Comprehension of metaphors in patients with schizophrenia-spectrum disorders

Background

Metaphors, mainly proverbs and idiomatic expressions of ordinary life are commonly used as a model for concretism. Previous studies have shown impaired metaphor comprehension in patients with schizophrenia-spectrum disorders compared to either psychiatric or non-psychiatric control subject. The aim of this study was to detect possible quantitative differences in figurative processing between patients with schizophrenia-spectrum disorders and healthy controls.

Methods

In order to analyse possible dissociations of different aspects of figurative speech, a range of metaphor tasks was used to distinguish between recognition of familiar metaphors, paraphrasing the meaning of the latter and generating novel metaphors: we used a standard proverb test for conventional metaphors consisting of a multiple-choice and a paraphrasing task, and the Metaphoric Triads Test for the assessment of novel metaphors. We included 40 patients with schizophrenia-spectrum disorders and 43 healthy control subjects.

Results

Our results showed that patients had impaired figurative speech processing regarding novel and conventional metaphors. Associations with cognitive functions were detected. Performance on the paraphrasing task was associated with the severity of negative symptoms.

Conclusion

We conclude that patients with schizophrenia-spectrum disorders do exhibit impairments in the recognition and paraphrasing of conventional and the generation of novel metaphors and that some cognitive domains as well the extent of negative symptoms might be associated with these deficits.     

Lower negative symptom scores among cannabis-dependent patients with schizophrenia-spectrum disorders: preliminary evidence from an African American first-episode sample

Substance use disorders, especially cannabis abuse and dependence, are common comorbid diagnoses among patients in the early course of schizophrenia. Some prior research suggests that individuals with schizophrenia and related disorders and comorbid substance abuse may have fewer negative symptoms than those without substance abuse. This pilot study examined the association between cannabis dependence and negative symptoms in a relatively homogenous sample of 18 African American first-episode, first-hospitalization patients. Those with cannabis dependence had significantly lower Positive and Negative Syndrome Scale (PANSS) negative subscale scores compared to those without cannabis dependence (p<0.012). The two groups did not differ on PANSS positive and general psychopathology subscale scores. Additional research is needed on the correlates of substance abuse among first-episode patients, including socially disadvantaged African American patients.     

Facial emotion processing in schizophrenia: no evidence for a deficit specific to negative emotions in a differential deficit design

People with schizophrenia perform poorly when recognising facial expressions of emotion, particularly negative emotions such as fear. This finding has been taken as evidence of a "negative emotion specific deficit", putatively associated with a dysfunction in the limbic system, particularly the amygdala. An alternative explanation is that greater difficulty in recognising negative emotions may reflect a priori differences in task difficulty. The present study uses a differential deficit design to test the above argument. Facial emotion recognition accuracy for seven emotion categories was compared across three groups. Eighteen schizophrenia patients and one group of healthy age- and gender-matched controls viewed identical sets of stimuli. A second group of 18 age- and gender-matched controls viewed a degraded version of the same stimuli. The level of stimulus degradation was chosen so as to equate overall level of accuracy to the schizophrenia patients. Both the schizophrenia group and the degraded image control group showed reduced overall recognition accuracy and reduced recognition accuracy for fearful and sad facial stimuli compared with the intact-image control group. There were no differences in recognition accuracy for any emotion category between the schizophrenia group and the degraded image control group. These findings argue against a negative emotion specific deficit in schizophrenia.     

Clinical and neurocognitive course in early-onset psychosis: a longitudinal study of adolescents with schizophrenia-spectrum disorders

Aim: Adolescents with psychotic disorders show deficits in IQ, attention, learning and memory, executive functioning, and processing speed that are related to important clinical variables including negative symptoms, adaptive functioning and academics. Previous studies have reported relatively consistent deficits with varying relationships to illness status and symptoms. The goals of this study were to examine these relationships in a larger sample at baseline, and also to examine the longitudinal course of these deficits in a smaller subset of adolescents. Method: Thirty‐six subjects, aged 10 to 17 years, were included at baseline. All had Diagnostic and Statistical Manual‐Fourth Edition diagnoses of schizophrenia, schizoaffective disorder, schizophreniform disorder and psychosis – not otherwise specified, as determined by Kiddie‐Schedule for Affective Disorders and Schizophrenia for School‐Age Children structured interviews. Patients were administered a neuropsychological battery, and Positive and Negative Syndrome Scale ratings were completed at baseline and again at 1 year (n = 14). Most participants were inpatients at baseline, and 13 of 14 were on atypical antipsychotic medication during both sessions. Results: At baseline, the patients demonstrated impairments in working memory, processing speed, executive function and verbal learning. No significant cognitive change was detected at 1‐year follow‐up. In contrast, clinical symptoms were variable across 1 year, with an improvement in positive symptoms at 1 year. No relationships between clinical and cognitive symptoms were observed, with the exception of baseline IQ predicting negative symptoms at 1 year. Conclusions: Young patients with schizophrenia‐spectrum disorders displayed neurocognitive impairments at baseline. Despite measurable fluctuations in clinical symptoms over the year, no significant changes were measured in cognition. Lower IQ at baseline was predictive of more negative symptoms at 1 year.     

