The crucial role of sustained attention in community functioning in outpatients with schizophrenia

The aim was to explore the pattern of associations between visual cognitive performance and community functioning in a sample of outpatients with schizophrenia participating in a rehabilitation program. Visuo-spatial tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were administered to assess cognitive performances in 88 subjects. The Multnomah Community Ability Scale (MCAS) was used to measure dimensions of community functioning. Our results showed that the sustained attention score was significantly associated with the global community functioning score and with two specific dimensions: "adjustment to living" and "behavioral problems". No association was found between other cognitive indices and MCAS scores. Since the sustained attention task mainly involves the executive component of working memory, these findings suggest that attentional control processes are limiting factors for community functioning in schizophrenia outpatients. Measures of such processes could serve as key indices of disability in clinical practice. Attention and working memory training may be helpful to improve community functioning in subjects with schizophrenia.     

Verbal memory, problem-solving skills and community status in schizophrenia

Neuropsychological deficits have been associated with poor community functioning in individuals with schizophrenia. Previous research suggests that verbal memory capacity is related to functional capacity. The purpose of this study was to investigate the relationship between verbal memory, problem-solving skills and community functioning, as measured by treatment status (inpatient vs. outpatient) in people with schizophrenia spectrum disorders. Evaluations were done on 162 individuals with schizophrenia or schizoaffective disorder, seen in inpatient (n=87) and outpatient settings (n=75). Verbal memory was assessed using narrative recall and list recall measures. Problem-solving skills for independent living were assessed using a social reasoning measure and a daily problem-solving skills measure. Better verbal memory performance was associated with better problem solving for independent living. However, inpatient vs. outpatient status was best determined by problem-solving skills for independent living rather than verbal memory performance. The results reveal the importance of daily problem-solving skills for community status in schizophrenia. Although verbal memory performance is associated with problem-solving skills for independent living, predictive probability of community status does not improve when memory performance is taken into account.     

Negative symptoms and specific cognitive impairments as combined targets for improved functional outcome within cognitive remediation therapy

Negative symptoms and poor cognition are both associated with poor functional outcome in schizophrenia. This poor functional outcome has been attributed to poor cognition rather than any independent contribution from symptoms. Identifying target cognitive processes and mechanisms that predict community function, and possible moderator effects of negative symptoms, will allow the development of cognitive remediation programs that are successful in improving functional outcome. A referred sample of 53 in- and outpatients with schizophrenia with general cognitive impairment (including 28 with severe negative symptoms) and 22 healthy controls, balanced for premorbid IQ, were compared cross sectionally on measures of community shopping skills, executive function, and working memory. Across the groups, there were direct relationships between community functioning and specific executive functions, and there were interactions between group membership and the types of associations found. Working memory was independently associated with accurate community functioning only in people with schizophrenia and negative symptoms. This association was not due to the sole presence of working memory impairment or just to negative symptoms. Poor community function is predicted both by specific cognitive impairments that are prominent in people with negative symptoms and through the moderating effect of negative symptoms on the working memory-community function relationship. This may reflect a synergistic association between symptoms and cognition: negative symptoms arise from cognitive impairment but also impact detrimentally on working memory functioning. Both cognitive processes and negative symptoms should be targeted in cognitive remediation to effect the greatest change in community functions.     

Determinants of real-world functional performance in schizophrenia subjects: correlations with cognition, functional capacity, and symptoms

OBJECTIVE: Impairments in adaptive life skills are a major source of disability in patients with schizophrenia. The relationship between adaptive life skills in real-world settings and performance on neuropsychological tests may be complicated by other factors that interfere with deployment of skills. Assessment of the ability to perform life skills under optimal conditions (i.e., assessment of functional capacity) has been proposed as a means to clarify these relationships. METHOD: The authors examined cross-sectional data from a study of the course of neuropsychological and adaptive life skills of older (age 50-85) schizophrenia patients (N=78). Functional capacity was examined with a performance-based measure (UCSD Performance-Based Skills Assessment), and case managers rated real-world adaptive functions (i.e., interpersonal skills, work skills, and community activities). Neuropsychological performance was assessed with a comprehensive battery, while symptoms were assessed with patient self-report and clinical ratings. RESULTS: Confirmatory path analyses were used to evaluate the effects of neuropsychological performance, functional capacity, and symptoms on the various domains of real-world functioning. Neuropsychological performance predicted functional capacity, which predicted all three domains of real-world functioning. Depression predicted interpersonal and work skills, while negative symptoms affected interpersonal skills independently of other predictors. CONCLUSIONS: Real-world adaptive life skills are predicted by neuropsychological performance, symptoms, and functional capacity. Neuropsychological performance contributes little to the prediction of real-world performance after accounting for functional capacity. In some domains, negative and depressive symptoms influenced real-world performance while not relating to functional capacity or neuropsychological performance.     

