Effectiveness of attention training in schizophrenia.

This study assessed the impact of attention training on information processing in schizophrenia. Fifty-four inpatients with chronic schizophrenia were randomly assigned to two groups after baseline assessment with the Continuous Performance Test (CPT). Patients in the experimental group participated in individual sessions of computerized attention remediation, while patients in the control group participated in individual sessions during which they viewed video documentaries. After 18 sessions, reassessment with the CPT showed that patients in the experimental group had made significantly more improvement than the control group, which made no significant change. Brief Psychiatric Rating Scale assessments before and after the study phase indicated that both groups improved on the total score but the experimental group made significantly more improvement. These results suggest that it is feasible to use practice and behavioral learning to remediate a core attention deficit in chronic schizophrenia.

The neuropsychological sequelae of attempted hanging.

Only one report on the neuropsychological sequelae of attempted hanging exists in the English language. Two cases of attempted hanging with subsequent isolated memory deficits are reported. Possible mechanisms for induction of this amnesia are discussed. In these two cases it is most likely that circulatory disturbance produced by the ligatures caused ischaemic hippocampal damage, which in turn led to amnesia.

Neuroradiological facets of cognitive abnormality in schizophrenia.

Cognitive abnormality has long been regarded as a core feature of schizophrenia, but its nature and etiopathology have been poorly understood. Predicated on new tests that characterize fundamental cognitive impairments, we investigated their relationship to four neuroradiological markers that have been previously implicated in schizophrenia: choroid plexus calcification, cerebellar atrophy, third ventricle enlargement, and pineal calcification. Twenty-three chronic schizophrenic inpatients meeting RDC and DSM-III diagnostic criteria were stabilized on chlorpromazine and assessed independently on a cognitive battery and on CT scan. The results indicated that all four neuroradiological variables were independent of one another and of demographic, historical, and general intellectual measures. The neuroradiological assessments, however, correlated significantly with different cognitive parameters, implying separate pathophysiological bases for distinct profiles of cognitive abnormality. The findings support a "dual-process model" of cognitive dysfunction that posits developmental and arousal-related components which may, more generally, underlie the positive-negative dimension of schizophrenia.

Atrophy of the cerebellar vermis: relevance to the symptoms of schizophrenia.

Degeneration of the cerebellar vermis is a common pathological and neuroradiological feature of chronic schizophrenia, but its relationship to symptoms of the disease are poorly understood. We investigated the relationship of vermal cerebellar atrophy on CT scan to features of positive (productive) and negative (defect) dimensions of schizophrenia as well as to symptoms of general psychopathology in a sample of 23 chronic schizophrenic patients. For comparison, we also studied the relationship of third ventricular width (TVW), which reflects periventricular and diencephalic atrophy, to these features of schizophrenic symptomatology. Vermal cerebellar atrophy was found in 43.5% of patients and correlated significantly with general psychopathology and, more specifically, with feelings of guilt and disturbance of volition. It was unrelated to global positive or negative features of schizophrenia. By contrast, TVW was uniquely associated with global negative syndrome. These observations indicate that degeneration of the cerebellar vermis and enlargement of the third ventricle are integral aspects of schizophrenia, and that each contributes independently to specific clinical aspects of the disease.

Visual information processing in positive, mixed, and negative schizophrenic syndromes.

The purpose of this study was to determine whether schizophrenics with positive, mixed, and negative syndromes are distinguished in terms of visual stimulus registration thresholds and efficiency of information processing. Forty-five schizophrenic inpatients were classified accordingly into groups of 15 each and compared with one another and with 15 normal control subjects on a visual backward masking task. Repeated-measures analysis of variance revealed that all three schizophrenic groups were less efficient information processors than were normal subjects. Relative to the positive group, the negative group displayed significantly longer registration thresholds, fewer correct target stimulus detections, and longer time intervals to achieve their first significant improvement in performance and to first exceed chance response levels. The three syndrome groups were not significantly different in their rates of improvement over trials. Secondary correlational analyses showed that the information-processing measures were unrelated to a variety of demographic, psychiatric, and cognitive developmental variables, although shorter recognition thresholds and shorter unmasking interval scores were associated with faster psychomotor rates. Complex interrelationships were uncovered between the information-processing measures, positive and negative symptomatology, and general psychopathology. The results were interpreted as supporting the validity of the positive-negative distinction for explaining some of the heterogeneity in schizophrenia.

Neurological signs and the positive-negative dimension in schizophrenia.

Schizophrenic patients have been observed to manifest a variety of abnormal neurological signs, but the nature of their association with differing clinical presentations is less well established. To address this issue, we administered a newly compiled neurological inventory to 28 well-characterized chronic schizophrenic inpatients and separately assessed them on the Positive and Negative Syndrome Scale and on control variables that included measures of global pathology, chronicity of illness, neuropsychological and intellectual integrity, and extrapyramidal dysfunction. We found, first, that our neurological battery provided statistically independent measures of apraxia, fine motor function, and prefrontal, parietal, and nonlocalizing signs. A significant association emerged between negative symptomatology and neurological signs of prefrontal impairment (p less than 0.01), which could not be accounted for by any of the control variables. Positive symptoms were associated with an absence of parietal and nonlocalizing signs; however, these correlations were mediated by higher neuroleptic doses in these patients. There was no association between any neurological sign and age, extrapyramidal symptoms, general neuropsychological integrity, education, IQ, or severity or chronicity of illness. We concluded that the negative syndrome in schizophrenia represents a distinct dimension of psychopathology that is related specifically to prefrontal deficit.