Exaggerated leftward bias in the mental number line of patients with schizophrenia

Several visuo-motor tasks can be used to demonstrate biases towards left hemispace in schizophrenic patients, suggesting a minor right hemineglect. Recent studies in neglect patients used a new number bisection task to highlight a lateralized defect in their visuo-spatial representation of numbers. To test a possible lateralized representational deficit in schizophrenia, we used the number bisection task in 11 schizophrenic patients compared to 11 healthy controls. Participants were required to orally indicate the central number of an interval orally presented. Whereas healthy subjects showed no significant bias, schizophrenic patients presented a significant leftward bias. Therefore, these results suggest an impairment in higher order representations of the number space in patients with schizophrenia, an impairment that is qualitatively similar to the deficit described in neglect patients.     

Decisional processing in paranoid and non-paranoid schizophrenics

40 schizophrenic subjects, divided into paranoid/non-paranoid categories and 14 normal controls were presented a task which involved making "same-different" judgments during random presentations of a series of visual comparison stimuli with a standard which represented the midpoint of the stimulus continuum. Using Sternberg's Choice RT paradigm for studying the locus of cognitive deficit, difficulty at the response-selection stage was manipulated while holding other stages constant. It was predicted that paranoids would have shorter RTs at easy decision points and longer RTs at difficult decision points relative to non-paranoids. The directions of the differences were as predicted but did not attain statistical significance. Both schizophrenic groups, compared to normals, made significantly fewer "same" responses on those trials where the comparison and standard were most similar.     

Parent and Child Effects on Cognitive Performance: An Experimental Approach to the Etiological and Responsive Theories of Schizophrenia

While many theorists have assumed that the family has an etiological part in the development of schizophrenia, most findings, since they come predominantly from observations after the illness has occurred, could plausibly be interpreted as family responses to the illness. In this experimental study, we constructed artificial families in order to measure independently of each other the effects of parents of schizophrenics on children and the effects of schizophrenic children on parents. Findings from a cognitive task requiring abilities to attend and abstract show that the presence of a schizophrenic child has only minor disruptive effects upon the performance of normal parents; parents of schizophrenics also have little effect upon normal children. Instead, the most consistent effects are those of normal parents on the schizophrenic child. Adolescent schizophrenic patients whose cognitive performance deficit is apparent prior to the experiment show significant improvement after having worked on the cognitive task with normal parents; their cognitive deficit disappears, and their performance is not different from matched normal children. Further investigation will center on the quality of the normal parents' “normalizing” effects.     

Effect of Adrenalectomy on Food,Water, and Saltwater Consumption in the Rat: A Methodological Study

The theory has been proposed that given sustained maternal control and rejection, the son may develop one of two primary styles of adapting to social evaluation; a closed style combines defensive tactics of social withdrawal and perceptual blocking, whereas an open style involves manipulative social approach and perceptual vigilance. The schizophreniform character of these two styles has been noted, drawing upon their parallels with process and reactive distinctions in schizophrenia, thereby presenting a hypothetical linkage between mother-child dynamics and the learning of schizophrenic behaviors. The present study tested the prediction that closed-style late-adolescents would show a deficit in recognizing evaluative words spoken near threshold in a female (“mother-figure”) voice. This prediction was generated by both the adaptive-style theory and empirical demonstration of this deficit in process schizophrenics. Results confirmed the prediction. Closed-style subjects recognized fewer female-spoken (relative to male-spoken) words than their control subjects, and open-style subjects did not. The closed-style deficit was especially obvious for those words on the list not having unfavorable connotations.     

Schizophrenic deficit in span of apprehension

We investigated two hypotheses about the span of apprehension task in schizophrenia: (a) schizophrenics show performance deficit on the forced-choice (FC) version but not on the full-report (FR) version, and (b) schizophrenic impairment on the FC version is greater when the display subtends a wide visual angle than when it subtends a narrow one. Schizophrenic (n = 21) and normal (n = 22) groups were tested on 3 versions of the task. A narrow-angle FC version was matched psychometrically with a wide-angle one by use of a greater number of noise letters in the narrow version. Schizophrenics reported fewer correct letters than normals on the FR version but did not differ on either the wide or the narrow FC versions. The results imply that schizophrenic deficit is not specific to the FC version and that on the FC version, visual angle is not more important than number of noise letters for demonstrating schizophrenic deficit.     

