Cognition-UPSA score relationships: a further analysis of Silverstein et al. (2010) data and some caveats.

Silverstein et al. (2010) reported correlations between scores on the UCSD Performance-Based Skills Assessment (UPSA) and scores on two cognitive test batteries (MATRICS Consensus Cognitive Battery and IntegNeuro) that were lower than those reported in past studies. The large sample size of that 4-site study (155 patients with schizophrenia) allowed for further analyses of the data to explore the reasons for the discrepancy. We examined the data from Silverstein et al. (2010) to determine if the correlation values obtained were affected by UPSA scoring method, site differences, patient level of functioning, range restriction, missing data, and/or whether data from the first or second administration of each cognitive test battery were used. Results indicate that the overall lower cognition-UPSA correlations were a function of a single site with unusually low correlations. However, the low correlations at this site were not a function of any of the potential causes we examined. Correlations at the other sites were close to or within the range reported in past studies. Interestingly, the correlation between IntegNeuro and UPSA composite scores was higher at Time 2, suggesting that cognition-UPSA correlations are affected by familiarity with the computerized test format.

Perceptual organization and visual search processes during target detection task performance in schizophrenia, as revealed by fMRI.

BACKGROUND: Past studies of perceptual organization in schizophrenia have demonstrated impairments binding fragmented stimulus components into unified representations. ERP and fMRI data indicate that even under conditions of adequate behavioral task performance, significant and meaningful changes in cortical and subcortical activation are present. Here, we examined, using fMRI, activation differences on a visual task wherein feature grouping was a precursor to the formation of distinct groups in the service of target location and identification. METHOD: Fourteen schizophrenia patients and 16 healthy controls completed a target detection task with 2 conditions: one in which target-distractor grouping facilitates detection (the Isolated condition) and one in which it hinders detection (the Embedded condition). Stimuli were blocked by condition. Accuracy and RT data were obtained in addition to fMRI data. RESULTS: Patients and controls did not differ significantly in accuracy or RT in either condition. Within this context, controls demonstrated greater recruitment of brain regions involved in visual-spatial processing, and the groups differed in activity in areas known to support visual search, visual analysis, decision making and response generation. CONCLUSION: These findings are consistent with past data indicating reduced processing of stimulus organization, and the subsequent use of inefficient visual search strategies, even under conditions when behavioral performance is at a high level and matches that of healthy controls.

FMRI indices of auditory attention in schizophrenia.

The present study sought to identify abnormalities in activation in several brain regions in response to an auditory attention task in patients with schizophrenia. Ten patients and twenty healthy control participants were examined using Functional Magnetic Resonance Imaging (FMRI) measures acquired during an auditory attention task. Region of interest analyses of activation of targeted regions implicated in attention included: anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), hippocampus, parahippocampal gyrus (PHG), and superior temporal gyrus (STG). The results indicated over-activation in patients with schizophrenia. While the control group showed notable coherence in activation within and across hemispheres the schizophrenia group showed relatively less coherence overall that was only present in the right hemisphere. These findings suggest that patients with schizophrenia show both an over-engagement of brain regions during attention task as well as a lack of communication among neural regions involved.