[Show abstract][Hide abstract] ABSTRACT: Objective
We aimed to investigate the brain functional substrate underlying relationships between metabolic syndrome (MetS) and cognitive impairment in schizophrenia.
In this cross-sectional study, we collected socio-demographic, clinical, anthropometric, blood, and cognition data and performed brain 99mTc-ECD-SPECT imaging of cerebral blood flow in patients with schizophrenia. Patients were grouped according to the absence or presence of MetS. Whole-brain perfusion SPECTs were compared at voxel level between these two groups, and voxel-wise interregional correlation was performed to compare functional connectivity (voxel level significance of p < 0.005, uncorrected; p < 0.05 for the cluster, uncorrected; using SPM8). A structural equation model (SEM) was applied to examine the relationships between brain perfusion, connectivity between brain areas, and cognition.
Of the 55 patients, 17 had MetS. They performed significantly worse than patients without MetS on tests of executive functions (processing speed p = 0.005 for TMT-A; and reactive flexibility p = 0.014 for TMT-B), attention (D2 attention task p = 0.007), and memory (California Verbal Learning Test p = 0.039). In comparison to patients without MetS, those with MetS exhibited significant hypoperfusion within the left orbital prefrontal cortex and greater functional connectivity from this left frontal cluster within the left insula and middle/superior frontal gyrus. SEM confirmed the effect on executive functions of brain hypoperfusion and of increased connectivity, suggesting possible compensatory networks in patients with MetS.
Our study identifies the brain functional impact of MetS on cognition, with orbital prefrontal impairment and possible compensatory networks.
[Show abstract][Hide abstract] ABSTRACT: Progressive atrophy occurs in brain regions involved in the working memory network along the schizophrenia's course, but without parallel evolution of working memory impairment. We investigated the functional organization inside this network at different stages of the disease.
Twenty-eight patients with schizophrenia (16 with long disease duration (>60months) and 12 with short disease duration (<60months)) and eleven healthy controls underwent structural and functional MRI during an n-back task to determine atrophy and activation patterns.
At similar n-back performances and relative to short disease duration patients, long disease duration patients activated more frontal temporal parietal and frontal network during 0-back and 1-back tasks respectively. n-back scores were correlated to atrophy in the frontal-temporal areas.
Functional reorganization in the working memory network may play a compensatory role during the first ten years of schizophrenia.
Schizophrenia Research 11/2013; · 4.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: The aim of this study was to develop a functional remission threshold for the Functional Remission Of General Schizophrenia (FROGS) scale, and test its validity regarding clinical and quality of life outcomes. METHODS: Design: Cross-sectional study. Inclusion criteria: Schizophrenia according to DSM-IV-TR criteria. Data collection: Functioning was assessed using the FROGS and the Global Assessment of Functioning (GAF) scales; psychotic symptoms using the Positive and Negative Syndrome Scale; memory, attention, and executive functions were assessed using the California Verbal Learning Test, the D2 attention task, the Stroop color-word test, the verbal fluency test, the Trail Making Test A and B and the Wechsler Adult Intelligence Scale; and quality of life using the schizophrenia quality of life (S-QoL 18) scale. Analysis: A logistic regression analysis including the different dimensions of the FROGS was used to create a composite score to classify patients into remitted and non-remitted according a gold standard (cut-off: GAF>= 61). Receiver operating characteristics analyses were then performed to determine the area under the curve (AUC). RESULTS: Of 137 patients enrolled, 26 were functionally remitted and 111 were not remitted according to GAF score. The AUC for the combination of the FROGS's dimensions to detect functional remission was 0.903 (p<0.001). Sensitivity and specificity for the combination of the FROGS dimensions using the Youden index were 88.5 [69.8; 97.6] and 81.1 [72.5; 87.9], respectively. Validity of this combination was satisfactory. Patients in functional remission had a lower severity of the disease, especially for PANSS negative (p<0.001) and general psychopathology (p<0.001) symptoms. Only two cognitive functions (i.e. fluency and episodic memory) were improved in remitted patients. Higher quality of life levels were globally associated with better functioning. CONCLUSIONS: These findings provide for first accurate FROGS thresholds to detect functional remission in schizophrenia.
[Show abstract][Hide abstract] ABSTRACT: Preserved insight into illness has been suggested to be predictive of outcome in patients with schizophrenia. We aimed to investigate the functional substrate underlying preserved insight in these patients.
We recruited patients with paranoid schizophrenia and healthy controls matched for age and sex. Patients were grouped according to preserved or impaired insight into illness using the Scale to assess Unawareness of Mental Disorder (SUMD). Whole-brain technetium-99m ethyl cysteinate dimer single photon emission computed tomography regional cerebral blood flow was compared at the voxel level between the 2 groups using a statistical parametric map (voxel-level significance of p < 0.001, uncorrected; cluster level significance of p < 0.05, uncorrected).
We enrolled 31 right-handed patients with schizophrenia and 18 controls in our study. Twenty-one (67.7%) patients had preserved insight. The 2 groups did not differ significantly in demographic and clinical characteristics or in treatment. Compared with controls, the whole group of patients showed bilateral frontotemporal hypoperfusions, with no statistical difference between patients with preserved or impaired insight for these areas. Patients with preserved insight showed significantly increased perfusion of the bilateral precuneus relative to those with impaired insight.
Patients with subtypes other than paranoid schizophrenia have to be investigated to assess whether involvement of the precuneus in patients with preserved insight can be identified across the full spectrum of subtypes and symptoms of schizophrenia. Moreover, our study concerned only the central dimension (awareness of mental disorder) of 1 scale (SUMD); other dimensions of insight could be studied.
Our results show that schizophrenia with preserved insight is associated with greater perfusion of the precuneus, a brain area known to be involved in self- consciousness, suggesting a compensatory mechanism of fronto-temporal impairment.