Blink rate in childhood-onset schizophrenia: comparison with normal and attention-deficit hyperactivity disorder controls

Several lines of evidence have implicated central dopaminergic pathways in the modulation of blink rate. In the present study, blink rate during smooth pursuit was examined in 17 children with childhood-onset schizophrenia, on and off of clozapine, and compared to that of age-matched normal children and unmedicated children with attention-deficit hyperactivity disorder (ADHD). As has been observed in adolescent and adult schizophrenics, blink rate was significantly higher in schizophrenic children relative to normal and ADHD controls. Within the schizophrenic group, blink rate did not significantly change with the introduction of clozapine and was not related to clinical variables. Blink rate was positively correlated with deterioration in smooth pursuit in normal subjects.     

Cognitive Impairments and Disordered Speech in Schizophrenia: Thought Disorder, Disorganization, and Communication Failure Perspectives.

This article posits that basic cognitive impairments in schizophrenia are more highly related to speech disorder measured as communication failures than speech disorder measured as thought disorder or disorganization. The author tested 47 schizophrenia patients and 36 control participants for sustained attention, sequencing, and conceptual sequencing ability. Their speech was also rated for communication failures, thought disorder, and conceptual disorganization. Attention and sequencing impairments, examined hierarchically, explained a substantial 38% of the variance in the communication measure of speech disorder but little of the variance in formal thought disorder or conceptual disorganization. The author concludes that (a) impairments in attention and sequencing abilities contribute substantially to schizophrenic communication failures, and (b) it is important to consider lower level cognitive "3rd variables" when examining higher level cognitive associates of speech disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blink rate in pediatric complex partial seizure disorder

This study examined spontaneous blink rate, a putative measure of dopamine function, in 30 children with complex partial epilepsy and 61 normal children. The children with epilepsy had significantly lower blink rates than the normal children in a conversation and a verbal recall task, particularly if they had a schizophrenia-like psychosis, EEG evidence for left focal epileptic activity, illogical thinking, discourse deficits, and distractibility. They modulated their blink rates across a listening, a conversation, and a verbal recall task like the normal children. Given previously reported low blink rates in schizophrenic children, these findings suggest that children with complex partial epilepsy or schizophrenia might have similar biological features.     

Global attentional deviance as a marker of risk for schizophrenia: Specificity and predictive validity.

Evaluated global attentional deficits as possible childhood markers of schizophrenia. Performance deviance was assessed across a continuous performance test, an attention span task, and the Digit Span subtest of the Wechsler Intelligence Scale for Children (WISC). 63 children of schizophrenic parents, 43 children of parents with affective disorders, and 100 children of normal parents were tested when the children were 7–12 yrs old. A subgroup of Ss at risk for schizophrenia displayed extreme global deviance across attentional measures. Only a small number of Ss at risk for affective disorders and normal comparison Ss showed similar extreme attentional deficits. The global attentional deficits measured at these early ages were related to behavioral disturbances (behavior was assessed in 3–6 mo intervals since 1971) in young adulthood for Ss at risk for schizophrenia, but not for Ss in the affective risk group or in the normal comparison group. It is concluded that global attentional deficits have considerable specificity for predicting behavioral problems thought to be precursors of schizophrenia or schizophrenia-related disorders. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive substrates of thought disorder, I: the semantic system

