Memory and executive function impairments in deficit syndrome schizophrenia

Cognitive Dysfunctions Measured with the MCCB in Deficit and Non-Deficit Schizophrenia

This study compared cognitive domains between deficit schizophrenia (DS) and non-deficit schizophrenia (NDS) patients and healthy controls (HC), analyzing relationships between psychopathological dimensions and cognitive domains. A total of 29 DS patients, 45 NDS patients, and 39 HC subjects participated. Cognitive domains were measured using the Measurement and Treatment Research to Improve Cognition in Schizophrenia Battery. Psychopathological symptoms were evaluated with the Positive and Negative Syndrome Scale. Clinical groups performed poorer than HC groups in regards to speed of processing, attention/vigilance, working memory, verbal and visual learning and memory, reasoning and problem solving, and social cognition. DS patients scored poorer than NDS patients in terms of all cognitive domains and the overall score, except for reasoning and problem solving. Positive, negative, disorganization, and resistance symptoms were related to cognitive functions only in NDS patients. Our findings suggest that the MCCB battery is sensitive to detecting cognitive dysfunctions in both deficit and non-deficit schizophrenia.

"Guttmann Cognitest"®, preliminary validation of a digital solution to test cognitive performance

Thanks to technological advances, the administration of cognitive assessments via digital solutions continues to increase, both in research and clinical practice. "Guttmann Cognitest"°ledR is a digital solution for cognitive assessment which includes seven computerized tasks designed to assess main cognitive functions requiring approximately 20 min to be completed. The purpose of the present study was to validate it against standard and more extensive in-person neuropsychological assessments in the context of the Barcelona Brain Health Initiative (BBHI) cohort study. We studied 274 participants of the BBHI (126 women, mean age = 56.14, age range 44-69), who underwent an extensive in-person assessment, including a classical paper-and-pencil neuropsychological assessment and a cognitive assessment via the "Guttmann Cognitest"°ledR. Principal component analysis indicated that "Guttmann Cognitest"°ledR measures four main cognitive domains and convergent validity analysis demonstrated that cognitive performance was associated with gold standard paper and pencil tests. Results also showed an expected negative correlation with age, a relation with educational level as well as a gender effect. Regression-based norming equations for the sample tested are also reported. Performing a cognitive assessment with this digital solution is feasible and potentially useful to gather information about cognitive functioning in large samples and experimental settings.

Differences in inflammatory marker profiles and cognitive functioning between deficit and nondeficit schizophrenia

Deficit schizophrenia (DS) patient is a homogenous subtype of schizophrenia that includes primary and enduring negative symptoms. This study aimed to compare the differences in cognitive functioning and plasma levels of C-reactive protein (CRP) and inflammatory cytokines among DS patients, nondeficit schizophrenia (NDS) patients, and healthy controls (HCs). A total of 141 schizophrenia patients and 67 HCs were included in this study. The schizophrenia patients were divided into DS (N= 51) and NDS (N=90) groups based on the Proxy for the Deficit Syndrome Scale (PDS). The Positive and Negative Syndrome Scale (PANSS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were used to evaluate the clinical symptoms and cognitive performances, respectively. The plasma level of CRP, IL-1β, Il-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17, TNF-α, and IFN-γ were measured using enzyme-linked immunosorbent assays (ELISAs). Our results showed that DS patients had the worst cognitive performance, especially in the immediate memory, attention, and language dimensions, compared to the NDS and HC groups. Compared to the HCs group, DS patients had higher levels of CRP, IL-1β, IL-6, IL-8, IFN-γ, and total proinflammatory cytokines, and NDS patients had higher levels of IL-1β, IFN-γ, and proinflammatory cytokines. We also found that CRP levels were significantly increased in DS patients compared to NDS patients. Moreover, stepwise logistic regression analysis revealed that CRP is an independent risk factor for DS. Sex stratification analysis showed significant differences in almost all cytokines in female samples but not in male samples. The significant differences in cognitive performance and inflammatory components among groups suggest that deficit syndrome is an independent endophenotype of schizophrenia patients with unique immune-inflammatory features, but may have sex characteristics.

The effect of acculturation on cognitive performance among older Hispanics in the United States

The effect of acculturation on cognition was examined among 142 older Hispanics: cognitively normal [CN; n = 70], Mild Cognitive Impairment, amnestic [aMCI; n = 27], and Dementia [D; n = 45]. Acculturation levels (high vs. low) were determined using the Short Acculturation Scale for Hispanics (SASH). ANCOVAs used a wide variety of neuropsychological tests as independent variables controlling for age and education. Among CN subjects, the highly acculturated group performed better on Logical Memory delayed recall (LM-II) [F(1, 56) = 9.26, p < .001, η p 2 = 0.14], Digit Span Forward [F(1, 56) = 4.37, p < .05, η p 2 = 0.07], Trail Making Test A [F(1, 56) = 7.74, p < .05, η p 2 = 0.12], and Trail Making Test B [F(1, 56) = 4.66, p = .03, η p 2 = 0.08], indicating that high acculturation was associated with a better performance on tests of episodic memory, auditory attention, working memory, cognitive flexibility, and processing speed among CN Hispanics. ANCOVA analyses were not significant among the other groups. In the absence of acculturation scales in clinical practice, caution should be exerted when interpreting neurocognitive results.

From Memories of Past Experiences to Present Motivation? A Meta-analysis on the Association Between Episodic Memory and Negative Symptoms in People With Psychosis

Based on findings from cognitive science, it has been theorized that the reductions in motivation and goal-directed behavior in people with psychosis could stem from impaired episodic memory. In the current meta-analysis, we investigated this putative functional link between episodic memory deficits and negative symptoms. We hypothesized that episodic memory deficits in psychosis would be related to negative symptoms in general but would be more strongly related to amotivation than to reduced expressivity. We included 103 eligible studies (13,622 participants) in the analyses. Results revealed significant, moderate negative associations of episodic memory with negative symptoms in general (k = 103; r = -.23; z = -13.40; P ≤ .001; 95% CI [-.26; -.20]), with amotivation (k = 16; r = -.18; z = -6.6; P ≤ .001; 95% CI [-.23; -.13]) and with reduced expressivity (k = 15; r = -.18; z = -3.30; P ≤.001; 95% CI[-.29; -.07]). These associations were not moderated by sociodemographic characteristics, positive symptoms, depression, antipsychotic medication or type of negative symptom scale. Although these findings provide sound evidence for the association between episodic memory deficits and amotivation, the rather small magnitude and the unspecific pattern of this relationship also indicate that episodic memory deficits are unlikely to be the only factor relevant to amotivation. This implicates that future research should investigate episodic memory in conjunction with other factors that could account for the association of episodic memory deficits and amotivation in psychosis.

Morphologic Variants of the Hand Motor Cortex in Developing Brains from Neonates through Childhood Assessed by MR Imaging

BACKGROUND AND PURPOSE

Knowledge of anatomic markers of the hand motor cortex is essential in the evaluation and treatment of motor neurologic diseases for both adults and developing populations. However, hand motor cortex variants in developing brains remain to be investigated. Our objective was to observe morphologic variants of the hand motor cortex in developing brains from neonates through childhood.

MATERIALS AND METHODS

In this study, 542 participants (0∼15 years of age) were retrospectively enrolled and divided into different age groups. The hand motor cortex morphology was evaluated on the basis of 3D T1WI. Variations in hand motor cortex variants were compared among different age groups. Inter-gender and interhemispheric differences of hand motor cortex variants were also evaluated.

RESULTS

Various hand motor cortex variants could be observed in developing brains, even in the neonatal period. One new morphologic shape, "immature Ω," was found in neonates and infants. The proportion of this new shape decreased dramatically during the first year after birth, then disappeared after 1 year of age. It persisted for a longer time in the right hemisphere and in males. However, sex or hemispheric effects on the distribution of the proportion of variants were not statistically significant. Furthermore, the proportion of concordance of the bilateral hand motor cortex showed an increasing trend with age (P = .006), higher in females than males.