Neurocognitive and symptom correlates of daily problem-solving skills in schizophrenia

Functional outcome for individuals with schizophrenia has been associated with cognitive impairment. Deficits in attention, memory, speed of information processing and problem-solving skills affect independent functioning, vocational performance, and interpersonal functioning. This study investigated the relationship between neurocognitive functioning, clinical symptoms and daily problem-solving skills in seriously and persistently ill persons. Thirty-eight inpatients and outpatients were administered a neurocognitive battery for attention, working memory, processing speed, perceptual organization, and executive functioning; and semi-structured clinical interviews using the BPRS and SANS. Estimates of daily problem-solving skills were obtained using the relevant factor subscale from the Independent Living Scales (ILS-PB). Daily problem-solving skills were significantly correlated with negative symptoms, processing speed, verbal memory, and working memory scores. A regression model using an enter method suggests that working memory and negative symptoms are significant predictors of daily problem-solving skills and account for 73.2% of the variance. Further analyses demonstrate that daily problem-solving skills and negative symptoms were significantly different for inpatients and outpatients and significantly correlated with community status. The findings suggest the ILS-PB has utility as a proxy measure for assessing real-world functioning in schizophrenia.     

Verbal memory, negative symptomatology and prediction of psychosocial functioning in schizophrenia

Negative symptomatology and neurocognitive variables have been considered good predictors of functional outcome in schizophrenia. Specifically, secondary verbal memory has been proposed to be one of the main predictors of psychosocial functioning. In this study, negative symptoms and memory performance were analyzed for associations with psychosocial function. Linear regression methods were used to analyze the value of verbal memory and negative symptomatology as predictors of everyday life skills in a sample of 29 DSM-IV schizophrenia outpatients with predominant negative symptoms. We also took into account the role of gender in the analyses. Secondary verbal memory was found to explain 40% of the variance in psychosocial functioning, independently of gender, whereas the negative symptoms predicted 26%. When both variables were combined, the explained variance was about 49%. These results support the hypothesis that cognitive variables are better predictors than symptomatology. Finally, secondary verbal memory is a good predictor of psychosocial functioning in chronic schizophrenia with predominant negative symptomatology.     

Recollection and familiarity in negative schizophrenia

Using the "remember-know" procedure to assess recognition memory, previous studies yielded evidence of impaired recollection but intact familiarity in schizophrenia patients. However, so far, the recognition memory performance of schizophrenia patients has not yet been analysed using the dual-process signal detection model (DPSD) by Yonelinas [Yonelinas, A. P. (2001). Components of episodic memory: The contribution of recollection and familiarity. Philosophical Transactions of Royal Society of London. Series B: Biological Sciences, 356(1413), 1363-1374], which accurately accounts for response and memory bias. Also, clinical symptoms have not yet been taken into account. Based on findings from neuropsychological and neurobiological research we hypothesized that high negative symptoms might be associated with a profile of impaired recollection and spared familiarity. The recognition memory performance of 22 schizophrenia patients scoring higher or lower on the negative symptoms subscale of the Positive and Negative Syndrome Scale (PANSS) was assessed by means of a word list discrimination task. Following the rationale of the dual-process signal detection model, estimates of recollection and familiarity were derived. The recollection estimate, derived by the DPSD model, was lower in patients with more severe negative symptomatology compared with both the patients with lower negative symptoms scores and healthy individuals. Familiarity was not affected if IQ was partialled out. Furthermore, the results yielded increased false alarm rates in patients with negative schizophrenia. The findings confirm an association of negative symptoms and recollection impairment in schizophrenia.     