Functioning of the phonological loop in auditory hallucinations

Two experiments designed to assess the functioning of the phonological store and loop were carried out with schizophrenic patients experiencing auditory hallucinations, schizophrenic patients not experiencing hallucinations and normal subjects. In the first experiment, phonological encoding was assessed. Although both groups of psychiatric patients performed more poorly overall than the normal subjects, there were no significant differences between the performances of the hallucinating and nonhallucinating patients. In the second experiment, the unattended speech effect (a phenomenon thought to reflect the functioning of the phonological store in normal subjects) was assessed in hallucinating schizophrenic patients, non-hallucinating schizophrenic patients and normal controls. The psychiatric patients performed more poorly overall than the normal subjects, but there was no evidence of abnormal functioning of the phonological store or loop in either patient group. Overall, the findings indicate that phonological store and loop abnormalities are not implicated in the experience of auditory hallucinations.     

Schizotypy and sustained attention

We examined sustained attention in 32 schizotypic and 43 normal control subjects from a large, randomly ascertained nonclinical university population. Schizotypy status was determined with the Perceptual Aberration Scale. Sustained attention was measured with the Continuous Performance Test-Identical Pairs. Schizotypic subjects displayed significantly poorer sustained-attention performance than did control subjects, as measured by d and overall hit rate. Although schizotypic subjects evidenced greater levels of anxiety and depression, sustained-attention performance was not significantly associated with these mental state factors. Our results provide evidence for a subtle sustained-attention deficit among schizotypes and are interpreted in light of previous attention research with actual schizophrenic patients as well as children at risk for schizophrenia. Utility of the psychometric high-risk strategy in psychopathology research is discussed.     

Monaural and binaural story recall by schizophrenic subjects.

P. Green and other investigators have reported that schizophrenic Ss have poorer recall of stories presented to both ears than to the single best ear (binaural deficit) and poorer recall of stories presented to the left ear than to the right ear (monaural asymmetry) than do normal control Ss. These studies are plagued by potential methodological problems, including differences in overall accuracy, which artifactually affect the difference scores, and scoring methods that are vulnerable to systematic bias. In this study, scores of schizophrenic, bipolar, and normal control Ss on the Auditory Comprehension Test were compared. Scoring bias was avoided by the use of blind scoring and a revised scoring manual, and artifactual effects of accuracy were considered in interpreting the results. Contrary to previous findings, the groups did not differ on either monaural asymmetry or binaural deficit.     

Maintenance of grip-induced muscle tension: a behavioral marker of schizophrenia.

A grip-induced muscle tension maintenance task distinguished between schizophrenic patients, regardless of medication or hospitalization status, and both normals and controls with affective (unipolar and bipolar) disorders. Unaffected first-degree relatives of schizophrenic patients also showed a grip deficit. Coupling the grip task with a visual discrimination task that divided attention through instruction or reinforcement contingency, increased grip error times for all groups. No group differences appeared on the discrimination task, regardless of difficulty level, and the tone used to provide corrective feedback was not implicated in the grip deficit. The results suggest that the grip task is tapping, in a systematic and reliable manner, a motor-control abnormality that may be useful as a behavioral marker of schizophrenia.     

Self-focused attention in schizophrenic patients with and without auditory hallucinations and normal subjects: A comparative study

Self-focused attention has been implicated in a number of psychiatric disorders, but little research has examined this in schizophrenic subjects. In this study, a sample of schizophrenic patients experiencing auditory hallucinations, schizophrenic patients not experiencing auditory hallucinations and normal controls were asked to complete the private self-consciousness subscale of the Self Consciousness Scale. It was found that patients experiencing auditory hallucinations exhibited significantly higher levels of self-focus than those not experiencing hallucinations, although they did not differ from normal subjects. It was also shown that level of self-focus predicted whether or not subjects experienced hallucinations. These results, and their implications, are discussed with reference to the literature.     

What is perseverated in schizophrenia? Evidence of abnormal response plasticity in the saccadic system

Although perseveration is sometimes attributed to defective set switching, the authors have recently shown that set-switching is normal in schizophrenia. In this article, the authors tested for persistent states of the saccadic response system, rather than set perseveration. Schizophrenic and healthy subjects performed antisaccades and prosaccades. The authors analyzed for 3 carry-over effects. First, whereas the latency of the current saccade correlated with that of the prior saccade in both groups, the correlations under mixed-task conditions declined in healthy but not in schizophrenic subjects. Second, antisaccades in penultimate trials delayed upcoming saccades in schizophrenic but not in healthy subjects. Third, schizophrenic subjects were more likely to erroneously perseverate the direction of a prior antisaccade but not a prior prosaccade. The authors concluded that, in schizophrenia, the effects of correct antisaccades are persistent not weak. Saccades in schizophrenia are characterized by perseveration of antisaccade-induced changes in the saccadic response system rather than failures to switch task set.     

