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Biomedical subjects

J Gruzelier

Publications and source records attributed to J Gruzelier.

51 records · Page 3Linked to original sources
PubMed1990

Psychological and psychophysiological characteristics in irritable bowel syndrome.

Psychiatric disorder is reported to occur in a large proportion of patients with irritable bowel syndrome (IBS) and psychological treatment methods have been advocated for this patient group. In a sample of 25 out-patients with intractable IBS, only four patients with psychiatric disorder were identified. The majority did not have elevated levels of anxiety or depression nor was there evidence of significant abnormal illness behaviour. Electrodermal activity did not show the extremes of responding and habituation associated with anxiety, depression or chronic pain. It is suggested that, when accurate diagnostic criteria are employed, a specific relationship between IBS and psychopathology is no longer evident.

Adult↗
PubMed1989

Electrodermally differentiated subgroups of anxiety patients and controls. II: Relationships with auditory, somatosensory and pain thresholds, agoraphobic fear, depression and cerebral laterality.

Patients diagnosed (DSM III) with anxiety disorders (agoraphobia, panic syndrome, generalised anxiety syndrome) were classified along with controls as electrodermally stabile or labile on the basis of non-specific electrodermal activity and rate of habituation to tones. While patients showed more evidence of psychopathology than controls on scales of anxiety, neuroticism, depression and agoraphobic fear, patient labiles scored higher than stabiles on agoraphobic fear and were differentiated by higher scores of Beck depression. They were also more sensitive to pain, whereas patient stabiles were less sensitive at absolute somatosensory threshold. Amongst controls agoraphobic fear was associated with lability and stabiles scored higher on autonomy in locus of control. Lateral asymmetries in auditory thresholds were consistent with reciprocal hemispheric influences on electrodermal reactivity and habituation, modifiable by anxiety. Interrelationships between fear, depression, sensitivity to somatosensory stimulation, pain, and superior vigilance performance in patient labiles were consistent with elevated right hemisphere function.

Agoraphobia↗
PubMed1988

Impairments on neuropsychologic tests of temporohippocampal and frontohippocampal functions and word fluency in remitting schizophrenia and affective disorders.

Experimental neuropsychologic tests were administered to acute patients with schizophrenia and affective psychosis and to normal controls. Patients had remitting illnesses. Tests included memory for recurring digit and block spans (left and right temporohippocampal), digit and block spans (lateralized parietal/frontal), spatial and nonspatial conditional associate learning (frontohippocampal), and oral word fluency to letter-designated categories (frontal) and semantic-designated categories (left-sided). In 81% of schizophrenic patients patterned deficits incompatible with generalized losses of function were disclosed. Patterns were heterogeneous and characterized by (1) the frequency and severity of left temporohippocampal impairment; (2) asymmetric frontohippocampal function such that severity of bilateral impairment was associated with poorer nonspatial learning and superior performance with better nonspatial learning; (3) syndrome relationships predicted by the hemisphere imbalance syndrome model pertaining to positive and negative symptoms and the catatonic syndrome; (4) a generalized deficit independent of temporohippocampal functions; and (5) no relationship between performance and computed tomographic signs or medication. Patients with affective disorders had patterned deficits characterized by bilateral impairments that disclosed a preponderance of deficits in spatial learning and memory; depressives demonstrated impairments in digit span.

Affective Disorders, Psychotic↗
PubMed1988

The use of bilateral skin conductance measurement in elucidating stimulus versus response processing influences on the orienting reaction.

In three experiments the importance of behavioural consequences as a determinant of the amplitude of the electrodermal response is demonstrated. Bilateral skin conductance responses were examined to same-different stimuli consisting of moderate intensity tones differing in pitch (S1, S2), to a response cue to make a unimanual button-press if the stimulation were judged the same (S3), and to feedback (S4). In the first two experiments in which a right-hand action was required, responses were larger to S2 than S1 on 'response', compared with 'no-response' trials. This was replicated in the second experiment where the same effect was also found to S3. In the third experiment the hand performing the action was varied; the influence of stimulus consequences on responses to S2 was replicated when the right hand performed the action; when the left hand was involved elevated responses to S2 occurred, irrespective of the perceptual judgement. In all experiments responses tended to be larger on trials where a correct judgement was made. The use of bilateral recording with a unilateral behavioural response confirmed the influence of effector functions on electrodermal responses. Hemispheric influences were contralateral and excitatory. The results were discussed in terms of multiple central determinants on electrodermal responses, the influence of cerebral laterality, and of sympathetic-somatic coupling.

