Language and thought disorder in schizophrenia: brain morphological correlates

Structural and Functional Brain Patterns Predict Formal Thought Disorder's Severity and Its Persistence in Recent-Onset Psychosis: Results From the PRONIA Study

BACKGROUND

Formal thought disorder (FThD) is a core feature of psychosis, and its severity and long-term persistence relates to poor clinical outcomes. However, advances in developing early recognition and management tools for FThD are hindered by a lack of insight into the brain-level predictors of FThD states and progression at the individual level.

METHODS

Two hundred thirty-three individuals with recent-onset psychosis were drawn from the multisite European Prognostic Tools for Early Psychosis Management study. Support vector machine classifiers were trained within a cross-validation framework to separate two FThD symptom-based subgroups (high vs. low FThD severity), using cross-sectional whole-brain multiband fractional amplitude of low frequency fluctuations, gray matter volume and white matter volume data. Moreover, we trained machine learning models on these neuroimaging readouts to predict the persistence of high FThD subgroup membership from baseline to 1-year follow-up.

RESULTS

Cross-sectionally, multivariate patterns of gray matter volume within the salience, dorsal attention, visual, and ventral attention networks separated the FThD severity subgroups (balanced accuracy [BAC] = 60.8%). Longitudinally, distributed activations/deactivations within all fractional amplitude of low frequency fluctuation sub-bands (BACslow-5 = 73.2%, BACslow-4 = 72.9%, BACslow-3 = 68.0%), gray matter volume patterns overlapping with the cross-sectional ones (BAC = 62.7%), and smaller frontal white matter volume (BAC = 73.1%) predicted the persistence of high FThD severity from baseline to follow-up, with a combined multimodal balanced accuracy of BAC = 77%.

CONCLUSIONS

We report the first evidence of brain structural and functional patterns predictive of FThD severity and persistence in early psychosis. These findings open up avenues for the development of neuroimaging-based diagnostic, prognostic, and treatment options for the early recognition and management of FThD and associated poor outcomes.

Conversational metrics, psychopathological dimensions and self-disturbances in patients with schizophrenia

Difficulties in interpersonal communication, including conversational skill impairments, are core features of schizophrenia. However, very few studies have performed conversation analyses in a clinical population of schizophrenia patients. Here we investigate the conversational patterns of dialogues in schizophrenia patients to assess possible associations with symptom dimensions, subjective self-disturbances and social functioning. Thirty-five schizophrenia patients were administered the Positive and Negative Syndrome Scale (PANSS), the Clinical Language Disorder Rating Scale (CLANG), the Scale for the Assessment of Thought, Language and Communication (TLC), the Examination of Anomalous Self-Experience Scale (EASE), and the Social and Occupational Functioning Assessment Scale (SOFAS). Moreover, participants underwent a recorded semi-structured interview, to extract conversational variables. Conversational data were associated with negative symptoms and social functioning, but not with positive or disorganization symptoms. A significant positive correlation was found between "pause duration" and the EASE item "Spatialization of thought". The present study suggests an association between conversational patterns and negative symptom dimension of schizophrenia. Moreover, our findings evoke a relationship between the natural fluidity of conversation and of the natural unraveling of thoughts.

Multisite schizophrenia classification by integrating structural magnetic resonance imaging data with polygenic risk score

Previous brain structural magnetic resonance imaging studies reported that patients with schizophrenia have brain structural abnormalities, which have been used to discriminate schizophrenia patients from normal controls. However, most existing studies identified schizophrenia patients at a single site, and the genetic features closely associated with highly heritable schizophrenia were not considered. In this study, we performed standardized feature extraction on brain structural magnetic resonance images and on genetic data to separate schizophrenia patients from normal controls. A total of 1010 participants, 508 schizophrenia patients and 502 normal controls, were recruited from 8 independent sites across China. Classification experiments were carried out using different machine learning methods and input features. We tested a support vector machine, logistic regression, and an ensemble learning strategy using 3 feature sets of interest: (1) imaging features: gray matter volume, (2) genetic features: polygenic risk scores, and (3) a fusion of imaging features and genetic features. The performance was assessed by leave-one-site-out cross-validation. Finally, some important brain and genetic features were identified. We found that the models with both imaging and genetic features as input performed better than models with either alone. The average accuracy of the classification models with the best performance in the cross-validation was 71.6%. The genetic feature that measured the cumulative risk of the genetic variants most associated with schizophrenia contributed the most to the classification. Our work took the first step toward considering both structural brain alterations and genome-wide genetic factors in a large-scale multisite schizophrenia classification. Our findings may provide insight into the underlying pathophysiology and risk mechanisms of schizophrenia.

Fronto-Parietal Gray Matter Volume Loss Is Associated with Decreased Working Memory Performance in Adolescents with a First Episode of Psychosis

Cognitive maturation during adolescence is modulated by brain maturation. However, it is unknown how these processes intertwine in early onset psychosis (EOP). Studies examining longitudinal brain changes and cognitive performance in psychosis lend support for an altered development of high-order cognitive functions, which parallels progressive gray matter (GM) loss over time, particularly in fronto-parietal brain regions. We aimed to assess this relationship in a subsample of 33 adolescents with first-episode EOP and 47 matched controls over 2 years. Backwards stepwise regression analyses were conducted to determine the association and predictive value of longitudinal brain changes over cognitive performance within each group. Fronto-parietal GM volume loss was positively associated with decreased working memory in adolescents with psychosis (frontal left (B = 0.096, p = 0.008); right (B = 0.089, p = 0.015); parietal left (B = 0.119, p = 0.007), right (B = 0.125, p = 0.015)) as a function of age. A particular decrease in frontal left GM volume best predicted a significant amount (22.28%) of the variance of decreased working memory performance over time, accounting for variance in age (14.9%). No such association was found in controls. Our results suggest that during adolescence, EOP individuals seem to follow an abnormal neurodevelopmental trajectory, in which fronto-parietal GM volume reduction is associated with the differential age-related working memory dysfunction in this group.

Analysis of the superior temporal gyrus as a possible biomarker in schizophrenia using voxel-based morphometry of the brain magnetic resonance imaging: a comprehensive review

The lack of predictive biomarkers for therapeutic responses to schizophrenia leads clinical procedures to be decided without taking into account the subjects' neuroanatomical features, a consideration, which could help in identifying specific pharmacological treatments for the remission of symptoms. Magnetic resonance imaging (MRI) is a technique widely used for radiological diagnosis and produces 3-dimensional images in excellent anatomical detail, and with a great capacity to differentiate soft tissue. Various MRI techniques of the human brain have emerged as a result of research, enabling structural tests that may help to in consolidate previous findings and lead to the discovery of new patterns of abnormality in schizophrenia. A literature review was undertaken to assess the superior temporal gyrus (STG) as a possible biomarker in schizophrenia with the use of voxel-based morphometry of the brain using MRI. Many findings in studies of schizophrenia using MRI have been inconclusive and, in some cases, conflicting, although interesting results have been obtained when attempting to correlate neuroimaging changes with aspects of clinical features and prognosis of the disease. The individuals affected by this mental illness appear to have smaller STG volumes when compared to healthy controls and also to subjects with a diagnosis of first-episode affective psychosis or groups of individuals at high risk of psychosis. However, the wide variety of definitions surrounding the STG found in a number of studies is a contributing factor to the lack of correlation between brain abnormalities and clinical symptoms. For instance, disagreements have arisen due to studies using regions of interest to analyze the STG whereas other studies prioritize the analysis of only STG subregions or specific supratemporal plane regions. It is necessary to standardize the nomenclature of the areas to be studied in the future, as this will enable more consistent results, allowing higher clinical and morphological correlations.

