Search

Background: Electrophysiological impairments in the magnocellular visual system have been reported among patients with schizophrenia, but previous theories proposed that these deficits may begin in the retina. We therefore sought to evaluate the potential contribution of the retina by comparing retinal and cortical visual electrophysiological impairments between patients with schizophrenia and healthy controls., Methods: We recruited patients with schizophrenia and age- and sex-matched healthy controls. We recorded the P100 amplitude and latency using electroencephalography (EEG) while projecting low (0.5 cycles/degree) or high (15 cycles/degree) spatial frequency gratings at a temporal frequency of 0 Hz or 8 Hz. We compared the P100 results with previous results for retinal ganglion cell activity (N95) in these participants. We analyzed data using repeated-measures analysis of variance and correlation analyses., Results: We recruited 21 patients with schizophrenia and 29 age- and sex-matched healthy controls. Results showed decreased P100 amplitude and increased P100 latency among patients with schizophrenia compared with healthy controls ( p < 0.05). Analyses reported the main effects of spatial and temporal frequency but no interaction effects of spatial or temporal frequency by group. Moreover, correlation analysis indicated a positive association between P100 latency and previous retinal results for N95 latency in the schizophrenia group ( p < 0.05)., Discussion: Alterations in the P100 wave among patients with schizophrenia are consistent with the deficits in early visual cortical processing shown in the literature. These deficits do not seem to correspond to an isolated magnocellular deficit but appear to be associated with previous retinal measurements. Such an association emphasizes the role of the retina in the occurrence of visual cortical abnormalities in schizophrenia. Studies with coupled electroretinography-EEG measurements are now required to further explore these findings., Clinical Trials Registration: https://clinicaltrials.gov/ct2/show/NCT02864680., Competing Interests: Competing interests: Vincent Laprévote reports travel support from Boehringer Ingelheim France and Janssen-Cilag. No other competing interests were declared., (© 2023 CMA Impact Inc. or its licensors.)

Background: Retinal dysfunction is widely documented in schizophrenia using flash (fERG) and pattern electroretinograms (PERG), but the role of dopamine transmission has seldom been explored., Methods: We explored the role of dopamine transmission by evaluating the spatial location of retinal anomalies using multifocal ERG (mfERG) in photopic condition and the oscillatory potentials (OPs) extracted from fERG measured in scotopic condition in 29 patients with schizophrenia and 29 healthy controls., Results: With the mfERG, our main results revealed reduced amplitudes in the center of the retina: P1 (p < .005) and N2 amplitudes (p < .01) in the <2° region, N1 (p < .0005) and P1 amplitudes (p < .001) in the 2-5° region and P1 amplitude (p < .05) in the 5-10° region. For OPs, our results showed a decrease in the O1 (p < .005), O2 (p < .005), O3 (p < .05) and overall O1, O2, O3 index amplitudes (p < .005) in patients with schizophrenia., Conclusions: Both the central location of retinal dysfunctions of the mfERG and OPs results could reflect a hypodopaminergic effect in patients with schizophrenia. In future studies, OPs should be considered as a measure to evaluate the hypodopaminergy in patients., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aim: Psychosis can be preceded by a clinical high risk for psychosis (CHR) and visual anomalies are predictors of transition to psychosis. Visual retinal processing is altered in psychosis, but no study has explored the links between visual symptoms and retinal functions in CHR patients. We report here the case of NR, an antipsychotic-naive young adult with CHR and severe visual symptoms in whom we explored the retinal function., Methods: A flash electroretinogram (fERG) and a pattern electroretinogram (pERG) protocol were conducted and we compared NR results to a group of patients with schizophrenia and a group of healthy controls., Results: Despites an overlap between the measures of NR and the two groups, visual analyses revealed that NR showed increased b-wave implicit time (rod response) compared to the control group and NR's response was at an intermediate level between two subgroups of schizophrenia patients regarding presence or absence of visual hallucinations., Discussion: The relevance of retinal dysfunctions as a marker of vulnerability for psychosis is discussed., (© 2020 John Wiley & Sons Australia, Ltd.)

