Comparison of the touch-screen and traditional versions of the Corsi block-tapping test in patients with psychosis and healthy controls.

BACKGROUND: Working memory (WM) refers to the capacity system for temporary storage and processing of information, which is known to depend on the integrity of the prefrontal cortex. Impairment in working memory is a core cognitive deficit among individuals with psychotic disorders. The Corsi block-tapping test is a widely-used instrument to assess visuospatial working memory. The traditional version is composed of 9 square blocks positioned on a physical board. In recent years, the number of digital instruments has increased significantly; several advantages might derive from the use of a digital version of the Corsi test. METHODS: This study aimed to compare the digital and traditional versions of the Corsi test in 45 patients with psychotic disorders and 45 healthy controls. Both groups completed a neuropsychological assessment involving attention and working memory divided into the two conditions. RESULTS: Results were consistent between the traditional and digital versions of the Corsi test. The digital version, as well as the traditional version, can discriminate between patients with psychosis and healthy controls. Overall, patients performed worse with respect to the healthy comparison group. The traditional Corsi test was positively related to intelligence and verbal working memory, probably due to a more significant effort to execute the test. CONCLUSIONS: The digital Corsi might be used to enhance clinical practice diagnosis and treatment.The digital version can be administered in a natural environment in real-time. Further, it is easy to administer while ensuring a standard procedure.

Clinical and non-clinical hallucinations are similarly associated with source memory errors in a visual memory task.

Hallucinations have been found to be associated with various types of source memory failure in both schizophrenia patients and hallucination-prone healthy individuals. We investigated the associations of clinical and non-clinical hallucinations with source memory errors in a visual memory task that involved the remembering of picture presentation context. 59 schizophrenia patients and 61 healthy individuals took part in the study. Pictures were presented either at different locations or in association with different visual stimuli. The participants were required afterwards to recognize the target pictures among distractors, and then to remember their spatial location or the visual stimulus that was associated with them. Liberal response bias in picture recognition was associated with hallucination proneness and auditory-verbal hallucinations in subsamples of participants with significant non-clinical or clinical hallucinations. After controlling for overall memory performance, failure to remember the spatial location of the pictures was associated with visual hallucinations in male patients; failure to remember the associated visual stimulus was related to auditory-verbal hallucinations in female patients and to hallucination proneness in healthy women. The findings suggest that both clinical and non-clinical hallucinations are associated with loss of contextual information relative to the acquisition of events.

Predictors of clinical insight in first-episode psychosis: Different patterns in men and women.

BACKGROUND: We aimed to explore gender-related differences in the associations of insight impairment with clinical symptoms, metacognition, and social cognition in psychosis. METHODS: Regression analysis of several clinical insight dimensions was conducted on the data from 116 men and 56 women with first-episode psychosis. Various clinical symptoms and measures of metacognition and social cognition were entered as predictors. RESULTS: In both men and women, delusions emerged as a strong predictor of all insight dimensions, and verbal hallucinations as a strong predictor of symptom relabelling. In men, certain negative symptoms as well as self-certainty, lack of self-reflectiveness, impaired theory of mind, attributional biases, and a jumping-to-conclusions bias were additional predictors of poor insight, while good insight was associated with depression, anxiety, avolition, blunted affect, and impaired emotional recognition. In women, poor insight was associated with a self-serving/externalising bias, impaired emotional recognition, and attention disorders. CONCLUSIONS: Poor insight in first-episode psychosis is strongly linked to deficits in metacognition and social cognition, with marked differences between men and women with respect to the specific skills involved in the impairment. Meanwhile, good insight is linked to a variety of affective manifestations in men. These findings suggest new avenues for more targeted cognitive interventions to improve clinical insight in psychosis.

Neurocognitive bases of self-monitoring of inner speech in hallucination prone individuals.

Verbal hallucinations in schizophrenia patients might be seen as internal verbal productions mistaken for perceptions as a result of over-salient inner speech and/or defective self-monitoring processes. Similar cognitive mechanisms might underpin verbal hallucination proneness in the general population. We investigated, in a non-clinical sample, the cerebral activity associated with verbal hallucinatory predisposition during false recognition of familiar words -assumed to stem from poor monitoring of inner speech-vs. uncommon words. Thirty-seven healthy participants underwent a verbal recognition task. High- and low-frequency words were presented outside the scanner. In the scanner, the participants were then required to recognize the target words among equivalent distractors. Results showed that verbal hallucination proneness was associated with higher rates of false recognition of high-frequency words. It was further associated with activation of language and decisional brain areas during false recognitions of low-, but not high-, frequency words, and with activation of a recollective brain area during correct recognitions of low-, but not high-, frequency words. The increased tendency to report familiar words as targets, along with a lack of activation of the language, recollective, and decisional brain areas necessary for their judgement, suggests failure in the self-monitoring of inner speech in verbal hallucination-prone individuals.