Less reduced gray matter volume in the subregions of superior temporal gyrus predicts better treatment efficacy in drug-naive, first-episode schizophrenia

Decreased gray matter volume (GMV) in the superior temporal gyrus (STG) has been implicated in the neurophysiology of schizophrenia. However, it remains unclear whether volumetric reduction in the subregions of the STG can predict treatment efficacy for schizophrenia. Our cohort included 44 drug-naive, first-episode patients, 42 unaffected siblings and 44 healthy controls. Voxel-based morphometry and pattern classification were utilized to analyze the acquired imaging data as per the anatomical subdivision by a well-defined brainnetome atlas. The patients presented lower GMV values in left TE1.0/1.2 (TE, anterior temporal visual association area) than the siblings, and lower GMV values in the left/right TE1.0/1.2 and left A22r (rostral area 22) than the controls. A positive correlation is observed between the GMV values in the right A38l (lateral area 38) and baseline Positive and Negative Syndrome Scale (PANSS) total scores in the patients. Support vector regression (SVR) results exhibited a significant association between predicted (based on the GMV values in the right A38l) and actual symptomatic improvement based on the reduction ratio of the PANSS total scores (r = 0.498, p = 0.001). Our results suggest that normal structure in the right A38l of the STG may be an important factor indicative of the effects of antipsychotic drugs, which can be potentially used to monitor drug effects for first-episode patients at an early stage in clinical practice.

Is formal thought disorder in schizophrenia related to structural and functional aberrations in the language network? A systematic review of neuroimaging findings

Formal thought disorder (FTD) is a core feature of schizophrenia, a marker of illness severity and a predictor of outcome. The underlying neural mechanisms are still a matter of debate. This study aimed at 1) reviewing the literature on the neural correlates of FTD in schizophrenia, and 2) testing the hypothesis that FTD correlates with structural and functional aberrations in the language network. Medline, PsychInfo, and Embase were searched for neuroimaging studies, which applied a clinical measure to assess FTD in adults with schizophrenia and were published in English or German in peer-reviewed journals until December 2016. Of 412 articles identified, 61 studies were included in the review. Volumetric studies reported bilateral grey matter deficits (L > R) to be associated with FTD in the inferior frontal gyrus, the superior temporal gyrus and the inferior parietal lobe. The same regions showed hyperactivity in resting state functional magnetic resonance imaging (fMRI) studies and both hyper- and hypoactivity in fMRI studies that employed semantic processing or free speech production tasks. Diffusion tensor imaging studies demonstrated white matter aberrations in fibre tracts that connect the frontal and temporo-parietal regions. FTD in schizophrenia was found to be associated with structural and functional aberrations in the language network. However, there are studies that did not find an association between FTD and neural aberrations of the language network and regions not included in the language network have been associated with FTD. Thus, future research is needed to clarify the specificity of the language network for FTD in schizophrenia.

A systematic review of task-based functional neuroimaging studies investigating language, semantic and executive processes in thought disorder

The aim of the current systematic review was to synthesise the research that has investigated thought disorder (TD) using task-based functional neuroimaging techniques to target executive, language, or semantic functions. Thirty-five pertinent studies were identified from January 1990 to August 2016. Functional correlates of TD included the superior and middle temporal, fusiform, and inferior frontal gyri bilaterally, as well as the left and right cingulate cortex, the right caudate nucleus, and the cerebellum. TD-related increases and decreases in activation were both evident in most of these regions. However, the specificity of these correlates from general clinical and cognitive influences is unknown. The cortical regions implicated overlap with those thought to contribute to language and semantic systems. Cortico-striatal circuitry may also play a role in some aspects of TD through aberrant salience representation and inappropriate attentional prioritisation. To advance the field further, greater integration across structural, functional, and behavioural measures is required, in addition to non-unitary considerations of TD.

The Arcuate Fasciculus Network and Verbal Deficits in Psychosis

Background

Verbal learning (VL) and fluency (VF) are prominent cognitive deficits in psychosis, of which the precise neuroanatomical contributions are not fully understood. We investigated the arcuate fasciculus (AF) and its associated cortical regions to identify structural abnormalities contributing to these verbal impairments in early stages of psychotic illness.

Methods

Twenty-six individuals with recent-onset psychosis and 27 healthy controls underwent cognitive testing (MATRICS Consensus Cognitive Battery) and structural/diffusion-weighted MRI. Bilaterally, AF anisotropy and cortical thickness, surface area and volume of seven cortical regions were investigated in relation to VL and VF performance in both groups.

Results

Reduced right superior temporal gyrus surface area and volume related to better VF in controls. In psychosis, greater right pars opercularis volume and reduced left lateralization of this region related to better VL, while greater right long AF fractional anisotropy and right pars orbitalis volume related to better VF, these findings not present in controls. Psychosis had reduced right pars orbitalis thickness compared to controls.

Conclusion

Anatomical substrates for normal processing of VL and VF appear altered in recent-onset psychosis. A possible aberrant role of the right hemisphere arcuate fasciculus and fronto-temporal cortical regions in psychosis may contribute to deficits in VL and VF.

Inner Speech and Clarity of Self-Concept in Thought Disorder and Auditory-Verbal Hallucinations

Eighty patients and thirty controls were interviewed using one interview that promoted personal disclosure and another about everyday topics. Speech was scored using the Thought, Language and Communication scale (TLC). All participants completed the Self-Concept Clarity Scale (SCCS) and the Varieties of Inner Speech Questionnaire (VISQ). Patients scored lower than comparisons on the SCCS. Low scores were associated the disorganized dimension of TD. Patients also scored significantly higher on condensed and other people in inner speech, but not on dialogical or evaluative inner speech. The poverty of speech dimension of TD was associated with less dialogical inner speech, other people in inner speech, and less evaluative inner speech. Hallucinations were significantly associated with more other people in inner speech and evaluative inner speech. Clarity of self-concept and qualities of inner speech are differentially associated with dimensions of TD. The findings also support inner speech models of hallucinations.

Reliability and validity of the Korean version of the Scale for the Assessment of Thought, Language, and Communication

BACKGROUND

Our study aimed to assess the inter-rater and test-retest reliability, as well as concurrent and convergent validity, of the Korean version of the Scale for the Assessment of Thought, Language, and Communication (TLC scale).

METHODS

The factor solutions and psychometric properties of the Korean version of the TLC scale were evaluated among 167 schizophrenia inpatients (study subjects) at two sites in South Korea. Using Pearson's correlation, the concurrent and convergent validities of each of the factor solutions were represented by the correlations with the scores on the Clinical Language Disorder Rating Scale, Brief Psychiatric Rating Scale, Young Mania Rating Scale, and Calgary Depression Scale. Using receiver operating characteristics curves, the optimal cut-off score for the Korean version of the TLC scale to distinguish between study subjects with and without disorganized speech, was identified.

RESULTS

The results showed that the Korean version of the TLC scale has a three-factor solution: fluent disorganization, speech emptiness, and speech peculiarity. In addition, the interrater reliability of the Korean version of the TLC scale was moderately good (intraclass correlation coefficient = 0.51) and its test-retest reliability was very good (Pearson's correlation coefficient = 0.94). For detecting the current presence of disorganized speech, the optimal cut-off total score on the TLC scale was proposed to be 8 points (sensitivity = 88.1%; specificity = 82.9%).

LIMITATIONS

Psychometric tools covering cognitive functions were not used in our study.

CONCLUSIONS

The Korean version of the TLC scale is a promising psychometric method for examining formal thought disorder (FTD) and disorganized speech in schizophrenia patients.

Neural correlates of the relationship between discourse coherence and sensory monitoring in schizophrenia

Unusual language use is a core feature of psychosis, but the nature and significance of this are not understood. In particular, thought disorder in schizophrenia (SZ) is characterized by markedly bizarre speech, but the cognitive components that contribute to this and the brain correlates of these components are unknown. A number of studies have demonstrated language abnormalities in single word processing, but few have examined speech in SZ at the discourse level. This has been at least partly due to the difficulty in quantifying content of discourse. Recently, methods in computational linguistics have been found to be useful for detecting differences in semantic coherence during discourse between different clinical groups. We build on this work by demonstrating how these methods can be combined with funtional magnetic resonance imaging (fMRI) in order to tease apart factors that underlie free discourse and its deviations, and how they relate to brain activity. Eleven volunteers with SZ and eleven controls participated in an interview during which they were asked to talk as much as they could about 'religious belief'. These same participants underwent fMRI during a word monitoring task, during which modality of monitoring was manipulated by varying the congruence of auditory and visual stimuli. Semantic coherence scores, measured from free discourse, were examined for their relationship to brain activations during fMRI. In healthy controls, regions associated with executive function were related to coherence. In persons with SZ, coherence was mainly related to auditory and visual regions, depending on the modality of monitoring, but superior/middle temporal cortex related to coherence regardless of task. These findings are consistent with existing evidence for a role of superior temporal cortex in thought disorder, and demonstrate that computational measures of semantic content capture objective measures of coherence in speech that can be usefully related to underlying neurophysiological processes.