Adult↗
PubMed1988

A psychophysiological differentiation between hypnotic behaviour and simulation.

Psychophysiological differentiation between conditions of hypnosis and simulation were examined with markers evolved from a series of experiments charting neuropsychophysiological accompaniments of hypnotic behaviour. Eighteen subjects participated in two sessions in which bilateral electrodermal activity was monitored to moderate intensity tones. Measurement in Session I, a Baseline-Control, of individual variation in rates of habituation of orienting responses, non-specific responses and tonic levels of skin conductance, enabled allocation of matched groups to Session II in which the same auditory stimuli were mixed with a taped hypnotic induction. Half the subjects were instructed to fake hypnosis and the others to comply. In session II the groups were differentiated as follows: (1) rate of habituation to the tones was retarded in the simulation condition and facilitated in the hypnosis condition compared with baseline; (2) the incidence of non-specific electrodermal responses was elevated in simulators after instructions to 'fake hypnosis'; (3) right-hand levels of skin conductance were elevated in simulators; (4) all but one subject in the hypnosis condition admitted to hearing the tones whereas all but one in the simulation condition claimed not to have heard them.

Adolescent↗
PubMed1987

Rate of habituation of electrodermal orienting responses: a comparison of instructions to stop responding, count stimuli, or relax and remain indifferent.

Thirty-nine subjects listened to two series of repetitive tones, the second series of which was of higher or lower pitch and of higher intensity. Before the first series all subjects were given conventional instructions to relax and adopt a passive attitude to the tones. Before the second tone series one of three instructions was given: to maintain a relaxed and passive attitude, to inhibit responding, to count the stimuli silently. The three groups showed roughly equivalent rates of habituation to the first tones series but the group instructed to count the tones showed slower habituation than the groups instructed to remain indifferent or to inhibit responses. A recommendation to clarify task demands in habituation experiments, by informing subjects that the aim was to see how quickly subjects stopped responding, showed no advantages over conventional instructions.

Adult↗
PubMed1984

Electrodermal activity to auditory stimuli in autistic, retarded, and normal children.

Electrodermal activity to auditory stimuli was compared in 20 autistic children and their matched retarded and normal controls (N = 80). The autistic children were virtually indistinguishable in individual features of electrodermal activity from controls when both chronological and mental age comparisons were accounted for. When patterns of activity were considered globally, both autistic and retarded children could be distinguished from one another and from normal controls. However, in some respects autistic and same-aged normal children were alike--both showed sensitization to 70-dB tones and both had a higher incidence of children with larger left- than right-hand responses, interpreted as evidence of focused attention under left hemisphere control.

Acoustic Stimulation↗
PubMed1984

Hypnotic susceptibility: a lateral predisposition and altered cerebral asymmetry under hypnosis.

Psychophysiological and behavioural evidence is reported of altered cerebral asymmetry under hypnosis in favour of the right hemisphere. This occurred in Susceptible as distinct from Unsusceptible subjects. Measures included bilateral electrodermal responses to tones and bimanual processing times for sorting letters and numbers with eyes closed. Subjects listened to a tape recording of a procedure for inducing relaxation under hypnosis. Susceptible subjects, unlike Unsusceptibles, showed lateral asymmetries in baseline conditions in favour of the left hemisphere. Electrodermal responses were larger on the left than the right hand and haptic processing times were faster with the right than the left hand. Under hypnosis there was a reduction in electrodermal orienting responses coupled with faster habituation and a reversal in lateral asymmetries. Haptic processing revealed a slowing in right hand processing times whereas left hand times were reduced as was the case with bilateral processing times in both Unsusceptible subjects and controls who experienced no hypnosis. Unlike earlier reports left hemisphere dynamic processes were fundamental to the induction of hypnosis. A neuropsychological model is proposed whereby susceptibility is associated both with a left bias prior to hypnosis and left hemisphere inhibition under hypnosis. Unsusceptibles retain a right hemisphere orientation without undergoing left hemisphere inhibition. Thus hypnosis involves an inhibition of left-sided processes which permits the ascendancy of the right hemisphere through the attenuation of left hemisphere control.

