Cognitive concomitants of hemispheric dysfunction in schizophrenia

Forty-eight schizophrenics (24 paranoids, 24 nonparanoids) and 24 matched controls (12 men and 12 women in each group) were asked to detect the differences between 30 pairs of altered pictures presented successively (15 pairs) and simultaneously (15 pairs) in a counterbalanced order. Overall performance, as measured by reaction time and response quality, was better for controls than for schizophrenics. However, schizophrenics, like right hemisphere brain-damaged patients who presumably rely on their left hemisphere, reacted faster in the successive presentation procedure while the controls reacted equally fast in both conditions. These results support the hypothesis that schizophrenics tend to overactivate their left dysfunctional hemisphere. Twenty-four depressed patients, tested in the same procedure, showed a pattern of results similar to that of controls, suggesting that the results obtained for schizophrenics are not a general characteristic of psychosis.

Visual evoked response modified recovery cycle and personality dimensions in healthy and schizophrenic subjects

The aim of this study was to compare the results of the VER recovery cycle as modified by Shagass, in correlation with Eysenck's PEN personality questionnaire scores, in 41 schizophrenic inpatients and 41 healthy subjects. All the subjects were male. In the patient group, a lack of R2 response amplitude facilitation was found. In normals with a high score on the neuroticism scale, less facilitation was found in comparison with the group with low scores in the scale. In the schizophrenic group, the R2 latency did not change with increased S1 stimulus intensity, but in the group of normals the R2 latency increased. The schizophrenic group got higher scores on the scales of psychoticism and neuroticism and lower scores on the extroversion scale. Differences between groups on the psychoticism scale were not significant. A small but significant negative correlation was found between the psychoticism score and facilitation of R2 amplitude in the group of normals. This correlation was greater in the group with low neuroticism.

The sensory filter in schizophrenia: a study of habituation, arousal, and the dopamine hypothesis

The possible failure of a notional sensory filter in schizophrenia was studied by means of habituation of the orienting response. Non-paranoid schizophrenics failed to habituate, but paranoids habituated normally. Paranoids, however, showed a different impairment: they responded to a dishabituating tone as if the novel stimulus were somewhat familiar. The failure of habituation in non-paranoids could not be explained in terms of arousal when the index was the rate of skin conductance fluctuation. Neurotic controls showed considerably higher levels than either group of schizophrenics. Non-paranoid schizophrenics had lost the normal inverse relationship between habituation and level of arousal as manifested in the rate of spontaneous skin conductance fluctuation.

Visual evoked potential characteristics and subtypes of schizophrenia

Visual evoked potentials (VEPs) were recorded from the midoccipital area of 72 schizophrenic patients. The amplitude of wave VI (100- to 115-millisecond latency) was reduced after the addition test for 15 minutes. It recovered to the pretest level later, and four types of recovery curves were found; marked reduction in amplitude occurred in A1 (A1 type), in A3 with fast recovery (A3f type), in A3 with slow recovery (A3s type), and in A5 (A5 type) (A1, A3, A5: averaged potentials evoked by 1-Hz flashes which started 1 minute, 3 minutes, and 5 minutes after the end of the test). Each type closely corresponded to paranoid, atypical hebephrenic, typical hebephrenic, and simple schizophrenia, respectively.

[Alpha activity in a group of schizophrenics: spectral analysis and comparison with a control group (author's transl)]

Spectral analysis of tracings from four leads; C3-P3, P3-O1, C4-P4, and P4-O2, were used to compare the results of fiftyseven electroencephalograms from 10 schizophrenics, and 14 normal subjects used as controls. The results show that the mean frequencies of the alpha waves are identical in schizophrenics and controls. Patients with hebephrenia show the lowest variations in alpha wave frequency but with the highest voltage, whereas paranoid schizophrenics have tracings with the lowest amplitude and the greatest variation in frequency. There is also better left intrahemispheric correlation of relative alpha intensities in those patients with the lowest variation in right alpha intensity in relation to controls. The preliminary results suggest that there is a reduction in functional asymmetry of the hemispheres in the electroencephalograms from schizophrenics, when looking at the alpha activity.

Vestibular responses in schizophrenia

In a study of vestibular responses to caloric stimulation that controlled opportunity for fixation and state of alertness, we evaluated previous findings of diminished nystagmus in schizophrenia. We failed to replicate earlier reports in these respects: (1) None of the psychotic patient groups, when compared with normal controls, showed lower response intensity, latency, or culmination time of the nystagmic response. (2) The schizophrenic groups did not manifest a prevalence of clinically significant asymmetry. We did, however, observe that chronic deteriorated schizophrenics and recent schizophrenics have significantly greater dysrhythmic responses. This diminished orderliness of nystagmus may explain previous reports of absent or diminished nystagmus in the schizophrenics. The results are not compatible with peripheral vestibular disease in schizophrenia, but they may reflect state-related phenomena consistent with disturbances in alertness, which are not necessarily voluntary or motivational in origin.