CONCLUSIONS

Various hand motor cortex variants already existed at birth. The distribution of proportions of different variants developmentally varied during the first year after birth and became stable after 1 year of age. The concordance of the bilateral hand motor cortex could be influenced by age and sex.

Eye movement characteristics in male patients with deficit and non-deficit schizophrenia and their relationships with psychiatric symptoms and cognitive function

BACKGROUND

The cognitive impairment pattern of deficit schizophrenia (DS) is centered on an impaired attention function. Previous studies have suggested that the exploratory eye movement (EEM) tests reflect attention deficits in patients with schizophrenia. However, no study has investigated the characteristics of eye movement in DS in the Chinese Han population. This study aimed to investigate the pattern of eye movement characteristics in DS patients and to examine whether eye movement characteristic is associated with serious negative symptoms and cognitive decline in this schizophrenia subtype.

METHODS

A total of 86 male patients [37 DS and 49 non-deficit schizophrenia (NDS)] and 80 healthy controls (HC) participated in this study. Clinical symptoms were assessed using the Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS). Cognitive function was assessed using the Mattis Dementia Rating Scale (MDRS-2). Eye movement data of subjects were collected using an eye movement tracking analyzer.

RESULTS

There were significant differences in the overall eye movement data and cognitive test scores among the three groups (all P < 0.001). Both DS and NDS schizophrenia subgroups showed more severe eye movement and cognitive impairment compared with the control group. The number of eye fixations (NEF), total of eye scanning length (TESL), and cognitive function in DS patients were significantly lower than those in NDS patients. The discriminant analysis (D score) was higher than that of the control group (P < 0.001). In the DS group, the inattention factor of SANS was negatively correlated with the attention factor (r = - 0.545, P = 0.001) and structure factor of cognitive (r = - 0.389, P = 0.023), the affective flattening factor of SANS was negatively correlated with TESL (r = - 0.353, P = 0.041) and initiation/retention factor of cognitive (r = - 0.376,P = 0.028). TESL was found to positively correlate with the MDRS-2 total score (r = 0.427, P = 0.012), attention factor (r = 0.354, P = 0.040), and memory factor (r = 0.349, P = 0.043) in the DS group, whereas the mean of eye scanning length (MESL) positively correlated with cognitive impairments in the NDS group. The negative symptoms showed no significant correlation with cognition in the NDS group.

CONCLUSIONS

Total of eye scanning length may be a characteristic eye movement symptom in DS patients, which is associated with serious negative symptoms and cognitive impairment in this schizophrenia subtype.

Aberrant cerebellar neural activity and cerebro-cerebellar functional connectivity involving executive dysfunction in schizophrenia with primary negative symptoms

Deficit schizophrenia (DS) is a distinct subtype of schizophrenia characterized by primary and enduring negative symptoms. More severe executive dysfunctions were observed in DS patients, however, the associated neuroimaging characteristics, especially cerebellar functional anomalies in DS, remain largely unknown. We employed resting-state functional and structural MRI data of 106 male participants, including data from 29 DS patients, 39 non-deficit schizophrenia (NDS) patients and 38 healthy controls (HCs). Z-standardized fractional amplitude of low-frequency fluctuation (zfALFF) values were calculated in order to examine spontaneous regional brain activity. Cerebro-cerebellar functional connectivity and changes in the volume of gray matter in the cerebellum were also examined. Relative to the HCs, both DS and NDS patients exhibited decreased zfALFF in the bilateral cerebellar lobules VIII and IX. The zfALFF in the left Crus II was lower in DS patients compared to NDS patients. No significant difference was observed in the volume of cerebellar gray matter among the three groups. Compared with NDS patients, cerebro-cerebellar functional connectivity analysis revealed increased connectivity in the left orbital medial frontal cortex and right putamen regions in DS patients. Reduced zfALFF in the left Crus II in the DS group was significantly positively correlated with Stroop Color and Word scores, while negatively correlated with Trail-Making Test part B scores. The increased functional connectivity in the right putamen in DS patients was significantly positively correlated with Animal Naming Test and semantic Verbal Fluency Test scores. These results highlight cerebellar functional abnormality in DS patients and provide insight into the pathophysiological mechanism of executive dysfunction.

Anxious attachment is associated with heightened responsivity of a parietofrontal cortical network that monitors peri-personal space

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A parietofrontal cortical network is more active when stimuli are near the body.

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Responses of this network were positively correlated with “attachment anxiety”.

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No other types of attachment or symptoms accounted for this association.

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Connectivity strength within this network was not linked with attachment anxiety.

Background

Attachment, or affiliative bonding among conspecifics, is thought to involve neural mechanisms underlying behavioral responses to threat and reward-related social signals. However, attachment-oriented responses may also rely on basic sensorimotor processes. One sensorimotor system that may play a role in attachment is the parietofrontal cortical network that responds to stimuli that are near or approaching the body, the peripersonal space (PPS) monitoring system. We hypothesized that this network may vary in responsivity to such potentially harmful stimuli, particularly those with social salience, based on individual differences in attachment styles.

Methods

Young adults viewed images of human faces or cars that appeared to move towards or away from them, while functional magnetic resonance imaging data were collected. Correlations between each of four adult attachment styles, measured using the Relationship Questionnaire, and responses of the PPS network to approaching (versus withdrawing) stimuli were measured.

Results

A region-of-interest (ROI) analysis, focused on six cortical regions of the PPS network that showed significant responses to approaching versus withdrawing face stimuli in an independent sample (n = 80), revealed that anxious attachment style (but not the other 3 attachment styles) was significantly positively correlated with responses to faces (but not to cars) in all six ROIs (r = 0.33–0.49, p = 0.01–0.0001, n = 50).

Conclusions

These findings suggest that anxious attachment is associated with over-responsivity of a sensorimotor network involved in attending to social stimuli near the body.

The effect of non-invasive brain stimulation on executive functioning in healthy controls: A systematic review and meta-analysis

In recent years, there has been a heightened interest in the effect of non-invasive brain stimulation on executive functioning. However, there is no comprehensive overview of its effects on different executive functioning domains in healthy individuals. Here, we assessed the state of the field by conducting a systematic review and meta-analysis on the effectiveness of non-invasive brain stimulation (i.e. repetitive transcranial magnetic stimulation and transcranial direct current stimulation) over prefrontal regions on tasks assessing working memory, inhibition, flexibility, planning and initiation performance. Our search yielded 63 studies (n = 1537), and the effectiveness of excitatory and inhibitory non-invasive brain stimulation were assessed per executive functioning task. Our analyses showed that excitatory non-invasive brain stimulation had a small but positive effect on Stop Signal Task and Go/No-Go Task performance, and that inhibitory stimulation had a small negative effect on Flanker Task performance. Non-invasive brain stimulation did not affect performance on working memory and flexibility tasks, and effects on planning tasks were inconclusive.

Altered third-party punishment in Huntington's disease: A study using neuroeconomic games

BACKGROUND

Huntington's disease (HD) is a heritable degenerative brain disease caused by a mutation in the huntingtin gene with excessive repeats of the base triplet cytosine-adenine-guanine (CAG), which codes for the aminoacid glutamine. HD is associated with a broad spectrum of neurocognitive dysfunction, including deficits in social cognition. The appreciation of fairness rules and reciprocity has not been studied in HD. Based on theoretical considerations suggesting that brain regions known to be affected from HD are involved in economic decision-making, the present study sought to examine HD patients' performance in two neuroeconomic games.

METHODS

Twenty-nine manifest HD mutation carriers (20 males, nine females) performed an Ultimatum Game (UG) and a Dictator Game (DG) where third-party punishment of observed unfairness was required. In addition, patients were tested for neurocognition and the ability to understand other people's mental states ("theory of mind"). For comparison, a clinical control group of 30 patients with chronic schizophrenia, and 30 unaffected healthy controls matched for age and verbal intelligence took part in the study.