Th.o.m.a.s.: an exploratory assessment of Theory of Mind in schizophrenic subjects

A large body of literature agrees that persons with schizophrenia suffer from a Theory of Mind (ToM) deficit. However, most empirical studies have focused on third-person, egocentric ToM, underestimating other facets of this complex cognitive skill. Aim of this research is to examine the ToM of schizophrenic persons considering its various aspects (first- vs. second-order, first- vs. third-person, egocentric vs. allocentric, beliefs vs. desires vs. positive emotions vs. negative emotions and how each of these mental state types may be dealt with), to determine whether some components are more impaired than others. We developed a Theory of Mind Assessment Scale (Th.o.m.a.s.) and administered it to 22 persons with a DSM-IV diagnosis of schizophrenia and a matching control group. Th.o.m.a.s. is a semi-structured interview which allows a multi-component measurement of ToM. Both groups were also administered a few existing ToM tasks and the schizophrenic subjects were administered the Positive and Negative Symptoms Scale and the WAIS-R. The schizophrenic persons performed worse than control at all the ToM measurements; however, these deficits appeared to be differently distributed among different components of ToM. Our conclusion is that ToM deficits are not unitary in schizophrenia, which also testifies to the importance of a complete and articulated investigation of ToM.     

Fluency versus conscious recollection in category-production performance: the performance of schizophrenic patients

The purpose of this study was to investigate the relative contribution in schizophrenics of automatic processes (fluency) and conscious processes (conscious recollection) for the control of preencoded material in category production tasks. In one condition (Exclusion condition), subjects were told specifically not to produce previously presented words during the category-production task. This condition was compared with a standard category-production task in which subjects were told to produce the six first words that came to mind for a semantic category (Inclusion condition). In the inclusion condition, the effects of conscious control and automatic processes operated in the same direction, whereas in the exclusion condition automatic influences and conscious control were opposed. A recognition task followed the category-production tasks. Since the exclusion condition required conscious control of encoded items, we hypothesized that schizophrenic patients would be less able than control subjects to avoid producing study list items. These results indicated that schizophrenics' performance differed from these of control subjects in the exclusion condition but not in inclusion condition. Recognition performance was similar in both the schizophrenic and the control groups. These results suggest a defective conscious control in schizophrenic patients and confirm the data from the literature on explicit memory in these patients.     

The inappropriate smile and zygomatic muscle activity

Long-term recording of activity of the zygomatic muscle, the most important mimic muscle involved in smiling, was performed in 22 disorganized type schizophrenic patients with inappropriate smiles and 15 normal subjects in two separate experiments. During inappropriate smiles, the zygomatic muscle exhibited waxing and waning bursts of activity with an amplitude of 75 to 120 microV, which could not be distinguished from the activity observed during usual smiling in normal subjects. However, the duration of such activity tended to be longer when compared to that in usual smiling by normal subjects as well as by schizophrenic patients. In contrast to usual smiles, inappropriate smiles decreased with personal contact. When asked about their thoughts during smiling shortly after inappropriate smiles, more patients reported that they thought of nothing at all or something not necessarily pleasant rather than something pleasant that would be expected to induce smiling.     

Role of fear in mediating shuttle escape learning deficit produced by inescapable shock

The relation between the shuttlebox escape deficit produced by prior inescapable shock (IS) and fear during shuttlebox testing as assessed by freezing was investigated in rats. IS rats learned to escape poorly and were more fearful than either escapably shocked subjects or controls, both before and after receiving shock in the shuttlebox. However, fear and poor escape performance did not covary with the manipulation of variables designed to modulate the amount of fear and the occurrence of the escape deficit. A 72-hr interval between IS and testing eliminated the escape deficit but did not reduce preshock freezing. Diazepam before testing reduced both preshock and postshock fear in the shuttlebox but had no effect on the escape deficit. Naltrexone had no effect on fear but eliminated the escape deficit. This independence of outcomes suggests that the shuttlebox escape deficit is not caused by high levels of fear in IS subjects.     

Judging psychopathology: Expectation and contrast

An experiment was performed to assess the role of expectations in psychosocial contrast effects. Subjects were initially presented with a series of word definitions that were either high or low pathology; their task was to indicate those definitions that had been produced by schizophrenic (vs nonschizophrenic) patients. After this “induction” series, subjects were presented with a common “test” series that included both definitions and handwriting samples; they evaluated the degree of psychopathology that was implied by each item. Some subjects were required to state their expectations in connection with the test items. First they attempted to guess the percentage of schizophrenics in the overall test series; second, before being presented with each test item, they guessed whether the patient in question was (or was not) schizophrenic. Subjects' expectations were consistent with the induction series to which they were assigned; those assigned to the high-pathology induction expected the test series to include more schizophrenic patients than those in the low-pathology group. Nonetheless, despite these expectations, subjects showed a contrast effect in their evaluations of the test definitions (but not in evaluating the handwriting samples). That is, subjects from the low-pathology induction group rated the test definitions as being more pathological than did those in the high-pathology condition. Within-group correlations indicated that the subjects' expectations were directly related to subsequent judgments. A two-path model is discussed, relating (a) the respondents' induction group assignment, (b) his/her expectations, and (c) subsequent test judgments.     

