Optimization and Validation of a Visual Integration Test for Schizophrenia Research

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Abstract
The Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia initiative highlighted a contour integration test as a promising index of visual integration impairment because of its well-established psychometric properties; its prior validation in healthy adults, patients, and nonhuman primates; and its potential sensitivity to treatment effects. In this multisite study, our goals were to validate the task on the largest subject sample to date, clarify the task conditions and number of trials that best discriminate patients from controls, and determine whether this discrimination can occur in standard clinical trial settings. For our task, subjects briefly observed a field of disconnected, oriented elements and attempted to decide whether a subset of those elements formed a leftward- or rightward-pointing shape. Difficulty depended on the amount of orientational jitter that was added to the shape's elements. Two versions of this Jittered Orientation Visual Integration task (JOVI) were examined. Study 1 did not reveal between-group differences in threshold (ie, the jitter magnitude needed to reach a performance level of ∼80%), but this likely owed to the wide sampling distribution of jitter levels and resulting floor/ceiling effects in many conditions. Study 2 incorporated a narrower range of difficulty levels and revealed lower thresholds (worse performance) among patients (p < .001). This group difference remained even when only the first half of the trials was analyzed (p = .001). Thus, the JOVI-2 provides a brief, sensitive measure of visual integration deficits in schizophrenia. Neural implications and potential future applications of the JOVI are discussed.