A developmental look at the attentional system in the at risk and first episode of psychosis: age related changes in attention along the psychosis spectrum.

INTRODUCTION: Neurodevelopmental processes of adolescence, when superimposed on a vulnerable brain, may produce additive effects reflecting the subthreshold psychotic symptoms, cognitive, and functional deterioration that are the hallmark of the early stages of schizophrenia. METHODS: As part of a longitudinal study, we investigated Continuous Performance Task, Identical Pairs Version (CPT-IP) performance in a sample of 301 participants (at risk for psychosis: 109; first episode-FE: 90; and controls: 102). Performance across groups was compared using d' of fast and slow, spatial and verbal conditions over two time points. Age effects were investigated using a regression model. RESULTS: Across all four CPT-IP conditions FE patients performed significantly worse than controls while AR individuals significantly differed from healthy subjects in the verbal condition. Age-related performance associations across groups significantly differed in the slow verbal condition because the FE sample did not show a significant association with increasing age like the AR and NC samples. CPT performance was stable over time. CONCLUSIONS: Sustained attention in the putative prodrome of psychosis is not only impaired but associated with age. Research focusing on cognitive and neurobiological age-related changes can help to address fundamental questions about the nature of the disorder, including whether the underlying pathophysiology of early psychosis is static or deteriorating.

P50 suppression in individuals at risk for schizophrenia: the convergence of clinical, familial, and vulnerability marker risk assessment.

BACKGROUND: Identification of individuals at risk for the development of schizophrenia is important because it can lead to a greater understanding of the early stages of the illness. The aim of the present study was to determine whether individuals "at risk" for schizophrenia have deficits in P50 suppression, a preattentive measure of sensory gating. METHODS: Thirty-one at-risk and 21 normal comparison subjects were referred to the CARE (Cognitive Assessment and Risk Evaluation) Program at University of California San Diego. The primary aim of the CARE Program is to identify individuals who are at the greatest risk for conversion to psychosis, with a combination of clinical, familial, and vulnerability markers, including P50 suppression. RESULTS: As a group, the at-risk subjects had modestly lower levels (effect size=.43) of P50 suppression (55.1%, SD=39.8) relative to comparison subjects (71.5%, SD=34.7). At-risk subjects with a first-degree relative with schizophrenia had profoundly deficient P50 suppression (16.4%, SD=33.8) compared with other at-risk (p<.05) and comparison subjects (p<.005). CONCLUSIONS: Ongoing longitudinal follow-up studies will determine whether it is possible to improve the predictive validity of the clinical and familial variables by using P50 suppression alone or in combination with other measures in determining which individuals are at greatest risk for schizophrenia.

The relationship between central corneal thickness-adjusted intraocular pressure and glaucomatous visual-field loss.

BACKGROUND: Although measurement of central corneal thickness (CCT) is increasingly becoming an important component of glaucoma risk analysis, significant controversy exists regarding the benefit of calculating a corrected intraocular pressure (IOP) value from measured IOP and CCT data. METHODS: Three hundred forty-four male subjects were identified from a VA eye clinic with one of the following clinical diagnoses: ocular hypertension (OHT), primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and normal tension glaucoma suspect (NTGS). Using one eye per subject, multivariate logistic regression and correlational analyses were performed to determine relationships between glaucomatous visual-field loss and several glaucoma risk factors, including adjusted IOP values. RESULTS: Multivariate logistic regression analysis did not identify CCT-adjusted IOP values as independent risk factors for development of either NTG or POAG-related glaucomatous visual-field loss. CCT, however, was found to be strongly associated with both NTG and POAG-related visual-field loss. Correlational analysis revealed a weak correlation between Ehlers-adjusted pre-treatment IOP and severity of POAG-related visual-field loss, but no other adjusted IOP values significantly correlated with severity of visual-field loss in either POAG or NTG. CONCLUSIONS: Our results suggest that adjusted IOP, as calculated using current algorithms, is not useful within glaucoma risk analysis, since adjusted IOP was unable to predict either presence or severity of glaucomatous visual-field loss in this study. CCT, conversely, was found to be a robust and independent predictor of glaucomatous visual-field loss. These findings, while supporting routine CCT measurements for all glaucoma suspects, do not support routine clinical computation of adjusted IOP values using current algorithms.

Lateralized perceptual organization deficits on the global-local task in schizotypal personality disorder.

Right and left hemisphere contributions to perceptual organization functions were examined using a divided-attention version of the global-local task in a sample of 21 unmedicated participants diagnosed with schizotypal personality disorder (SPD) and 20 controls. The SPD participants showed an abnormal global processing advantage. When the visual angle of the hierarchical stimuli was increased from 3 degrees to 9 degrees, the controls showed an increasing local processing advantage, but the SPD participants continued to show an abnormal global processing advantage. These findings suggest a local processing deficit on divided-attention versions of the global-local task in schizophrenia spectrum disorders. Female SPD participants, who had less severe interpersonal deficit symptoms, showed a more abnormal global processing advantage. Hemispheric and processing resource mechanisms that might explain these findings are discussed.