Pattern evoked potential measurements suggesting lateralized hemispheric dysfunction in chronic schizophrenics

Visual evoked potentials (VEP) were measured to obtain evidence concerning possible lateralized hemispheric dysfunction in schizophrenia. The main results are based on the spatial distribution (12 electrodes) of a measure of VEP wave form stability over time. Subjects were 86 psychiatric inpatients and 33 nonpatients; these were grouped in three ways to permit comparisons of various age- and sex-matched diagnostic classes. Main findings were: (i) VEP wave form stability was generally lower in all types of schizophrenia than in nonpatients, nonpsychotic patients and, probably, psychotic depressives. (ii) VEP stability differed more between the hemispheres in schizophrenics and psychotic depressives than in nonpsychotic subjects; in schizophrenics, left hemisphere stability was lower than normal, whereas it was normal in psychotic depressives. (iii) VEP stability differences between the hemispheres were also greater than normal in latent schizophrenics, with less stability on the left. The results provide a direct demonstration of a left hemisphere involvement in schizophrenic dysfunction.

How do normal subjects learn a simple adaptative task: how and why do paranoid schizophrenic patients fail?

The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment. The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective. In schizophrenics further factors of importance were (1) an 'inertia' factor and (2) the rigidly continued use of unsuccessfuly or only partially successful decision criteria. The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on thses hypotheses was tested in a stimulation experiment. The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.

Evoked potentials of schizophrenics in several sensory modalities

This is the initial report of results obtained by a comprehensive approach to investigation of evoked potential (EP) characteristics of psychiatric patients. EP to left and right medion nerve, visual (checkerboard flash), and auditory (click) stimuli were obtained for 14 monopolar scalp and one EOG derivation in 32 schizophrenics and 16 nonpatients, matched for age and sex. Results showed amplitude attenuation of EP events 100 msec poststimulus or later in the patients' EPs of all modalities and in most lead locations. Attenuation of later EP events thus appears to be a general characteristic of schizophrenia. Comparisons of chronic paranoid and undifferentiated with other patient subtypes revealed a relatively specific correlate of the chronic subgroup, increased negativity of a negative somatosensory peak occurring 60 msec poststimulus (N60) at contralateral central leads.

Somesthetic hallucinations and motility in schizophrenia: neurophysiological views and information flow model

Clinical study of three schizophrenic men without known seizure disorders has heuristic implications, pointing to neurophysiological factors in their somesthetic hallucinations: (a) In two instances the body areas involved in such hallucinations (the abdominal cavity and the top of one foot) also happen to be represented side by side on the "map" of the receptive somesthetic areas at the postcentral gyrus. (b) In all three schizophrenic men the occurrence of their somesthetic hallucinations can be conceptualized along the lines of MacKay's (1970) information flow model for perception in general, with some specific modifications, which center around the key roles of sufficient change occurring in two specific aspects of this model. (c) Further conceptualization is suggested within Grey Walter's (1973) testable model of triple association among Conditional, Imperative and Operant Response--albeit mostly in reverse sequence with respect to somesthetic hallucinations under discussion. These schizophrenic men reveal in their past and present experiences a pattern in which the sequence of events is initiated through changes at the efferent side (restriction of voluntary motility), which trigger afferent experiences, albeit hallucinated ones. Practical implications center around the probably salutary role of voluntary motility performed purposefully and at the person's own pace.

[Dysfunctions of space perception and spatial ability in schizophrenia (author's transl)]

Thirty-seven acute schizophrenics and 25 normal subjects were investigated with regard to their spatial perception, representation, and their spatial ability, Schizophrenics showed significantly poorer performances (in terms of quantity) in those variables, which characterized the ocular apprehension of structures and wholes, the relation of parts to a whole, or the analysis of a whole in its various components as well as the availability of visual engrams, partly in the sense of spatial representation, and the practical realization of imagined spatial configurations. On the other hand, in ocular apprehension, interpretation, and when necessary the practical realization of two-dimensional represented spatial symbols and configurations and perspective abilities there was only statistical trend for quantitatively poorer performances in schizophrenics compared with healthy persons. Factor analysis of the intercorrelation matrices for 14 variables separated out the same 4 factors in each group for space perception and spatial ability. In spite of the demonstrated "quantitative" differences for the single variables between the two groups a marked similarity in a "qualitative" sense was found, when the two-factor structures were compared mathematically (similarity coefficient: 0.664). In order to specify these differences, 56 schizophrenics were classified as paranoid or nonparanoid and investigated in the above-mentioned manner. While these groups did not show any significant quantitative difference concerning their performances at variable level, they showed entirely different structures using factor analysis. Spatial perception of the paranoid schizophrenics seemed less structured and their perceptual conception less systematical. On the other hand, when factor structures from nonparanoids and healthy controls were compared mathematically, both groups showed a marked similarity (0.783). An attempt was made to relate these results to other findings of literature and to theories of cognitive and perceptual dysfunctions of schizophrenics.