Social cognition mediates illness-related and cognitive influences on social function in patients with schizophrenia-spectrum disorders

Background

Although cognition has been studied extensively among patients with schizophrenia, social cognition has only recently emerged as an area of interest. The objective of the current study was to use structural equation modelling to test the hypothesis that the relation between cognitive performance and social function is mediated by patients’ social cognitive abilities.

Methods

We assessed participants who met criteria for a schizophrenia-spectrum disorder, with equal distribution among first- and multi-episode participants, and nonpsychiatric controls on a range of measures within each of the domains of cognition, social cognition and social function.

Results

Using structural equation modelling, we derived a model that explained 79.7% of the variance in social function and demonstrated that the link between cognition and social function was fully mediated by social cognition.

Limitations

A limitation of this study is that the measures contributing to the structural equation modelling analysis were obtained at the same point in time. Thus, the temporal order of causation suggested by Model 2 remains theoretically specified.

Conclusion

This study provides some first steps in understanding the complex relation between cognition and social function. Such a relation has potential implications for the design of remediation strategies.     

Attentional dysfunction of the central executive in AD: evidence from dual task and perseveration errors

This study examined the capacity of 27 Alzheimer's disease (AD) patients to divide attention between two simultaneous tasks, as compared to 27 elderly controls. In order to determine whether distribution of attention is affected by age, a younger group was included. The results showed a marked impairment in the capacity of the AD patients to combine performance in two simultaneous tasks compared to the elderly controls, but the latter group did not differ from the younger participants, indicating a disease rather than an age effect, and replicating the results of Baddeley et al. (2001). The present study also analysed whether perseverations committed in a previous study (Sebastian et al., 2001) by some AD and elderly control participants in the Brown-Peterson (B-P) task (Brown, 1958; Peterson and Peterson, 1959) were related to their attentional capacity in the dual task. Although the elderly controls committed perseveration errors, a negative correlation was only found in the AD group between the index of attention distribution in the dual task and the frequency of perseverations in the B-P task. Our results would therefore suggest that AD patients show a dysfunction of the central executive and/or a deficit in their ability to allocate cognitive resources. This could be interpreted in terms of problems in updating the contents of working memory and suppressing activation of no-longer-relevant information in the early stages of AD, leading to perseveration errors in the B-P task.     

Cerebral dominance and schizophrenia-spectrum disorders in adults with intellectual disability

Studies of the general population without intellectual disability have suggested an association between atypical handedness and schizophrenia‐spectrum disorders (SSDs). Mixed handedness is taken as an index of diminished cerebral dominance or laterality. The present study addressed the question of whether such findings extend to the neurodevelopmentally ‘at risk’ population of adults with intellectual disability and SSDs compared with appropriate controls. Fourteen patients with a dual diagnosis of intellectual disability and SSD were compared with 14 controls with intellectual disability alone. Assessments of self‐reported hand preference and relative hand skill were completed. Self‐report of hand preference revealed highly significantly greater mixed‐handedness in the SSD group. Furthermore, relative hand skill performance was significantly diminished for the dominant hand. The discrepancy between dominant and non‐dominant hand functioning was lower in the SSD group and this association was highly significant. The results of the present study support the usefulness of such detailed laterality assessment in this population. Mixed laterality, over and above that of the population with general intellectual disability and developmental disorder, was associated with SSD. These results are consistent with the neurodevelopmental hypothesis of schizophrenia and its cognitive neuropsychiatric/neuropsychological sequelae.     

Effects of yoga therapy on postural stability in patients with schizophrenia-spectrum disorders: A single-blind randomized controlled trial

Introduction

Postural instability is a serious concern in patients with schizophrenia-spectrum disorders since it is expected to increase the risk of falls that may lead to fractures. The impact of yoga therapy on postural stability has not been investigated.

