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Lisa Cruz, Steven Silverstein, Danielle Paterno, Brian Keane; Self-reported visual perceptual abnormalities predict schizophrenia, poor premorbid functioning, and more severe positive symptoms: New Insights from the Bonn Scale. Journal of Vision 2017;17(10):482. doi: 10.1167/17.10.482.
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© ARVO (1962-2015); The Authors (2016-present)
Background & Methods. Past studies using the Bonn Scale for Assessment of Basic Symptoms have shown that self-reported visual perceptual abnormalities (VPAs) predict which individuals convert to schizophrenia (Klosterkötter et al., 2001). To further consider the clinical value of VPAs and the Bonn Scale, we employed the instrument to assess lifetime occurrence of VPAs within 22 chronic schizophrenia/schizoaffective disorder patients and 21 first episode psychosis patients, and probed for potential relationships with illness duration, diagnosis, age of onset, symptom severity, and premorbid functioning. Corrections for multiple comparisons were implemented with the False Discovery Rate controlling procedure (Benjamini & Hochberg, 1995). Results. VPA frequency was similar between the chronic and first episode groups, and was uncorrelated with illness duration (ps>.45). Subjects with schizophrenia/schizoaffective diagnoses (SZ/SA; n=31) endorsed more VPAs compared to those with other less severe psychotic disorders (n=12; p=.04; d=0.79). Specifically, the SZ/SA group more frequently reported double/reversed vision and abnormal perception of color, faces, body parts, and object movement (ps< .05; ds>.65). Increased overall VPAs predicted more hallucinations, delusions, and bizarre behavior (ps< .001; rs>.57) but not negative, disorganized, excited, or depressed symptoms (rs< .34; ps>.05). Increased VPAs correlated with earlier age of onset, worse sociability and ability to adapt in school, and lower ability to function well during childhood and early adolescence (ps< .05; rs>.39). Conclusion. VPAs, as assessed with 17 simple yes/no questions from the Bonn Scale, are strongly linked to positive symptoms, premorbid functioning, and a schizophrenia/schizoaffective disorder diagnosis. Surprisingly, the full gamut of abnormal visual perceptual experiences will have already been experienced by the time a person reaches the first psychotic episode. These results underscore the relevance of VPAs and the Bonn Scale for understanding schizophrenia; they also highlight the need for vision researchers to document and explain the visual perceptual changes that accompany the disorder.
Meeting abstract presented at VSS 2017
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