Danielle Paterno

Effects of short-term inpatient treatment on sensitivity to a size contrast illusion in first-episode psychosis and multiple-episode schizophrenia

Introduction: In the Ebbinghaus illusion, a shape appears larger than its actual size when surrounded by small shapes and smaller than its actual size when surrounded by large shapes. Resistance to this visual illusion has been previously reported in schizophrenia, and linked to disorganized symptoms and poorer prognosis in cross-sectional studies. It is unclear, however, when in the course of illness this resistance first emerges or how it varies longitudinally with illness phase. Method: We addressed these issues by having first-episode psychosis patients, multiple-episode schizophrenia patients and healthy controls complete a psychophysical task at two different time points, corresponding to hospital admission and discharge for patients. The task required judging the relative size of two circular targets centered on either side of the screen. Targets were presented without context (baseline), or were surrounded by shapes that made the size judgment harder or easier (misleading and helpful contexts, respectively). Context sensitivity was operationalized as the amount of improvement relative to baseline in the helpful condition minus the amount of decrement relative to baseline in the misleading condition. Results: At hospital admission, context sensitivity was lower in the multiple-episode group than in the other groups, and was marginally less in the first episode than in the control group. In addition, schizophrenia patients were significantly more and less accurate than the other groups in the misleading and helpful conditions, respectively. At discharge, all groups exhibited similar context sensitivity. In general, poorer context sensitivity was related to higher levels of disorganized symptoms, and lower level of depression, excitement, and positive symptoms. Discussion: Resistance to the Ebbinghaus illusion, as a characteristic of the acute phase of illness in schizophrenia, increases in magnitude after the first episode of psychosis. This suggests that visual context processing is a state-marker in schizophrenia and a biomarker of relapse and recovery.

Public Mental Health Clients with Severe Mental Illness and Probable Posttraumatic Stress Disorder: Trauma Exposure and Correlates of Symptom Severity

Individuals with severe mental illness (SMI) are at greatly increased risk for trauma exposure and for the development of posttraumatic stress disorder (PTSD). This study reports findings from a large, comprehensive screening of trauma and PTSD symptoms among public mental health clients in a statewide community mental health system. In 851 individuals with SMI and probable PTSD, childhood sexual abuse was the most commonly endorsed index trauma, followed closely by the sudden death of a loved one. Participants had typically experienced an average of 7 types of traumatic events in their lifetime. The number of types of traumatic events experienced and Hispanic ethnicity were significantly associated with PTSD symptom severity. Clients reported experiencing PTSD in relation to events that occurred on average 20 years earlier, suggesting the clinical need to address trauma and loss throughout the lifespan, including their prolonged after-effects.

Is 20/20 vision good enough? Visual acuity differences within the normal range predict contour element detection and integration

Contour integration (CI) combines appropriately aligned and oriented elements into continuous boundaries. Collinear facilitation (CF) occurs when a low-contrast oriented element becomes more visible when flanked by collinear high-contrast elements. Both processes rely at least partly on long-range horizontal connections in early visual cortex, and thus both have been extensively studied to understand visual cortical functioning in aging, development, and clinical disorders. Here, we ask: Can acuity differences within the normal range predict CI or CF? To consider this question, we measured binocular visual acuity and compared subjects with 20/20 vision to those with better-than-20/20 vision (SharpPerceivers) on two tasks. In the CI task, subjects located an integrated shape embedded in varying amounts of noise; in the CF task, subjects detected a low-contrast element flanked by collinear or orthogonal high-contrast elements. In each case, displays were scaled in size to modulate element visibility and spatial frequency (4–12 cycles/deg). SharpPerceivers could integrate contours under noisier conditions than the 20/20 group (p = .0002), especially for high spatial frequency displays. Moreover, although the two groups exhibited similar collinear facilitation, SharpPerceivers could detect the central target with lower contrast at high spatial frequencies (p <. 05). These results suggest that small acuity differences within the normal range—corresponding to about a one line difference on a vision chart—strongly predict element detection and integration. Furthermore, simply ensuring that subjects have normal or corrected-to-normal vision is not sufficient when comparing groups on contour tasks; visual acuity confounds also need to be ruled out.