Association of formal thought disorder in schizophrenia with structural brain abnormalities in language-related cortical regions

BACKGROUND

Formal thought disorder (FTD) in schizophrenia has been found to be associated with volume reductions in the left superior temporal cortex. However, there have been negative findings and some studies have also found associations in other cortical regions.

METHOD

Fifty-one schizophrenic patients were evaluated for presence of FTD with the Thought, Language and Communication (TLC) scale and underwent whole-brain structural MRI using optimized voxel-based morphometry (VBM). Fifty-nine matched healthy controls were also scanned.

RESULTS

Compared to 31 patients without FTD (global TLC rating 0 or 1), 20 patients with FTD (global TLC rating 2-5) showed clusters of volume reduction in the medial frontal and orbitofrontal cortex bilaterally, and in two left-sided areas approximating to Broca's and Wernicke's areas. The pattern of FTD-associated volume reductions was largely different from that found in a comparison between the healthy controls and the patients without FTD. Analysis of correlations within regions-of-interest based on the above clusters indicated that the 'fluent disorganization' component of FTD was correlated with volume reductions in both Broca's and Wernicke's areas, whereas poverty of content of speech was correlated with reductions in the medial frontal/orbitofrontal cortex.

CONCLUSIONS

The findings point to a relationship between FTD in schizophrenia and structural brain pathology in brain areas involved in language and executive function.

Frequency and neural correlates of pauses in patients with formal thought disorder

BACKGROUND

Pauses during speech may reflect the planning and monitoring of discourse, two processes putatively impaired in patients with schizophrenia, particularly those with formal thought disorder (FTD). We used functional MRI to examine the neural correlates of between-clause and of filled pauses, which are respectively associated with speech planning and speech monitoring.

METHODS

BOLD contrast was measured while six schizophrenia patients with FTD and six healthy subjects spoke about Rorshach inkblots. In an event-related design, we examined activity associated with pauses that occurred between clauses and with pauses that were filled.

RESULTS

There was no significant group difference in the frequency of between-clause pauses but patients with FTD made strikingly fewer filled pauses than controls. Between-clause pauses were associated with activation in the anterior part of the left superior temporal gyrus (STG) and the left insula in controls and the engagement of these regions was significantly attenuated in patients.

CONCLUSION

The anterior part of the left STG and the left insula are normally involved in both the planning and monitoring of discourse. The attenuated engagement of these regions with between-clause pauses and the striking infrequency of filled pauses in the patients are consistent with cognitive models implicating defective speech planning and speech monitoring in schizophrenia, especially in relation to FTD.

Semantic network disconnection in formal thought disorder

BACKGROUND

Structural and functional findings in schizophrenic patients with formal thought disorder (FTD) show abnormalities within left-side semantic areas. The present study investigate the network function of the involved brain regions as a function of FTD severity.

METHODS

We examined a group of 16 schizophrenia patients differing in FTD, but not in overall symptom severity, and 18 matched healthy controls. A passive word reading paradigm was applied during functional MRI (fMRI). A concatenated independent component analysis approach separated the fMRI signal into independent components, and spatial similarity was used to estimate the individual differences in spatial configuration of networks.

RESULTS

The semantic network was identified for both groups encompassing structures of the left inferior frontal gyrus, the left angular gyrus and the left middle temporal gyrus. The differences between the semantic networks of patients and controls increased with increasing severity of FTD. This difference was due to a decreasing contribution of the left inferior frontal gyrus (Brodmann area 45 and 47).

CONCLUSION

Severity of FTD was correlated with a disruption of the left semantic network in schizophrenic patients. We suggest that FTD is a consequence of a frontal-parietal/temporal disconnection due to a complex interaction between structural and functional abnormalities within the left semantic network.

Progressive loss of cortical gray matter in schizophrenia: a meta-analysis and meta-regression of longitudinal MRI studies

Cortical gray matter deficits have been found in patients with schizophrenia, with evidence of progression over time. The aim of this study was to determine the extent of progressive cortical gray matter volume changes over time in schizophrenia, their site and time of occurrence, and the role of potential moderators of brain changes. English language articles published between 1 January 1983 and 31 March 2012 in the MEDLINE and EMBASE databases were searched. Longitudinal magnetic resonance imaging studies comparing changes in cortical gray matter volume over time between patients with schizophrenia and healthy controls were included. Hedges g was calculated for each study. Analyses were performed using fixed- and random-effects models. A subgroup analysis was run to explore the pattern of brain changes in patients with first-episode schizophrenia. A meta-regression statistic was adopted to investigate the role of potential moderators of the effect sizes (ESs). A total of 19 studies, analyzing 813 patients with schizophrenia and 718 healthy controls, were included. Over time, patients with schizophrenia showed a significantly higher volume loss of total cortical gray matter, left superior temporal gyrus (STG), left anterior STG, left Heschl gyrus, left planum temporale and posterior STG bilaterally. Meta-analysis of first-episode schizophrenic patients showed a more significant pattern of progressive loss of whole cerebral gray matter volume involving the frontal, temporal and parietal lobes, and left Heschl gyrus compared with healthy controls. Clinical, pharmacologic and neuroradiological variables were found to be significant moderators of brain volume changes in patients with schizophrenia. The meta-analysis demonstrates that progressive cortical gray matter changes in schizophrenia occur with regional and temporal specificity. The underlying pathological process appears to be especially active in the first stages of the disease, affects the left hemisphere and the superior temporal structures more and is at least partly moderated by the type of pharmacological treatment received.

Social impairment in schizophrenia revealed by Autism-Spectrum Quotient correlated with gray matter reduction

One of the difficulties facing schizophrenia patients is a failure to construct appropriate relationships with others in social situations. This impairment of social cognition is also found in autism-spectrum disorder (ASD). Considering such commonality between the two disorders, in this study we adopted the Autism-Spectrum Quotient (AQ) score to assess autistic traits, and explored the association between such traits and gray matter (GM) alterations of the brain in schizophrenia. Twenty schizophrenia patients and 25 healthy controls underwent structural magnetic resonance imaging (MRI), and AQ was assessed, comprising five subscales measuring different facets of autistic traits. Voxel-based morphometry (VBM) was applied to investigate the correlation between these AQ scores and regional GM alterations. Schizophrenia patients showed significantly higher scores in total AQ, and in four of the five subscales, compared to healthy controls. The total AQ score in schizophrenia showed significant negative correlation with GM volume reduction in the cortical area surrounding the left superior temporal sulcus (STS), which is considered to be important in social perception. Our findings suggest a possible neuroanatomical basis of autistic tendencies in schizophrenia.

Morphometrical and morphological analysis of lateral ventricles in schizophrenia patients versus healthy controls

The goal of this report was to highlight lateral ventricle morphology and volume differences between schizophrenia patients and matched controls. Subjects identified as suitable for analysis comprised 15 schizophrenia patients and 15 healthy subjects. The method applied is three-dimensional (3D) volume rendering starting from structural magnetic resonance imaging (MRI) studies of selected ventricular regions. Differences between groups relative to the global ventricular system and its subdivisions were found. Total lateral ventricle volume, right ventricle volume and left ventricle volume were all higher in schizophrenia patients than in controls; unilateral differences between the two groups were also outlined (right ventricle volume>left ventricle volume in schizophrenia patients vs. healthy subjects). Furthermore, occipital and frontal horn enlargement was found in schizophrenia patients compared with normal controls, but the difference in the temporal horn was not statistically significant. A substantial difference was noted in lateral ventricle morphology between the two groups. Our findings were consistent with the literature and may shed light on some of the discrepancies in previous reports on differences in lateral ventricle volume enlargement.