Clinical insight in first-episode psychosis: Clinical, neurocognitive and metacognitive predictors.

OBJECTIVE: Poor insight is a major problem in psychosis, being detrimental for treatment compliance and recovery. Previous studies have identified various correlates of insight impairment, mostly in chronic samples. The current study aimed to determine clinical, neurocognitive, metacognitive, and socio-cognitive predictors of insight in first-episode psychosis. METHODS: Regression analyses of different insight dimensions were conducted in 190 patients with first-episode psychosis. Measures of clinical symptoms, neurocognition, metacognition, social cognition, and 'jumping to conclusions' bias were entered as predictors. RESULTS: Delusions, disorganisation, and certain negative symptoms were associated with unawareness in various domains, while depression was associated with greater awareness of illness. Deficit in theory of mind and self-reflective processes, as well as a 'jumping to conclusions' bias, contributed to poor insight. Several neuropsychological scores also contributed to this but their contribution was no longer observed in regression analyses that included all the previously identified clinical and cognitive predictors. A measure of perseverative errors was still associated with unawareness and misattribution of symptoms. CONCLUSION: In models that account for 28 % to 50 % of the variance, poor insight in first-episode psychosis is mainly associated with delusions and certain negative symptoms. At the cognitive level it does not appear to result from neuropsychological impairment but rather from altered reasoning bias and dysfunction in metacognitive processes. Therapeutic strategies specifically directed at these mechanisms could help improve the evolution of insight in first episode psychosis.

Processing speed and working memory span: their differential role in superficial and deep memory processes in schizophrenia.

Previous work has suggested that decrement in both processing speed and working memory span plays a role in the memory impairment observed in patients with schizophrenia. We undertook a study to examine simultaneously the effect of these two factors. A sample of 49 patients with schizophrenia and 43 healthy controls underwent a battery of verbal and visual memory tasks. Superficial and deep encoding memory measures were tallied. We conducted regression analyses on the various memory measures, using processing speed and working memory span as independent variables. In the patient group, processing speed was a significant predictor of superficial and deep memory measures in verbal and visual memory. Working memory span was an additional significant predictor of the deep memory measures only. Regression analyses involving all participants revealed that the effect of diagnosis on all the deep encoding memory measures was reduced to non-significance when processing speed was entered in the regression. Decreased processing speed is involved in verbal and visual memory deficit in patients, whether the task require superficial or deep encoding. Working memory is involved only insofar as the task requires a certain amount of effort.

Serial and semantic encoding of lists of words in schizophrenia patients with visual hallucinations.

Previous research has suggested that visual hallucinations in schizophrenia are associated with abnormal salience of visual mental images. Since visual imagery is used as a mnemonic strategy to learn lists of words, increased visual imagery might impede the other commonly used strategies of serial and semantic encoding. We had previously published data on the serial and semantic strategies implemented by patients when learning lists of concrete words with different levels of semantic organisation (Brébion et al., 2004). In this paper we present a re-analysis of these data, aiming at investigating the associations between learning strategies and visual hallucinations. Results show that the patients with visual hallucinations presented less serial clustering in the non-organisable list than the other patients. In the semantically organisable list with typical instances, they presented both less serial and less semantic clustering than the other patients. Thus, patients with visual hallucinations demonstrate reduced use of serial and semantic encoding in the lists made up of fairly familiar concrete words, which enable the formation of mental images. Although these results are preliminary, we propose that this different processing of the lists stems from the abnormal salience of the mental images such patients experience from the word stimuli.

Subclinical depression and anxiety impact verbal memory functioning differently in men and women -an fMRI study.

BACKGROUND: Depressive symptoms are known to affect memory efficiency in various populations. More specifically, several studies conducted in patients suffering from schizophrenia have indicated that memory efficiency is affected by depressed mood in female patients and by anxiety in male patients. We investigated, using neuroimaging techniques, whether similar gender-specific associations with subclinical depression and anxiety could be observed in a non-clinical sample. METHOD: Forty-five healthy Spanish-speaking individuals (23 females) were administered a verbal memory task. Lists of high- and low-frequency words were presented. Immediate free recall was requested after the learning of each list, and a yes/no recognition task was completed during the acquisition of the fMRI data. RESULTS: Regression analyses revealed that higher depression scores in women, and higher anxiety scores in men, were associated with poorer recall. In women, higher depression scores were further associated with decreased cerebral activity in the right temporoparietal junction, left inferior occipitotemporal gyrus, bilateral thalamus, and left anterior cingulate during correct recognition of target words. In men, anxiety scores were not associated with any cerebral activity. CONCLUSIONS: Subclinical depression in women appears to affect memory efficiency by impacting cerebral regions specifically recruited for the cognitive demands of the task, as well as cerebral regions more generally involved in arousal, decision-making, and emotional regulation. Anxiety in men might impact the encoding memory processes. The results, although preliminary, suggest that gender differences may need to be taken into account when developing strategies for the cognitive and pharmacological remediation of memory impairment.