Visual integration dysfunction in schizophrenia arises by the first psychotic episode and worsens with illness duration.

Visual integration dysfunction characterizes schizophrenia, but prior studies have not yet established whether the problem arises by the first psychotic episode or worsens with illness duration. To investigate the issue, we compared chronic schizophrenia patients (SZs), first episode psychosis patients (FEs), and well-matched healthy controls on a brief but sensitive psychophysical task in which subjects attempted to locate an integrated shape embedded in noise. Task difficulty depended on the number of noise elements co-presented with the shape. For half of the experiment, the entire display was scaled down in size to produce a high spatial frequency (HSF) condition, which has been shown to worsen patient integration deficits. Catch trials-in which the circular target appeared without noise-were also added so as to confirm that subjects were paying adequate attention. We found that controls integrated contours under noisier conditions than FEs, who, in turn, integrated better than SZs. These differences, which were at times large in magnitude (d = 1.7), clearly emerged only for HSF displays. Catch trial accuracy was above 95% for each group and could not explain the foregoing differences. Prolonged illness duration predicted poorer HSF integration across patients, but age had little effect on controls, indicating that the former factor was driving the effect in patients. Taken together, a brief psychophysical task efficiently demonstrates large visual integration impairments in schizophrenia. The deficit arises by the first psychotic episode, worsens with illness duration, and may serve as a biomarker of illness progression. (PsycINFO Database Record

Processing of Spatial-Frequency Altered Faces in Schizophrenia: Effects of Illness Phase and Duration

Low spatial frequency (SF) processing has been shown to be impaired in people with schizophrenia, but it is not clear how this varies with clinical state or illness chronicity. We compared schizophrenia patients (SCZ, n = 34), first episode psychosis patients (FEP, n = 22), and healthy controls (CON, n = 35) on a gender/facial discrimination task. Images were either unaltered (broadband spatial frequency, BSF), or had high or low SF information removed (LSF and HSF conditions, respectively). The task was performed at hospital admission and discharge for patients, and at corresponding time points for controls. Groups were matched on visual acuity. At admission, compared to their BSF performance, each group was significantly worse with low SF stimuli, and most impaired with high SF stimuli. The level of impairment at each SF did not depend on group. At discharge, the SCZ group performed more poorly in the LSF condition than the other groups, and showed the greatest degree of performance decline collapsed over HSF and LSF conditions, although the latter finding was not significant when controlling for visual acuity. Performance did not change significantly over time for any group. HSF processing was strongly related to visual acuity at both time points for all groups. We conclude the following: 1) SF processing abilities in schizophrenia are relatively stable across clinical state; 2) face processing abnormalities in SCZ are not secondary to problems processing specific SFs, but are due to other known difficulties constructing visual representations from degraded information; and 3) the relationship between HSF processing and visual acuity, along with known SCZ- and medication-related acuity reductions, and the elimination of a SCZ-related impairment after controlling for visual acuity in this study, all raise the possibility that some prior findings of impaired perception in SCZ may be secondary to acuity reductions.

Self-Reported Visual Perceptual Abnormalities Are Strongly Associated with Core Clinical Features in Psychotic Disorders