Investigating relationships between cortical thickness and cognitive performance in patients with schizophrenia and healthy adults

Relationships between prefrontal and temporal lobe grey matter volumes as assessed by magnetic resonance imaging and neurocognitive test results have been reported in schizophrenia. This investigation aimed to localize brain regions where cortical thickness and neurocognitive performance were related, and investigate if such relationships might differ in schizophrenia patients and healthy controls. Sixty-seven patients with schizophrenia and 69 healthy controls were characterized by neurocognitive testing and by brain cortical thickness maps. Putative cortical thickness/cognitive score relationships were investigated with contrast analyses of general linear models for the combined sample. Regions in which relationships were present were further investigated for diagnostic interaction. In the combined sample, significant positive relationships were found between frontal, temporal and occipital regions and tests for verbal IQ, verbal learning and executive functions. Diagnostic interaction was found for the relationships between verbal IQ and the right temporo-occipital junction and the left middle occipital gyrus. In conclusion, the significant relationships between cortical thickness and neurocognitive performances were localized in brain areas known to be involved in cognition. The relationships were similar in patients and controls, except for the right temporo-occipital and left occipital cortical areas, indicating a disrupted structure-function relationship in patients with schizophrenia compared to healthy control subjects.

Gray matter volume differences specific to formal thought disorder in schizophrenia

Formal thought disorder (FTD) is one of the main symptoms of schizophrenia. To date there are no whole brain volumetric studies investigating gray matter (GM) differences specifically associated with FTD. Here, we studied 20 right-handed schizophrenia patients that differed in the severity of formal thought disorder and 20 matched healthy controls, using voxel-based morphometry (VBM). The severity of FTD was measured with the Scale for the Assessment of Thought, Language, and Communication. The severity was negatively correlated with the GM volume of the left superior temporal sulcus, the left temporal pole, the right middle orbital gyrus and the right cuneus/lingual gyrus. Structural abnormalities specific for FTD were found to be unrelated to GM differences associated with schizophrenia in general. The specific GM abnormalities within the left temporal lobe may help to explain language disturbances included in FTD.

Formal thought disorder in non-clinical individuals with auditory verbal hallucinations

BACKGROUND

Auditory verbal hallucinations (AVH) and formal thought disorder (FTD) may originate from the same aberration in the language system. The hypothesis of a shared neurobiological basis would be strengthened by the presence of FTD in individuals who frequently experience AVH, but do not meet DSM-IV criteria for a psychotic disorder.

METHODS

In this study, FTD was quantified in 40 non-clinical subjects with AVH, in 50 healthy subjects without AVH and in 40 schizophrenia patients with AVH. Recorded speech samples were analysed by one rater who was blind to the presence/absence of AVH and to diagnosis, using the Thought and Language Index.

RESULTS

Negative FTD was barely present in non-clinical subjects with AVH and in healthy controls without AVH. Positive FTD, however, was significantly higher in both groups experiencing AVH than in controls without AVH. Severity of positive FTD did not differ significantly between non-clinical subjects with AVH and schizophrenia patients with AVH.

CONCLUSION

Negative FTD (alogia) appears not to be associated with AVH. However, the fact that positive FTD (disorganised speech) in schizophrenia patients with AVH is equally high in non-clinical subjects with AVH indicates that these two symptoms tend to co-occur, which may be suggestive of a shared neurobiological substrate.

Current source density (CSD) old/new effects during recognition memory for words and faces in schizophrenia and in healthy adults

We previously reported a preserved 'old-new effect' (enhanced parietal positivity 300-800 ms following correctly-recognized repeated words) in schizophrenia over mid-parietal sites using 31-channel nose-referenced event-related potentials (ERP) and reference-free current source densities (CSD). However, patients showed poorer word recognition memory and reduced left lateral-parietal P3 sources. The present study investigated whether these abnormalities are specific to words. High-density ERPs (67 channels) were recorded from 57 schizophrenic (24 females) and 44 healthy (26 females) right-handed adults during parallel visual continuous recognition memory tasks using common words or unknown faces. To identify and measure neuronal generator patterns underlying ERPs, unrestricted Varimax-PCA was performed using CSD estimates (spherical spline surface Laplacian). Two late source factors peaking at 442 ms (lateral parietal maximum) and 723 ms (centroparietal maximum) accounted for most of the variance between 250 and 850 ms. Poorer (76.6+/-20.0% vs. 85.7+/-12.4% correct) and slower (824+/-170 vs. 755+/-147 ms) performance in patients was accompanied by reduced stimulus-locked parietal sources. However, both controls and patients showed mid-frontal (442 ms) and left parietal (723 ms) old/new effects in both tasks. Whereas mid-frontal old/new effects were comparable across groups and tasks, later left parietal old/new effects were markedly reduced in patients over lateral temporoparietal but not mid-parietal sites, particularly for words, implicating impaired phonological processing. In agreement with prior results, ERP correlates of recognition memory deficits in schizophrenia suggest functional impairments of lateral posterior cortex (stimulus representation) associated with conscious recollection. This deficit was more pronounced for common words despite a greater difficulty to recall unknown faces, indicating that it is not due to a generalized cognitive deficit in schizophrenia.

The effect of ageing on grey and white matter reductions in schizophrenia

Total brain volume and, in particular gray matter (GM) volume is reduced in patients with schizophrenia and recent studies suggest there is greater progressive loss of brain volume in the patients with schizophrenia than in normal controls. However, as the longitudinal studies do not include life-long follow-up, it is not clear if this occurs across the lifespan or only in the early phase of the illness. In this study we investigated this by studying the effects of age on brain tissue volumes in schizophrenia (n=34, age range=27-65 years)to test the prediction that there is a progressive loss in grey matter volume with increasing age in patients compared to healthy controls (n=33, age range=18-73 years). The results showed there was diminished relative GM volume loss with age in patients with schizophrenia compared to controls--in contrast to our prediction. However, there was increased relative white matter (WM) loss with age in schizophrenia. The results also replicated previous findings that patients with schizophrenia have significantly lower total (1509 versus 1596 mm(3)) and regional GM volume (755 versus 822 mm(3)) and increased cerebrospinal fluid (CSF) volume when compared to matched healthy volunteers. Overall these findings indicate that the proportion of grey matter in schizophrenia is reduced compared to controls early in the illness, and this difference diminishes with age; the corresponding effect in the proportion of WM is an increase with age compared to controls. This suggests that illness related factors may differentially affect grey and white matter, with implications for understanding the pathophysiology of schizophrenia and related psychotic disorders.

Superior temporal gyrus volume change in schizophrenia: a review on region of interest volumetric studies

Imaging studies of schizophrenia (SCZ) have repeatedly demonstrated volume differences in superior temporal gyrus (STG) and its subregions. Among them, some studies employed the Region of Interest (ROI) method. We carried out a systematic review of the published literature on STG volumetry MRI studies to examine the potential of ROI method for identifying specific structural differences and correlations with clinical variables including hallucinations and thought disorder symptoms in SCZ. Forty-six studies were identified as suitable for review and analysis including 1444 patients with SCZ and 1327 controls. Female and left-handed subjects are under-represented in the literature and insight from sex and handedness differences may be lost. Thirty-five studies reported significant differences in STG or subregional volumes including bilateral or unilateral ROI, and volume reduction was the most common change in SCZ. Thirty studies reported correlations between volume changes and clinical symptoms or syndromes and 18 found positive results. Among them, left STG or subregions appear to be more involved in the generation of hallucinations and thought disorder than right side. The majority of five follow-up studies found evidence of progressive changes in volumes. Clinical heterogeneity, MRI acquisition parameters, anatomical landmarks for ROI, and sample characteristics, are likely to be the main factors leading to heterogeneous results. Clearly this research links pathophysiological changes in the STG with the development of hallucinations and thought disorder in patients with SCZ, especially in the left side. There is a suggestion that these changes may be progressive but this requires more thorough and comprehensive assessment.

Endophenotypes in schizophrenia: a selective review

BACKGROUND

Given the wealth of data in the literature on schizophrenia endophenotypes, it is useful to have one source to reference their frequency data. We reviewed the literature on disease-liability associated variants in structural and functional magnetic resonance images (MRI), sensory processing measures, neuromotor abilities, neuropsychological measures, and physical characteristics in schizophrenia patients (SCZ), their first-degree relatives (REL), and healthy controls (HC). The purpose of this review was to provide a summary of the existing data on the most extensively published endophenotypes for schizophrenia.

