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Biomedical subjects

F Lolas

Publications and source records attributed to F Lolas.

At least 55 records · Page 3Linked to original sources
PubMed1982

[Syndromic diversities in Creutzfeldt-Jakob disease: neurophysiological and histopathological correlates].

Two syndromatic forms of Creutzfeldt-Jakob disease are illustrated with data from two cases confirmed by necropsy and studied by means of electroencephalogram, evoked potential recording and neuropathological techniques. One of the cases presented the typical hypersynchronous periodic discharges through to be characteristic of this disease. The other did not exhibit epileptiform discharges, showing an evolution in which progressive diffuse slowing was the prominent feature. Cortical spongyosis, gliosis, and neuronal lose were intense in the case showing spikes, and moderate in the one without spikes. Subcortical involvement was similar in both cases. This different topography of pathological involvement might explain, in addition to electroencephalographic findings, the different behavior of somatosensory evoked potentials, which were of larger amplitude in the case showing epileptiform discharges, although in both cases deterioration of clinical state was accompanied by a progressive amplitude decrement in the evoked potential. Sleep induced by barbiturates was disrupted in the case with spikes, its pattern being closer to normal in the case with less severe cortical involvement. A Wada test demonstrated that discharges in the hemispheres were independent. Spike periodicity is discussed. It is postulated that the heavier involvement of cortical layers II to IV deprive the remaining pyramidal cells of inhibitory influences, a condition which might explain the generation of periodic spike discharges.

Adult↗
PubMed1982

Extraversion and inhibition: a slow-potential study.

This report presents data showing that extroverts (Eysenck Personality Inventory) develop larger positive vertex slow potentials than introverts under extinction conditions ("no go" instruction in a fixed foreperiod reaction time task). The effect was clearer in subjects with low neuroticism (N) scores than in those with a middle N level. Since independent evidence indicates that cortical positivity is associated with inhibitory phenomena, results are interpreted as lending support to the notion that extroverts may develop more inhibitory potential than introverts under certain conditions.

Adult↗
PubMed1981

Situational influences on verbal affective expression of psychosomatic and psychoneurotic patients.

Group comparisons between psychosomatic and psychoneurotic patients using the Gottschalk-Gleser method of speech content analysis are presented. Two matched patient groups (N = 40 each) were discriminated on the basis of anxiety and hostility scores derived from verbal samples collected during psychoanalytically conducted first interviews. A concordance with clinical classification was reached in 79.75 per cent of cases, with psychosomatic patients exhibiting lower affect scores. These results could not be replicated in a comparison between 92 psychoneurotic and 56 psychosomatic patients based upon verbal samples produced in responses to a request to narrate a dramatic life episode (standard instruction). Percentage of correctly classified cases was 62.84 in the second study. Factor structures derived from affective variables showed more similarity between independent samples of psychoneurotic than between samples of psychosomatic patients across both exploration situations (interview and standard instruction). A major factor exhibiting high loadings from guilt anxiety and ambivalent hostility was evinced, being more important in psychoneurotics. These results are discussed against the background of the alexithymia notion. Methodological considerations pertaining to diagnostic applications of the Gottschalk-Gleser content analysis are presented.

Adult↗
PubMed1981

Psychophysiology of the reaction time experiment: a factor analytic approach.

A principal component factor analysis with varimax rotation was applied to behavioral and physiological data from a group of 25 subjects comprising normals and depressives, in whom event-related slow brain potentials were recorded during performance of a fixed foreperiod, reaction time task. Five of the seven factors thus evinced were labelled 'activation', 'inhibition', 'resilience', 'depressivity-neuroticism' and 'extraversion', the remaining two factors being related to arousal in an unspecified manner. Although no clear-cut partitioning of variance into trait, state and task-related components was achieved, the contention is advanced that measurement of these factors and their patterning might contribute to psychophysiological diagnosis, provided they are substantiated by further research.

Adult↗
PubMed1981

[Psychophysiologic research].