OBJECTIVE: Few studies have explored in detail the relation of cognitive deficits in attention, working memory, and semantics to thought disorder. The authors sought to determine whether thought disorder resides in the semantic system or elsewhere. METHOD: Twenty-three normal comparison subjects and 23 patients with schizophrenia participated in the study. All subjects received tests of executive function and working memory, including the Wisconsin Card Sorting Test and the Letter-Number Span test; a test of deployment of attentional resources; and tests of semantic processing and language comprehension, including the Peabody Picture Vocabulary Test, the Speed and Capacity of Language-Processing Test, the Boston Naming Test, and tests of semantic verbal fluency and phonologic verbal fluency, from which was derived a difference score. All patients were also administered the Scale for the Assessment of Thought, Language, and Communication to assess thought disorder. RESULTS: The normal subjects were compared with the schizophrenic patients who were rated as having mild thought disorder (N=13) or moderate to severe thought disorder (N=10). While differences between the schizophrenic subgroups and the comparison subjects were observed on nearly all tests, a large difference in effect size between the two schizophrenic subgroups was apparent only in the verbal fluency difference score. In a series of multiple regression analyses, two variables made significant contributions to the prediction of positive thought disorder: the verbal fluency difference score and the Peabody Picture Vocabulary Test score. CONCLUSIONS: These results suggest that clinically rated thought disorder is associated with and may result from semantic processing abnormalities. In particular, patients with more severe thought disorder may have difficulty accessing semantic items because of disorganization of the semantic systems and, to a more limited degree, may also lack a semantic or conceptual knowledge base.     

Subclinical thought disorder in first-degree relatives of schizophrenic patients. Results from a matched-pairs study with the Thought Disorder Index

To assess the frequency and quality of formal thought disorder in schizophrenic patients and their first-degree relatives, a consecutive series of 36 unmedicated patients, 20 siblings of these patients and 37 normal control subjects were examined with Holzman's Thought Disorder Index (TDI). As a proof of the internal validity of this tool, the patients demonstrated significantly more thought disorder than the controls as measured by the TDI total score and various subscores, which proved the internal validity of this tool in a German-speaking sample. In addition, in a pairwise comparison with controls who were individually matched by age and sex the patients' siblings had a significantly higher total TDI score and nonsignificant elevations on several subscores (combinatory and flippant). As to the level of severity of the thought disorder, the siblings mostly took an intermediate position between patients and controls. In conjunction with previous reports from other authors, our findings lend further support to the notion of subclinical thought disorder as an indicator of familial vulnerability to schizophrenia.     

Spatial working memory deficits in the relatives of schizophrenic patients

BACKGROUND: Studies in nonhuman primates provide evidence that intact spatial working memory depends on the integrity of specific areas in the prefrontal cortex. Patients with schizophrenia have been shown to be impaired on spatial working memory tasks. Relatives of schizophrenic patients show a range of cognitive deficits in the absence of clinical symptoms (eg, thought disorder, eye tracking dysfunctions). We predicted that a significant proportion of relatives of schizophrenic patients would show deficits in working memory as measured by a delayed response task. METHODS: In experiment 1, we tested 18 schizophrenic patients, 15 first-degree relatives of schizophrenic patients, and 18 normal control subjects on an oculomotor delayed response task. In experiment 2, we assessed the performance of another group of 12 first-degree relatives of schizophrenic patients and 16 different normal control subjects on a visual-manual delayed response task. RESULTS: Relatives of schizophrenic patients showed significant deficits in working memory on both the oculomotor and visual-manual delayed response tasks. CONCLUSIONS: Some relatives of schizophrenic patients are impaired on tasks that tap spatial working memory and that implicate the prefrontal system. The delayed response paradigm may be useful in elucidating the multidimensionality of the schizophrenic phenotype.     

Schizophrenia and nicotinic receptors

Patients with schizophrenia often cannot respond to important features of their environment and filter out irrelevant stimuli. This dysfunction could be related to an underlying defect in inhibition--i.e., the brain's ability to alter its sensitivity to repeated stimuli. One of the neuronal mechanisms responsible for such inhibitory gating involves the activation of cholinergic nicotinic receptors in the hippocampus. These receptors are diminished in many specimens of hippocampal brain tissue obtained postmortem from schizophrenic patients. In living schizophrenic patients, stimulation of cholinergic receptors by nicotine transiently restores inhibitory gating of evoked responses to sensory stimuli. Many people with schizophrenia are heavy smokers, but the properties of the nicotinic receptor favor only short-term activation, which may explain why cigarette smoking is only a transient symptomatic remedy. This paper reviews the clinical phenomenology of inhibitory gating deficits in people with schizophrenia, the neurobiology of such gating mechanisms, and the evidence that some individuals with the disorder may have a heritable deficit in the nicotinic cholinergic receptors involved in this neurobiological function. Inhibitory gating deficits are only partly normalized by neuroleptic drugs and are thus a target for new therapeutic strategies for schizophrenia.     