Production of atypical category exemplars in patients with schizophrenia.

Previous studies have revealed semantic memory impairments in patients with schizophrenia, and suggested that certain of these impairments were related to thought disorganization. One explanation offered for this is a broadening of the boundaries of semantic categories in schizophrenia. We selected 16 semantic categories, and required a sample of 41 schizophrenia patients and 43 healthy control subjects to produce one exemplar from each category. The typicality of the subjects' responses was rated. The exemplars produced by the patients were on average less typical than those produced by the healthy controls. No significant association between typicality of the response and thought disorganization was revealed in the patient sample. Affective flattening, alogia, and anhedonia were significantly and inversely associated with the typicality score, that is, higher ratings of these symptoms were associated with more typical responses. Our results suggest that a broadening of semantic category boundaries is observed in patients with schizophrenia, but is unrelated to thought disorganization. This semantic abnormality is not a feature of the patients with high ratings of certain negative symptoms.

Impaired memory for temporal context in schizophrenia patients with hallucinations and thought disorganisation.

INTRODUCTION: Context processing deficiencies have been established in patients with schizophrenia and it has been proposed that these deficiencies are involved in the formation of positive symptoms. METHOD: We administered a temporal context discrimination task to 60 schizophrenia patients and 60 healthy individuals. Pictures were presented in two sessions separated by half an hour and the participants were required to remember afterwards whether the pictures had been presented in the first or the second session. RESULTS: The number of temporal context errors was significantly increased in the patient group. More specifically, it was highly significantly increased in a subgroup of patients presenting hallucinations, while the patients without hallucinations were equivalent to the healthy individuals. Regression analyses revealed that, independently of memory of the pictures themselves, verbal and visual hallucinations, as well as thought disorganisation, were associated with more temporal context errors. In contrast, affective flattening and anhedonia were associated with fewer of these errors. CONCLUSION: Inability to process or remember the temporal context of production of events might be a mechanism underlying both hallucinations and thought disorganisation.

Fluctuating asymmetry in patients with schizophrenia is related to hallucinations and thought disorganisation.

Fluctuating asymmetry represents the degree to which the right and left side of the body are asymmetrical, and is a sign of developmental instability. Higher levels of fluctuating asymmetry have been observed in individuals within the schizophrenia spectrum. We aimed to explore the associations of fluctuating asymmetry with psychotic and affective symptoms in schizophrenia patients, as well as with propensity to these symptoms in non-clinical individuals. A measure of morphological fluctuating asymmetry was calculated for 39 patients with schizophrenia and 60 healthy individuals, and a range of clinical and subclinical psychiatric symptoms was assessed. Regression analyses of the fluctuating asymmetry measure were conducted within each group. In the patient cohort, fluctuating asymmetry was significantly associated with the hallucination and thought disorganisation scores. T-test comparisons revealed that the patients presenting either hallucinations or thought disorganisation were significantly more asymmetrical than were the healthy individuals, while the patients without these key symptoms were equivalent to the healthy individuals. A positive association with the anxiety score emerged in a subsample of 36 healthy participants who were rated on affective symptoms. These findings suggest that fluctuating asymmetry may be an indicator of clinical hallucinations and thought disorganisation rather than an indicator of schizophrenia disease.

Depression, avolition, and attention disorders in patients with schizophrenia: associations with verbal memory efficiency.

The authors undertook a study of the clinical correlates of verbal memory deficits in schizophrenia. The first purpose was to replicate the finding of a significant association between depression and impairment in the deep encoding memory processes. The second purpose was to test the hypothesis that certain clinical symptoms--avolition, disorders of attention--also play a role in verbal memory impairment, distinct from a global negative symptomatology score. Forty-one patients with schizophrenia underwent a memory task including forward digit span and learning lists of words with different levels of semantic organization. Regression analyses revealed that the depression score was associated with the total number of recalled words, whereas the global negative symptom score was not. Depression score was not associated with the forward digit span, a measure of superficial serial encoding processes. An analysis of individual symptoms from the Scale for the Assessment of Negative Symptoms (SANS) indicated that avolition was associated with several memory scores, suggesting a pervasive effect of this symptom. Attention disorders were associated with impaired efficiency in serial learning, but not with word recall efficiency. It is suggested that more consideration should be given to depression and motivation in the investigation of cognitive impairment in schizophrenia, as well as in cognitive remediation strategies.