Cognitive predictors of psychosocial functioning outcome in schizophrenia: a follow-up study of subjects participating in a rehabilitation program

The aims of this prospective study were to explore in subjects with psychosis participating in a rehabilitation program whether cognitive performances at baseline predicted (i) psychosocial functioning over a 15-16 month follow-up; (ii) improvement in psychosocial functioning over the rehabilitation program. Visuo-spatial tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were administered to assess cognitive performance in 55 subjects with schizophrenia spectrum disorders who completed a rehabilitation program. The Multnomah Community Ability Scale (MCAS) was used to measure dimensions of community functioning. One subscale of the Client's Assessment of Strengths, Interests, and Goals (CASIG) provided a measure of subjective quality of life (QoL). Improvement was defined as a 15% or more increase in psychosocial scores between baseline and follow-up. Worse baseline sustained attention predicted better self-rated quality of life, and better baseline visual memory predicted better community functioning over the rehabilitation follow-up period, in particular, higher autonomy in activities of daily living, and less physical and psychiatric symptoms that could interfere with rehabilitation. Baseline cognitive performances predicted community functioning improvement during the follow-up period: visual memory predicted improvement in daily living autonomy and in social competence; sustained attention predicted improvement in behavioral problems (such as medication compliance, collaboration with treatment providers or impulse control) and social competence; planning performances predicted improvement in social competence. These cognitive functions could be specifically targeted in a rehabilitation program aimed at enhancing functioning in those particular dimensions.     

Social functioning, theory of mind and neurocognition in outpatients with schizophrenia; mental state decoding may be a better predictor of social functioning than mental state reasoning

Few studies have directly investigated the relationship between theory of mind (ToM) deficits and social functioning in schizophrenia. At the same time, the impact of mental state decoding tasks on social dysfunction has also not yet been investigated. In this study, the relationship between theory of mind deficits and social functioning was investigated among 50 patients with schizophrenia. A mental state decoding task known as 'The Eyes test' and a mental state reasoning task 'The Hinting test' were applied to assess ToM abilities, while the Social Functioning Scale (SFS) was used to assess social functioning. Non-ToM neurocognitive tests were also given to the patients. Results of the study show how theory of mind and working memory performances of patients with good functional outcome proved to be significantly better than those of inadequately functioning patients. Results also indicate that performance on the Eyes test was the best predictor of social functioning and that negative symptoms also contributed to poor social functioning. It is concluded in this study that mental state decoding skills appear to be the most important cognitive mediator of social functioning.     

Community dysfunction in schizophrenia: rate-limiting factors

The purpose of the present study was to investigate the impact of cognitive functioning, psychopathology, and severity of extrapyramidal side effects on community outcome in a group of Greek outpatients with schizophrenia. Participants were 40 outpatients with schizophrenia (25 men). Social adjustment was assessed with the Quality of Life Scale (QLS). Severity of symptoms of schizophrenia was measured with the Positive and Negative Syndrome Scale (PANNS), and extrapyramidal symptoms with the Extrapyramidal Symptom Rating Scale (ESRS). Finally, a battery of neuropsychological tests was administered in order to assess the following cognitive domains: executive functioning/set shifting, executive functioning/inhibition, fluency, verbal memory, visual memory, working memory, attention, visuospatial ability, and psychomotor speed/visual scanning. Total scores on the QLS were significantly correlated with negative symptoms, parkinsonism, and performance on the fluency tasks. Interpersonal relations subscale was significantly related with negative symptoms and fluency. No significant relationship was found between the Instrumental Role Functioning subscale and the PANSS, ESRS, or any cognitive domain. Scores on the Intrapsychic Foundation subscale were significantly correlated with negative symptoms and fluency. Finally, scores on the Common Objects and Activities subscale were significantly related with severity of negative symptoms, parkinsonism and visual memory. Our findings suggest that severity of negative symptoms, cognitive dysfunction, especially performance on fluency tasks and visual memory, as well as parkinsonism, are important determinants of functional outcome in schizophrenia.     