Are there sex differences in neuropsychological functions among patients with schizophrenia?

OBJECTIVE: Studies of sex differences in neuropsychological performance in schizophrenia report inconsistent results, due in part to methodological artifacts. The study presented here was specifically designed to examine sex differences in neuropsychological performance. It was hypothesized that schizophrenic women would exhibit fewer neuropsychological deficits than schizophrenic men and that their performance would be more similar to that of normal women than schizophrenic men's performance would be to that of normal men. METHOD: Thirty-one outpatients with DSM-III-R-defined schizophrenia were systematically sampled from an extensive service network serving a large urban catchment area for seriously mentally ill persons. Twenty-seven normal comparison subjects were matched within sex on the basis of age, parental socioeconomic status, ethnicity, and handedness. An extensive neuropsychological test battery was administered, and multivariate analysis of variance was used to test for the effects of sex and group and sex-by-group interactions. RESULTS: Male patients were significantly impaired across all functions in comparison with normal male subjects and on tests of attention, verbal memory, and executive functions in comparison with female patients. Female patients performed significantly worse than female normal comparison subjects only on tests of attention, executive functions, visual memory, and motor functions. CONCLUSIONS: The findings suggest that women with schizophrenia may be less vulnerable to particular cognitive deficits, especially those involving verbal processing, than schizophrenic men.     

Effects of verbal communications of parents and children: A comparison of normal and schizophrenic families.

Investigated, within an etiological vs responsive framework, the relationship between intrafamily communication and schizophrenic thought disorder. Members of 11 families with schizophrenic sons and 11 families with normal sons participated as communicators and respondents in a structured task. The disordered communications of schizophrenic sons had an adverse effect not only on their own parents but on all parents who attempted to respond to them (p     

"Conceptual level" vs. "conceptual area" analysis of object-sorting behavior of schizophrenic and nonpsychiatric groups.

The Rapaport modification of the Goldstein-Gelb-Weigl Object-Sorting Test is used on a sample of 37 pairs of paranoid schizophrenics and nonpsychiatric patients to determine if schizophrenic thought reflects a marked loss of ability to conceptualize on an abstract level; or, is a disorder of communication. On the basis of the test results, the following conclusions are drawn: "1)… our schizophrenic group demonstrated a loss of social communication without evidence of impairment in abstractive ability. 2) Differences in conceptualization in the object-sorting task were clearly more closely associated with estimated test intelligence and education than with the presence or absence of schizophrenia… ." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired generation and use of strategy in schizophrenia: evidence from visuospatial and verbal tasks

BACKGROUND: The aim of this study was to investigate mnemonic strategic deficits in schizophrenic patients. METHODS: Analogous tasks were used that required the self-generation of an efficient strategy and its implementation in two domains: visuospatial and verbal. The tasks were given to 20 IQ preserved schizophrenics and 20 matched normal controls. A number of different scores was derived from each task including strategy, short-term memory capacity and perseveration. RESULTS: Overall, the schizophrenic patients were significantly impaired in their ability to generate effective mnemonic strategies on both tasks. In addition, on the visuospatial task there was no difference between the groups on the memory scores, but the schizophrenic patients made significantly more perseverative errors than controls. They were disproportionately worse on the verbal strategy task, showing impairment on memory as well as on strategy scores and were also impaired at semantically classifying the words. Performance was similar to the deficit seen in patients with frontal lobe excisions and Parkinson's disease, in terms of the inability to generate an effective strategy. The deficit on the verbal task was similar to patients with temporal lobe excisions who show impaired verbal memory. However, the pattern differed in the sense that the temporal lobe patients were able to generate effective strategies, unlike the patients with schizophrenia. CONCLUSIONS: High functioning schizophrenic patients are impaired in utilizing visuospatial and verbal mnemonic strategies. By comparing the results with those of neurosurgical excision patients, further evidence is provided for both frontal and temporal lobe involvement in schizophrenia.     

