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Biomedical subjects

M Glabus

Publications and source records attributed to M Glabus.

5 recordsLinked to original sources
PubMed1994

Correlation of regional cerebral blood flow equivalents measured by single photon emission computerized tomography with P300 latency and eye movement abnormality in schizophrenia.

Single photon emission tomography with the intravenous blood flow marker 99mTc-exametazime was carried out in 14 acutely ill drug-free schizophrenic patients from whom P300 event-related potential, smooth eye pursuit eye tracking and verbal fluency were measured within a few days of scanning. Smooth pursuit eye movement abnormality correlated significantly with abnormal tracer uptake in superior pre-frontal cortex on the right and left and inferior pre-frontal cortex on the left. Abnormal eye movement was also associated with higher tracer uptake in left anterior cingulate and left posterior cingulate. P300 latency was significantly correlated with higher tracer uptake in left superior pre-frontal and left parietal regions. Verbal fluency performance was negatively correlated with tracer uptake in left frontal region. Eye tracking abnormality in schizophrenia is associated with bilateral frontal lobe disturbance and P300 latency increase with left-sided frontal and temporoparietal dysfunction. There was, however, a significant inverse relation between eye tracking abnormalities and abnormal perfusion in the left anterior cingulate region.

Adult↗
PubMed1990

Perceptual and physiological dysfunction in depression.

P300 responses to emotive words of different hedonic tones were assessed in depressed patients (unipolar major), patients recovered from the same type of depression and normal controls. Depressed patients showed a smaller amplitude of P300 in response to negatively toned words than to positive words; normal controls showed the opposite pattern and recovered patients showed a pattern of response which resembled that of depressed patients. The experimental trials comparing responses to negative and positive stimuli in relation to neutral words showed significant differences for negative as compared with neutral stimuli, but not for positive as compared with neutral stimuli. Latencies of P300 did not differentiate depressed patients from normal controls. The results are discussed within the context of the 'expectancy' theory of information processing.

Adult↗
PubMed1984

Delayed ventricular depolarization--correlation with ventricular activation and relevance to ventricular fibrillation in acute myocardial infarction.

Signal averaging to detect abnormalities in the terminal phase of ventricular depolarization has been performed in several groups of patients with various manifestations of ischaemic heart disease. Late potentials were common in patients with VT and in a group of patients having cardiac surgery. Findings in the surgical group highlighted the close correlation of late potentials with delayed, fragmented epicardial activation supporting the hypothesis that late potentials reflect a myocardial substrate which would support re-entrant VT. The findings in the surgical group allowed a definition of late potentials which could be applied to other patients in the study, and also demonstrated a spectrum of late depolarization abnormalities. Signal averaging is technically feasible in the noisy CCU environment but late potentials were detected in few patients early in AMI. Late potentials were also rarely seen in patients with VF and therefore cannot be construed as a predictive index of this arrhythmia.

Adult↗
PubMedDate not supplied

The effect of different high-pass filter settings on peak latencies in the event-related potentials of schizophrenics, patients with Parkinson's disease and controls.

Eighteen schizophrenic patients, 16 patients with idiopathic Parkinson's disease, and the same numbers of age, sex and education matched controls were examined with oddball experiments for the generation of P3. Individual averages were high-pass filtered at different cut-off frequencies with single-pole digital filters with equivalent analogue Butterworth filter profiles. The purpose of this procedure was to simulate analogue high-pass filters used in clinical studies from different centres and to examine their potential effect on group differences. Increasing high-pass filters resulted in a phase lead for all peaks examined (N1, P2, N2, P3). The only group differences were found for P3, which showed a greater phase lead in controls than in the patient groups, usually resulting in a more pronounced group difference. Similar wave forms and filter properties could be modelled by synthetic wave forms consisting of sine waves of different frequencies.

Acoustic Stimulation↗