P300 latency and the doses of antipsychotics used. Our results suggest two different mechanisms for both types of confabulation based on interference with the adequate retrieval of information and slowness in early stimulus detection.

Adolescent↗
PubMedDate not supplied

[Adaptation to the complexity of a task (a P300 study)].

In numerous studies the P300 component of the event-related brain potential (ERP) has been shown to occur in connection with stimulus evaluation processes. 10 healthy right-handed volunteers (3 women, 7 men) aged from 25 to 30 years (mean age 27.8 years) participated in the experiments. One of 5 equiprobably occurring two-letter strings appeared on the screen always at the same central location. The strings informed the subjects about the difficulty of subsequently presented mental arithmetic tasks. After the letter strings vanished from the screen the subjects were to press the space-bar whereby a mental arithmetic task was presented corresponding in difficulty to the preceding message. The EEG was recorded by means of Ag/AgCl electrodes from frontal (F zeta), central (C zeta) and parietal (P zeta) midline electrodes referenced to linked earlobes. EEG and EOG were sampled 1200 ms, starting 200 ms prior to string onset. P300 peak latencies, peak amplitudes and areas in the time range 300 to 900 ms were measured in ERPs averaged selectively for the 5 strings. The main finding was that the P300 amplitude in ERPs to the 5 different strings varied in a U-shaped trend as a function of announced task difficulty. This result gives further evidence that the P300 amplitude reflects distance between incoming information and current adaptation level at the inferred internal dimension, i.e. task difficulty in this experiment.

Adaptation, Physiological↗