Methods

In this eight-week single-blind randomized controlled study with an eight-week follow-up, outpatients with schizophrenia or related psychotic disorder (ICD-10) were randomly assigned to either yoga therapy or a control group. In the yoga therapy group, the subjects received weekly sessions of 60-min yoga therapy for eight weeks in addition to their ongoing treatment. In the control group, the subjects received a weekly regular day-care program. The assessments that were performed at the baseline and endpoint included the Clinical Stabilometric Platform (CSP), anteflexion in standing.

Results

Forty-nine patients participated in this study (32 men; mean ± SD age, 53.1 ± 12.3 years): yoga therapy group (n = 25) and control group (n = 24). In the yoga group, significant improvements were observed in a total length of trunk motion, the Romberg ratio, and anteflexion in standing at week 8 (mean ± SD: 63.9 ± 40.7–53.4 ± 26.2 cm, 1.6 ± 0.9–1.1 ± 0.6, and −8.7 ± 9.5 to −3.8 ± 12.4 cm, respectively) while there were no significant changes in the control group. However, those clinical gains returned to the baseline level at week 16.

Conclusions

The results confirmed the beneficial effects of the yoga therapy on postural stability in patients with schizophrenia. However, the therapeutic effects seemed transient, which warrants further investigations on strategies to sustain the improvements.     

Subjective well-being,but not subjective mental functioning shows positive associations with neuropsychological performance in schizophrenia-spectrum disorders

Objective

To assess the association of subjective quality of life as measured by the Subjective Well-being under Neuroleptic Treatment questionnaire (SWN-K) with neuropsychological functioning; to address interactions with the SWN-K domain mental functioning as a measure of subjective cognitive dysfunction; and to examine the interaction of subjective well-being and psychopathology ratings.

Methods

Forty-five patients diagnosed with schizophrenia spectrum disorder (SSD) were assessed regarding subjective well-being (SWN-K), neuropsychological impairment, and psychopathology (Brief Psychiatric Rating Scale; BPRS).

Results

After controlling for multiple comparisons, SWN-K total score showed significant positive correlations with concentration/attention (r = .498), working memory (r = .537), verbal memory (r = .522), and global cognition (r = .459). No correlations of SWN mental functioning and neuropsychological impairment remained significant after Bonferroni correction. Correlations between SWN-K subscales and neuropsychological functioning were generally positive, indicating higher subjective well-being in patients with better neurocognition. In multivariate analyses, global cognition was a significant predictor (p = .011), accounting for 19.7% of SWN total score variance. Adding BPRS total score as predictor (p = .054) explained an additional 6.9% of SWN-K variance. Linear regression analyses with SWN-K mental functioning as dependent variable did not yield statistically significant models.

Conclusion

Subjective well-being and objective neuropsychological functioning show only moderate associations and can be seen as largely independent parameters. In particular, subjective mental functioning cannot serve as a proxy for objective neuropsychological testing.     

Selective deficit in spatial memory strategies contrast to intact response strategies in patients with schizophrenia spectrum disorders tested in a virtual navigation task

Spatial memory is impaired among persons with schizophrenia (SCZ). However, different strategies may be used to solve most spatial memory and navigation tasks. This study investigated the hypothesis that participants with schizophrenia‐spectrum disorders (SSD) would demonstrate differential impairment during acquisition and retrieval of target locations when using a hippocampal‐dependent spatial strategy, but not a response strategy, which is more associated with caudate function. Healthy control (CON) and SSD participants were tested using the 4‐on‐8 virtual maze (4/8VM), a virtual navigation task designed to differentiate between participants' use of spatial and response strategies. Consistent with our predictions, SSD participants demonstrated a differential deficit such that those who navigated using a spatial strategy made more errors and took longer to locate targets. In contrast, SSD participants who spontaneously used a response strategy performed as well as CON participants. The differential pattern of spatial‐memory impairment in SSD provides only indirect support for underlying hippocampal dysfunction. These findings emphasize the importance of considering individual strategies when investigating SSD‐related memory and navigation performance. Future cognitive intervention protocols may harness SSD participants' intact ability to navigate using a response strategy and/or train the deficient ability to navigate using a spatial strategy to improve navigation and memory abilities in participants with SSD. © 2013 Wiley Periodicals, Inc.     