Evoked response and kinesthetic measures of augmenting/reducing in schizophrenics: replications and extensions

This study represents an attempt to replicate the central results of earlier work on stimulus intensity control. It uses a diverse sample of 40 hospitalized schizophrenic subjects, both chronic and acute. Two measures of stimulus intensity control were used: the Petrie kinesthetic figural aftereffects procedure (KFA), and the EEG method of average evoked response (AER). Finding the earlier results generally applicable, it presents a model of the function of stimulus intensity control in schizophrenia, which suggests that acute schizophrenics are particularly vulnerable to being inundated by stimuli, and therefore, that in order to protect themselves, they tend to reduce the perceived intensity of stimuli. Chronic schizophreniics have higher AER amplitudes and reduce less than acutes, suggesting that among chronics, the reducing mechanism either never was present or failed, whereas paranoid schizophrenics tend to be augmenters--a response style consistent with vigilant scanning.

[Speech behavior of schizophrenics. Assay of an experimental point of departure (author's transl)]

Schizophrenic subjects and a control group of healthy subjects were tested with the following three language tasks: (1) to complete interruptions in a text, (2) to compose sentences from a sample of words written on cards and (3) to associate word cards to certain concepts. Besides the correct words, so-called irrelevant words were given as distracting stimuli. The inferior performance of the acute paranoid hallucinating subjects is interpreted in the sense of disturbance of cognitive selective functions. It is assumed that the central nervous inhibition of irrelevant stimuli fails to work successfully in certain groups of schizophrenics.

Studies of higher nervous activity in functional phychoses

Psychiatric illnesses can be conceived of as experiments of nature, providing a variety of pathopsychological mechanisms which may elucidate normal psychological processes. Clinically the reactive psychoses are predominantly psychogenic reaction types. They present disturbances of higher nervous activity, similar to those of the neuroses. The unconditional reflex activity is practically as in normal controls, and the most outstanding finding was the large effect of psychodynamic complex structures. This is a physiological parallel to the clinical manifestations with great concern over experienced mental trauma. In the manic-depressive psychoses the most characteristic feature is a marked disturbance of unconditional reflex activity. This factor may be an important physiological mechanism underlying the more biological than psychodynamic reaction type and partly explain the changes of mood and associated interferences with sleep, body weight, sexual activity, aggression and other instinctual and vegetative functions. Schizophrenic psychoses also present changes of unconditional reflex activity, predominantly in the direction of inhibition of response. In addition there are severe dissociations within and between the three levels of unconditional reflexes and the two signaling systems. It is suggested that schizophrenia represents a functional maladaptation, which can be explained from the principles of autokinesis and schizokinesis established by Gantt in animal experiments. Prognostic models based on experimentally established impairment of performances were shown to predict long-term risks of schizophrenic defects just as well as models based on constellations of clinical symptoms. I would predict that psychophysiology and experimental psychology will become increasingly more important for establishing diagnosis and prognosis in the functional psychoses. The data of this article point toward a basis for a prophylactic psychiatry.

[Schizophrenia and neuro-endocrine functional disorders--a case study on the problem of paranoid psychosis]

Schizophrenia and neuro-endocrine functional defects - a case report concerning the problem of paranoid psychosis: The case of a female patient with paranoic psychosis and endocrine defects has been reported. Under the present pathophysiological concepts the possibility of a combination of schizophrenic and neuro-endocrine symptomatic is suggested. The results of more recent investigations are discussed in respect of organic origin of schizophrenia that is based on potential reduction in the region of the limbic-hypothalamic nervous system.

Autonomic control, selective attention and schizophrenic subtype

Groups of paranoid reactive and nonparanoid process schizophrenic subjects participated in an experiment in which they were reinforced to modify attentional and autonomic responsiveness to differential excitatory and inhibitory avoidance stimuli. Groups did not differ in autonomic responsiveness or in ability to modify GSR and FPV activity to the differential avoidance stimuli. Groups were found to differ in their response to experimental instructions. Parenoid subjects reported being able to exert considerable emotional control during emotional stress. Nonparanoid subjects reported an inability to exert emotional control during stressful stimulation.