Background Past studies using the Bonn Scale for the Assessment of Basic Symptoms (hereafter, Bonn Scale) have shown that self-reported perceptual/cognitive disturbances reveal which persons have or will soon develop schizophrenia. Here, we focused specifically on the clinical value of self-reported visual perceptual abnormalities (VPAs) since they are underexplored and have been associated with suicidal ideation, negative symptoms, and objective visual dysfunction. Method Using the 17 Bonn Scale vision items, we cross-sectionally investigated lifetime occurrence of VPAs in 21 first-episode psychosis and 22 chronic schizophrenia/schizoaffective disorder (SZ/SA) patients. Relationships were probed between VPAs and illness duration, symptom severity, current functioning, premorbid functioning, diagnosis, and age of onset. Results Increased VPAs were associated with: earlier age of onset; more delusions, hallucinations, bizarre behavior, and depressive symptoms; and worse premorbid social functioning, especially in the childhood and early adolescent phases. SZ/SA participants endorsed more VPAs as compared to those with schizophreniform or psychotic disorder-NOS, especially in the perception of color, bodies, faces, object movement, and double/reversed vision. The range of self-reported VPAs was strikingly similar between first-episode and chronic patients and did not depend on the type or amount of antipsychotic medication. As a comparative benchmark, lifetime occurrence of visual hallucinations did not depend on diagnosis and was linked only to poor premorbid social functioning. Conclusion A brief 17-item interview derived from the Bonn Scale is strongly associated with core clinical features in schizophrenia. VPAs hold promise for clarifying diagnosis, predicting outcome, and guiding neurocognitive investigations.

Relationships Between Indices of Retinal Thinning as Revealed by Spectral Domain Optical Coherence Tomography, and Visual and Cognitive Impairments in Schizophrenia

Schizophrenia is a neuropsychiatric disorder in which visual processing abnormalities are common. An unanswered question in this field is the extent to which some of these functional impairments (e.g., contrast sensitivity) may be due to altered retinal structure and function. This question has gained in importance with two recent studies showing retinal nerve fiber layer (RNFL) thinning in schizophrenia, as revealed by spectral domain optical coherence tomography (SD-OCT). OCT is a noncontact imaging technology that can image retinal structure (including thickness) in vivo with a resolution of 10 microns or less using optical backscattering of light. It has been used to document RNFL thinning in neuropsychiatric disorders such as multiple sclerosis and Parkinsons disease. A second unanswered question in the schizophrenia literature is whether retinal abnormalities can serve as markers of global brain function. Because the retina and optic nerve are outgrowths of brain tissue, they are considered part of the central nervous system, and some past OCT studies in other neuropsychiatric disorders (e.g., multiple sclerosis, Parkinsons disease) indicate that retinal tissue loss parallels cortical degeneration and cognitive decline. This has not yet been investigated in schizophrenia, however, although progressive gray and white matter loss, and cognitive decline, have been repeatedly documented, especially early in the illness. To make progress on the above questions, we are generating SD-OCT data on RNFL and macular thickness, and determining relationships with visual acuity, contrast sensitivity, perceptual organization, and global cognitive capacity (expected sample sizes of 20 patients and controls each before VSS 2015). To date, 6 of 7 schizophrenia patients have demonstrated significant RNFL and/or macular thinning compared to control norms. Moreover, extent of thinning is significantly related to illness chronicity, controlling for age, and to poorer visual acuity. Relationships between OCT findings and visual and cognitive task performance will be reported. Meeting abstract presented at VSS 2015.

7.1 ELECTRORETINOGRAPHIC ANOMALIES IN SCHIZOPHRENIA AND THEIR RELATIONSHIPS WITH RETINAL STRUCTURE, VISUAL FUNCTIONS, CLINICAL SYMPTOMS, AND MEDICAL COMORBIDITIES