Symptomatic and functional correlates of regional brain physiology during working memory processing in patients with recent onset schizophrenia

Patients with schizophrenia show altered patterns of functional activation during working memory processing; specifically, high-performing patients appear to hyper-activate and low-performing patients appear to hypo-activate when compared with controls. It remains unclear how these individual differences in neurophysiological activation relate to the clinical presentation of the syndrome. In this functional magnetic resonance imaging (fMRI) study, the relationship is examined using partial least squares (PLS), a multivariate statistical technique that selects underlying latent variables based on the covariance between two sets of variables, in this case, clinical variables and regional fMRI activations during a verbal working memory task. The PLS analysis extracted two latent variables, and the significance of these associations was confirmed through permutation. Lower levels of activation during task performance across frontal and parietal regions of interest in the left hemisphere were found to covary with poorer role functioning and greater severity of negative and disorganized symptoms, while lower activation in right frontal and subcortical regions of interest was found to covary with better social functioning and fewer positive symptoms. These results suggest that appropriately lateralized patterns of functional activation during working memory processing are related to the severity of negative and disorganized symptoms and to the level of role and social functioning in schizophrenia.     

Abnormal prediction error is associated with negative and depressive symptoms in schizophrenia

Prediction error in learning is where learning occurs to the degree to which an outcome consequent to a stimulus is surprising. It has been suggested that abnormal use of prediction error in schizophrenia may underlie the formation of inappropriate associations giving rise to psychotic symptoms. Kamin blocking is a phenomenon that demonstrates prediction error. Kamin blocking is shown where prior learning about a stimulus A paired with an outcome retards learning about a stimulus B when presented subsequently as part of a stimulus compound AB paired with the same outcome. Prior studies have indicated reduced Kamin blocking in schizophrenia specifically in non-paranoid patients. It is however unclear how reduced Kamin blocking is associated with specific symptoms in schizophrenia. The present study examined Kamin blocking performance in a high functioning community-based sample of 34 people with schizophrenia and 48 controls closely matched for pre-morbid IQ. In these patients we measured Kamin blocking and symptoms using positive and negative symptom scales (PANSS) and Scale for the Assessment of Negative Symptoms (SANS) and Scale for the Assessment of Positive Symptoms (SAPS). Results confirmed that people with schizophrenia had significantly reduced Kamin blocking. Kamin blocking performance was associated with negative and depressive symptoms. These associations with symptoms were crucially not found with baseline associative learning or unblocking measures, confirming specificity to the Kamin blocking effect. These data demonstrate first that abnormal prediction error as assessed in the Kamin blocking task is associated with negative and depressive symptoms rather than positive symptoms in high functioning schizophrenia patients. Second this strongly suggests that reduced Kamin blocking may be useful as an animal model of specific relevance to negative and depressive symptoms in schizophrenia.     

Relation of prefrontal cortex dysfunction to working memory and symptoms in schizophrenia.

OBJECTIVE: The dorsolateral prefrontal cortex has been implicated in both working memory and the pathophysiology of schizophrenia. A relationship among dorsolateral prefrontal cortex activity, working memory dysfunction, and symptoms in schizophrenia has not been firmly established, partly because of generalized cognitive impairments in patients and task complexity. Using tasks that parametrically manipulated working memory load, the authors tested three hypotheses: 1) patients with schizophrenia differ in prefrontal activity only when behavioral performance differentiates them from healthy comparison subjects, 2) dorsolateral prefrontal cortex dysfunction is associated with poorer task performance, and 3) dorsolateral prefrontal cortex dysfunction is associated with cognitive disorganization but not negative or positive symptoms. METHOD: Seventeen conventionally medicated patients with schizophrenia and 16 healthy comparison subjects underwent functional magnetic resonance imaging while performing multiple levels of the "n-back" sequential-letter working memory task. RESULTS: Patients with schizophrenia showed a deficit in physiological activation of the right dorsolateral prefrontal cortex (Brodmann's area 46/9) in the context of normal task-dependent activity in other regions, but only under the condition that distinguished them from comparison subjects on task performance. Patients with greater dorsolateral prefrontal cortex dysfunction performed more poorly. Dorsolateral prefrontal cortex dysfunction was selectively associated with disorganization symptoms. CONCLUSIONS: These results are consistent with the hypotheses that working memory dysfunction in patients with schizophrenia is caused by a disturbance of the dorsolateral prefrontal cortex and that this disturbance is selectively associated with cognitive disorganization. Further, the pattern of behavioral performance suggests that dorsolateral prefrontal cortex dysfunction does not reflect a deficit in the maintenance of stimulus representations per se but points to deficits in more associative components of working memory.     