Psychophysiology is characterized as an experimental discipline aimed at the description of behavior which makes use of physiological analytical principles in order to formulate causation mechanisms. Psychophysiology expands behavioral description and focuses upon mediating mechanisms and intervening variables; it studies "whole organisms" under specified and controlled conditions permitting simultaneous evaluation of subjective experience and physiological data using techniques that disrupt minimally the process under study and not disturbing the subject. It is emphasized that psychophysiology is primarily a descriptive endeavour, its position being intermediate between basic neurobiology and social psychology. It may generate "translation rules" between different levels of behavioral analysis. A brief introduction to electrophysiological techniques is presented along with selected theoretical issues. Among these, a discussion of "intensity" and "direction" aspects of behavior is presented, emphasizing their interrelatedness and the fact that a "cerebral" and a "peripheral" psychophysiology could be distinguished on the basis of the "effector systems" explored and the purpose of the investigation. The contributions of psychophysiology to diagnosis, prognosis and treatment are discussed within the framework of different theoretical contexts.

Arousal↗
PubMed1981

[Psychophysiology and behavioral medicine. Reformulation of the psychosomatic approach].

A view on psychosomatic research is presented, based ona simplified version of general systems theory. Taking into account the difficulties derived from energetic and economic theories of affect, it is suggested that the three main relevant systems in the psychosomatic approach -person, two-persons, and group- could be studied resorting to the distinction between overt and covert behavior. This distinction is based on the position of the observer, which, along with the specification of the system under study and of the relationships between systems, constitutes an integral part of any general theory of behavior. Although the question concerning the usefulness of concrete, abstract and conceptual systems is left open, it is suggested that the system person might be profitably studied as a concrete system, thus granting an unified approach which could be provisorily defined as psychophysiological. Here the term is meant to imply a broad background to behavioral medicine, one of the major tenets being the notion of the information processing paradigm. From this viewpoint, affect is viewed as an aspect of information-processing mechanisms operating in living systems. Although the position outlined is primarily descriptive, it is contended that it might solve the difficulties posed by the "practical dualism" which has pervaded psychosomatic research, and lead as well empirically testable hypotheses related to the mechanisms responsible for psychophysiological dysfunction. From a broad notion of behavioral medicine, discrepancies derived from the use of apparently differing languages in psychosomatic research may be avoided.

Behavior↗
PubMed1980

On the measurement of alexithymic behavior.

It is suggested in this paper that alexithymia may be a graded behavioral characteristic in much the same way as psychological dimensions are. Under this assumption every person would possess an alexithymic score, however low it could be, and the basis for distinguishing between diagnostic groups would thence be quantitative rather than qualitative. The measurement of alexithymia in any given individual poses two main problems: the nature of the underlying phenomenon and the instruments that should be used for its depiction. Whether alexithymia is a trait, a state, or both cannot be answered confidently at present. On the other hand, its quantitative assessment depends upon an interaction between phenomenon, observer and situation. Some data bearing on the application of the Beth Israel Alexithymic and Psychosomatic Questionnaire by informed and uninformed interviewers suggest the need for reliability studies of this instrument. Also advanced is the possibility that some aspects of the syndrome (reflected differently in the questionnaire items) might be easier to detect or more amenable to quantitative assessment, thus suggesting that some weighting of items is needed in order to obtain a total alexithymia score.

Adult↗
PubMed1980

[Augmenting-reducing construct in evoked brain potentials: dynamic test of Eysenck's dimensions].

