The Clinical Translation of a Measure of Gain Control: The Contrast-Contrast Effect Task

Abstract

The goal of the current project was to further develop a measure of gain control-the Contrast-Contrast Effect (CCE)-for use in clinical studies of schizophrenia. The CCE is based on an illusion in which presenting a medium contrast patch surrounded by a high-contrast patch induces individuals to perceive that center patch as having lower contrast than when the patch is presented in isolation. Thus, in the CCE, impaired gain control should lead to more accurate perceptions of the center patch. We tested 132 individuals with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, schizophrenia or schizoaffective disorder and 130 demographically similar healthy controls. The results indicated that the CCE effect can be obtained with standard equipment, simplified scoring, and a short interstimulus interval (100 ms), revealing a robust suppression of perceived contrast of the center patch when surrounded by a high-contrast annulus. Furthermore, we found a significant reduction in the effect of the high-contrast surround among individuals with schizophrenia, though the effect size was smaller than original reported by Dakin. However, when we eliminated subjects who performed poorly on ''catch'' trials that controlled for off-task performance, the reduced surround effect among patients was no longer significant in the main analyses. Importantly, this suggests that at least part of the reduced surround effect (if not all) in schizophrenia could be attributable to impaired attentional mechanisms that contribute to off-task performance. Additional analyses suggested that the length of the task could be shortened without losing power to detect surround effects in healthy individuals.

Clinical, Functional, and Intertask Correlations of Measures Developed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia Consortium

“…That is, one could observe this pattern of results if the tasks were all highly unreliable, a possibility that is unlikely given the reliability data presented in the prior papers for each of the tasks. [6][7][8][9] It is noteworthy that the RISE and DPX demonstrated minimal correlations with one another, even though both are thought to depend, in part, on the DLPFC. In the RISE, relational processing is thought to depend on higher order strategic encoding processes that require the DLPFC as shown in previous imaging studies.…”

“…In addition, we focused on the version of each task that was deemed to be the most ''optimal'' based on the analyses presented in the cases where more than one version of the task was evaluated (see Henderson et al, 6 Barch et al, 7 Silverstein et al, 8 and Ragland et al 9 for discussion of task optimization). Thus, for the RISE, we used the visual object version and focused on recognition D# scores for items encoded in the Item Encoding condition (D'-IRIE), for items encoded in the Relational Encoding condition (D'-IRRE), and for Relational Recognition (D'-RR).…”

“…The tasks are briefly described in table 1 which also provides the web site URL that can be used to download the tasks (see also Henderson et al, 6 Barch et al, 7 Silverstein et al, 8 and Ragland et al 9 for task details). The procedures and order of testing are described in detail in the first article in this set of articles.…”

“…The four other articles on each of the individual tasks report on measures of internal consistency that suggest atleast reasonable reliability for the CNTRACSmeasures,reducingthelikelihood that ourfindings are explained on this basis. [6][7][8][9] However, the results of the ongoing study on test-retest reliability will be necessary in order to more fully compare the reliability of the CNTRACS measures to measures from neuropsychological batteries. Lastly, it is also possible that the use of SLOF informant reports presented some challenges to assessing functional outcome.…”

“…5 These tasks were then tested in a multisite study with large samples of schizophrenia patients and healthy controls. The results for each of these measures were described in the 4 other articles accompanying this article [6][7][8][9] (see also table 1). Here, we present an analysis of intertask, clinical, and functional correlates of these 4 tasks.…”