Blood flow and oxidative metabolism of the brain in patients with schizophrenia

55 patients with schizophrenia were divided into three groups according to the clinical symptoms: (1) productive schizophrenias, i.e. patients with hallucinations, catatonic excitation and stupor; (2) paranoia and schizophrenia simplex, and (3) non-productive schizophrenias, i.e. patients with schizophrenic defects and hebephrenia. Total cerebral blood flow (CBF) and the rates of cerebral oxygen, carbon dioxide, glucose and lactate metabolism were investigated. Patients with productive schizophrenias displayed a significant increase in CBF (to an average of 101.4 ml/100 g min), CMR oxygen (to an average of 6.26 ml/100 g min) and CMR glucose (to an average of 12.11 mg/100 g min), i.e. CBF and CMR oxygen nearly doubled and CMR glucose more than doubled in comparison with normal findings. In patients with paranoia and schizophrenia simplex CBF and oxidative metabolism did not vary much and were within the normal range. Non-productive schizophrenias showed a significant decrease in CBF (to an average of 36.7 ml/100 g min), CMR oxygen (to an average of 2.20 ml/100 g min) and CMR glucose (to an average of 3.86 mg/100 g min) in comparison with both other groups of schizophrenias and the group of healthy young men. The results demonstrated variations in CBF and oxidative metabolism of the brain in patients with distinct types of schizophrenia. It was possible to find a correlation between the mental state of the psychosis on the one hand and CBF and metabolism on the other. The high CBF and metabolic rates of the brain in productive schizophrenias might be due to disturbances in the cerebral metabolism of biogenic amines.

Speech perception in schizophrenia

Although there have been several reports of investigations of speech perception in schizophrenia (Laffal, 1961; Lawson, McGhie and Chapman, 1964) in all cases the assumption was made that the patients’ difficulties arose, not from an inability to perceive the individual words, but from a deficiency in perceiving the words in a meaningful relationship to each other, as part of an organized pattern. In this study, however, instead of examining the performance of schizophrenic patients on a task involving the perception of sentences, as these earlier workers had done, we have used individual words as stimuli in a series of tests of speech perception.

Psychosis, neurosis and epilepsy. Developmental and gender-related effects and their aetiological contribution

It is generally accepted that in mammalian evolution from rodents to primates, including man, aggressiveness, and more particularly intra-species aggression related to the assertion of dominance in the social hierarchy of the group, is a characteristic of the male (Gray, 1971). There is also an increasing body of evidence which shows that mammalian behaviour patterns are basically female and that male patterns are determined by the action of the sex hormone testosterone on neural structures during critical phases of intra-uterine development (Seymour Levine, 1966). Ounsted and Taylor (1972) have proposed that the X chromosome is sexually neutral, essentially equivalent to an autosome, and that its role in sexual differentiation lies in that it maintains ovarian function in the female. The Y chromosome is sex-determining by causing potential autosomal and X-coded information to become manifest in the phenotype. This is achieved in part by determining the development of foetal testosterone during a critical phase of foetal life. In the absence of testosterone the fundamental female morphology would be established in either sex.

Eye-tracking patterns in schizophrenia

A significant number of schizophrenic patients show patterns of smooth pursuit eye-tracking patterns that differ strikingly from the generally smooth eye-tracking seen in normals and in nonschizophrenic patients. These deviations are probably referable not only to motivational or attentional factors, but also to oculomotor involvement that may have a critical relevance for perceptual dysfunction in schizophrenia.

The relevance of the neurophysiological concepts of excitation and inhibition to clinical psychiatry

The discovery of the excitatory function of the brainstem reticular formation helped in the formulation of a number of psychological theories relating to arousal. The demonstration of sensory inhibition, and the discovery of inhibitory centres in the cortex, hippocampus and mid-pons provided a physiological explanation for the phenomenon of habitutation. The measurement of indices of arousal and habituation, together with careful clinical assessment, proved useful in a number of diagnostic studies.

In normal subjects arousal was subjectively perceived as wakefulness and was associated with predictable changes in physiological measures. The excitation-inhibition balance, measured by the amplitude of the orienteering reflex, its rate of habituation, and habituation point, was correlated with the Neuroticism Score on the Eysenck Personality Inventory.

Thought disorder schizophrenics failed in habituate, and paranoid schizophrenics had difficulty dishabituating, indicating abnormal inhibitory function. Some neurotic groups with symptoms of chronic anxiety, had an abnormally high state of arousal.

Impaired habituation in cases of Korsakoff's psychosis implicates the hippocampus in the mediation of inhibition. The catecholamines have an important role in regulating excitation, as shown by the increase in arousal associated with L-Dopa administration, and the decreased arousal shown after alpha methyl dopa.