Comparison of Beck Depression Inventories-IA and-II in Psychiatric Outpatients

The study of mental representations on projective tests such as the Rorschach has made substantial contributions to our understanding of psychopathology. It is not clear, however, whether the representations of paranoid schizophrenics can be differentiated from those of normals and whether the Rorschach is the best test for such comparison. Object representations on the Rorschach and a role-playing (Johnson & Quinlan, 1980, 1985) test were studied in groups of normal (n = 31) and schizophrenic subjects (divided into paranoid [n = 16], intermediate [n = 11], and nonparanoid groups [n = 16]). Developmental levels of representation on both tests were measured with the widely used system of Blatt, Brenneis, Schimek, and Glick (1976), derived from Werner's concepts of differentiation, articulation, and integration. Generally the groups were not differentiated on these measures on the Rorschach. The role-playing test showed greater discriminatory power than the Rorschach, possibly due to its explicit demand to produce representations of humans in interaction. Results of the role-playing test showed differentiation and integration scores were negatively correlated with measures of psychotic symptoms. Nonparanoids differed from the other three groups on differentiation measures, and paranoid and normal groups scored higher on integration measures than did the intermediate and nonparanoid groups. Paranoid subjects scored higher than nonparanoids on functional articulation and higher than intermediates on perceptual articulation; however, paranoid subjects were not differentiated from normals on any developmental measure. Differences between the schizophrenic sample and normals were explained entirely by the nonparanoid subgroup, supporting the paranoid-nonparanoid distinction and raising questions regarding the nature of the deficit in paranoid schizophrenia.     

Abstract conceptualization in schizophrenia: a fundamental psychological deficit?

Wright (1975) has recently argued that impairment in abstract conceptualization is an important schizophrenic deficit. We contend that the data to which he refers are insufficient support for that conclusion. Although schizophrenics' performance on sorting tasks may be less efficient than that of some other groups, the significance of this finding is debatable. A differential deficit in conceptual ability has not been shown and the confounding effects of third variables have not been ruled out. In addition, the validity of sorting techniques in measuring abstraction has not been adequately established. These methodological issues have a more general applicability to the study of psychopathology. Appreciation of them and a more specific definition of "acceptable evidence" would reduce considerably the continuing state of confusion in research on psychological deficit.     

The contingent negative variation laterality and dynamics in antisaccade task in normal and unmedicated schizophrenic subjects

Contingent negative variation (CNV) topography, hemispheric asymmetry and time-course were investigated in healthy subjects and non-medicated paranoid schizophrenic patients in two antisaccade paradigms with the short (800-1000 ms) and long (1200-1400 ms) durations of the fixation period. EEG and electrooculogram (EOG) were recorded. Saccade characteristics and mean amplitudes of slow cortical potentials time-locked to peripheral target were analyzed in 23 healthy volunteers and 19 schizophrenic patients. Compared to healthy control subjects, schizophrenic patients had significantly slower antisaccades and committed significantly more erroneous saccades in the both antisaccade tasks. The prolongation of the fixation period resulted in noticeable decrease of error percent in patients group. The analysis of CNV time-course has revealed two distinct stages in both groups. The early CNV stage was represented by a negative wave with the maximal amplitude over midline fronto-central area, and the late stage was characterized by increased CNV amplitude at the midline and left parietal electrode sites. In healthy subjects the simultaneous activation of frontal and parietal areas was observed in the paradigm with the shorter fixation interval; the increase of the fixation period produced consecutive activation of these areas. Schizophrenic patients' CNV amplitude was generally smaller than that of healthy subjects. The most pronounced between-group differences of the negative shift amplitude were revealed at frontal electrode sites during the early CNV stage in both modifications of the antisaccade task. The deficit of frontal activation revealed in patients at the early stage of antisaccade preparatory set in both antisaccadic paradigms may be related to pathogenesis of paranoid schizophrenia.     

The influence of reduced visual acuity on age-related decline in spatial working memory: an investigation

To investigate the relationship between visual acuity and cognitive function with aging, we compared low-vision and normally-sighted young and elderly individuals on a spatial working memory (WM) task. The task required subjects to memorise target locations on different matrices after perceiving them visually or haptically. The haptic modality was included as a control to look at the effect of aging on memory without the confounding effect of visual deficit. Overall, age and visual status did not interact to affect WM accuracy, suggesting that age does not exaggerate the effects of visual deprivation. Young participants performed better than the elderly only when the task required more operational processes (i.e., integration of information). Sighted participants outperformed the visually impaired regardless of testing modality suggesting that the effect of the visual deficit is not confined to only the most peripheral levels of information processing. These findings suggest that vision, being the primary sensory modality, tends to shape the general supramodal mechanisms of memory.