RESULTS

Patients with HD had some appreciation of fairness rules, as they tended to reject unfair offers in the UG similar to controls. However, unlike the other two groups, individuals with HD did not punish observed unfairness from a third-party perspective. This lack of "altruistic punishment" was associated with deficits in executive functioning including working memory, inhibitory control and cognitive flexibility, and to a lesser degree with poor "theory of mind."

CONCLUSIONS

HD seems to be associated with impairments in understanding of more complex rules of social exchange. Aside from deficits in executive functioning, this behavior could, in part, be linked to an inability to experience third-party punishment as rewarding.

Metacognitive preserved generation strategy benefits for both younger and elderly participants with schizophrenia

Cognitive memory and introspection disturbances are considered core features of schizophrenia. Moreover, it remains unclear whether or not participants with schizophrenia are more cognitively impaired with ageing than healthy participants. The aims of this study were to use a metacognitive approach to determine whether elderly participants with schizophrenia are able to improve their memory performance using a specific generation strategy and to evaluate the memory benefits for them using this strategy. 20 younger and 20 older participants with schizophrenia and their comparison participants matched for age, gender and education learned paired associates words with either reading or generation, rated judgment of learning (JOL) and performed cued recall. Participants with schizophrenia recalled fewer words than healthy comparison participants, but they benefited more from generation, and this difference was stable with ageing. Their JOL magnitude was lower than that of healthy comparison participants, but JOL accuracy was not affected by either age or the pathology. In spite of their memory deficit, elderly and younger participants with schizophrenia benefited remarkably from the memory generation strategy. This result gives some cause for optimism as to the possibility for participants with schizophrenia to reduce memory impairment if learning conditions lead them to encode deeply.

Recognition of Social Rule Violation in "Deficit Syndrome" Schizophrenia: A Study Using Economic Games

Aberrant social behavior is a frequent clinical feature of schizophrenia and seems related to the duration and chronicity of the disorder. However, there is a paucity of research into the relationship between social behavior and social cognition in patients with severe chronic courses of schizophrenia. Accordingly, the present study sought to examine the appreciation of social rules and norms such as fairness and cooperation in schizophrenia patients who fulfilled the criteria for "deficit syndrome". To this end, we utilized a so-called Ultimatum Game, and a Dictator Game, in which participants had the option to punish others' unfair behavior. In addition, "theory of mind", the ability to appreciate others' mental states, was also examined using the Mental State Attribution Task (MSAT). Symptom severity was determined using the Positive and Negative Syndrome Scale. While patients with deficit schizophrenia responded to varying levels of fairness in similar ways to controls, the patients accepted fewer fair offers and engaged less in third-party punishment. Impaired theory of mind in patients reduced the latter, but not the former, group difference to non-significance. No significant correlations emerged between symptom severity and task performance. Together, these findings suggest that the understanding of others' minds partly contributes to the appreciation of social rules and norms in patients with severe chronic courses of schizophrenia.

A process approach to verbal memory assessment: Exploratory evidence of inefficient learning in women remitted from anorexia nervosa

Introduction: Anorexia nervosa (AN) is associated with deficits in set-shifting and cognitive flexibility, yet less is known about the persistence of these deficits after recovery and how they might contribute to reported difficulties organizing and learning new information. To address this question, the current study applied a process-focused approach, that accounts for errors and strategies by which a score is achieved, to investigate the relationship between verbal memory and executive function in women remitted from AN. Method: Twenty-six women remitted from anorexia nervosa (RAN) and 25 control women (CW) aged 19-45 completed the California Verbal Learning Test, Second edition (CVLT-II) and the Wisconsin Card Sorting Test (WCST). Groups were compared on overall achievement scores, and on repetition, intrusion, and perseverative errors on both tests. Associations between learning and memory performance and WCST errors were also examined. Results: RAN and CW groups did not differ on overall CVLT-II learning and memory performance or errors on the WCST, though the RAN group trended towards greater WCST non-perseverative and total errors. On the CVLT-II, the RAN group made significantly more repetition errors than CW (p = 0.010), and within-trial perseveration (WTP) errors (p = 0.044). For the CW group, CVLT-II learning and memory performance were negatively associated with errors on the WCST, whereas among RAN, primarily delayed memory was negatively correlated with WCST errors. Notably, for RAN, greater WCST perseverative responses were correlated with greater CVLT-II repetition and WTP errors, showing the convergence of perseverative responding across tasks. Conclusions: Despite similar overall learning and memory performance, difficulties with executive control seem to persist even after symptom remission in patients with AN. Results indicate an inefficient learning process in the cognitive phenotype of AN and support the use of process approaches to refine neuropsychological assessment of AN by accounting for strategy use.

Neurocognitive functioning and quality of life in patients with and without deficit syndrome of schizophrenia

Deficit syndrome of schizophrenia is a subtype of schizophrenia characterized by primary and enduring negative symptoms. This study examined the differences in neurocognitive functioning and quality of life (QOL) between deficit and non-deficit patients, and specific predictors of both clinical measures. Overall, 344 subjects (175 patients with non-deficit schizophrenia (NDSZ), 58 patients with deficit schizophrenia (DSZ) and 111 healthy controls) were evaluated on severity of psychopathology, QOL and a smaller subset of 198 subjects (104 NDSZ, 27 DSZ, 67 healthy controls) underwent neurocognitive assessments. Multivariate analyses were used to determine differences in outcomes between subject groups and predictors of clinical measures. Both DSZ and NDSZ had significantly worse QOL compared with healthy controls. DSZ had more extensive cognitive deficits compared with healthy controls and performed worse on semantic fluency task compared to NDSZ. Multiple linear regression analysis found that DSZ, shorter duration of illness were associated with poorer QOL whereas fewer years of education, lower premorbid intelligence were associated with poorer overall neurocognitive functioning. The poorer QOL, greater extent of neurocognitive deficits especially semantic fluency associated with DSZ behoves the need for greater attention during clinical evaluation and treatment planning of this subgroup of individuals with schizophrenia.

Informationally administered reward enhances intrinsic motivation in schizophrenia

Even when individuals with schizophrenia have an intact ability to enjoy rewarding moments, the means to assist them to translate rewarding experiences into goal-directed behaviors is unclear. The present study sought to determine whether informationally administered rewards enhance intrinsic motivation to foster goal-directed behaviors in individuals with schizophrenia (SZ) and healthy controls (HCs). Eighty-four participants (SZ=43, HCs=41) were randomly assigned to conditions involving either a performance-contingent reward with an informationally administered reward or a task-contingent reward with no feedback. Participants were asked to play two cognitive games of equalized difficulty. Accuracy, self-reported intrinsic motivation, free-choice intrinsic motivation (i.e., game play during a free-choice observation period), and perceived competency were measured. Intrinsic motivation and perceived competency in the cognitive games were similar between the two participant groups. The informationally administered reward significantly enhanced self-reported intrinsic motivation and perceived competency in both the groups. The likelihood that individuals with schizophrenia would play the game during the free-choice observation period was four times greater in the informationally administered reward condition than that in the no-feedback condition. Our findings suggest that, in the context of cognitive remediation, individuals with schizophrenia would benefit from informationally administered rewards.

Neurocognitive impairment in deficit and non-deficit schizophrenia: a meta-analysis

BACKGROUND

Most studies suggested that patients with deficit schizophrenia have more severe impairment compared with patients with non-deficit schizophrenia. However, it is not clear whether deficit and non-deficit schizophrenia are associated with differential neurocognitive profiles.

METHODS

The aim of this meta-analytic review was to compare cognitive performances of deficit and non-deficit patients with each other and with healthy controls. In the current meta-analysis, differences in cognitive abilities between 897 deficit and 1636 non-deficit patients with schizophrenia were examined. Cognitive performances of 899 healthy controls were also compared with 350 patients with deficit and 592 non-deficit schizophrenia.