Superior temporal gyrus and planum temporale in schizophrenia: a selective review

1. The normal structure of the superior temporal gyrus (STG) has been elucidated from human and non-human primate research. This brain region is structurally complex, contains several distinct cellular regions and the area known as the planum temporale. 2. The STG connects with heteromodal neocortical regions and temporolimbic areas. 3. Functional studies of the normal STG in animals and in humans, using electrophysiology and PET/fMRI, emphasize the STG's role as part of a cortical network important in the interpretation, production and self-monitoring of language. 4. There is evidence for structural abnormalities of the STG in schizophrenia including both volume reductions and disturbances of normal asymmetries. 5. Functional studies of this region in schizophrenic patients, including measurements of evoked potentials and of bloodflow, are abnormal, especially when patients perform language tasks or experience hallucinations. 6. This structural and functional pathology in the STG probably represents one example of a more general disruption in schizophrenia of the neocortical network of which this region is an essential part. This disturbance may be closely associated with the symptoms of formal thought disorder and of auditory hallucinations commonly seen in the disorder.     

Thinking disorders in parents of young psychotic children.

Tested 17 parents of young psychotic children on the Object Sorting Test. 2 control groups were used. The sample differed from the replicated studies in that parents of adult schizophrenics were tested. Since childhood psychosis has substantial differences from adult schizophrenia, it was anticipated that parents of psychotic children would not show the same extent of thought impairment found in parents of adult schizophrenics. The Ss, however, showed more thought impairment than parents of normal children. Mothers showed more impairment than fathers. Findings were interpreted to suggest circumscribed test anxiety in association with a psychotic child rather than representing a formal thought disorder. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formal thought disorder and psychopathology in pediatric primary generalized and complex partial epilepsy

OBJECTIVE: To examine whether formal thought disorder and psychopathology occurred in children with complex partial seizures (CPS) rather than children with primary generalized epilepsy with absences (PGE) or nonepileptic children. METHOD: Formal thought disorder was coded in 30 children with CPS, 24 children with PGE, and 61 nonepileptic children, and structured interview-based psychiatric diagnoses were obtained for the epileptic subjects. RESULTS: The CPS subjects had significantly more illogical thinking than the PGE and nonepileptic children. The severity of their illogical thinking was related to global cognitive dysfunction and a schizophrenia-like psychosis. Age of onset and seizure control, however, were significantly associated with the severity of illogical thinking in the PGE group. One or more psychiatric diagnoses were found in 63% of the CPS and 54% of the PGE patients, particularly if they had global cognitive deficits. CONCLUSION: Illogical thinking, associated with cognitive dysfunction or schizophrenia-like symptoms, might be a feature of pediatric CPS. Psychopathology might be related to global cognitive dysfunction in pediatric CPS and PGE.     

Neurobiological findings in first admission patients with schizophrenia or schizophreniform disorder