Patients with schizophrenia have altered visual cognition and retinal functions. No studies have explored if retinal anomalies are related to visual cognition and the presence of visual hallucinations (VH). We explored functional responses of the retinal ganglion cells in schizophrenia patients with or without VH and conducted a neuropsychological evaluation to explore the links between cognition and retinal function. The VH+ group showed poorer visual cognition and we found correlations between the amplitudes of the P50 and the N95 waves and visual cognition. Our results provide arguments for a link between retinal dysfunction, impaired visual processing and VH in schizophrenia., (Copyright © 2021. Published by Elsevier B.V.)

The electroretinogram has revealed photoreceptor, bipolar cell, and, in one prior study, retinal ganglion cell (RGC) dysfunction in schizophrenia. The structural abnormalities of the RGC are well documented in schizophrenia and such abnormalities have been associated with visual hallucinations (VH) in neurological disorders. The goals of this study were: 1) to examine the functional responses of photoreceptors and RGC in schizophrenia patients in comparison with healthy controls; and 2) to compare the extent of retinal dysfunction in schizophrenia patients with or without VH. We recorded the flash electroretinogram in scotopic and photopic conditions, and the pattern electroretinogram, in schizophrenia patients (n = 29) and healthy controls (n = 29). Schizophrenia patients were divided in two groups: schizophrenia patients with VH (VH group, n = 12) and schizophrenia patients with auditory hallucinations or no hallucinations (AHNH group, n = 17). Our results replicate previous findings regarding photoreceptor dysfunction in schizophrenia. PERG results showed a significant increase of the P50 implicit time in schizophrenia patients compared with controls (t(55) = 2.1, p < .05, d = 0.55) and a significant increase of the N95 implicit time in schizophrenia patients compared with controls (t(55) = 4.2; p < .001, d = 0.66). We found an increased rod b-wave implicit time (dark-adapted 0.01 ERG) in the VH group compared to the AHNH group and to the control group, which was associated with lifetime VH score. Our results demonstrate a slowing of RGC signaling in schizophrenia patients, which could affect the quality of visual information reaching the visual cortex. The implications of the data for understanding VH in schizophrenia are discussed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Chronic psychosis, as for instance schizophrenia, usually begins in young adulthood and may cause severe disability. It causes a mean loss of life expectancy of 22 years. Actual models of psychosis do not trace the beginning of psychosis to the first franc psychotic episode only, but to earlier symptoms. In a classical health system only considering the first psychotic episode, the mean duration of untreated illness (DUI) can last several years. Yet this DUI has a direct impact on the prognosis of the disease. Actual international recommendations prescribe to early detect and treat at risk mental states of psychosis, thus reducing DUI. Such an attitude also helps the patient to integrate care in a moment where she/he is fully in condition to consent and to adhere. Generalist practitioners are crucial actors of early detection. We describe here simple and standardized tools helping early detection of high-risk mental states of psychosis in primary care and the appropriate attitude to do it properly. Numerous countries have developed early detection and treatment centers for psychosis. It has been established that such interventions clearly decrease the risk of transition towards chronic psychosis and improve the prognosis. These recent data about early detection and intervention in psychosis are a major step forward in psychiatry practice. It is now necessary to largely develop such actions in France., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Visual hallucinations are a psychotic symptom present in numerous clinical conditions such as eye disease, Parkinsonian syndromes, neurodegenerative disorders and psychosis. Alteration of low level visual processing is a common feature in these clinical conditions, and various stages of processing from the retina to visual cortices are involved. We undertook a literature review of abnormalities of the retina and their potential link with the occurrence of VHs in these clinical conditions of interest. We found that structural and functional abnormalities of the retina are frequently present. In Parkinson disease and eye disease, VHs have been related to dysfunctions of the retina. By contrast, in neurodegenerative disorders and psychosis, possible links have yet not been explored. We show that structural or functional abnormalities of the retina are given little consideration in cognitive models of VHs, which primarily postulate an alteration of sensory visual processing and a top-down attentional process. We conclude that contrast sensitivity measures and an exhaustive exploration of the retinal functions using the clinical electroretinography standards of the International Society for the Clinical Electrophysiology of Vision (ISCEV) are needed to explore retinal involvement in the occurrence of visual hallucinations. [ABSTRACT FROM AUTHOR]

The authors reflect on the study by F. Güell and J. Bernácer on sense organs' anatomical constitution as a mental disorder marker. The study reportedly involved an examination of the relevance of visual perception in mental illnesses including schizophrenia. They argue that pattern electroretinogram can offer a complementary measurement to gain a deeper understanding of schizophrenia's underlying brain disorders.