RESULTS

Both deficit (d = 1.04-1.53) and non-deficit (d = 0.68-1.19) schizophrenia were associated with significant deficits in all cognitive domains. Deficit patients underperformed non-deficit patients in all cognitive domains (d = 0.24-0.84) and individual tasks (d = 0.39-0.93). The relationship between deficit syndrome and impairment in olfaction, social cognition, verbal fluency, and speed-based cognitive tasks were relatively stronger.

CONCLUSIONS

Our findings suggest that there is consistent evidence for a significant relationship between deficit syndrome and more severe cognitive impairment in schizophrenia.

Neuropsychological Profile of Specific Executive Dysfunctions in Patients with Deficit and Non-deficit Schizophrenia

Objectives: Although it has been shown that there are more profound deficits present in deficit schizophrenia (DS) patients than in non-deficit schizophrenia (NDS) patients, there still remain some matters requiring further investigation. In this context, we formulated three research aims: (1) to compare executive functions between the investigated groups, (2) to determine the relationship between particular aspects of executive functions within the groups, and (3) to draw up a neuropsychological profile for executive functions.

Methods: The study involved 148 schizophrenia patients divided into two groups on the basis of the Schedule for the Deficit Syndrome: DS (n = 70) and NDS (n = 78). Patients were matched for sex, age, years of education, and overall cognitive functioning. For assessing executive functions we used the Wisconsin Card Sorting Test (WCST), the Trail Making Test (TMT), the Phonemic Verbal Fluency Test (VFT P), the Stroop Color and Word Test (SCWT), and the Go/No Go task (GNG).

Results: Deficit schizophrenia patients scored lower on the WCST and TMT (relative flexibility) than did the NDS patients. There were no inter-group differences in the VFT P, SCWT (relative inhibition), or GNG. There were significant correlations between WCST and TMT scores in both groups. The general neuropsychological profiles were similar in both groups.

Conclusion: Deficit schizophrenia patients exhibited slightly greater interference with concept formation and non-verbal cognitive flexibility. Therefore, such problems may be specific to this particular type of schizophrenia. These results may be useful for the development of neuropsychological diagnostic methods for patients with schizophrenia.

Primary and persistent negative symptoms: Concepts, assessments and neurobiological bases

Primary and persistent negative symptoms (PPNS) represent an unmet need in the care of people with schizophrenia. They have an unfavourable impact on real-life functioning and do not respond to available treatments. Underlying etiopathogenetic mechanisms of PPNS are still unknown. The presence of primary and enduring negative symptoms characterizes deficit schizophrenia (DS), proposed as a separate disease entity with respect to non-deficit schizophrenia (NDS). More recently, to reduce the heterogeneity of negative symptoms by using criteria easily applicable in the context of clinical trials, the concept of persistent negative symptoms (PNS) was developed. Both PNS and DS constructs include enduring negative symptoms (at least 6months for PNS and 12months for DS) that do not respond to available treatments. PNS exclude secondary negative symptoms based on a cross-sectional evaluation of severity thresholds on commonly used rating scales for positive symptoms, depression and extrapyramidal side effects; the DS diagnosis, instead, excludes all potential sources of secondary negative symptoms based on a clinical longitudinal assessment. In this paper we review the evolution of concepts and assessment modalities relevant to PPNS, data on prevalence of DS and PNS, as well as studies on clinical, neuropsychological, brain imaging electrophysiological and psychosocial functioning aspects of DS and PNS.

Premorbid, clinical and cognitive correlates of primary negative symptoms in first-episode psychosis

Negative symptoms are a core psychopathological dimension of psychotic disorders. Previous research on primary negative symptoms (PNS) mostly focused on chronic samples. Data regarding premorbid, clinical and cognitive correlates of PNS in the early illness course are limited and inconsistent. In this study, we assessed 355 Hong Kong Chinese adult patients presenting with first-episode psychosis (FEP) to early intervention service with an aim to examine the prevalence of PNS and its relationships with premorbid adjustment, clinical and cognitive profiles. PNS was defined as the presence of clinically significant negative symptoms excluding depression, positive symptoms and extrapyramidal signs. Results showed that 14.6% of patients exhibited PNS at service entry. PNS group had poorer premorbid social functioning, lower level of insight, and worse performance in Modified Wisconsin Card Sorting and digit symbol tests than non-PNS group. Logistic regression analysis showed that premorbid social functioning and digit symbol test score were independently associated with PNS. Our findings thus indicate that PNS are frequently observed in FEP patients. Deficits in proceeding speed, alongside impaired premorbid social functioning, might be specifically related to PNS in the early illness stage.

Neurocognitive Impairments in Deficit and Non-Deficit Schizophrenia and Their Relationships with Symptom Dimensions and Other Clinical Variables

Background

Deficit schizophrenia (DS) has been proposed as a pathophysiologically distinct subgroup within schizophrenia. Earlier studies focusing on neurocognitive function of DS patients have yielded inconsistent findings ranging from substantial deficits to no significant difference relative to non-deficit schizophrenia patients (NDS). The present study investigated the severity and characteristic patterns of neurocognitive impairments in DS and NDS patients and their relationships with clinical variables.

Methods

Attention, ideation fluency, cognitive flexibility and visuospatial memory function were assessed in 40 DS patients, 57 NDS patients, and 52 healthy controls by a comprehensive neuropsychological battery.

Results

Both schizophrenia subgroups had overall more severe cognitive impairments than controls while DS performed worse on every neuropsychological measure except the Stroop interference than the NDS patients with age and education as the covariates. Profile analysis found significantly different patterns of cognitive profiles between two patients group mainly due to their differences in attention and cognitive flexibility functions. Age, education, illness duration and negative symptoms were found to have the correlations with cognitive impairments in the NDS group, while only age and the negative symptoms were correlated with the cognitive impairments in the DS group. Multiple regression analyses revealed that sustained attention and cognitive flexibility were the core impaired cognitive domains mediating other cognitive functions in DS and NDS patients respectively.

Conclusions

DS patients exemplified worse in almost all cognitive domains than NDS patients. Sustained attention and cognitive flexibility might be the key impaired cognitive domains for DS and NDS patients respectively. The present study suggested the DS as a specific subgroup of schizophrenia.

Course of neurological soft signs in first-episode schizophrenia: Relationship with negative symptoms and cognitive performances

This prospective study examined the course of neurological soft signs (NSS) in patients with first-episode schizophrenia and its relationship with negative symptoms and cognitive functions. One hundred and forty-five patients with first-episode schizophrenia were recruited, 29 were classified as having prominent negative symptoms. NSS and neuropsychological measures were administered to all patients and 62 healthy controls at baseline. Patients were then followed-up prospectively at six-month intervals for up to a year. Patients with prominent negative symptoms exhibited significantly more motor coordination signs and total NSS than patients without prominent negative symptoms. Patients with prominent negative symptoms performed worse than patients without negative symptoms in working memory functions but not other fronto-parietal or fronto-temporal functions. Linear growth model for binary data showed that the prominent negative symptoms were stable over time. Despite general improvement in NSS and neuropsychological functions, the prominent negative symptoms group still exhibited poorer motor coordination and higher levels of NSS, as well as poorer working memory than patients without prominent negative symptoms. Two distinct subtypes of first-episode patients could be distinguished by NSS and prominent negative symptoms.