Adolescent↗
PubMed1982

The syndrome of schizophrenia: relations between electrodermal response, lateral asymmetries and clinical ratings.

Forty-eight undrugged hospital admissions with a present state examination (PSE) diagnosis of schizophrenia were subdivided by the direction of lateral differences in electrodermal response amplitudes to tones. The 29 with larger right-hand responses and the 19 with larger left-hand responses were compared on CATEGO syndromes and brief psychiatric rating scale (BPRS). The larger group had symptoms like those of classical Bleulerian schizophrenia--blunted affect, emotional withdrawal, impaired social functioning, disorganized thought and retarded motility. The other group manifested florid symptoms including hypomanic affect, pressure of speech, ideas of reference, depressive hallucinations and delusions, hypochondriasis, grandiosity and situational anxiety. The psychophysiological measures may provide an objective aid to diagnosis and implications for altered cerebral organization in psychotic patients.

Adolescent↗
PubMed1981

Effect of propranolol and phenothiazines on electrodermal orienting and habituation in schizophrenia.

Bilateral electrodermal orienting responses were measured to repeated auditory stimuli in schizophrenic patients and controls. In 3 studies phasic activity to moderate intensity sounds of patients on no drugs or phenothiazines was predominantly hyper- or hypo-responsive. Controls showed moderate or slow habituation. Propranolol was found to facilitate habituation in slow habituators and to reinstate responses in half of non-responders, especially when given as the sole drug. The effects seldom had a counterpart in changes in non-specific responses or levels of skin conductance. Modulatory influences on stimulus and response processing and on lateral asymmetries in responses may underlie propranolol's efficacy in treating schizophrenia.

Acoustic Stimulation↗
PubMed1980

Active and passive avoidance learning in controls and schizophrenic patients on racemic propranolol and neuroleptics.

Normal controls and schizophrenic patients on propranolol as sole drug or combined with neuroleptics showed superior active and passive avoidance learning to schizophrenic patients who were medicated with conventional neuroleptics only. Active avoidance involved responding quickly, passive avoidance withholding a response to avoid an unpleasant noise and reacting to the appropriate stimulus. This may reflect an improvement brought about by propranolol in the limbic regulation of stimulus and response processes.

Adult↗
PubMed1975

Changes in serum tryptophan and albumin binding of tryptophan in chlorpromazine-treated chronic schizophrenics on withdrawal and restoration of drug therapy.

Withdrawal of drug from a group of chlorpromazine-treated chronic male schizophrenics led to a significant rise in the initially low serum tryptophan concentration, and a rise in the fraction freely diffusible. These changes, which would be expected to lead to an increase in tryptophan influx into the brain, and hence to an increase in cerebral serotonin synthesis, could be related to the clinical effects of drug withdrawal.

Adult↗
PubMedDate not supplied

Orienting, habituation, sensitisation, and dishabituation in the electrodermal system of consecutive, drug free, admissions for schizophrenia.

Thirty-three consecutive admissions for schizophrenia with PSE diagnoses and free of neuroleptics were compared with 31 hospital staff for distinguishing features of bilateral electrodermal activity to a sequence of mild tones followed by a sequence of conspicuous tones with variation of temporal parameters. To mild tones most patients were either non-responders or non-habituators whereas most controls were habituators or non-habituators. To conspicuous tones patients as a group were more responsive but without the features of sensitisation to a test stimulus shown by controls. Patients as a group had more non-specific response and higher levels of skin conductance which showed less adaptation than controls. To a large extent previously reported difference in response latencies, rise-times and half-recovery times would appear to be a function of habituation rate. Patient -control differences may reflect anxiety and stress in patients, though lateral asymmetries in activity have a deeper salience for the nature of schizophrenia.

Acoustic Stimulation↗
PubMedDate not supplied

15O positron emission tomographic scanning in predominantly never-treated acute schizophrenic patients.

Positron emission tomography with oxygen-15 was used to compare regional cerebral blood flow and the regional cerebral metabolic rate of oxygen in a group of predominantly never-treated, acute schizophrenic patients and in matched controls. The results of this study did not support the hypothesis that schizophrenics have reduced frontal blood flow and/or metabolism; and only equivocal support was obtained for the hypothesis that metabolism within the basal ganglia is reduced in schizophrenics. However, support was obtained for the hypothesis that an abnormality in hemisphere laterality may underlie schizophrenic illness.

Acute Disease↗