Attentional deficits in cocaine-dependent patients: converging behavioral and electrophysiological evidence

Although there are several reports of patients with cocaine dependence displaying cognitive deficits, the nature of their information processing deficits is not well characterized. In the present study, the attentional performance of cocaine-dependent patients (n=14) was examined and compared with that of healthy control individuals (n=15). Attention was assessed using an auditory oddball event-related task as well as the Continuous Performance Test (CPT, Identical Pairs version). The cocaine-dependent group displayed P300 amplitude reduction compared to controls. The group difference in P300 response latency did not reach significance. On the CPT, the cocaine-dependent patients displayed significantly poorer discriminability and greater errors of commission than the controls. There was a positive correlation between performance on the oddball event-related task and performance on the CPT. This investigation provides converging behavioral and electrophysiological evidence of attentional deficits in cocaine-dependent patients.     

Functional deficit in the medial prefrontal cortex during a language comprehension task in patients with schizophrenia

OBJECTIVE: We and others have observed that patients with schizophrenia commonly presented a reduced left recruitment in language semantic brain regions. However, most studies include patients with leftward and rightward lateralizations for language. We investigated whether a cohort comprised purely of patients with typical lateralization (leftward) presented a reduced left recruitment in semantic regions during a language comprehension task. The goal was to reduce the inter-subject variability and thus improve the resolution for studying functional abnormalities in the language network. METHODS: Twenty-three patients with schizophrenia (DSM-IV) were matched with healthy subjects in age, sex, level of education and handedness. All patients exhibited leftward lateralization for language. Functional MRI was performed as subjects listened to a story comprising characters and social interactions. Functional MRI signal variations were analyzed individually and compared among groups. RESULTS: Although no differences were observed in the recruitment of the semantic language network, patients with schizophrenia presented significantly lower signal variations compared to controls in the medial part of the left superior frontal gyrus (MF1) (x=-6, y=58, z=20; Z(score)=5.6; p<0.001 uncorrected). This region corresponded to the Theory of Mind (ToM) network. Only 5 of the 23 patients (21.7%) and 21 of the 23 (91.3%) control subjects demonstrated a positive signal variation in this area. CONCLUSIONS: A left functional deficit was observed in a core region of the ToM network in patients with schizophrenia and typical lateralizations for language. This functional defect could represent a neural basis for impaired social interaction and communication in patients with schizophrenia.     

Impaired performance in a working memory binding task in patients with schizophrenia

This study investigated feature binding in a working memory task in patients with schizophrenia and in normal controls. Twenty-five patients and 25 controls participated. On each trial, three drawings of familiar objects were presented sequentially, each in a different cell of a 3 x 3 grid. In different blocks of trials, participants remembered either individual features (object and location conditions) or an object and its location (combination condition). The results showed that patients were slower and less accurate than controls under all conditions. Accuracy of both groups was reduced in the combination condition relative to the single-feature conditions, but patients showed disproportionately poorer performance in the combination condition than in the object and location conditions. Thus, patients with schizophrenia exhibit deficits in working memory, particularly when the task requires binding objects to their locations. This finding demonstrates that processes that establish coherent and temporary episodic representations in working memory are impaired in schizophrenia.     

Effect of methylphenidate on Stroop Color-Word task performance in children with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a neuropsychiatric syndrome common in the pediatric population. It is associated with multiple nonspecific deficits on neuropsychological tests of executive function, and a beneficial response to pharmacotherapy with methylphenidate (MPH) and other psychostimulants. The Stroop Color-Word task is used empirically as an aid in diagnosis and treatment monitoring of ADHD; however, data on the sensitivity of the Stroop interference score to the effects of MPH are limited. To address this issue, we studied Stroop performance in a cohort of 18 MPH-treated prepubescent boys with ADHD and six healthy controls on and off MPH treatment conditions. MPH significantly improved performance in both groups, with the ADHD participants consistently displaying worse scores than those of controls both on and off MPH. These results suggest that though the diagnostic value of the Stroop task in ADHD remains controversial, it has heuristic value for monitoring clinical responses to MPH treatment. More research is needed to ascertain the clinical significance of our findings and to replicate this relatively small effect in a larger cohort, to determine whether MPH effects on Stroop performance are specific to ADHD symptoms or they generalize to other forms of symptomatology.     

Structural connectivity alterations in the motor network of patients with scans without evidence of dopaminergic deficit (SWEDD)

Journal of Neurology - Approximatively, 10% of patients initially diagnosed with Parkinson’s disease (PD) show preserved presynaptic dopaminergic function in the nigrostriatal pathway on...     