The Use of Canonical Correlation Analysis to Assess the Relationship Between Executive Functioning and Verbal Memory in Older Adults

Executive functioning (EF), which is considered to govern complex cognition, and verbal memory (VM) are constructs assumed to be related. However, it is not known the magnitude of the association between EF and VM, and how sociodemographic and psychological factors may affect this relationship, including in normal aging. In this study, we assessed different EF and VM parameters, via a battery of neurocognitive/psychological tests, and performed a Canonical Correlation Analysis (CCA) to explore the connection between these constructs, in a sample of middle-aged and older healthy individuals without cognitive impairment (N = 563, 50+ years of age). The analysis revealed a positive and moderate association between EF and VM independently of gender, age, education, global cognitive performance level, and mood. These results confirm that EF presents a significant association with VM performance.

Impaired processing speed and attention in first-episode drug naive schizophrenia with deficit syndrome

Although first-episode drug naive patients with schizophrenia are known to show cognitive impairment, the cognitive performances of these patients, who suffer deficit syndrome, compared with those who suffer non-deficit syndrome is undetermined. The aim of this study was to compare cognitive performances in first-episode drug-naive schizophrenia with deficit syndrome or non-deficit syndrome. First-episode drug naive patients (n=49) and medicated patients (n=108) with schizophrenia, and age, sex, and education matched healthy controls (n=57 for the first-episode group, and n=128 for the medicated group) were enrolled. Patients were divided into deficit or non-deficit syndrome groups, using the Schedule for Deficit Syndrome. Cognitive performance was assessed using the CogState computerized cognitive battery. All cognitive domains in first-episode drug naive and medicated patients showed significant impairment compared with their respective control groups. Furthermore, cognitive performance in first-episode drug naive patients was significantly worse than in medicated patients. Interestingly, the cognitive performance markers of processing speed and attention, in first-episode drug naive patients with deficit syndrome, were both significantly worse than in equivalent patients without deficit syndrome. In contrast, no differences in cognitive performance were found between the two groups of medicated patients. In conclusion, this study found that first-episode drug naive schizophrenia with deficit syndrome showed significantly impaired processing speed and attention, compared with patients with non-deficit syndrome. These findings highlight processing speed and attention as potential targets for pharmacological and psychosocial interventions in first-episode schizophrenia with deficit syndrome, since these domains are associated with social outcomes.

Systematic review of appropriate cognitive assessment instruments used in clinical trials of schizophrenia, major depressive disorder and bipolar disorder

Cognitive dysfunction is increasingly recognized as a symptom in mental conditions including schizophrenia, major depressive disorder (MDD), and bipolar disorder (BPD). Despite the many available cognitive assessment instruments, consensus is lacking on their appropriate use in clinical trials. We conducted a systematic literature review in Embase, PubMed/Medline and PsychINFO to identify appropriate cognitive function instruments for use in clinical trials of schizophrenia, MDD, and BPD. Instruments were identified from the articles. Instruments and articles were excluded if they did not address schizophrenia, MDD, or BPD. Instrument appropriateness was further assessed by the criteria of the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative: test-retest reliability, utility, relationship to functional status, potential changeability to pharmacological agents, and tolerability and practicality for clinical trials. The database search yielded 173 articles describing 150 instruments used to assess cognitive function. Seventeen additional instruments were identified through Google and clinicaltrials.gov. Among all these, only 30 (18%) were deemed appropriate for use in the diseases of interest. Of these, 27 were studied in schizophrenia, one in MDD and two in BPD. These findings suggest the need for careful selection of appropriate cognitive assessment instruments, as not all may be valid in these disorders.

Executive functioning and psychopathological profile in relatives of individuals with deficit v. non-deficit schizophrenia: a pilot study

Aims. Heterogeneity of schizophrenia is known to be reflected in neuropsychological functioning of patients, but its expression in relatives is understudied. This study aims at exploring relationship between executive functioning and clinical profiles of first-degree relatives of patients who are classified as having or not having the deficit subtype of schizophrenia (DSRELs v. non-DSRELs), with the prediction of greater executive impairment in DSRELs. Methods. DSRELs (n = 15) and non-DSRELs (n = 40) were compared with community controls (CCs, n = 55) on executive functioning measured by the Wisconsin Card Sorting Test (WCST) and the phonemic verbal fluency (PVF), and clinical measures. Effects of psychopathology and intelligence quotient (IQ) measures were investigated to determine their association with executive performance. Results. DSRELs showed more executive dysfunction on WCST and poorer social functioning than CCs and more severe negative symptoms than non-DSRELs. Differences on WCST-categories achieved (WCST-CA) remained significant after adjustment for clinical confounders and IQ. WCST-CA was associated with apathy and paranoid ideation only within the DSREL subgroup. Conclusions. Executive functioning and negative symptoms are severely impaired in first-degree relatives of deficit syndrome patients, thus suggesting that some neurocognitive deficits in patients may be transmitted within families according to the pathophysiology of the probands.

Executive functioning in schizophrenia: the result of impairments in lower order cognitive skills?

Executive functioning (EF) impairments are common in schizophrenia. There are two propositions regarding the causes of these impairments: (1) executive impairments are the result of the compounding effects of deficits in lower order cognitive skills (e.g. processing speed, attention) or (2) EF impairments exist in their own right regardless of lower order skills. It is difficult to examine the separable effects of lower order cognitive skills on EF given the overlap required to complete most neuropsychological measures. One battery designed to parcel out the contributions of lower order skills from EF is the Delis-Kaplan Executive Function System (D-KEFS). Inhibition and switching specifically were examined using the D-KEFS versions of the Stroop and Trails task. No group differences in task performance after controlling for lower level skills would provide evidence for a generalised cognitive deficit. Group differences remaining after controlling for these influences would suggest a disproportionate deficit. Results supported both propositions. On both tasks, group differences reflecting slowed reaction time in the schizophrenia group disappeared when lower order skills were controlled for. Differences between groups performance in errors were only evident on the most complex versions of each task with more errors made by the schizophrenia group. These results suggest that (1) both RT and error data are needed to provide a full picture of performance and (2) the relationship between lower order and EF is too complex to provide support for one or the other proposal.

Emotional verbal fluency: a new task on emotion and executive function interaction

The present study introduces "Emotional Verbal Fluency" as a novel (partially computerized) task, which is aimed to investigate the interaction between emotionally loaded words and executive functions. Verbal fluency tasks are thought to measure executive functions but the interaction with emotional aspects is hardly investigated. In the current study, a group of healthy subjects (n = 21, mean age 25 years, 76% females) were asked to generate items that are either part of a semantic category (e.g., plants, toys, vehicles; standard semantic verbal fluency) or can trigger the emotions joy, anger, sadness, fear and disgust. The results of the task revealed no differences between performance on semantic and emotional categories, suggesting a comparable task difficulty for healthy subjects. Hence, these first results on the comparison between semantic and emotional verbal fluency seem to highlight that both might be suitable for examining executive functioning. However, an interaction was found between the category type and repetition (first vs. second sequence of the same category) with larger performance decrease for semantic in comparison to emotional categories. Best performance overall was found for the emotional category "joy" suggesting a positivity bias in healthy subjects. To conclude, emotional verbal fluency is a promising approach to investigate emotional components in an executive task, which may stimulate further research, especially in psychiatric patients who suffer from emotional as well as cognitive deficits.

Correlation between insight dimensions and cognitive functions in patients with deficit and nondeficit schizophrenia

Previous studies have shown correlations between poor insight and neurocognitive impairment in schizophrenia. Deficit schizophrenia has been associated with worse cognitive functioning and poorer insight. This study aimed at investigating the relationship between insight dimensions (measured by Schedule for the Assessment of Insight-Expanded Version and its factors) and specific neurocognitive functions (assessed through a battery of neuropsychological tests) considering separately patients with deficit (n=29) and nondeficit schizophrenia (n=44), categorized according to the Schedule for the Deficit Syndrome. We found that working memory correlated positively and significantly with awareness of mental illness in both groups. In nondeficit group, awareness of mental illness correlated additionally with verbal fluency and attention. If confirmed by further studies, these results may have important consequences, such as the need of tailoring differently cognitive rehabilitation for each group.