METHODS

We searched PubMed and MedLine for all studies on schizophrenia endophenotypes comparing SCZ to HC and/or REL to HC groups. Percent abnormal values, generally defined as >2 SD from the mean (in the direction of abnormality) and/or associated effect sizes (Cohen's d) were calculated for each study.

RESULTS

Combined, the articles reported an average 39.4% (SD=20.7%; range=2.2-100%) of abnormal values in SCZ, 28.1% (SD=16.6%; range=1.6-67.0%) abnormal values in REL, and 10.2% (SD=6.7%; range=0.0-34.6%) in HC groups.

CONCLUSIONS

These findings are reviewed in the context of emerging hypotheses on schizophrenia endophenotypes, as well as a discussion of clustering trends among the various intermediate phenotypes. In addition, programs for future research are discussed, as instantiated in a few recent large-scale studies on multiple endophenotypes across patients, relatives, and healthy controls.

Stimulus- and response-locked neuronal generator patterns of auditory and visual word recognition memory in schizophrenia

Examining visual word recognition memory (WRM) with nose-referenced EEGs, we reported a preserved ERP 'old-new effect' (enhanced parietal positivity 300-800 ms to correctly-recognized repeated items) in schizophrenia ([Kayser, J., Bruder, G.E., Friedman, D., Tenke, C.E., Amador, X.F., Clark, S.C., Malaspina, D., Gorman, J.M., 1999. Brain event-related potentials (ERPs) in schizophrenia during a word recognition memory task. Int. J. Psychophysiol. 34(3), 249-265.]). However, patients showed reduced early negative potentials (N1, N2) and poorer WRM. Because group differences in neuronal generator patterns (i.e., sink-source orientation) may be masked by choice of EEG recording reference, the current study combined surface Laplacians and principal components analysis (PCA) to clarify ERP component topography and polarity and to disentangle stimulus- and response-related contributions. To investigate the impact of stimulus modality, 31-channel ERPs were recorded from 20 schizophrenic patients (15 male) and 20 age-, gender-, and handedness-matched healthy adults during parallel visual and auditory continuous WRM tasks. Stimulus- and response-locked reference-free current source densities (spherical splines) were submitted to unrestricted Varimax-PCA to identify and measure neuronal generator patterns underlying ERPs. Poorer (78.2+/-18.7% vs. 87.8+/-11.3% correct) and slower (958+/-226 vs. 773+/-206 ms) performance in patients was accompanied by reduced stimulus-related left-parietal P3 sources (150 ms pre-response) and vertex N2 sinks (both overall and old/new effects) but modality-specific N1 sinks were not significantly reduced. A distinct mid-frontal sink 50-ms post-response was markedly attenuated in patients. Reductions were more robust for auditory stimuli. However, patients showed increased lateral-frontotemporal sinks (T7 maximum) concurrent with auditory P3 sources. Electrophysiologic correlates of WRM deficits in schizophrenia suggest functional impairments of posterior cortex (stimulus representation) and anterior cingulate (stimulus categorization, response monitoring), primarily affecting memory for spoken words.

Structural and metabolic changes in language areas linked to formal thought disorder

BACKGROUND

The role of the language network in the pathophysiology of formal thought disorder has yet to be elucidated.

AIMS

To investigate whether specific grey-matter deficits in schizophrenic formal thought disorder correlate with resting perfusion in the left-sided language network.

METHOD

We investigated 13 right-handed patients with schizophrenia and formal thought disorder of varying severity and 13 matched healthy controls, using voxel-based morphometry and magnetic resonance imaging perfusion measurement (arterial spin labelling).

RESULTS

We found positive correlations between perfusion and the severity of formal thought disorder in the left frontal and left temporoparietal language areas. We also observed bilateral deficits in grey-matter volume, positively correlated with the severity of thought disorder in temporoparietal areas and other brain regions. The results of the voxel-based morphometry and the arterial spin labelling measurements overlapped in the left posterior superior temporal gyrus and left angular gyrus.

CONCLUSIONS

Specific grey-matter deficits may be a risk factor for state-related dysfunctions of the left-sided language system, leading to local hyperperfusion and formal thought disorder.

The neural correlates of ego-disturbances (passivity phenomena) and formal thought disorder in schizophrenia

Ego-disturbances (passivity phenomena) and formal thought disorder are two hallmark symptoms of schizophrenia. Formal thought disorder has been highlighted already very early by Eugen Bleuler in his concept of basic symptoms (Grundsymptome). In contrast ego-disturbances (Ich-Störungen) or passivity phenomena have been declared as core symptoms of schizophrenia by Kurt Schneider in his concept of first-rank symptoms (Erstrangsymptome) that influenced the whole concept of schizophrenia until today (ICD10; DSM IV). We present new neuroimaging and cognitive neuropsychological results that help to explain what brain and cognitive functions may be involved in the emergence of these symptoms. Questions on cognitive and neural correlates of notions such as self-awareness, self-consciousness, introspective perspective or subjective experiences have re-emerged as topics of great interest in the scientific community. Employing new neuroscientific methods such as functional brain imaging, advances into thus far unexplored territory of mind-brain relationships have been made. These findings give new impulses for the search on the neural basis of psychopathological symptoms. We will review neuroscientific data and models on the pathogenesis of two of the core symptoms of schizophrenia, i.e. passivity phenomena and formal thought disorder.

Hallucinations, thought disorders, and the language domain in schizophrenia

Auditory hallucinations and formal thought disorders are major diagnostic features of schizophrenia. From a neurobiological point of view, they are of particular interest since both can be attributed to the language domain of human communication. In the last decade, brain imaging studies have contributed to the understanding of the functional dynamics underlying these phenomena. In particular, auditory hallucinations were found to involve the regions generating inner speech as well as the primary acoustical cortex and the intrahemispheric fiber bundles connecting the left frontal with the temporal lobe. In patients with formal thought disorders, on the other hand, the left temporal language area showed structural deficits and functional abnormalities, i.e., reduced reactivity to stimulation and increased activity at rest; left frontal language regions were also hyperactive at rest but showed no structural deficits. The available evidence indicates a dynamic imbalance of the language system, triggered by subtle structural changes, as the possible common neurobiological basis of hallucinations and formal thought disorders.

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.

Effect of retrieval effort and switching demand on fMRI activation during semantic word generation in schizophrenia

Verbal fluency deficits in schizophrenia are difficult to interpret because the tasks are multi-factorial and groups differ in total words generated. We manipulated retrieval and switching demands by requiring alternation between over-learned sequences in which retrieval is relatively automatic (OS) and semantic categories requiring increased retrieval effort (SC). Controlled processing was also manipulated by including switching and non-switching conditions, and formal thought disorder (FTD) was assessed with the communication disorders index (CDI). The OS/SC semantic fluency paradigm was administered during fMRI to 13 patients with schizophrenia and 14 matched controls. Images were acquired on a 3 Tesla Siemens scanner using compressed image acquisition to allow for cued overt word production. Subjects alternated between OS, SC, OS-switch, SC-switch, and baseline blocks. Images were pre-processed in SPM-2, and a two-stage random effects analysis tested within and between group contrasts. There were no group performance differences. fMRI analysis did not reveal any group differences during the OS non-switching condition. Both groups produced expected activation in bilateral prefrontal and inferior parietal regions. However, during the SC condition patients had greater activation than controls in left prefrontal, right anterior cingulate, right superior temporal, bilateral thalamus, and left parietal regions. There was also evidence of patient over-activation in prefrontal, superior temporal, superior parietal, and visual association areas when a switching component was added. FTD was negatively correlated with BOLD response in the right anterior cingulate, cuneus and superior frontal gyrus during increased retrieval demand, and positively correlated with fMRI activation in the left lingual gyrus, right fusiform gyrus and left superior parietal lobule during increased switching demand. These results indicate that patients are able to successfully perform effortful semantic fluency tasks during non-speeded conditions. When retrieval is relatively automatic there does not appear to be an effect of schizophrenia on fMRI response. However, when retrieval and controlled processing demands increase, patients have greater activation than controls despite unimpaired task performance. This inefficient BOLD response may explain why patients are slower and less accurate on standard self-paced fluency tasks.

