Overinclusion, broad scanning, and picture recognition in schizophrenics

Rey-Osterrieth Complex Figure - copy and immediate recall: Normative data for the Latin American Spanish speaking adult population

OBJECTIVE

To generate normative data on the Rey-Osterrieth Complex Figure Test (ROCF) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate.

METHOD

The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the ROCF as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms.

RESULTS

The final multiple linear regression models explained 7-34% of the variance in ROCF copy scores and 21-41% of the variance in immediate recall scores. Although t-tests showed significant differences between men and women on ROCF copy and immediate recall scores, none of the countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated.

CONCLUSIONS

The present study is the first to create norms for the ROCF in Latin America. As a result, this study will have important implications for the formation and practice of neuropsychology in this region.

Perceptual Organization in Schizophrenia Spectrum Disorders: Empirical Research and Theoretical Implications

The research into perceptual organization in schizophrenia spectrum disorders has found evidence for and against a perceptual organization deficit and has interpreted the data from within several different theoretical frameworks. A synthesis of this evidence, however, reveals that this body of work has produced reliable evidence for deficits in schizophrenia, as well as for the clinical, stimulus, and task parameters associated with normal and abnormal performance. Recent models of cognition have also advanced understanding of the underlying pathophysiological processes of perceptual organization dysfunction in schizophrenia spectrum disorders. These suggest that deficits in perceptual organization may be one manifestation of a wider disturbance in the integration of contextually related information across space and time.

Parametric study of accuracy and response time in schizophrenic persons making visual or auditory discriminations

The inability to modulate processing time in conjunction with varying difficulty levels may be a core component of schizophrenia's cognitive deficit. In this study we used a parametric design to demonstrate this group's inability to increase and decrease response times in association with varying levels of task demand during auditory and visual recognition tasks. Unlike participants with schizophrenia, healthy volunteers responded to increasing levels of difficulty and high error by robustly increasing their average response times. In the group with schizophrenia, the greater the correlation between a subject's Response-Time and error rate the better was the subject in his/her overall discrimination accuracy. The higher their correlations the better they performed across all levels of difficulty in both modalities. The schizophrenia group's tendency to process high and low error conditions with similar behavioral resources may reflect a relatively static, non-dynamic cognitive repertoire.

A process-oriented approach for averting confounds resulting from general performance deficiencies in schizophrenia

The most pervasive and least well-addressed problem in cognitive studies of schizophrenia is the propensity of schizophrenia patients to show inferior performance on a variety of cognitive tasks. Consequently, apparent specific cognitive abnormalities may actually reflect the interaction of task discriminating power with generalized deficit. L. J. Chapman and J. P. Chapman (1973a) suggested psychometric approaches for eliminating such artifactual group differences. Unfortunately, their solution neglects important issues of process specification and does not provide a viable strategy for process-oriented investigators. Psychometric remediation of artifactual Group x Task interactions inevitably confounds the processes being measured, resulting in theoretically ambiguous findings. Moreover, evidence that changes in measurement reliability can both increase and decrease group discrimination challenges a basic underlying assumption of the Chapmans' matching solution. This article presents a process-oriented approach to solving this problem in schizophrenia research.

Visuomotor performance of schizophrenic patients and normal controls in a picture viewing task

The eye movements of 20 partially remitted schizophrenic outpatients (ICD-9) under neuroleptic maintenance medication and those of 20 normal controls were recorded using corneal reflection pupil-center measurement. The visuomotor performance during a 1-min picture viewing task was studied on the basis of several eye movement parameters. Clinical evaluation comprised self-ratings (Frankfort Complaint Questionnaire) and observer ratings (BPRS, CGI, GAS), as well as recording of current daily neuroleptic dosage (mg CPZ). The main results are that schizophrenics differ from normals in their correlational pattern of fixation- and movement-related parameters, reflecting two opposite viewing styles in schizophrenics: staring and extensive scanning. Both styles are differently related to clinical symptomatology. There was no strongly marked relationship with neuroleptic dosage.

Frontal lobe dysfunctions in schizophrenia--II. Impairments of psychological and brain functions

In Part I of this paper (Levin, 1984), it was proposed that the phenomena of eye movement impairments in schizophrenia are consistent with a dysfunction of frontal eye field mechanisms of ocular-motor control. In Part II, a frontal lobe dysfunction in schizophrenia is also proposed on the basis of clinical, psychological, neurochemical, and neuropathological grounds. There are striking similarities between the clinical frontal syndrome and negative symptom schizophrenia. Parallels between experimental studies of disturbances in attention and information processing, in humans and animals with frontal lobe lesions on the one hand, and in schizophrenics on the other, are noteworthy. The evidence for seemingly disparate dysfunctions in schizophrenia of eye movements, psychomotility, cognition, arousal, motivation and affect, is consistent with a disruption of frontal lobe mechanisms of stimulus-response and drive-response modulation. Studies on the neurochemistry and neuroanatomy of schizophrenia provide further evidence for a frontal lobe dysfunction in a subgroup of schizophrenic patients, particularly those with negative symptoms.

Verbal memory tasks showing no deficit in schizophrenia--fact or artefact?

Schizophrenics show a deficit in a variety of verbal memory tasks, except recognition memory, and incidental learning when recall is preceded by an ‘orienting task’ which ensures effective encoding. These two exceptions provide experimental evidence for the currently prevailing theory that it is a defect in effective encoding which is responsible for the observed schizophrenic verbal memory deficit. The present review concludes that these two exceptions are probably artefacts of unmatched tasks, and cannot be used to support the theory.

Overinclusion and manic symptomatology in schizophrenics

Examined the relationship between overinclusion and manic symptomatology in 46 schizophrenics using a reliable, structured research interview to assess symptomatology, and research diagnostic criteria to identify a subgroup of schizophrenics with concurrent manic syndromes. Of the three measures of overinclusive thinking employed in the study, only one significantly differentiated the schizoaffective and schizophrenic groups. Similarly, only one overinclusion test was correlated with the number of manic symptoms that patients exhibited. Finally, overinclusive and nonoverinclusive schizophrenics did not differ on specific manic signs and symptoms. Overinclusion also was unrelated to patients' overall levels of schizophrenic symptomatology. These results indicate that overinclusive thinking is related only weakly to manic symptomatology in schizophrenics, which suggests that this factor cannot account fully for the prognostic and cognitive benefits associated with overinclusion.