Multi-components of evoked-brain potentials in deficit and nondeficit schizophrenia

INTRODUCTION

The present study aims to detect the specific and common impairment index relative to evoked brain potentials (EBPS ) in deficit schizophrenia (DS) and nondeficit schizophrenia (NDS), and investigates the relationship between EBPs and clinical variables.

METHODS

The study used EBPs in 21 patients with DS, 38 patients with NDS, and 50 healthy controls (HCs) to investigate P300 waves, mismatch negative (MMN), sensory gating (SG) P50 and contingent negative variation (CNV). A comparison of three groups and the relationship between EBPs and clinical variables were performed using general linear model analyses and partial correlation, respectively.

RESULTS

Compared with HCs, both groups of patients showed delayed N1 , N2 , and P3a latency, and reduced N1 and N2 amplitude. The MMN showed delayed latency. The P50 ratios and the inhibited ratios were impaired, whereas SG loss ratios increased. CNV amplitude was reduced. Compared with HCs, NDS showed delayed latency of S2'-C in CNV, whereas DS showed shortened latency. Only NDS, when compared with HCs, showed delayed latency of P3b , Also, only DS, when compared with HCs, showed delayed latency of point A in CNV. Latency of point A in CNV of DS, correlated with a poorer Global Assessment of Functioning Scale (6 weeks) and was independent of clinical characteristics.

DISCUSSION

Schizophrenia represents a clinical syndrome with shared impairments in brain function, whereas DS is a relatively homogeneous subgroup of schizophrenia with unique pathophysiological changes.

Distinct episodic verbal memory profiles in schizophrenia

According to some authors, episodic memory impairment may be a feature shared by all schizophrenic patients, whereas others argue in favor of the mnesic heterogeneity. Our aims were to determine whether patients can be grouped based on according to their mnesic performances. The California Verbal Learning Test (CVLT), an episodic verbal learning test, was compared in 61 schizophrenic patients and 61 matched healthy subjects. The 32 indices were calculated using CVLT Scoring Software. This process allowed us to describe patients' episodic processes in detail (encoding, storage, retrieval). We isolated one group with normative data, another showed impairment of both encoding and retrieval processes, and in the last one, only encoding process was impaired. As schizophrenia is heterogeneous with regard to episodic memory, impairments should not be considered as a common core to the various forms of the illness and it would be fruitful to systematically assess episodic processes in detail to take into account individual abilities and challenges.

Differential patterns of premorbid social and academic deterioration in deficit and nondeficit schizophrenia

Numerous studies indicate that social dysfunction is associated with negative symptoms of schizophrenia during the chronic phase of illness. However, it is unclear whether social abnormalities exist during the premorbid phase in people who later develop schizophrenia with prominent negative symptoms, or whether social functioning becomes progressively worse in these individuals from childhood to late adolescence. The current study examined differences in academic and social premorbid functioning in people with schizophrenia meeting criteria for deficit (i.e., primary and enduring negative symptoms) (DS: n = 74) and non-deficit forms of schizophrenia (ND: n = 271). Premorbid social and academic functioning was assessed for childhood, early adolescence, and late adolescence developmental periods on the Premorbid Adjustment Scale (PAS). Results indicated that both DS and ND participants showed deterioration in social and academic functioning from childhood to late adolescence. However, while ND schizophrenia demonstrated greater deterioration of academic compared to social premorbid functioning from childhood to late adolescence, the DS group exhibited comparable deterioration across both premorbid domains, with more severe social deterioration than the ND group. Findings suggest that people with DS show poorer social premorbid adjustment than those with ND as early as childhood, and are particularly susceptible to accelerated deterioration as the onset of schizophrenia becomes imminent. Thus, poor premorbid social adjustment and significant social deterioration from childhood to adolescence may be a hallmark feature of people who later go on to develop prominent negative symptoms and a unique marker for the DS subtype of schizophrenia.

General and domain-specific neurocognitive impairments in deficit and non-deficit schizophrenia

Earlier studies suggested more severe overall cognitive impairments in deficit versus non-deficit schizophrenia; however, the specific contribution of different cognitive domains to this overall cognitive impairment remains unclear. The purpose of this study was to compare the two subtypes in general cognitive functioning as well as in individual cognitive domains using the composite score approach. One hundred and forty-three patients fulfilling the criteria for the deficit syndrome were compared with 123 patients diagnosed with non-deficit schizophrenia. Neurocognitive functioning was assessed by a neuropsychological test battery measuring the domains of sustained vigilance/attention, working memory, short-term memory, verbal memory, cognitive flexibility, and ideation fluency. Using the raw neuropsychological measures, we calculated a global index of cognitive impairment and domain-specific composite z-scores. Association between these composite scores and the deficit syndrome was examined by logistic regression analysis. After adjusting for relevant covariates including sex, age, education, smoking, and antipsychotic dose, results indicated a significant increase in the likelihood of deficit syndrome as a function of global (OR = 5.40; 95% CI 3.02-9.65) as well as domain-specific impairments (OR > 2 for all individual domains except for short-term memory). Cognitive flexibility was an independent predictor (OR = 2.92; 95% CI 1.47-5.80), whereas other cognitive domains demonstrated no unique contribution to the general cognitive impairment. Patients with deficit schizophrenia suffer from a more severe degree of neurocognitive impairment, which is qualitatively similar to the dysfunction seen in non-deficit schizophrenia. However, our results indicate that cognitive flexibility is specifically impaired in deficit versus non-deficit patients and may therefore represent a core feature of this subtype.

Dissociation of response and feedback negativity in schizophrenia: electrophysiological and computational evidence for a deficit in the representation of value

Contrasting theories of schizophrenia propose that the disorder is characterized by a deficit in phasic changes in dopamine activity in response to ongoing events or, alternatively, by a weakness in the representation of the value of responses. Schizophrenia patients have reliably reduced brain activity following incorrect responses but other research suggests that they may have intact feedback-related potentials, indicating that the impairment may be specifically response-related. We used event-related brain potentials and computational modeling to examine this issue by comparing the neural response to outcomes with the neural response to behaviors that predict outcomes in patients with schizophrenia and psychiatrically healthy comparison subjects. We recorded feedback-related activity in a passive gambling task and a time estimation task and error-related activity in a flanker task. Patients' brain activity following an erroneous response was reduced compared to comparison subjects but feedback-related activity did not differ between groups. To test hypotheses about the possible causes of this pattern of results, we used computational modeling of the electrophysiological data to simulate the effects of an overall reduction in patients' sensitivity to feedback, selective insensitivity to positive or negative feedback, reduced learning rate, and a decreased representation of the value of the response given the stimulus on each trial. The results of the computational modeling suggest that schizophrenia patients exhibit weakened representation of response values, possibly due to failure of the basal ganglia to strongly associate stimuli with appropriate response alternatives.

Emerging cerebral connectivity in the human fetal brain: an MR tractography study

Cerebral axonal connections begin to develop before birth during radial migration in each brain area. A number of theories are still actively debated regarding the link between neuronal migration, developing connectivity, and gyrification. Here, we used high angular resolution diffusion tractography on postmortem fetal human brains (postconception week (W) 17-40) to document the regression of radial and tangential organization likely to represent migration pathways and the emergence of corticocortical organization and gyrification. The dominant radial organization at W17 gradually diminished first in dorsal parieto-occipital and later in ventral frontotemporal regions with regional variation: radial organization persisted longer in the crests of gyri than at the depths of sulci. The dominant tangential organization of the ganglionic eminence at W17 also gradually disappeared by term, together with the disappearance of the ganglionic eminence. A few immature long-range association pathways were visible at W17, gradually became evident by term. Short-range corticocortical tracts emerged prior to gyrification in regions where sulci later developed. Our results suggest that the regional regression of radial organization and regional emergence of fetal brain connectivity proceeds in general from posterodorsal to anteroventral with local variations.