Neuropsychological functioning and brain structure in schizophrenia

Cognitive deficits are core features of schizophrenia that are already evident at early phases of the illness. The study of specific relationships between cognition and brain structure might provide valuable clues about neural basis of schizophrenia and its phenomenology. The aim of this article was to review the most consistent findings of the studies exploring the relationships between cognitive deficits and brain anomalies in schizophrenia. Besides several important methodological shortcomings to bear in mind before drawing any consistent conclusion from the revised literature, we have attempted to systematically summarize these findings. Thus, this review has revealed that whole brain volume tends to positively correlate with a range of cognitive domains in healthy volunteers and female patients. An association between prefrontal morphological characteristics and general inability to control behaviour seems to be present in schizophrenia patients. Parahippocampal volume is related to semantic cognitive functions. Thalamic anomalies have been associated with executive deficits specifically in patients. Available evidence on the relationship between cognitive functions and cerebellar structure is still contradictory. Nonetheless, a larger cerebellum appears to be associated with higher IQ in controls and in female patients. Enlarged ventricles, including lateral and third ventricles, are associated with deficits in attention, executive and premorbid cognitive functioning in patients. Several of these reported findings seem to be counterintuitive according to neural basis of cognitive functioning drawn from animal, lesion, and functional imaging investigations. Therefore, there is still a great need for more methodologically stringent investigations that would help in the advance of our understanding of the cognition/brain structure relationships in schizophrenia.

Brain activation mediates the association between structural abnormality and symptom severity in schizophrenia

Thought disorder is a symptom of schizophrenia expressed as disorganized or incoherent speech. Severity of thought disorder correlates with decreased left superior temporal gyrus grey matter volume and cortical activation in posterior temporal regions during the performance of language tasks. The goal of this study was to determine whether language-related activation mediates the association between thought disorder and left superior temporal lobe grey matter volume. 12 patients with schizophrenia were assessed for thought disorder. FMRI images were acquired for each subject while they listened to English speech, along with a high resolution structural image. Thought disorder was used as a covariate in the functional analysis to identify brain regions within which activation correlated with symptom severity. Voxel based morphometry was used to calculate grey matter volume of the planum temporale. A mediation model waste-tested using a four-step multiple regression approach incorporating cortical volume, functional activation and symptom severity. Thought disorder correlated with activation in a single cluster within the left posterior middle temporal gyrus during listening to speech. Grey matter volume within the planum temporale correlated significantly with severity of thought disorder and activation within the functional cluster. Regressing thought disorder on grey matter volume and BOLD response simultaneously led to a significant reduction in the correlation between grey matter volume and thought disorder. These results support the hypothesis that the association between decreased grey matter volume in the left planum temporale and severity of thought disorder is mediated by activation in the posterior temporal lobe during language processing.

Structural brain abnormalities in early onset first-episode psychosis

BACKGROUND

Brain morphometry in children and adolescents with first-episode psychosis offer a unique opportunity for pathogenetic investigations.

METHODS

We compared high-resolution 3D T1-weighted magnetic resonance images of the brain in 29 patients (schizophrenia, schizotypal disorder, delusional disorder or other non-organic psychosis), aged 10-18 to those of 29 matched controls, using optimized voxel-based morphometry.

RESULTS

Psychotic patients had frontal white matter abnormalities, but expected (regional) gray matter reductions were not observed. Post hoc analyses revealed that schizophrenia patients (n = 15) had significantly larger lateral ventricles as compared to controls. Duration and dose of antipsychotics correlated negatively with global gray matter volume in minimally medicated patients (n = 18).

CONCLUSION

Findings of white matter changes and enlarged lateral ventricles already at illness onset in young schizophrenia spectrum patients, suggests aberrant neurodevelopmental processes in the pathogenesis of these disorders. Gray matter volume changes, however, appear not to be a key feature in early onset first-episode psychosis.

Brain-behaviour relationships in people at high genetic risk of schizophrenia

The brain is known to be structurally abnormal in schizophrenia, with replicated findings between anatomical deficits and some dysfunctions. These structure-function associations have, however, only very rarely been studied in relatives at risk of schizophrenia. We studied the relationships between structure and schizotypal features (assessed using RISC and SIS) and verbal learning and memory (measured using RAVLT) in relatives at high risk of developing schizophrenia and normal controls. Since these behavioural test scores are strong predictors of schizophrenia in the Edinburgh High Risk Study, we hypothesised that these relationships would differ between those high-risk subjects who will develop schizophrenia from those who will not. We performed multiple regressions of the grey matter segments of the subjects and controls, produced using grey matter optimised, voxel-based morphometry, with their RAVLT, SIS and RISC scores in SPM. Where significant relationships were found, we used SPSS to test for subject group by behavioural score interactions. In those high-risk subjects who became ill, grey matter density (GMD) was significantly correlated with RISC in the left superior temporal gyrus. In subjects who remained well, SIS was significantly correlated with GMD in the right pulvinar. Across the whole HR group, GMD in the right medial dorsal thalamic nucleus was significantly correlated with RAVLT. In those subjects who developed symptoms, RAVLT significantly correlated with GMD in right parahippocampal gyrus whereas in those who became ill, significant correlations existed bilaterally in the pulvinar. These results suggest complex and changing patterns of structural-functional relationships in those subjects at high-risk of schizophrenia.

The brain, language, and schizophrenia

Language is a defining and prominent feature in humans. This faculty is impaired in those with schizophrenia. Individuals with schizophrenia show numerous abnormalities in language function, including symptoms of disorganized speech, auditory hallucinations, thought disorders, and verbal memory impairments. Structural and functional brain imaging with neurocognitive testing shows various aspects of brain structure and function associated with language that also are abnormal in schizophrenia. This article comparatively reviews this research and relates it to understanding the symptoms and pathophysiologic features of schizophrenia. Understanding the neural basis of language and its disruption in schizophrenia provides a guide for diagnosis, subtyping, treatment, and future research.

Superior temporal gyrus differences in childhood-onset schizophrenia

The posterior superior temporal gyrus (STG) is the approximate site of Wernicke's area, a language region, which in previous studies has been reported to be abnormal in adults with schizophrenia. The present study assesses volumetric differences in the superior temporal gyrus of subjects with childhood-onset schizophrenia (COS). MRI scans of 18 subjects diagnosed with childhood-onset schizophrenia and 16 age- and sex-matched normals were analyzed to assess possible volume differences. The COS subjects displayed significant enlargement of the right posterior superior temporal gyrus, showing white matter increases bilaterally in this region. Our findings are consistent with studies that have found increased volumes in temporal lobe regions in COS and may provide a possible neural correlate for the language impairment observed in COS patients.

Neuroanatomical correlates of formal thought disorder in schizophrenia

INTRODUCTION

We attempted to extend findings of a relationship between formal thought disorder and left superior temporal gyrus (STG) volume in schizophrenia by examining two indices of formal thought disorder.

METHODS

Three brain regions of interest were selected from magnetic resonance imaging slices in 15 young, right-handed, male schizophrenia patients: the STG, the anterior hippocampus, and the amygdala. Thought disorder was assessed using the Bizarre-Idiosyncratic Thinking (BIZ) scale, a sensitive measure of formal thought disorder based on responses to a standard set of stimuli, and the BPRS Conceptual Disorganization item, a global rating based on a clinical interview.

RESULTS

BIZ ratings of thought disorder were significantly correlated with the left STG volume (Spearman r = -.73) and with the right STG volume (Spearman r = -.58). BIZ ratings were not significantly correlated with either the left or right anterior hippocampus or amygdala volumes. The BPRS Conceptual Disorganisation rating was not significantly related to the STG, anterior hippocampus, or amygdala volumes.

CONCLUSIONS

This study confirms the previously reported association between the left STG and formal thought disorder, and suggests that detection of this relationship may be facilitated by use of highly sensitive formal thought disorder assessments.

Morphology of the lateral superior temporal gyrus in neuroleptic nai;ve patients with schizophrenia: relationship to symptoms

OBJECTIVE

The superior temporal gyrus (STG) is a large structure in the temporal lobe with multiple sub-regions that are structurally and functionally distinct. This study evaluates the structural morphology of a specific sub-region of the STG, the anterior and posterior portions of the lateral aspect of the STG. Furthermore, relationships between the morphology of these regions and symptoms of the illness were explored.

