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Representative pattern-reversal VEPs and PERGs in the affected (a, c) and fellow (b, d) eyes in a patient with non-acute optic neuritis (Subject 1; a, b) and in an elderly patient with a severe non-arteritic anterior ischemic optic neuropathy (Subject 2; c, d). The P100 component of the pattern VEP in optic neuritis shows a 35-ms delay compared with the normal fellow eye, without significant amplitude reduction, consistent with optic nerve conduction delay; pattern ERGs are normal in this case and reveal no evidence of macular or retinal ganglion cell dysfunction. The pattern VEP P100 component in c is undetectable, and PERG shows a reduced N95:P50 ratio and shortening of P50 peak time (inter-ocular difference 7 ms) compared with the fellow eye, indicating severe optic nerve dysfunction with retinal ganglion cell involvement. Two responses for each stimulus condition are superimposed to illustrate reproducibility
Source publication
Clinical electrophysiological testing of the visual system incorporates a range of noninvasive tests and provides an objective indication of function relating to different locations and cell types within the visual system. This document developed by the International Society for Clinical Electrophysiology of Vision provides an introduction to stand...
Citations
... Electrodiagnostic procedures are commonly performed according to the published standards and guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV; available at www.ISCEV.org), to facilitate meaningful interpretation and interlaboratory communication. Detailed descriptions of standardised methods [1][2][3][4][5] and common clinical applications including those for retinal disease [6] are beyond the scope of this review, but the main tests are outlined below. ...
... The P50 component is closely dependant on macular cone system function but is largely generated by retinal ganglion cell (RGC) activity (approximately 70% contribution) and partly in more anterior retinal structures such as the bipolar cells (approximately 30%) [7]. Despite the major RGC contribution, the PERG P50 component has a well-established clinical value in the assessment of macular cone system function [6,8]. The N95 component originates wholly in the RGCs and the N95:P50 ratio provides a clinically useful measure of RGC function. ...
This article describes the main visual electrodiagnostic tests relevant to neuro-ophthalmology practice, including the visual evoked potential (VEP), and the full-field, pattern and multifocal electroretinograms (ffERG; PERG; mfERG). The principles of electrophysiological interpretation are illustrated with reference to acquired and inherited optic neuropathies, and retinal disorders that may masquerade as optic neuropathy, including ffERG and PERG findings in cone and macular dystrophies, paraneoplastic and vascular retinopathies. Complementary VEP and PERG recordings are illustrated in demyelinating, ischaemic, nutritional (B12), and toxic (mercury, cobalt, and ethambutol-related) optic neuropathies and inherited disorders affecting mitochondrial function such as Leber hereditary optic neuropathy and dominant optic atrophy. The value of comprehensive electrophysiological phenotyping in syndromic diseases is highlighted in cases of SSBP1- related disease and ROSAH (Retinal dystrophy, Optic nerve oedema, Splenomegaly, Anhidrosis and Headache). The review highlights the value of different electrophysiological techniques, for the purposes of differential diagnosis and objective functional phenotyping.
... PERG recording was conducted following the recommendations of the International Society for Clinical Electrophysiology of Vision (ISCEV) [18,44] using the EP2000 acquisition module [45] for stimulation and recording. Corneal DTL electrodes [46] were positioned along the lower eyelid with contact to the cornea for recording. ...