Clinical significance of neurological soft signs in schizophrenia: factor analysis of the Neurological Evaluation Scale

BACKGROUND

Nonlocalizing neurologic deficits detectable by clinical evaluation-"soft signs"-are a robust finding in patients diagnosed with schizophrenia, but their conceptual and neuroanatomical correlates remain unclear. The purpose of this study was to evaluate the organization of these deficits and their clinical correlates using the Neurological Evaluation Scale (NES).

METHODS

Ninety-three male veterans with schizophrenia and schizoaffective disorder were evaluated using a detailed clinical assessment that included the NES, the Extrapyramidal Symptom Rating Scale, the Abnormal Involuntary Movement Scale (AIMS), the Barnes Akathisia Scale, the Positive and Negative Syndrome Scale, the Wisconsin Card Sorting Test (WCST), the Schedule for the Deficit Syndrome (SDS), and the Digit Symbol Substitution Task (DSST).

RESULTS

Four factors explained 73% of the variance and had distinct clinical and neuropsychological correlates. Factor 1 reflected deficits involved with memory and sensory integration, and was associated with lower PANSS positive and higher AIMS scores. Factor 2 reflected impairments in motor control, and was associated with lower intelligence, more cognitive deficits, and deficit-syndrome schizophrenia. Factor 3 was related to lower intelligence and more perseverative errors on the WCST. Factor 4 was related to increasing age, more extrapyramidal symptoms, more perseverative errors, and worse scores on the DSST.

CONCLUSIONS

Neurologic deficits in schizophrenia have an intrinsic organization that appears to have clinical significance, highlighting the continued utility of the NES in studies of neurological deficits in schizophrenia patients. The theoretical underpinning of this organization remains unclear.

Executive function in deficit schizophrenia: what do the dimensions of the Wisconsin Card Sorting Test tell us?

Neuropsychological characterization of the schizophrenia deficit syndrome is an unresolved issue. The initial assumption was that patients with deficit syndrome show more definitive impairments on tests sensitive for frontal and parietal functions compared with nondeficit patients,but recent studies failed to confirm this assumption. The fundamental question is whether a more refined delineation of executive dysfunctions is able to yield differences between deficit and nondeficit patients. To investigate this question, we implemented a factor analytic approach to explore potential differences between deficit and nondeficit patients using the Wisconsin Card Sorting Test (WCST). Our paper presents an exploratory factor analysis of the WCST on schizophrenia patients and healthy samples, and a comparison among deficit, non-deficit patients with schizophrenia and control samples using the identified factors. A total of 154 patients with schizophrenia fulfilling the criteria for the deficit syndrome, 121 nondeficit patients, and 130 healthy controls were compared. Factor analysis of the WCST variables using the principal component method resulted in a two-factor solution. Comparison of the diagnostic groups on each of the factors revealed that deficit schizophrenia patients suffer from a more severe degree of impairment on the 'General executive function' factor than nondeficit schizophrenia patients. To our knowledge this is the first study that compared patients with the deficit and non-deficit forms of schizophrenia using WCST factor analytic techniques. Our results provide an insight into the cognitive profile of schizophrenia patients with regard to WCST, which could serve as a framework for future clinical and research endeavors.

Olfactory hedonic judgment in patients with deficit syndrome schizophrenia

Olfactory perception was examined in deficit syndrome (DS) and nondeficit syndrome (ND) schizophrenia patients. Participants included 22 controls (CN) and 41 patients with schizophrenia who were divided into DS (n = 15) and ND (n = 26) subtypes using the Schedule for the Deficit Syndrome (SDS). Olfactory perception for pleasant and unpleasant odors was assessed using the Brief Smell Identification Test. Participants were instructed to identifying each smell as well as provide hedonic judgment ratings of each smell on a 7-point scale (1 = extremely pleasant, 4 = neutral, and 7 = extremely unpleasant). Results indicated that when compared with the ND patients, the DS patients rated pleasant smells as being significantly less pleasant, although no difference between the groups was present for unpleasant smells, and both ND and DS groups significantly differed from CN on rating and identifying pleasant and unpleasant items. Additionally, lower smell identification accuracy was negatively correlated with SDS symptom severity, and valence ratings for pleasant odors were positively correlated with SDS diminished emotional range. Findings suggest that the DS is characterized by a unique pattern of olfactory valence judgment that is characterized by abnormalities in processing positively valenced stimuli.

Executive function needs to be targeted to improve social functioning with Cognitive Remediation Therapy (CRT) in schizophrenia

While the role of impaired cognition in accounting for functional outcome in schizophrenia is generally established, the relationship between cognitive and functional change in the context of treatments is far from clear. The current paper tries to identify which cognitive changes lead to improvements in daily functioning among persons with chronic schizophrenia who had current negative symptoms and evidenced neuropsychological impairments. In a previous work, Cognitive Remediation Therapy (CRT) was compared with a control therapy, involving similar length of therapist contact but different targets. At the end of treatment, CRT conferred a benefit to people with schizophrenia in cognition and functioning [Schizophrenia Research, 87 (2006) 323-331]. Subsequently, analyses of covariance (ANCOVA) were conducted with baseline and cognitive change scores as covariates to test whether cognitive change predicted change in functioning. Additionally, statistical tests to establish the mediation path with significant variables were performed. Although verbal memory, but not executive functioning, was associated with functioning at baseline, it was the improvement in executive functioning that predicted improved daily functioning. Verbal memory played a mediator role in the change process. Consequently, in order to improve daily functioning with CRT, executive function still needs to be targeted in despite of multiple cognitive impairments being present.

The psychiatric symptomatology of deficit schizophrenia: a meta-analysis

A relatively large literature has emerged supporting the notion that the deficit syndrome reflects a distinct illness within schizophrenia. One topic that has received limited attention is how deficit schizophrenia differs from nondeficit schizophrenia in terms of psychiatric symptomatology. The present study conducted a meta-analysis of 47 published studies to compare deficit and nondeficit patients in severity of positive, disorganization, negative, mood and total psychiatric symptoms. The patient groups did not differ in terms of positive or total psychiatric symptoms but deficit patients showed less severe mood symptoms and slightly more severe disorganization symptoms. Not surprisingly, deficit patients had much more severe negative symptoms. These results are discussed in terms of the construct validity of the deficit syndrome and the larger heterogeneity of schizophrenia. Additionally, diagnostic issues regarding the deficit syndrome are considered.

Using virtual reality to evaluate executive functioning among persons with schizophrenia: a validity study

Persons with Schizophrenia experience difficulties with Executive Functioning (EF) that affect independence and participation in activities. Specifically, EF impacts performance in Instrumental Activities of Daily Living (IADL) that require flexible thinking and accommodation to complex environments. However, less is known how schizophrenia affects EF and individuals' performance in activities. IADL performance can be tested using a virtual reality (VR) environment that simulates real life activities. The purpose of this study was: 1) to examine the feasibility and validity of the Virtual Action Planning-Supermarket (VAP-S) to assess EF in persons with schizophrenia as compared to a standardized EF measure (the Behavioral Assessment of Dysexecutive Syndrome, BADS); 2) to compare performance of persons with schizophrenia and healthy controls in the VAP-S; 3) to assess the ability of the VAP-S to differentiate between different levels of EF within schizophrenia; 4) to explore the relationships between negative and positive symptoms and performance on the tests. Thirty persons with schizophrenia were matched with 30 healthy controls. Significant differences in performance between research and control groups were detected on the VAP-S and BADS, with the research group performing worse. Large variations in number of purchases within the VAP-S by the research group point to level of task completion thus secondary analysis was conducted. There was a significant negative correlation between level of the negative signs and overall performance on the BADS and on most measures of the VAP-S. Results of this study support the use the VAP-S to assess EF among persons with Schizophrenia.