Abstract Background Although several studies have documented retinal cell dysfunction in schizophrenia (Silverstein & Rosen, Scz Res: Cogn, 2015), the extent to which these abnormalities contribute to, and/or result from, other features of the condition is unclear. Thus we sought to: 1) evaluate associations between retinal signaling anomalies as measured with flash electroretinography (fERG) and previously reported changes in visual evoked potentials (VEPs), contrast sensitivity, visual acuity, and contour integration in people with schizophrenia (Silverstein, Neb Symp Motiv, 2016); 2) determine whether fERG anomalies are related to retinal structural abnormalities as indicated by optical coherence tomography (OCT); 3) examine relationships between fERG changes and psychiatric symptoms; 4) determine relationships between fERG anomalies and frequent medical comorbidities in schizophrenia that are known to affect the retina (e.g., diabetes, hypertension); and 5) examine potential medication effects on these findings. Methods We have assessed 25 patients with schizophrenia and 25 controls who are free of medical comorbidity with fERG and measures of visual function and symptom severity, and data collection is ongoing with patients and controls with diabetes and/or hypertension using these same measures. In addition, we are in the process of completing data collection with two additional groups of patients and controls, one with fERG and OCT (n=12 to date), and another with fERG and VEPs (n=13 to date). fERG data are being collected under both light- and dark-adapted conditions, using a range of flash intensities, backgrounds, and temporal frequencies. The primary fERG variables of interest are a-wave and b-wave amplitudes, which reflect photoreceptor and bipolar cell responses, respectively, and the photopic negative response (PhNR), which reflects ganglion cell activity. Results On photopic fERG tests, patients with schizophrenia demonstrated significantly weaker photoreceptor response when a flash was presented against an unlit background (p<.05), and during a steady-state flicker test (p<.005). On scotopic tests, the rate of response gain per unit of intensity increase was significantly weaker for patients than controls (p=.001). In both light- and dark-adapted conditions, patients demonstrated weaker signaling of bipolar cells (ps < .005). The schizophrenia group was also characterized by a weaker PhNR (p<.05). Weaker retinal cell responses were related to contrast sensitivity impairments in the schizophrenia group (ps < .05 and .001), but not to visual acuity or contour integration. Reduced responsiveness to low-intensity light was related to more severe negative symptoms, suggesting a reduced dynamic range within which environmental events (i.e., salience) are represented. Measures of retinal cell function were not related to antipsychotic medication dose. Preliminary findings indicate that attenuated fERG signals are not associated with weaker visual cortical responses (EEG-measured VEPs), presumably due to gain control mechanisms. We will report on the extent to which fERG anomalies are related to retinal structural changes and comorbid medical conditions. Discussion Reduced signaling of photoreceptor, bipolar, and ganglion cells are characteristics of schizophrenia, and are not related to extent of antipsychotic medication use. These changes are related to reduced contrast sensitivity and increased negative symptoms, and may reflect an attenuated ability to accurately represent changes in the intensity of environmental stimuli. Data collection is ongoing for studies examining relationships between ERG indices and VEPs and medical comorbidities.

Intact illusory contour formation but equivalently impaired visual shape completion in first- and later-episode schizophrenia.

Visual shape completion is a fundamental process that constructs contours and shapes on the basis of the geometric relations between spatially separated edge elements. People with schizophrenia are impaired at distinguishing visually completed shapes, but when does the impairment emerge and how does it evolve with illness duration? The question bears on the debate as to whether cognition declines after illness onset. To address the issue, we tested healthy controls (n = 48), first-episode psychosis patients (n = 23), and chronic schizophrenia patients (n = 49) on a classic psychophysical task in which subjects discriminated the relative orientations of four sectored circles that either formed or did not form visually completed shapes (illusory and fragmented conditions, respectively). Visual shape completion was quantified as the extent to which performance in the illusory condition exceeded that of the fragmented. Half of the trials incorporated wire edge elements, which augment contour salience and improve shape completion. Each patient group exhibited large visual shape completion deficits that could not be explained by differences in age, motivation, or orientation tuning. Patients responded normally to changes in illusory contour salience, indicating that they were forming but not adequately employing such contours for discriminating shapes. Shape completion deficits were most apparent for patients with cognitive disorganization, poor premorbid early adolescent functioning, and normal orientation discrimination. Visual shape completion deficits emerge maximally by the first psychotic episode and arise from higher-level disturbances that are related to premorbid functioning and disorganization.