METHOD

Regions of cortex were consecutively traced on a set of serial coronal slices in 25 male neuroleptic nai;ve patients with first episode schizophrenia and 25 age-matched healthy volunteers. Regional gray matter volumes were calculated and compared, and their correlations with three symptom dimensions were explored.

RESULTS

The left anterior STG had a significant inverse correlation with psychotic symptoms, whereas the right posterior STG had a significant positive correlation with negative symptoms. These findings were confirmed by a follow-up analysis using extreme groups. There was no significant correlation between any region and disorganized symptoms.

CONCLUSIONS

These findings suggest that abnormalities in the lateral side of the STG may be associated with both psychotic and negative symptoms through different pathophysiological mechanisms.

Quantification of frontal and temporal lobe brain-imaging findings in schizophrenia: a meta-analysis

Magnetic resonance imaging (MRI) and positron emission tomography (PET) studies of the frontal and temporal lobes in schizophrenia patients and healthy controls have proliferated over the past 2 decades, but there have been relatively few attempts to quantify the evidence. In this meta-analytic review, 155 studies on frontal and temporal lobe neurobiology were synthesized, reflecting results from 4043 schizophrenia patients and 3977 normal controls. Cohen's d was used to quantify case-control differences, and moderator variable analysis indexed the relation of sample and imaging characteristics to the magnitude of these differences. Frontal metabolic and blood flow deficiencies in conjunction with cognitive activation tasks ("hypofrontality") emerged as the strongest body of evidence, demonstrating abnormalities that distinguish approximately half of schizophrenia patients from healthy people. Most case-control comparisons with structural and functional imaging yield small and in many cases unstable findings. Technical scanning parameters like slice thickness and magnet strength did not vary with case-control differences consistently across the meta-analyses. However, patient sample characteristics including sample size, handedness and gender composition emerged frequently as moderators of brain-imaging effect sizes.

Altered hemispheric asymmetry and positive symptoms in schizophrenia: equivalent current dipole of auditory mismatch negativity

The abnormality of mismatch negativity (MMN) in schizophrenia is thought to be associated with perceptional disturbance and cognitive dysfunction. The purpose of the present study was to investigate the change of the normal functional hemispheric lateralization in schizophrenia by employing the equivalent current dipole (ECD) model of auditory MMN with individual MRI and high-density electroencephalography (EEG). The MMNs resulting from auditory stimuli with passive oddball paradigm in a group of schizophrenics (n = 15), and also a group of age-, sex-, and handedness-matched normal controls, were recorded by 128 channel EEG. The location and power of ECD sources at the peak point were calculated. Individual 3-D brain magnetic resonance images (MRI) were used for realistic head modeling and for source localization. For both groups, the MMN source was determined to be located in the superior temporal gyrus (STG). However, the normal functional hemispheric asymmetry of ECD power was significantly altered in the schizophrenics (chi(2) test = 16.13, p < 0.001). Left MMN ECD power and the asymmetry coefficient (AC) were negatively correlated with the positive scores from Positive and Negative Syndrome Scale (PANSS) (r = -0.673, p = 0.008), especially with the hallucinatory behavior subscale (r = -0.677, p = 0.008). These findings support the deficits in preattentive automatic processing of auditory stimuli, especially in the left hemisphere, and indicate the correlation between positive symptoms, especially auditory hallucination, and left temporal lobe dysfunction in schizophrenia.

Quantification of lateral ventricular subdivisions in schizophrenia by high-resolution three-dimensional magnetic resonance imaging

In vivo brain imaging and postmortem investigations have demonstrated ventricular enlargement in the brains of schizophrenic patients. However, the extent of changes in the volume of discrete ventricle subdivisions has not been clearly established. We conducted high-resolution three-dimensional magnetic resonance imaging in 40 schizophrenic patients (20 males and 20 females) and 40 healthy volunteers (20 males and 20 females). The lateral ventricle in each hemisphere was divided into the anterior horn, body, posterior horn and temporal horn. The volumes of the hemispheres, four subdivisions of the lateral ventricles and the third ventricle were measured. Compared to the control subjects, the bilateral hemisphere volumes were significantly lower in the patients than in the control subjects. In the lateral ventricular subdivisions of the male patients, the most substantial volume increase was in the left temporal horn, and volume increases were also observed in the bilateral anterior horns and the right body. The male patients also had a significantly increased volume of the third ventricle. The female patients showed similar patterns with less statistical significance. Thus, the schizophrenia patients showed ventricular enlargement, particularly in the left temporal horn, being more severely affected in the male than in the female.

Cognitive performance in schizophrenia: relationship to regional brain volumes and psychiatric symptoms

In an all-male sample of schizophrenic patients stabilized by medication (n=62) and normal controls (n=27), we obtained neuropsychological test data and high-resolution whole brain magnetic resonance scans, as well as detailed psychiatric rating scales on a subset of the patients (n=47). Schizophrenic patients had significantly worse overall age-adjusted cognitive performance than normal controls (average z-score=-0.90, range=-0.60 to -1.81), which included relatively more severe deficits with different types of memory, psychomotor speed, verbal fluency and verbal abstraction. Schizophrenic patients also had significantly smaller bilateral volumes in gray but not white matter in the prefrontal region, superior temporal gyrus and whole temporal lobe, but no group differences were observed in the hippocampus and parahippocampus. Correlations between the brain regions and cognitive performance revealed different sets of significant relationships for the two groups, particularly in the prefrontal and hippocampal regions. In addition, inverse correlations were observed between certain cognitive abilities (psychomotor speed, cognitive flexibility and verbal fluency) and patients' psychiatric ratings, especially with measures of negative symptoms. The convergence of findings for schizophrenic patients regarding the prefrontal region, negative symptoms, psychomotor speed and cognitive flexibility suggests that schizophrenic negative symptoms may involve disruption of frontal-subcortical connections.

The brain in schizotypal personality disorder: a review of structural MRI and CT findings

Studies of schizotypal personality disorder (SPD) are important because the condition is genetically related to schizophrenia and because data accumulating to confirm its biological underpinnings are challenging some traditional views about the nature of per-sonality disorders. This review of 17 structural imaging studies in SPD indicates that individuals with this disorder show brain abnormalities in the superior temporal gyrus, parahippocampus, temporal horn region of the lateral ventricles, corpus callosum, thalamus, and septum pellucidum, as well as in total cerebrospinal fluid volume, similar to those seen in persons with schizophrenia. Differences between SPD and schizophrenia include lack of abnormalities in the medial temporal lobes and lateral ventricles in SPD. Whether the normal volume, and possibly normal functioning, of the medial temporal lobes in individuals with SPD may help to suppress psychosis in this disorder remains an intriguing but still unresolved question. Such speculation must be tempered due to a paucity of studies, and additional work is needed to confirm these preliminary findings. The imaging findings do suggest, however, that SPD probably represents a milder form of disease along the schizophrenia continuum. With further clarification of the neuroanatomy of SPD, researchers may be able to identify which neuroanatomical abnormalities are associated with the frank psychosis seen in schizophrenia.

Prefrontal cortex, negative symptoms, and schizophrenia: an MRI study

The present study measured prefrontal cortical gray and white matter volume in chronic, male schizophrenic subjects who were characterized by a higher proportion of mixed or negative symptoms than previous patients that we have evaluated. Seventeen chronic male schizophrenic subjects and 17 male control subjects were matched on age and handedness. Regions of interest (ROI) were measured using high-resolution magnetic resonance (MR) acquisitions consisting of contiguous 1.5-mm slices of the entire brain. No significant differences were found between schizophrenic and control subjects in mean values for prefrontal gray matter volume in either hemisphere. However, right prefrontal white matter was significantly reduced in the schizophrenic group. In addition, right prefrontal gray matter volume was significantly correlated with right hippocampal volume in the schizophrenic, but not in the control group. Furthermore, an analysis in which the current data were combined with those from a previous study showed that schizophrenic subjects with high negative symptom scores had significantly smaller bilateral white matter volumes than those with low negative symptom scores. White matter was significantly reduced in the right hemisphere in this group of schizophrenic subjects. Prefrontal volumes were also associated with negative symptom severity and with volumes of medial-temporal lobe regions - two results that were also found previously in schizophrenic subjects with mostly positive symptoms. These results underscore the importance of temporal-prefrontal pathways in the symptomatology of schizophrenia, and they suggest an association between prefrontal abnormalities and negative symptoms.