Associative memory encoding and recognition in schizophrenia: an event-related fMRI study.

BACKGROUND: We used an event-related functional Magnetic Resonance Imaging (fMRI) approach to examine the neural basis of the selective associative memory deficit in schizophrenia. METHODS: Fifteen people with schizophrenia and 18 controls were scanned during a pair and item memory encoding and recognition task. During encoding, subjects studied items and pairs of visual objects. In a subsequent retrieval task, participants performed an item recognition memory test (old/new decisions) and an associative recognition test (intact/rearranged decisions). The fMRI analysis of the recognition data was restricted to correct items only and a random effects model was used. RESULTS: At the behavioral level, both groups performed equally well on item recognition, whereas people with schizophrenia demonstrated lower performance on associative recognition relative to the control group. At the brain level, the comparison between associative and item encoding revealed greater activity in the control group in the left prefrontal cortex and cingulate gyrus relative to the schizophrenia group. During recognition, greater left dorsolateral prefrontal and right inferior prefrontal activations were observed in the control group relative to the schizophrenia group. CONCLUSION: This fMRI study implicates the prefrontal cortex among other brain regions as the basis for the selective associative memory encoding and recognition deficit seen in schizophrenia.     

Further support for the role of dysfunctional attitudes in models of real-world functioning in schizophrenia

According to A.T. Beck and colleagues’ cognitive formulation of poor functioning in schizophrenia, maladaptive cognitive appraisals play a key role in the expression and persistence of negative symptoms and associated real-world functioning deficits. They provided initial support for this model by showing that dysfunctional attitudes are elevated in schizophrenia and account for significant variance in negative symptoms and subjective quality of life. The current study used structural equation modeling to further evaluate the contribution of dysfunctional attitudes to outcome in schizophrenia. One hundred eleven outpatients and 67 healthy controls completed a Dysfunctional Attitudes Scale, and patients completed a competence measure of functional capacity, clinical ratings of negative symptoms, and interview-based ratings of real-world functioning. Patients reported higher defeatist performance beliefs than controls and these were significantly related to lower functional capacity, higher negative symptoms, and worse community functioning. Consistent with Beck and colleagues’ formulation, modeling analyses indicated a significant indirect pathway from functional capacity → dysfunctional attitudes → negative symptoms → real-world functioning. These findings support the value of dysfunctional attitudes for understanding the determinants of outcome in schizophrenia and suggest that therapeutic interventions targeting these attitudes may facilitate functional recovery.     

Symptoms and neurocognition as rate limiters in skills training for psychotic patients.

OBJECTIVE: This study aimed to replicate findings that neurocognitive capacity in schizophrenia is more predictive of acquisition of social skills than are symptoms. METHOD: Thirty-two hospitalized patients with chronic psychotic disorders were randomly assigned to community reintegration skills training or supportive group therapy. Neurocognitive functioning was assessed before treatment, and symptoms and skill levels were measured before and after treatment. RESULTS: The skills training group showed significantly greater skill acquisition. In a regression model, skill acquisition was predicted by group membership and verbal memory capacity and not by symptoms. CONCLUSIONS: With methodological advances, the authors replicated findings regarding the importance of neurocognition in determining treatment outcome in schizophrenia.     

