Longitudinal and prospective associations between neuropsychophysiological functions and immune status in HIV infection

Abstracts 7th IOP Scientific Meeting/International EEG spectra in delta, theta, alpha, beta I and beta II bandwidths were recorded from a 28 electrode array both in schizophrenic patients subclassified as belonging to an Active syndrome consisting only of positive symptoms, and Withdrawn or Mixed syndromes consisting of negative or a combination of negative and positive features. They were compared with normal controls. Recordings were taken in a resting, eyes-open baseline condition and while subjects performed a recognition memory task divided into four conditions: word acquisition and recognition, face acquisition and recognition. At baseline the patients with negative symptoms were distinguished by a right posterior temporal reduction (T6) in alpha Q~0.01). With both word and face tasks Active syndrome patients showed greater alpha reduction in the left than right hemisphere. In both beta I and II the Active syndrome when compared with the controls was characterised by elevations in left-sided activity. This was localised to T.5 in face recognition (beta I), and word and face acquisition and word recognition (beta II), but was widely distributed throughout the left hemisphere in face recognition for beta II. Compared with patients with negative symptoms the Active syndrome also had raised left frontocentral beta 11 activity. In contrast patients with negative symptoms were distinguished from controls by (1) a reduction in beta I activity in the left temporoparietal region, and in the anterior central region, extending to the right in the baseline and word acquisition conditions. and (2) an elevation of beta I activity in the right posterior region. The results provide some support for the syndrome/hemispheric imbalance model (Gruzelier, 1984). The Active syndrome shows increased left-sided activation, particularly in the faces recognition condition where it may be interpreted as incompatible with the right hemispheric task demands of faces processing and in keeping with the faces memory deficit of the Active syndrome. The patients with negative symptoms show abnormal activation in the right hemisphere in alpha and beta I. Both groups share a region of abnormal activity in the posterior left temporoparietal area.

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J. Gruzelier, A. Burgess, T. Baldeweg, M. Riccio, D. Hawkins, G. Irving. J. Stygall, S. Catt, P. Catalan, Department of Psychiotq Chclri12g Cross aid Westminster Me&cd School, University of Lmdon. Lmrdor~, UK We have examined the prognosis of up to 47 men in the course of a double-blind treatment trial in which zidovudine or placebo were given to asymptomatic, HIV-positive

Journal of Psychophysiology 18 (1994) 87-159

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men. Measures included neurological and psychiatric evalmood inventories, neuropsychophysiological uations, tests, EEG spectra, cortical evoked potentials and immune status. Individuals differed widely in changes in T cell counts over the 3-year study, with associations between increases in T4 counts with drug and decreases with placebo @<0.05). Of the various measures decline in immune status (T4 and T8 cells) was paralleled by a decline in visuomotor and manipulo-spatial functions, and the amplitude of EEG slow wave activity. Alpha amplitude increases across the study were more pronounced in those who progressed to symptomatic disease. Left hemispheric functions, or a left-right asymmetry pattern advantaging the left hemisphere, in the first 6 months of treatment were associated with: (1) time on drug such that the drug benefited performance, and (2) decline in immune status 2-3 years later, such that the poorer the initial performance, the poorer the outcome. Compared with other measures the neuropsychophysiology was sensitive to changes in immune function.

Incidence of epileptic focus location on the memory-related activity recorded from temporal lobe structures F. Guillem, B. N’kaoua. A. Rougier, B. Claverie, Lnborntoire de Neuropsychologie Exptrimentde, Universite’ de Bordeaux II, 83076 Bordeaux Cedex, France Neuropsychological research with epileptic patients has suggested that the location of the seizure focus may be an important variable determining the nature and severity of memory impairment. Assuming that memory traces are embodied by the activity of specific neural networks involving associative cortices and limbic structures, it has been argued that an epileptic focus located in one element of these networks may specifically affect memory-related activity in some structures while leaving such activity intact in others. This study was designed to investigate the hypothesis by examining the incidence of different epileptic lesions on the activity recorded directly from different temporal lobe structures during a recognition memory task. Intracranial event-related potentials (ERPs). were recorded from the hippocampus, amygdala and lateral temporal cortex in 23 epileptic patients. The patients were separated into three groups according to location of their epileptic focus: unilateral temporal (n=lO). bitemporal (t7=7) and multifocal (temporal plus extra-temporal; r1=6). The task was a continuous recognition memory task requiring the subjects to determine on each trial if the item had been seen previously (old) or not (new). For each subject the depth activity was averaged according to correctly classified new and old items. The