Symptoms as mediators of the relationship between neurocognition and functional outcome in schizophrenia: a meta-analysis

BACKGROUND

Neurocognitive functioning in schizophrenia has received considerable attention because of its robust prediction of functional outcome. Psychiatric symptoms, in particular negative symptoms, have also been shown to predict functional outcome, but have garnered much less attention. The high degree of intercorrelation among all of these variables leaves unclear whether neurocognition has a direct effect on functional outcome or whether that relationship to functional outcome is partially mediated by symptoms.

METHODS

A meta-analysis of 73 published English language studies (total n=6519) was conducted to determine the magnitude of the relationship between neurocognition and symptoms, and between symptoms and functional outcome. A model was tested in which symptoms mediate the relationship between neurocognition and functional outcome. Functional outcome involved measures of social relationships, school and work functioning, and laboratory assessments of social skill.

RESULTS

Although negative symptoms were found to be significantly related to neurocognitive functioning (p<.01) positive symptoms were not (p=.97). The relationship was moderate for negative symptoms (r=-.24, n=4757, 53 studies), but positive symptoms were not at all related to neurocogniton (r=.00, n=1297, 25 studies). Negative symptoms were significantly correlated with functional outcome (r=-.42, p<.01), and again the correlation was higher than for positive symptoms (r=-.03, p=.55). Furthermore, our findings support a model in which negative symptoms significantly mediate the relationship between neurocognition and functional outcome (Sobel test p<.01).

CONCLUSIONS

Although neurocognition and negative symptoms are both predictors of functional outcome, negative symptoms might at least partially mediate the relationship between neurocognition and outcome.

Deficit schizophrenia: an overview of clinical, biological and treatment aspects

The concept of deficit schizophrenia is regarded as one of the most promising attempts to reduce heterogeneity within schizophrenia. This paper summarizes the clinical, neurocognitive, brain imaging and electrophysiological correlates of this subtype of schizophrenia. Attempts to identify genetic and non-genetic risk factors are reviewed. Methodological limitations of studies supporting the efficacy of atypical antipsychotics in the treatment of the syndrome are highlighted. Two decades of research on deficit schizophrenia have failed to prove that it represents the extreme end of a severity continuum in schizophrenia, while some findings support the claim that it may be a separate disease entity.

Is executive impairment associated with schizophrenic syndromes? A meta-analysis

BACKGROUND

A key neuropsychological proposal in schizophrenia is that negative and disorganization symptoms are associated with different patterns of impairment on executive tasks.

METHOD

Studies reporting correlations between positive, negative or disorganization symptoms and any type of executive test were meta-analysed. The influence of moderating factors was also examined, including age, treatment and stage of illness and whether symptoms were relapsing or persistent. The magnitudes of the correlations were compared with those for general intellectual impairment.

RESULTS

Pooled correlations between executive impairment and both negative symptoms and disorganization were significant in the small-to-moderate range. That for positive symptoms ('reality distortion'), however, was close to zero. The pattern of correlations among different executive tests differed significantly for negative symptoms and disorganization. Patients with stable clinical pictures showed significantly higher correlations with executive impairment than those with relapsing and remitting illnesses. Both negative symptoms and disorganization also correlated significantly with general intellectual function as indexed by current IQ.

CONCLUSIONS

Meta-analysis supports the view that negative symptoms and disorganization are associated with partially dissociable patterns of executive impairment. However, co-existent general intellectual impairment has been an important confounding factor in the studies to date.

Deficit schizophrenia: an update

The criteria for deficit schizophrenia were designed to define a group of patients with enduring, primary (or idiopathic) negative symptoms. In 2001, a review of the literature suggested that deficit schizophrenia constitutes a disease separate from nondeficit forms of schizophrenia. Here we provide a review of new studies, not included in that paper, in which patients with deficit schizophrenia and those with nondeficit schizophrenia were compared on dimensions typically used to distinguish diseases: signs and symptoms, course of illness, pathophysiological correlates, risk and etiological factors, and treatment response. Replicated findings and new evidence of double dissociation supporting the separate disease hypothesis are highlighted. Weaknesses in research and treatment options for these patients are also emphasized.

Neuropsychological impairment in deficit vs. non-deficit schizophrenia

This study aimed to assess the severity and specificity of cognitive impairments that affect individuals with deficit versus non-deficit schizophrenia. We compared 26 patients with the deficit subtype of schizophrenia (SZ-D) and 79 with non-deficit schizophrenia (SZ-ND) to 316 healthy adults (NC). All study participants completed a battery with 19 individual cognitive measures. After adjusting their test performance for age, sex, race, education and estimated premorbid IQ, we derived regression-based T-scores for each measure and the six derived cognitive domains including attention, psychomotor speed, executive function, verbal fluency, visual memory, and verbal memory. Multivariate analyses of variance revealed significant group effects for every individual measure and domain of cognitive functioning (all ps<0.001). Post hoc comparisons revealed that patients with SZ-D performed significantly worse than NCs in every cognitive domain. They also produced lower scores than the SZ-ND group in every domain, but only the difference for verbal fluency reached statistical significance. The correlations of the effect sizes shown by the SZ-D and SZ-ND patients were of intermediate magnitude for the individual tests (r=0.56, p<0.01) and higher, but not statistically significant for the cognitive domains (r=0.79, p=0.06). Patients with SZ-D demonstrate cognitive deficits that are both common and distinct from those shown by patients with SZ-ND. Their impairment of verbal fluency is consistent with the observation that poverty of speech is a clinically significant feature of patients with SZ-D.

Psychopathology and neuropsychological impairments in deficit and nondeficit schizophrenia of Chinese origin

Deficit schizophrenia is a relatively homogeneous subtype of patients which is considered helpful to explore the pathogenesis of schizophrenia. The aim of the present study was to reexamine the clinical characteristics of deficit (n=30) and nondeficit schizophrenia (n=93) in a Chinese sample and investigate the differences of neurocognitive function among the two subtypes of schizophrenia and the normal controls (n=103). Schizophrenia patients completed the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS) and Scale for the Assessment of Positive Symptoms (SAPS). Additionally, all participants completed an abbreviated version of the Wechsler Adult Intelligence Scale (WAIS-RC) and a neuropsychological test battery examining the executive functions, visuospatial abilities and explicit memory related to the frontal, parietal, and temporal lobe functions. The deficit group received higher scores than the nondeficit group on the BPRS anergia factor and SANS affective flattening, alogia, avolition-apathy, anhedonia-asociality subscales, but not on the SAPS. Both two schizophrenia subgroups performed more poorly on the WAIS-RC and neuropsychological tests than the normal controls. Moreover, deficit patients performed worse than nondeficit patients on the prorated IQ, the Trail Making Test, Wisconsin Card Sorting test and Block Design test. The present study replicated symptom profiles in deficit vs. nondeficit schizophrenia in the Chinese sample. Furthermore, this study suggested that deficit schizophrenia is associated with frontal and parietal lobe impairment, and that temporal lobe dysfunction may be a common basis for cognitive impairment in schizophrenia as a whole.

A two-factor structure for the Schedule for the Deficit Syndrome in schizophrenia

The deficit subtype is hypothesized to constitute a homogeneous subgroup of schizophrenia patients. The Schedule for the Deficit Syndrome (SDS) was developed to categorize schizophrenia patients into deficit and non-deficit subtypes. Only one report, however, has suggested the use of a two-factor SDS. The present study used a two-factor SDS and examined the relationships between the factors and the demographic and clinical variables in deficit-type schizophrenia patients. Principal component analysis was performed on data obtained from 70 schizophrenia patients with the deficit syndrome. The two-factor SDS was replicated. Factor 1, avolition, was significantly correlated only with the relational disorder domain, which consisted of two negative items from the Positive and Negative Syndrome Scale. Factor 2, poor emotional expression, was significantly correlated with both the negative symptom domain, which consisted of three negative items, and the relational disorder domain. Since the SDS has two factors, there appear to be different underlying processes for these two factors.