Subjective and objective quality of life in schizophrenia

OBJECTIVE: Quality of life (QOL) is considered an important outcome in the treatment of schizophrenia, but the determinants of QOL are poorly understood in this population. Furthermore, previous studies have relied on combined measures of subjective QOL (usually defined as life satisfaction) and objective QOL (usually defined as participation in activities and relationships). We examined separately the clinical, functional, and cognitive predictors of subjective and objective QOL in outpatients with schizophrenia. We hypothesized that better subjective QOL would be associated with less severe negative and depressive symptoms, better objective QOL, and greater everyday functioning capacity, and that better objective QOL would be associated with less severe negative and depressive symptoms, better cognitive performance, and greater functional capacity. METHOD: Participants included 88 outpatients with schizophrenia or schizoaffective disorder who completed a comprehensive series of assessments, including measures of positive, negative, and depressive symptoms; performance-based functional skills; a neuropsychological battery; and an interview measure of subjective and objective QOL. RESULTS: In the context of multiple predictor variables, more severe depressive symptoms and better neuropsychological functioning were independent predictors of worse subjective QOL. More severe negative symptoms predicted worse objective QOL. Functional capacity variables were not associated with subjective or objective QOL. CONCLUSION: Treatments to improve QOL in schizophrenia should focus on negative symptoms and depressive symptoms.     

Functional cooking skills and neuropsychological functioning in patients with stroke: An ecological validity study

Efforts to relate neuropsychological performance to real-world task functioning have predominantly yielded lackluster results, typically with neuropsychological performance accounting for modest amounts of variance in function. Nonetheless, the ecological validity of neuropsychological measures for predicting functional abilities remains a strong research interest and clinical necessity. This study relates neuropsychological performance to performance on a standardised cooking task (Rabideau Kitchen Evaluation – Revised; RKE-R) in persons with stroke. Results showed that while the composite score of mean neuropsychological performance had the largest association with meal preparation, several neuropsychological measures were significantly related to the RKE-R. Groups of left and right hemisphere stroke patients were not significantly different in terms of RKE-R performance. These results suggest that functional cooking task performance is related to intact cognitive abilities in delayed verbal memory, simple auditory attention, and visuospatial skills, as well as overall cognitive performance. Implications for neuropsychologists are discussed.     

Clinical, functional, and intertask correlations of measures developed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia Consortium

The goal of the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRACS) Consortium was to develop measures of discrete cognitive processes, allowing for the interpretation of specific deficits that could be linked to specific neural systems. Here we report on the intertask, clinical, and functional correlates of the 4 tasks that were investigated in large groups of patients with schizophrenia (>100) and healthy controls (>73) at 5 sites across the United States. In both healthy and patient groups, the key dependent measures from the CNTRACS tasks were minimally intercorrelated, suggesting that they are measuring discrete abilities. Correlations were examined between CNTRACS tasks and measures of functional capacity, premorbid IQ, symptom severity, and level of community functioning. Performance on tasks measuring relational memory encoding, goal maintenance, and visual gain control were correlated with premorbid IQ and the former 2 tasks with the functional capacity. Goal maintenance task performance was negatively correlated with negative symptom severity and informant reports of community function. These correlations reflect the relationship of specific abilities with functional outcome. They are somewhat lower than functional outcome correlations observed with conventional neuropsychological tests that confound multiple cognitive and motivational deficits. The measures of visual integration and gain control were not significantly correlated with clinical symptoms or function. These results suggest that the CNTRACS tasks measure discrete cognitive abilities, some of which relate to aspects of functional capacity/outcome in schizophrenia.     

Spatial working memory deficit correlates with disorganization symptoms and social functioning in schizophrenia

Both spatial working memory deficit and disorganization symptoms have been considered significant components of schizophrenic impairment involved with the dorsolateral prefrontal cortex. The purpose of the present study was to investigate the relationships among spatial working memory, psychiatric symptoms including disorganization symptoms, and social functioning in schizophrenia. Fifty clinically stable patients with schizophrenia and 34 healthy controls participated in the study. Patients were rated with the Brief Psychiatric Rating Scale and the Rehabilitation Evaluation Hall and Baker. The Advanced Trail Making Test was used to evaluate spatial working memory. Patients demonstrated significantly reduced spatial working memory compared to that of healthy controls. Spatial working memory in patients correlated significantly with social functioning such as self-care skills, community skills and speech disturbance, and with disorganization symptoms. Disorganization symptoms also correlated with these aspects of social functioning. In conclusion it is suggested that both spatial working memory deficit and disorganization symptoms, which are impairments involved with the dorsolateral prefrontal cortex dysfunction, can serve as effective predictors of social functioning.