Burdens and difficulties experienced by caregivers of children and adolescents with schizophrenia-spectrum disorders: a qualitative study

Aim: The purpose of this qualitative study was to investigate the burdens and difficulties associated with the experience of caring for youth with schizophrenia‐spectrum disorders. Methods: Ten caregivers participated in a modified version of the Knowledge about Schizophrenia Illness interview. Results: The most common areas of general difficulties reported by caregivers were emotional burdens and the everyday practical demands and sacrifices required in caring for their dependents. Results also suggested high levels of burden for caregivers concerning difficulties with mental health services. Conclusion: Additional work is needed to learn more about the challenges that caregivers of youth with schizophrenia‐spectrum disorders are facing, as well as to develop empirically based strategies for helping these caregivers and their dependents.     

Methylphenidate mediated change in prosody is specific to the performance of a cognitive task in female adult ADHD patients

Objectives. Prosody production is highly personalized, related to both the emotional and cognitive state of the speaker and to the task being performed. Fundamental frequency (F main) is a central measurable feature of prosody, associated with having an attention deficit hyperactive disorder (ADHD). Since methylphenidate is an effective therapy for ADHD, we hypothesized that it will affect the fundamental frequency of ADHD patients. Methods. The answers of 32 adult ADHD patients were recorded while performing two computerized tasks (cognitive and emotional). Evaluations were performed at baseline and an hour after patients received methylphenidate. Results. A significant effect of methylphenidate was observed on the fundamental frequency, as opposed to other parameters, of prosody. This change was evident while patients performed a cognitive, as opposed to an emotional, task. This change was seen in the 14 female ADHD patients but not in the 18 male ADHD patients. The fundamental frequency while performing a cognitive task without methylphenidate was not different in the female ADHD group, from 22 female controls. Conclusions. This pilot study supports prosodic changes as possible objective and accessible dynamic biological marker of treatment responses specifically in female ADHD.     

Ethnic variation in symptoms and response to risperidone in youths with schizophrenia-spectrum disorders

BACKGROUND: Evaluation of symptom presentation and antipsychotic response based on ethnicity in children and adolescents with schizophrenia is limited. The purpose of this naturalistic, retrospective database study was to compare symptom presentation of children and adolescents of different ethnicities with schizophrenia-spectrum disorders, and response to risperidone. METHOD: African-American (n = 38), Caucasian (n = 30), or Hispanic (n = 37) youths started on risperidone were eligible. Child Behavior Checklist (CBCL) total, internalizing, and externalizing scores were evaluated at baseline, 90 days, 1 year, and 2 year intervals. RESULTS: At baseline, Hispanic patients had lower CBCL externalizing scores than African-Americans or Caucasians. African-Americans showed significant differences in CBCL total, internalizing, and externalizing scores at 90 days compared to baseline. Hispanics showed improvement in CBCL internalizing scores over the 2 year period. No significant improvements were observed in Caucasians. African-American patients had significantly lower CBCL total at 90 days compared to Hispanic patients. No significant difference existed in 2 year hospitalization rates between groups. CONCLUSIONS: These findings suggest that ethnicity may play a role in symptom presentation and treatment response to risperidone for children and adolescents with schizophrenia-spectrum disorders. Future studies in children and adolescents are necessary to examine ethnospecific differences in antipsychotic use and treatment response.     

Attentional and executive dysfunctions in schizophrenia and depression: evidence from dichotic listening performance.

BACKGROUND: We compared performance on a dichotic listening (DL) task between schizophrenic, depressed, and healthy control subjects. A variant of the traditional DL paradigm was used in which the subjects were required to focus attention either on the left (forced-left condition) or right (forced-right condition) ear stimulus. METHODS: The subjects were 51 patients with a DSM-IV diagnosis of schizophrenia, 49 patients with recurrent unipolar major depression, and 49 healthy control subjects. They were tested with a consonant-vowel syllables dichotic listening task under three attentional instructions. RESULTS: There was a significant overall right ear advantage during the nonforced condition, which increased dramatically during the forced-right condition and was eliminated during the forced-left condition. The depressed patients showed no signs of impairments compared with the healthy control group. Thus, they showed a right ear advantage during the nonforced and forced-right conditions, which was shifted to a left ear advantage during the forced left condition. The schizophrenic patients, however, were impaired on the forced-left condition compared with the healthy control and depressed subjects. CONCLUSIONS: The results are discussed in terms of separating attentional and inhibitory executive impairments in schizophrenia and depression, taking into consideration illness duration and information-processing demands.