Working memory span and motor and cognitive speed in schizophrenia.

OBJECTIVE: The aim of this study was to investigate the verbal working memory deficit and decrease of motor and cognitive speed in patients with schizophrenia, and to clarify their associations with negative and depressive symptomatology. METHODS: Forty patients with schizophrenia and 41 healthy control individuals were administered the backward digit span to assess the working memory capacity, along with 3 tests of processing speed. RESULTS: Patients demonstrated reduced backward digit span, as well as decreased motor and cognitive speed. Regression analyses indicated that the backward digit span was associated with cognitive speed. It was not associated with either negative or depressive symptoms. Decreased processing speed was unrelated to negative symptoms, but the depression score was significantly associated with the cognitive speed measure. CONCLUSIONS: Working memory and processing speed seem to share a cognitive component. Depression, but not negative symptoms, affects processing speed, especially by decreasing cognitive speed.

Depression, auditory-verbal hallucinations, and delusions in patients with schizophrenia: Different patterns of association with prefrontal gray and white matter volume.

Structural brain abnormalities, including decreased gray matter (GM) and white matter (WM) volume, have been observed in patients with schizophrenia. These decrements were found to be associated with positive and negative symptoms, but affective symptoms (depression and anxiety) were poorly explored. We hypothesized that abnormalities in GM and WM volume might also be related to affective symptoms. GM and WM volumes were calculated from high-resolution T1 structural images acquired from 24 patients with schizophrenia and 26 healthy controls, and the associations of positive, negative, and affective symptoms with the brain volumes that showed significant reduction in patients were investigated. Patients demonstrated GM volume reductions in the bilateral prefrontal cortex, and WM volume reductions in the right frontal and left corpus callosum. Prefrontal cortex volume was significantly and inversely associated with both auditory-verbal hallucinations and depression severity. WM volume alterations, in contrast, were related to alogia, anhedonia, and delusions. The combined impact of auditory-verbal hallucinations and depression on similar sub-regions of the prefrontal cortex suggests that depression is involved in hearing voices. Further, this adverse impact of depression on prefrontal GM volume may underlie the impairment demonstrated by these patients in cognitive tasks that rely on executive processes.

Visual hallucinations in schizophrenia: confusion between imagination and perception.

OBJECTIVE: An association between hallucinations and reality-monitoring deficit has been repeatedly observed in patients with schizophrenia. Most data concern auditory/verbal hallucinations. The aim of this study was to investigate the association between visual hallucinations and a specific type of reality-monitoring deficit, namely confusion between imagined and perceived pictures. METHOD: Forty-one patients with schizophrenia and 43 healthy control participants completed a reality-monitoring task. Thirty-two items were presented either as written words or as pictures. After the presentation phase, participants had to recognize the target words and pictures among distractors, and then remember their mode of presentation. RESULTS: All groups of participants recognized the pictures better than the words, except the patients with visual hallucinations, who presented the opposite pattern. The participants with visual hallucinations made more misattributions to pictures than did the others, and higher ratings of visual hallucinations were correlated with increased tendency to remember words as pictures. No association with auditory hallucinations was revealed. CONCLUSIONS: Our data suggest that visual hallucinations are associated with confusion between visual mental images and perception.

Theory of mind deficits in chronic schizophrenia: evidence for state dependence.

There is evidence that people with schizophrenia show specific deficits in theory of mind (ToM). However, it is a matter of debate whether these are trait or state dependent, and the nature of the relationship between ToM deficits and particular symptoms is controversial. This study aimed to shed further light on these issues by (1) examining ToM abilities in 61 individuals with chronic schizophrenia during a stable phase as compared with 51 healthy controls matched by gender, age, educational level and current IQ, and (2) exploring the relationship between ToM and symptoms. Second order verbal stories and a non-verbal picture-sequencing task were used as ToM measures. Results showed no differences in ToM performance between patients and controls on either measure. Subsequent subgrouping of patients into remitted and non-remitted showed a worse performance of non-remitted patients only on second order ToM tasks. Specific ToM deficits were found associated with delusions. Association with negative symptoms was found to be less specific and accounted for by illness chronicity and general cognitive impairment. The results from the present study are in line with models which hypothesise that specific ToM deficits in schizophrenia are state dependent and associated with delusions. Such associations may also be task specific.