The electroretinogram (ERG), a non-invasive electrophysiological tool used in ophthalmology, is increasingly applied to investigate neural correlates of depression. The present study aimed to reconsider previous findings in major depressive disorder (MDD) reporting (1) a diminished contrast sensitivity and (2) a reduced patten ERG (PERG) amplitude ratio, and additionally, to assess (3) the photopic negative response (PhNR) from the flash ERG (fERG), with the RETeval® device, a more practical option for clinical routine use. We examined 30 patients with a MDD and 42 healthy controls (HC), assessing individual contrast sensitivity thresholds with an optotype-based contrast test. Moreover, we compared the PERG ratio, an established method for early glaucoma detection, between both groups. The handheld ERG device was used to measure amplitudes and peak times of the fERG components including a-wave, b-wave and PhNR in both MDD patients and HCs. MDD patients exhibited diminished contrast sensitivity together with a reduced PERG ratio, compared to HC. With the handheld ERG device, we found reduced a-wave amplitudes in MDD, whereas no significant differences were observed in the fERG b-wave or PhNR between patients and controls. The reduced contrast sensitivity and PERG ratio in MDD patients supports the hypothesis that depression is associated with altered visual processing. The findings underscore the PERG’s potential as a possible objective marker for depression. The reduced a-wave amplitude recorded with the RETeval® system in MDD patients might open new avenues for using handheld ERG devices as simplified approaches for advancing depression research compared to the PERG.
... T HE full-field electroretinogram (ERG) is the waveform recorded from the eye under dark-or light-adapted (DA or LA) conditions in response to a brief flash of light. Clinically, the ERG waveform can be used for the diagnosis of conditions affecting the retina, such as inherited or acquired diseases [1]. Because the retina is an extension of the central nervous system (CNS), and its function is readily accessible through the ERG, several studies have investigated changes in the ERG waveform in conditions affecting the CNS in human and animal studies [2]. ...
... The shape of the ERG waveform depends on the state of retinal adaptation with the DA-and LA-ERG responses dominated by rod and cone pathways, respectively [1], [6]. The main excitatory neurotransmitter of the retina is glutamate, which contributes to the main positive b-wave generated by the bipolar cells [7]. ...
... Fig.1 shows an LA-ERG signal waveform of a control subject used in this study. By analyzing the parameters of the ERG waveform, such as the amplitude of the a-and b-waves (Va, Vb) and their respective time to peaks (Ta, Tb), clinicians can identify abnormalities that help diagnose a range of retinal disorders [1]. Fig.2 illustrates a further series of representative LA-ERG waveforms at four flash strengths: -0.367, 0.114, 0.799, and 1.204 (log cd.s.m −2 ), for an ASD and control participant. ...
The electroretinogram (ERG) is a clinical test that records the retina’s electrical response to a brief flash of light as a waveform signal. Analysis of the ERG signal offers a promising non-invasive method for studying different neurodevelopmental and neurodegenerative disorders. Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by poor communication, reduced reciprocal social interaction, and restricted and/or repetitive stereotyped behaviors that should be detected as early as possible to ensure timely and appropriate intervention to support the individual and their family. In this study, we applied gated Multilayer Perceptron (gMLP) for the light-adapted ERG waveform classification as an effective alternative to Transformers. In this first reported application of this model to ASD classification which consisted of basic multilayer perceptrons, with fewer parameters than Transformers. We compared the performance of different time-series models on an ASD-Control dataset and found that the superiority of gMLP in classification accuracy was the best at 89.7% compared to alternative models and supports the use of gMLP in classification models based on ERG recordings involving case-control comparisons.
... p.(lle80Thr) variant. Furthermore, it has been shown that a murine strain with dominant retinal degeneration carried a large inversion on chromosome 4 causing the inactivation of Gnb1 [14]. We report here the second case ever described of a person with rod-cone dystrophy, who also presented mild intellectual disability, ADHD, truncal obesity and a heterozygous mutation in GNB1, confirming the involvement of this gene in hereditary retinal diseases. ...