Eysenck's personality dimensions (neuroticism N, and extraversion, E) are formulated on the basis of levels of activity within the Central Nervous System. These can be explored by means of electroencephalographic techniques, such as the cerebral evoked potential (CEP). The augmenting-reducing construct allows the prediction of individual differences according to the tendency of subjects to augment or reduce sensory experience and CEP amplitude. The present work explores auditory CEP at increasing intensities in order to develop a stimulus-response function. A negative correlation between N score and the slope of the stimulus-response function for some CEP components was found. Together with the positive correlation between N score - CEP amplitude at minimum intensity, such data suggest a higher nervous system reactivity in subjects with high N score. For E dimension, a positive correlation between E score and latency of CEP components was found (inhibition effect). These findings support to some extent Eysenck's theory. The augmenting-reducing construct is discussed in terms of its contribution as a dynamic test of Eysenck's dimensions.

Adult↗
PubMed1979

Interhemispheric and sex differences in the visual evoked response recovery cycle.

The recovery cycle of the flash-evoked response was studied in 6 female and 6 male right-handed subjects of comparable age. The aim of the study was to evidence possible interhemispheric differences between occipital leads. Two flashes, presented at graded time intervals between 20 and 150 msec, allowed the computation of an amplitude ratio between the second and the first evoked response, considering the III--IV peak-to-peak amplitude. A faster recovery was found for the left hemisphere, with more pronounced interhemispheric differences in male than in female subjects. Women showed a more reduced amplitude recovery than men and a somewhat different time-course of the recovery function. Women also showed less waveshape similarity between evoked responses elicited by the second of a pair of flashes in the right and left hemisphere. These findings are discussed in terms of differences in speed of information processing by both cerebral hemispheres. It is suggested that recovery cycle studies may contribute to brain laterality research and be of particular relevance to psychiatric studies involving assumptions about differential hemispheric excitability.

Adult↗
PubMed1979

Alexithymia: anxiety and hostility in psychosomatic and psychoneurotic patients.

Verbal samples obtained from 40 psychoneurotic and 40 psychosomatic patients, matched with respect to age, sex, intelligence and some social indicators, were examined using different methods of content analysis. According to the concept of 'alexithymia' it was postulated that the restricted fantasy life and difficulty in expressing feelings attributed to psychosomatic patients would be reflected at the speech level (psycho-analytic interviews). The measurement of anxiety and hostility using the Gottschalk-Gleser scales gave the following results: with total anxiety in particular, and its subscales guilt, shame, separation and diffuse anxiety, and with hostility, the psychosomatic patients showed lower values than the neurotic patients, which were in part highly significant. The results confirm the existence of the 'psychosomatic phenomenon' but they do not permit statements concerning its etiology.

Anxiety↗
PubMed1979

The BAER profile: a method for reporting electrophysiologic brainstem examinations in clinical practice.

We present a method for graphically reporting the results of brainstem auditory evoked response examinations on the basis of multiple parameters. The method is based on a transform that normalizes the many latency and amplitude measures obtained from the averaged evoked responses of normal subjects tested under standardized conditions. Among the advantages of the method are the simplicity of its use, the identification of disease profiles, and the isolation of relevant parameters for research and diagnosis.

Adult↗
PubMed1979

[Event-related cerebral potentials. Classification and clinical use].

Event-related potentials (ERP) constitute an heterogeneous group of brain electrical signals time-locked to sensory stimulation, motor responses, and associative processes, recorded using computer averaging. Several kinds of brain electric activity are encompassed by the generic term "event related potentials": sensory evoked potentials, time-coherent cerebral events related to motor acta, long-latency potentials associated with psychological variables, slow potential shifts linked to psychological constructs, and "emitted" cerebral events of endogenous origin. Shortcomings of this classification are pointed out and a simpler one is proposed, distinguishing between sensory, motor, and associative time-locked potentials. Their clinical use is illustrated under six major headings: testing of sensory function, localization of lesions, maturation of the central nervous system, genetic markers, evaluation of pharmacologic agents, and indicators of cognitive processes. Some methodological issues relevant to the clinical use of ERP are discussed.

Association↗
PubMed1979

[Psychiatric perspectives of ethological anthropology].