Thought disorder in attention-deficit hyperactivity disorder

OBJECTIVE

This study compared thought disorder and associated cognitive variables in attention-deficit hyperactivity disorder (ADHD) and schizophrenia.

METHOD

Speech samples of 115 ADHD, 88 schizophrenic, and 190 normal children, aged 8 to 15 years, were coded for thought disorder. A structured psychiatric interview, the WISC-R, the Continuous Performance Test, and the Span of Apprehension task were administered to each child.

RESULTS

The ADHD and schizophrenic groups had thought disorder compared with the normal children. However, the subjects with ADHD had a narrower range of less severe thought disorder than did the schizophrenic subjects. The younger children with ADHD and schizophrenia had significantly more thought disorder than did the older children with these diagnoses. IQ, attention, and working memory were associated with thought disorder in the ADHD but not the schizophrenic group.

CONCLUSIONS

Thought disorder in childhood is not specific to schizophrenia and reflects impaired development of children's communication skills.

Differential activation of temporal cortex during sentence completion in schizophrenic patients with and without formal thought disorder

The neural correlates of processing linguistic context in schizophrenic patients with formal thought disorder (FTD) were examined. Six right-handed male patients with prominent 'positive' FTD were compared with six schizophrenic patients without FTD and seven volunteers, matched for cognitive and demographic variables. Functional magnetic resonance imaging (IMRI) was used to measure cerebral activation while subjects read and completed sentence stems out loud. During a GENERATION condition, subjects were required to generate a word which completed the sentence stem appropriately. During a DECISION condition, subjects selected and articulated one of two presented terminal words. A READING condition served as baseline. The three conditions were compared with each other. Regions activated were identified in each group, and between-group differences were detected using an ANCOVA. When GENERATION was compared with READING, FTD patients showed less activation in the right superior temporal gyrus than patients without FTD or controls, but greater activation in the left inferior frontal, inferior temporal and fusiform gyri. FTD patients also showed an attenuated right temporal response when GENERATION was compared with DECISION. This differential engagement of the right temporal cortex was independent of differences in the speed or accuracy of responses, whereas the left fronto-temporal differences in activation were not evident after covarying for task errors. The attenuated engagement of right temporal cortex, which is implicated in language comprehension at the discourse level, is consistent with neuropsychological evidence linking thought disorder with deficits in processing linguistic context.

Are auditory hallucinations the consequence of abnormal cerebral lateralization? A morphometric MRI study of the sylvian fissure and planum temporale

BACKGROUND

Auditory verbal hallucinations (AVHs) are a characteristic feature of schizophrenia. Patients with schizophrenia have been found to have reduced volumes of a variety of brain structures as well as a reduction in right-left asymmetries, using postmortem and magnetic resonance imaging (MRI) measures. There is also evidence that patients with AVHs differ in these structural asymmetries, relative to those patients who do not hallucinate. The aim of this study was to examine whether patients with and without a prominent history of AVHs differ, both from each other and in comparison with normal subjects, in the asymmetry of the sylvian fissure (SF) and planum temporale (PT).

METHODS

We recruited 74 DSM-IV male patients with schizophrenia (on the basis of their AVH history) and 32 matched normal control subjects. Thirty patients had no history of AVHs and 44 had a strong definitive history of AVHs. The SF length and PT area and volume were measured on a three-dimensional MRI spoiled GRASS volume sequence. Absolute measures and laterality coefficients were calculated.

RESULTS

: All groups had the normal leftward asymmetry in both the SF and PT. Planum temporale volume and surface area and SF length were all larger in the left hemisphere. There were no significant differences in any measures between the two patient groups or between schizophrenic patients and control subjects. Greater leftward asymmetry of the SF correlated with hallucinations and thought disorder within the prominent hallucinator group. An association was found between handedness and brain size, but this did not interact with diagnosis.

CONCLUSIONS

The results of this study do not confirm reports, based on smaller samples, of reduced structural asymmetries of either the SF or PT in schizophrenia, nor do they indicate a specific relationship to a propensity to experience AVHs. A modest correlation between leftward asymmetry of the SF and some positive symptomatology was found.

A review of MRI findings in schizophrenia

After more than 100 years of research, the neuropathology of schizophrenia remains unknown and this is despite the fact that both Kraepelin (1919/1971: Kraepelin, E., 1919/1971. Dementia praecox. Churchill Livingston Inc., New York) and Bleuler (1911/1950: Bleuler, E., 1911/1950. Dementia praecox or the group of schizophrenias. International Universities Press, New York), who first described 'dementia praecox' and the 'schizophrenias', were convinced that schizophrenia would ultimately be linked to an organic brain disorder. Alzheimer (1897: Alzheimer, A., 1897. Beitrage zur pathologischen anatomie der hirnrinde und zur anatomischen grundlage einiger psychosen. Monatsschrift fur Psychiarie und Neurologie. 2, 82-120) was the first to investigate the neuropathology of schizophrenia, though he went on to study more tractable brain diseases. The results of subsequent neuropathological studies were disappointing because of conflicting findings. Research interest thus waned and did not flourish again until 1976, following the pivotal computer assisted tomography (CT) finding of lateral ventricular enlargement in schizophrenia by Johnstone and colleagues. Since that time significant progress has been made in brain imaging, particularly with the advent of magnetic resonance imaging (MRI), beginning with the first MRI study of schizophrenia by Smith and coworkers in 1984 (Smith, R.C., Calderon, M., Ravichandran, G.K., et al. (1984). Nuclear magnetic resonance in schizophrenia: A preliminary study. Psychiatry Res. 12, 137-147). MR in vivo imaging of the brain now confirms brain abnormalities in schizophrenia. The 193 peer reviewed MRI studies reported in the current review span the period from 1988 to August, 2000. This 12 year period has witnessed a burgeoning of MRI studies and has led to more definitive findings of brain abnormalities in schizophrenia than any other time period in the history of schizophrenia research. Such progress in defining the neuropathology of schizophrenia is largely due to advances in in vivo MRI techniques. These advances have now led to the identification of a number of brain abnormalities in schizophrenia. Some of these abnormalities confirm earlier post-mortem findings, and most are small and subtle, rather than large, thus necessitating more advanced and accurate measurement tools. These findings include ventricular enlargement (80% of studies reviewed) and third ventricle enlargement (73% of studies reviewed). There is also preferential involvement of medial temporal lobe structures (74% of studies reviewed), which include the amygdala, hippocampus, and parahippocampal gyrus, and neocortical temporal lobe regions (superior temporal gyrus) (100% of studies reviewed). When gray and white matter of superior temporal gyrus was combined, 67% of studies reported abnormalities. There was also moderate evidence for frontal lobe abnormalities (59% of studies reviewed), particularly prefrontal gray matter and orbitofrontal regions. Similarly, there was moderate evidence for parietal lobe abnormalities (60% of studies reviewed), particularly of the inferior parietal lobule which includes both supramarginal and angular gyri. Additionally, there was strong to moderate evidence for subcortical abnormalities (i.e. cavum septi pellucidi-92% of studies reviewed, basal ganglia-68% of studies reviewed, corpus callosum-63% of studies reviewed, and thalamus-42% of studies reviewed), but more equivocal evidence for cerebellar abnormalities (31% of studies reviewed). The timing of such abnormalities has not yet been determined, although many are evident when a patient first becomes symptomatic. There is, however, also evidence that a subset of brain abnormalities may change over the course of the illness. The most parsimonious explanation is that some brain abnormalities are neurodevelopmental in origin but unfold later in development, thus setting the stage for the development of the symptoms of schizophrenia. Or there may be additional factors, such as stress or neurotoxicity, that occur during adolescence or early adulthood and are necessary for the development of schizophrenia, and may be associated with neurodegenerative changes. Importantly, as several different brain regions are involved in the neuropathology of schizophrenia, new models need to be developed and tested that explain neural circuitry abnormalities effecting brain regions not necessarily structurally proximal to each other but nonetheless functionally interrelated. (ABSTRACT TRUNCATED)