... Color fundus photographs, short wavelength fundus autofluorescence, enhanced depth imaging spectral-domain optical coherence tomography, functional examinations such as visual field test and ffERG were carried out. The investigations were mostly performed in accordance with the ERG standards of the International Society of Clinical Electrophysiology of Vision (ISCEV) [14]. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. ...
b> Introduction: The GNB1 (guanine nucleotide-binding protein, β1) gene encodes for the ubiquitous β1 subunit of heterotrimeric G proteins, which are associated with G-protein-coupled receptors (GPCRs). GNB1 mutations cause a neurodevelopmental disorder characterized by a broad clinical spectrum. A novel variant has recently been confirmed in a case of rod-cone dystrophy. Case Presentation: We describe the second confirmed case of a classical rod-cone dystrophy associated with a mutation located in exon 6 of GNB1 [NM_002074.5:c.217G>C, p.(Ala73Pro)] in a 56-year-old patient also presenting mild intellectual disability, attention deficit/hyperactivity disorder, and truncal obesity. Conclusion: This paper confirms the role of GNB1 in the pathogenesis of a classic rod-cone dystrophy and highlights the importance of including this gene in the genetic analysis panel for inherited retinal diseases.
... These include Standards for full-field ERG testing [2], multifocal electroretinography (mfERG) [3], electro-oculography [4] and visual evoked potentials (VEP) [5]. There is also a guideline for calibration and verification of stimuli and recordings instruments for use in clinical electrophysiology [6]; a guide to visual electrodiagnostic procedures which highlights the typical clinical applications of all ISCEV standard tests including the PERG [7]. In addition, extended protocols are published and may be indicated for enhanced or supplementary characterization. ...
... The N95 component or N95:P50 amplitude can be used as an indicator of macular RGC function. In severe or chronic retinal ganglion cell dysfunction, there may be P50 reduction, but in such circumstances P50 often shortens in peak time, reflecting loss of the retinal ganglion cell contribution to P50 [7]. ...
... The PERG is a contrast-dependent response and assesses both macular cone and RGC function, and although both mfERG and PERG require good patient compliance, small fixation errors have a greater impact on the quality of mfERGs due to eccentricity-dependent scaling factors [3] and smaller responses (each derived from a far smaller area than the standard checkerboard). The application of PERG and mfERG in clinical practice, with specific examples including advantages and disadvantages, is further described in the ISCEV guide to visual electrodiagnostic procedures [7].The photopic negative response of the full-field ERG may also be used to assess RGC activity [13] but reflects global function rather than the more localized central retinal area assessed by the PERG, the latter more sensitive to optic nerve disorders that preferentially or selectively involve the papillomacular bundle. ...
The pattern electroretinogram (PERG) is a localized retinal response evoked by a contrast-reversing pattern, usually a black and white checkerboard, which provides information about macular and retinal ganglion cell function. This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV; www.iscev.org) presents an updated and revised Standard for clinical PERG testing. This replaces the 2013 and all earlier versions. Minimum protocols for basic PERG stimuli, recording methods and reporting are specified, to promote consistency of methods for diagnosis and monitoring purposes, while responding to evolving clinical practices and technology. The main changes in the updated ISCEV Standard for clinical PERG include expanded guidance about large stimulus fields, stimulus parameters for simultaneous PERG and pattern visual evoked potential recording, baseline drift correction, and use of consistent ambient room lighting. These changes aim to provide a clinically relevant document about current practice which will facilitate good quality recordings and inter-laboratory comparisons.
... In addition to the structural examination with optical coherence tomography (OCT), visual electrophysiology plays an important role in the assessment of retinal integrity in LHON. Typically, affected LHON patients show abnormal pattern-reversal visual evoked potential (VEP) and pattern electroretinogram (PERG) with abnormal N95 amplitude or N95/P50 amplitude ratio and shortening of P50 peak time, revealing the primary dysfunction of RGCs [12][13][14][15][16][17]. The a-wave and the b-wave of the standard (ISCEV) full-field flash ERG may be classified as normal or slightly reduced in LHON patients [16,18]. ...
Purpose
Leber hereditary optic neuropathy (LHON) affects retinal ganglion cells causing severe vision loss. Pattern electroretinogram and photopic negative response (PhNR) of the light-adapted (LA) full-field electroretinogram (ERG) are typically affected in LHON. In the present study, we evaluated dark-adapted (DA) and LA oscillatory potentials (OPs) of the flash ERG in genetically characterized LHON patients to dissociate slow from fast components of the response.