Ethological anthropology is characterized as a biologically-based discipline aimed at the study of overt behaviour. Two of its main features are presented and discussed: its historical character and its protective nature. The first is a direct result of its being based upon evolutionary principles, emphasizing the adaptive character of behaviour and tracing back its origins and causation to phylogenetic adaptation and ontogenetic modification. The protective aspect is contrasted with other approaches--reflective theories--which adding a predominant role in the causation of behaviour to environmental influences. Within ethological theory the distinction is made between peristolabile and peristostable behaviours on the basis of their liability to environmental modification during individual development. For psychiatric research, ethological concepts are relevant both from a methodological and a theoretical standpoint. Their usefulness in comparative, transcultural and psychophysiologic studies is pointed out, as well as their applicability to research on human non-verbal communication and implicit behaviour. The contention is advanced that they provide an integrative framework of reference which combined with other approaches may permit the development of a comprehensive theory of human behaviour.

Anthropology, Cultural↗
PubMed1978

Event-related slow potential (ERSP) correlates of thyroid gland function level.

This study shows an association between thyroid gland function level and event-related slow brain potential (ERSP) parameters (peak amplitude and area under the curve), obtained during "classical" and "operant" reaction-time paradigms. A significant positive correlation between ERSP parameters and 24-hr I131 uptake and a negative nonsignificant one between them and ankle jerk reflex were found. Organismic factors related to thyroid function had greater influence upon ERSP amplitude and area than situational ones, for no significant effect of task was evidenced and no interaction between them was found under the conditions employed. Hyper- and hypothyroids showed also a tendency to present longer reaction times than euthyroids. These results are discussed within the framework of the arousal-distraction coupling hypothesis as proposed by Tecce and Cole (1976) and compared to those previously obtained in high-neuroticism anxiety-prone indivuduals. Although these and hyperthyroids do show indications of similar behavioral manifestations (excessive reactive arousal), both groups are considered to differ regarding empirical referennts of anticipatory arousal (ERSP parameters). A major difference seems to be the absence of a "ceiling effect" in hyperthyroids. This hypothetical phenomenon can be expected on the basis of the inverted U-shaped relation between ERSP amplitude and arousal level. A stronger "distraction" effect associated with increased arousal in anxiety neurotics is postulated and tentatively attributed to covert verbalizations of worry and feelings added to increased awareness of autonomic input. The contention is advanced that similar behavioral manifestations could be distinguishable at the physiological level employed and this might add further insights to diagnostic typologies (e.g., "psychosomatic" vs. "psychoneurotic" patients).

Adult↗
PubMed1978

Visual evoked responses and visual symptoms in multiple sclerosis.

Absolute latency, interocular difference in latency, and waveform of visual evoked responses (VER) to checkerboard reversal stimuli recorded from the midline of the skull were studied in 104 multiple sclerosis patients, 25 to 50 years of age, classified according to visual symptomatology. Group 1 had strong evidence of past or present optic neuritis. Patients with blurring of vision, diplopia, and undefined visual complaints were assigned to group 2, while group 3 contained patients with no visual symptoms but suspected diagnosis of multiple sclerosis on other grounds. The three parameters explored showed consistent association with the degree of visual involvement, as assessed by clinical impression, but their discriminatory power was diverse. Absolute latency was significantly longer in group 1 patients compared with groups 2 and 3, but it did not discriminate between the last two, whereas interocular difference in latency proved to be sensitive to differences between symptomatic (diplopia, blurring) and asymptomatic groups (2 and 3). Waveshapes were grouped into three categories based upon degree of distortion of the major positive peak, and their relative distribution among the three patient groups was found to be associated with symptomatology. We suggest that, in the production of symptoms such as diplopia, a temporal disparity of afferent impulses might be involved in much the same way that spatial incongruities between both eyes lead to impaired function. In this regard, interocular difference in latency rather than absolute latency would be a more accurate predictor of symptom development. The analysis of VER waveshape suggests, in addition, the importance of inhomogeneous involvement of the visual pathways in the production of symptoms during the evolution of multiple sclerosis.

Adult↗