Verbal fluency in male and female schizophrenia patients: Different patterns of association with processing speed, working memory span, and clinical symptoms.

OBJECTIVE: Decreased processing speed in schizophrenia patients has been identified as a major impairment factor in various neuropsychological domains. Working memory span has been found to be involved in several deep or effortful cognitive processes. We investigated the impact that these 2 cognitive functions may have on phonological and semantic fluency in schizophrenia patients and healthy participants. METHOD: Fifty-five patients with schizophrenia and 60 healthy participants were administered a neuropsychological battery including phonological and semantic fluency, working memory, and cognitive and motor speed. RESULTS: Regression analyses revealed that motor speed was related to phonological fluency in female patients, whereas cognitive speed was related to semantic fluency in male patients. In addition, working memory span was related to verbal fluency in women from both the patient and the healthy control groups. Decreased processing speed, but not decreased working memory span, accounted for the verbal fluency deficit in patients. Verbal fluency was inversely related to attention deficit in female patients and to negative symptoms in male patients. CONCLUSIONS: Decreased processing speed may be the main factor in verbal fluency impairment of patients. Further, the cognitive and clinical predictors of verbal fluency efficiency are different in men and women. (PsycINFO Database Record

Amendment of traditional assessment measures for the negative symptoms of schizophrenia.

Schizophrenia research based on traditional assessment measures for negative symptoms appears to be, to some extent, unreliable. The limitations of the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS) have been extensively acknowledged and should be taken into account. The aim of this study is to show how the PANSS and the SANS conflate negative symptoms and cognition and to offer alternatives for the limitations found. METHODS: A sample of 117 participants with schizophrenia from two independent studies was retrospectively investigated. Linear regression models were computed to explore the effect of negative symptoms and illness duration as predictors of cognitive performance. RESULTS: For the PANSS, the item "abstract thinking" accounted for the association between negative symptoms and cognition. For the SANS, the "attention" subscale predicted the performance in verbal memory, but illness duration emerged as a stronger predictor than negative symptoms for outcomes of processing speed, verbal and working memory. CONCLUSION: Utilizing alternative models to the traditional PANSS and SANS formats, and accounting for illness duration, provide more precise evidence on the relationship between negative symptoms and cognition. Since these measures are still extensively utilized, we recommend adopting more rigorous approaches to avoid misleading results.

A large-scale study on the effects of sex on gray matter asymmetry.

Research on sex-related brain asymmetries has not yielded consistent results. Despite its importance to further understanding of normal brain development and mental disorders, the field remains relatively unexplored. Here we employ a recently developed asymmetry measure, based on the Dice coefficient, to detect sex-related gray matter asymmetries in a sample of 457 healthy participants (266 men and 191 women) obtained from 5 independent databases. Results show that women's brains are more globally symmetric than men's (p < 0.001). Although the new measure accounts for asymmetries distributed all over the brain, several specific structures were identified as systematically more symmetric in women, such as the thalamus and the cerebellum, among other structures, some of which are typically involved in language production. These sex-related asymmetry differences may be defined at the neurodevelopmental stage and could be associated with functional and cognitive sex differences, as well as with proneness to develop a mental disorder.

Second-to-fourth digit length ratio is associated with negative and affective symptoms in schizophrenia patients.

BACKGROUND: Higher levels of circulating oestrogens in women and testosterone in men have been shown to have a protective effect against the clinical manifestations of schizophrenia, mostly with respect to negative symptomatology. Certain studies suggest that they also have a protective effect against the neuropsychological impairment observed in the disease. We investigated whether greater prenatal exposure to estrogens in women and to testosterone in men, reflected by the 2D:4D ratio, was similarly associated with decreased negative symptomatology and improved neuropsychological functioning in patients. METHOD: 51 schizophrenia patients and 50 healthy participants were administered a neuropsychological battery. The 2D:4D ratio was measured in all participants. Positive, negative, and affective symptoms were assessed in patients. Regression analyses were conducted separately in male and female subgroups. RESULTS: No associations with positive symptoms were revealed. In male patients, the 2D:4D ratio was positively associated with avolition and inversely associated with anxiety. In female patients, it was inversely associated with alogia, and tended to be positively associated with depression. No association between higher prenatal concentration of the relevant sex hormone and improved neuropsychological performance emerged in patients. CONCLUSIONS: Higher concentrations of prenatal testosterone in male patients, and prenatal oestrogens in female patients, are associated with a decrement in certain aspects of negative symptomatology. In addition, prenatal sex hormone concentration seems to be associated with predisposition to anxiety in male patients, and to depression in female patients.