Methods
Seven adult patients (mean age = 28.4 ± 5.6) in whom genetic diagnosis confirmed LHON with mtDNA or nuclear DNAJC30 (arLHON) pathogenic variants were compared to 12 healthy volunteers (mean age = 35.0 ± 12.1). Full-field ERGs were recorded from both eyes. Offline digital filters at 50, 75 and 100 Hz low cutoff frequencies were applied to isolate high-frequency components from the original ERG signals.
Results
ERG a-waves and b-waves were comparable between LHON patients and controls, while PhNR was significantly reduced (p = 0.009) in LHON patients compared to controls, as expected. OPs derived from DA signals (75 Hz low cutoff frequency) showed reduced peak amplitude for OP2 (p = 0.019). LA OP differences between LHON and controls became significant (OP2: p = 0.047, OP3: p = 0.039 and OP4: p = 0.013) when the 100 Hz low-cutoff frequency filter was applied.
Conclusions
Reduced OPs in LHON patients may represent disturbed neuronal interactions in the inner retina with preserved photoreceptoral (a-wave) to bipolar cell (b-wave) activation. Reduced DA OP2 and high-cutoff LA OP alterations may be further explored as functional measures to characterize LHON status and progression.
... ERG can inform about subtle changes long before any structural alterations can be detected using images. Nevertheless, its application which consists of exposing the subject to a series of specific light flash protocols can be time-consuming, often requires dark adaptation and sometimes mydriasis, and is not recommended for DME detection [43], even though patients with DME showed alterations in some ERG parameters [44]. In this context, the predictive power of 5-min photopic ERGs in the absence of any light flash demonstrated by our data is a huge improvement. ...
Diabetic Macular Edema (DME) is the most common sight-threatening complication of type 2 diabetes. Optical Coherence Tomography (OCT) is the most useful imaging technique to diagnose, follow up, and evaluate treatments for DME. However, OCT exam and devices are expensive and unavailable in all clinics in low- and middle-income countries. Our primary goal was therefore to develop an alternative method to OCT for DME diagnosis by introducing spectral information derived from spontaneous electroretinogram (ERG) signals as a single input or combined with fundus that is much more widespread. Baseline ERGs were recorded in 233 patients and transformed into scalograms and spectrograms via Wavelet and Fourier transforms, respectively. Using transfer learning, distinct Convolutional Neural Networks (CNN) were trained as classifiers for DME using OCT, scalogram, spectrogram, and eye fundus images. Input data were randomly split into training and test sets with a proportion of 80 %–20 %, respectively. The top performers for each input type were selected, OpticNet-71 for OCT, DenseNet-201 for eye fundus, and non-evoked ERG-derived scalograms, to generate a combined model by assigning different weights for each of the selected models. Model validation was performed using a dataset alien to the training phase of the models. None of the models powered by mock ERG-derived input performed well. In contrast, hybrid models showed better results, in particular, the model powered by eye fundus combined with mock ERG-derived information with a 91 % AUC and 86 % F1-score, and the model powered by OCT and mock ERG-derived scalogram images with a 93 % AUC and 89 % F1-score. These data show that the spontaneous ERG-derived input adds predictive value to the fundus- and OCT-based models to diagnose DME, except for the sensitivity of the OCT model which remains the same. The inclusion of mock ERG signals, which have recently been shown to take only 5 min to record in daylight conditions, therefore represents a potential improvement over existing OCT-based models, as well as a reliable and cost-effective alternative when combined with the fundus, especially in underserved areas, to predict DME.
... The pattern electroretinogram (PERG) is used to record ganglion cell responses in a variety of clinical and research contexts [1,2]. This includes not only testing of macular function [3] and early detection of glaucoma [4,5], but also assessment of drug effects [6][7][8][9]. ...