Fifty patients with a DSM-III-R diagnose of schizophrenia or schizophreniform disorder were compared to 25 healthy volunteers on structural and functional brain measurements. The patients were studied during their first admission to psychiatric hospital. In the patient group correlations between structural and functional brain measurements and clinical symptoms were performed. Brain structure was studied by CT scans. The schizophrenic patients had significantly smaller brain volume and brain length and more sulcal, but not ventricular, CSF than the controls. These findings were not an effect of sex, abuse, educational status or neuroleptic treatment. Brain function was studied by rCBF measurement (at baseline conditions and during mental activation), neuropsychological tests and neurological examination. The patients had significantly lower rCBF in the prefrontal regions during baseline condition and this was more pronounced during mental activation when compared with the controls. In the striatal region the patients had higher rCBF than the controls during activation. In no other region did rCBF differ between the patients and the controls. This points to a dysfunction in schizophrenic patients somewhere in th fronto-striatal-thalamic circuit. The patients performed poorer than the controls on practically all the psychological tests. Especially poor performance was seen in the more complicated tests depending on ability of abstraction, planning and sequential organisation and on semantic memory. The patients had more neurological abnormalities than the controls. Correlations between brain structure and rCBF were few. The neurological impaired patient group had more signs of structural brain deficits than the neurological normal patient group. Poor performance on a variety of psychological tests was correlated to signs of structural cerebral deficits. The significant correlations between the neurobiological measurements and clinical symptoms in the patients were sparse. However there was a trend that more symptoms both positive, negative and thought disorder were correlated to higher rCBF values in frontal, temporal and striatal regions, and that absence of positive symptoms correlated to structural brain deficits. Thus both structural and functional brain deficits can be detected early in the disease of schizophrenia. The findings point to primary cortical deficits probably located in the frontal and temporo-limbic areas.     

A constant current source for extracellular microiontophoresis

There is evidence that some schizophrenic patients have deficits on tests of cognitive function, particularly tests of executive function, including the Wisconsin Card Sorting Test (WCST) and the Trail-making Test, Part B. This study was conducted to determine the generalizability of these findings across the schizophrenia spectrum to schizotypal personality disorder (SPD). Forty DSM-III SPD patients, 56 nonschizophrenia-related other personality disorder (OPD) patients, and 32 normal volunteers from two medical centers performed tests of executive function such as the WCST, Trail-making Part B, Stroop Word-Color Test, and Verbal Fluency, as well as tests of more general intellectual functioning such as the Wechsler Intelligence Scale-Revised Vocabulary and Block Design subtests, and Trail-making Part A. SPD patients performed more poorly on the WCST and on Trail-making Part B than did OPD patients or normal subjects; the groups did not differ on tests of general intellectual functioning. SPD patients may share some of the cognitive deficits observed in schizophrenia.     

Signal detection in vigilance tasks and behavioral attributes among offspring of schizophrenic mothers and among hyperactive children.

24 children of schizophrenic mothers, 20 children of mothers with nonpsychotic psychiatric disorders falling outside the schizophrenia spectrum, and 14 hyperactive children were examined relative to groups of individually matched comparison children and to a representatively stratified group of 67 normal children. Ss were 9–16 yrs of age. Children of schizophrenic mothers showed lower mean perceptual sensitivity (PS) than matched and stratified normal children and included an excessive number of extremely poor scorers. Neither children of mothers with nonpsychotic disorders outside the schizophrenia spectrum nor hyperactive children displayed a significant deficit in PS. Hyperactive children scored lower on a beta response criterion factor across vigilance tasks and were rated as higher on an Emotionality factor and lower on a Fearful Inhibition factor than their normal peers. The perceptual sensitivity deficit among children of schizophrenic mothers was found across motivational feedback conditions and was evident throughout the vigilance period. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability of formal thought disorder and referential communication disturbances in schizophrenia.

This study examined the degree to which different types of communication disturbances in the speech of 48 schizophrenia patients and 28 controls were variable and state related versus stable and traitlike. Clinically rated formal thought disorder and 5 types of referential disturbance showed substantial stability within participants over time. The sixth type of referential disturbance, the vague reference, was not stable over time. Formal thought disorder was associated with the severity of core psychotic symptoms in patients, whereas referential disturbances showed little or no association with positive or negative symptom severity. Furthermore, changes in psychotic symptoms over time were accompanied by corresponding changes in formal thought disorder but not referential disturbances. These results support the idea that some types of referential disturbances are traitlike and may be reflective of vulnerability as well as manifest illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)