Background: Structural and functional retinal anomalies are documented in neurologic, substance use and psychiatric disorders. In schizophrenia, flash electroretinogram (fERG) measures have revealed photoreceptors, bipolar cells and retinal ganglion cells (RGC) dysfunctions. To date, no study has explored RGC using a pattern electroretinogram (pERG) protocol as recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV) standards for RGC measurements. We aim to study retinal functional responses of the photoreceptors and RGC in schizophrenia patients in comparison with healthy controls. Methods: fERG conducted in scotopic (dark-adapted 0.01 and dark-adapted 3.0 ERG) and photopic conditions (light-adapted 3.0 ERG) and pERG were recorded in schizophrenia patients (n=29) and healthy controls (n=29). PERG provides the measurements of 2 waves: the P50 wave which arises in RGC with a contribution of bipolar cells and relates to the spatial distribution and density of the RGC bodies and the N95 wave which represents ganglion cell activity. Results: fERG results showed a decrease in the b-wave amplitude (t(51)=- 3.4, p<.05, d=0.63) (dark-adapted 0.01 ERG), a-wave amplitude (t(48)=4.7, p<.001, d =1.33) (dark-adapted 3.0 ERG), b-wave amplitude (t(48)=-2.8, p<.005, d=0.78) (dark-adapted 3.0 ERG), a-wave amplitude (t(52)=2.8, p<.001, d=0.29) (light-adapted 3.0 ERG) in schizophrenia patients compared to controls. We found as well a significant decrease of the a-wave implicit time (t(52)=-2.5, p<.05, d =1.19) (light-adapted 3.0 ERG) in schizophrenia patients compared to controls. pERG results showed a significant increase of the P50 (t(55)=2.1, p<.05, d=0.55) and a significant increase of the N95 implicit time in schizophrenia patients compared with controls (t(55)=4.2; p<.001, d=0.66). Discussion: Our results replicate previous findings regarding photoreceptors and bipolar cells dysfunction in schizophrenia patients. pERG results demonstrate a delay in transmission of action potentials by the ganglion cells along the visual pathway via the optic nerve and the lateral geniculate nucleus to the visual cortex in schizophrenia patients which could support alterations in cerebral visual processing in schizophrenia. [ABSTRACT FROM AUTHOR]

Background Patients with schizophrenia are abnormally disturbed by information onsets, which may result in a disadvantage in filtering relevant information. The paradigm of change blindness offers the interesting possibility of studying sensitivity to the sudden irruption of visual information with ecological stimuli in schizophrenia. An increased attentional capture by the irruption of visual information would suggest better performance in patients than in healthy controls. This approach has the advantage of circumventing a non-specific general attentional deficit in schizophrenia. Methods Sixteen patients with schizophrenia and 16 healthy controls were asked to detect changes in 99 scenes with 0, 1 or 3 changes. We measured the participants' speed and accuracy in explicitly reporting the changes via motor responses and their capacity to implicitly detect changes via eye movements. Results Although the controls were faster and more efficient in explicitly reporting changes, the patients' eyes shifted more quickly toward the changes. Regardless of the group, increasing the magnitude of change improved the performance. Conclusions The better capacity of the patients to shift their eyes toward changes confirmed the capture by the sudden irruption of visual information in schizophrenia while avoiding the effects of general attentional deficits. However, the striking dissociation between this implicit response and the capacity to explicitly report changes could be interpreted as a deficit in access to conscious perception. [ABSTRACT FROM AUTHOR]