Purpose
The steady-state pattern electroretinogram (ssPERG) is used to assess retinal ganglion cell function in a variety of research contexts and diagnostic applications. In certain groups of patients or study participants, stable central fixation of the stimulus is not guaranteed. The present study aimed at assessing the effects of misfixation on the ssPERG response to checkerboard reversal stimuli.
Methods
Using two check sizes (0.8° and 15°), we compared ssPERG responses for several amounts of fixation deviation, ranging from 0° to 19° horizontally and from 0° to 14° diagonally. The stimulus area extended to 15° eccentricity, stimulus reversal rate was 15/s.
Results
Up to around 7° eccentricity, there was no sizable effect of fixation deviation under most conditions. Effects were somewhat larger for nasal than for temporal deviation, in particular for small checks. Diagonal deviation was associated with a response to luminance onset/offset at 7.5 Hz (subharmonic of the reversal rate), most prominently when the interior of a large check was fixated.
Conclusion
Generally, moderate inaccuracies of fixation do not have a sizable effect on ssPERG amplitude. However, with large checks, the luminance response has to be considered.
... However, we did not observe associations between variables from MRI or cerebrospinal uid and the risk of clinical conversion, contrary to ndings in previous studies. 41 This lack of observation was expected, given that our sample was not optimized to detect these associations, nor was it the primary focus of this study. ...
... VEP signals in this study was custom-developed by our laboratory in collaboration with the Department of Electronic Engineering at the University of Alcalá. As there is currently no standard protocol for acquiring and analyzing multifocal VEP responses, generic recommendations from the International Society for Clinical Electrophysiology of Vision (ISCEV)41 were followed. We applied similar recommendations for multifocal VEP as those suggested for conventional VEP.26 ...
Background: The early identification of individuals with radiologically isolated syndrome (RIS) who are at an elevated risk of progressing to multiple sclerosis (MS) is essential for making informed treatment decisions.
Objective: This study aimed to evaluate the predictive potential of multifocal Visual Evoked Potentials (mfVEP) measures in individuals with RIS with respect to their conversion to MS.
Methods: A prospective observational cohort study was conducted, involving 21 individuals with RIS recruited from a MS center. Baseline assessments, including mfVEP, magnetic resonance imaging (MRI), and clinical examinations, were performed, and participants were longitudinally followed for up to 24 months. The primary outcome measures were the conversion to MS.
Results: Over a clinical follow-up period of 24 months, five individuals (5/21) with RIS progressed to MS. MfVEP amplitude responses (interocular and monocular probability analysis) demonstrated abnormal cluster visual field defects in 47.6% of RIS eyes at baseline, whereas multifocal VEP latency analysis showed significant delays in 38.4%. A reduction in interocular amplitude [OR= 0.036, (95% CI, 0.003 - 0.503); P= 0.014], monocular amplitude [OR= 0.083, (95% CI, 0.007 - 0.982); P= 0.048], and a prolonged interocular latency [OR= 0.095, (95% CI, 0.009 - 0.972); P= 0.047] were associated with a higher relative risk of clinical conversion at the two-year follow-up.
Conclusion: Multifocal VEP may serve as a novel and independent risk factor for predicting the conversion to MS in individuals with Radiologically Isolated Syndrome.
... iscev. org) publishes standards, guidelines and extended protocols for electrophysiological methods including the fullfield ERG [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]; the Imaging and Perimetry Society (IPS, www. perim etry. ...
The full-field stimulus test (FST) is a psychophysical technique designed for the measurement of visual function in low vision. The method involves the use of a ganzfeld stimulator, as used in routine full-field electroretinography, to deliver full-field flashes of light. This guideline was developed jointly by the International Society for Clinical Electrophysiology of Vision (ISCEV) and Imaging and Perimetry Society (IPS) in order to provide technical information, promote consistency of testing and reporting, and encourage convergence of methods for FST. It is intended to aid practitioners and guide the formulation of FST protocols, with a view to future standardisation.
