The ‘two global flash' mfERG in high and normal tension primary open-angle glaucoma

Purpose: To analyse the sensitivity of the ‘2 global flash' multifocal electroretinogram (mfERG) to detect glaucomatous dysfunction in normal tension (NTG) and high tension primary open angle glaucoma (POAG) patients. Methods: MfERGs were recorded from 20 NTG and 20 POAG patients and compared to those of 20 controls. The mfERG array consisted of 103 hexagons. Each m-sequence step started with a focal flash that could be either dark or light (m-sequence: 2^13, L max: 200cd/m2, L min: 1cd/m2), followed by two global flashes (L max: 200cd/m2) at an interval of ∼26ms. Focal scalar products (SP) were calculated using focal templates derived from the control recordings (VERIS 4.8). We analyzed 5 response averages (central 7.5 degrees and 4 adjoining quadrants) of the response to the focal flash, the direct component at 10-40 ms (DC) and the following two components induced by the effects of the preceding focal flash on the response to the global flashes at 40-70ms (IC-1) and at 70-100 ms (IC-2). Results: Both NTG and POAG patients differed from controls in the IC-1 response to the superior quadrants, and POAG patients also differed from controls in the centre. The most sensitive parameter was the IC-1 of the superior temporal quadrant with an area under the ROC curve of 0.82 for POAG and 0.79 for NTG. The DC and the IC-2 did not differ significantly between the groups. When all five response averages of the IC-1 were taken into consideration 90% of the NTG patients and 85% of the POAG patients were correctly classified as abnormal while 80% of the control subjects were correctly classified as normal. Conclusions: This stimulus sequence holds promise for the diagnosis of early functional changes in POAG. A new finding is that both NTG, as well as POAG can be differentiated from control subject

ISCEV standard for clinical pattern electroretinography—2007 update

The pattern electroretinogram (PERG) is a retinal response evoked by viewing a temporally alternating pattern, usually a black and white checkerboard or grating. The PERG is important in clinical and research applications because it provides information both about retinal ganglion cell function and, because the stimulus is customarily viewed with central fixation, the function of the macula. The PERG can therefore facilitate interpretation of an abnormal pattern VEP by revealing the retinal responses to a similar stimulus to that used for the VEP. However, practitioners may have difficulty choosing between the different techniques for recording the PERG that have been described in the literature. The International Society for Clinical Electrophysiology of Vision published a standard for clinical PERG recording in 2000 to assist practitioners in obtaining good quality reliable responses and to facilitate inter-laboratory communication and comparison. This document is the scheduled revision of that standard

ISCEV Standard for Clinical Electro-oculography (EOG) 2006

The Clinical Electro-oculogram (EOG) is an electrophysiological test of function of the outer retina and retinal pigment epithelium (RPE) in which the change in the electrical potential between the cornea and the ocular fundus is recorded during successive periods of dark and light adaptation. This document sets out a Standard Method for performance of the test, and also gives detailed guidance on technical and practical issues, and on reporting test results. The main object of the Standard is to promote consistent quality of testing and reporting within and between centres. This 2006 Standard, from the International Society for Clinical Electrophysiology of Vision (ISCEV: www.iscev.org ), is a revision of the previous Standard published in 1993, and reviewed and re-issued in 1998

A New Approach to Staging Diabetic Eye Disease: Staging of Diabetic Retinal Neurodegeneration and Diabetic Macular Edema

Biomarkers; Diabetic retinal disease; Neuro-retinal layersBiomarcadores; Enfermedad de la retina diabética; Capas neurorretinianasBiomarcadors; Malaltia de la retina diabètica; Capes neurorretinàriesTopic The goal of this review was to summarize the current level of evidence on biomarkers to quantify diabetic retinal neurodegeneration (DRN) and diabetic macular edema (DME). Clinical relevance With advances in retinal diagnostics, we have more data on patients with diabetes than ever before. However, the staging system for diabetic retinal disease is still based only on color fundus photographs and we do not have clear guidelines on how to incorporate data from the relatively newer modalities into clinical practice. Methods In this review, we use a Delphi process with experts to identify the most promising modalities to identify DRN and DME. These included microperimetry, full-field flash electroretinogram, spectral-domain OCT, adaptive optics, and OCT angiography. We then used a previously published method of determining the evidence level to complete detailed evidence grids for each modality. Results Our results showed that among the modalities evaluated, the level of evidence to quantify DRN and DME was highest for OCT (level 1) and lowest for adaptive optics (level 4). Conclusion For most of the modalities evaluated, prospective studies are needed to elucidate their role in the management and outcomes of diabetic retinal diseases

ISCEV guidelines for clinical multifocal electroretinography (2007 edition)

The clinical multifocal electroretinogram (mfERG) is an electrophysiological test of local retinal function. With this technique, many local ERG responses, typically 61 or 103, are recorded from the cone-driven retina under light-adapted conditions. This document specifies guidelines for performance of the test. It also provides detailed guidance on technical and practical issues, as well as on reporting test results. The main objective of the guidelines is to promote consistent quality of mfERG testing and reporting within and among centers. These 2007 guidelines, from the International Society for Clinical Electrophysiology of Vision (ISCEV: http://www.iscev.org), replace the ISCEV guidelines for the mfERG published in 2003

The pattern visual evoked potential

The peak latency of the pattern-reversal visual evoked potential is a sensitive measure of conduction delay in the optic nerve caused by demyelination. Despite its clinical utility, the pattern-reversal visual evoked potential has not previously been used in multicenter clinical trials, presumably because of difficulty in standardizing conditions between centers. To establish whether the pattern-reversal visual evoked potential could be adequately standardized for use as a measure in multicenter therapeutic trials for optic neuropathy or multiple sclerosis, stimulus and recording variables were equated at four centers and pattern-reversal visual evoked potentials were recorded from 64 normal subjects and 15 patients with resolved optic neuritis. Results showed equivalent latency and amplitude data from all centers, suggesting that stimulus and recording variables can be satisfactorily standardized for multicenter clinical trials. N70 and P100 peak latencies and N70-P100 interocular amplitude difference were sensitive measures of resolved optic neuritis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42623/1/10633_2005_Article_BF01224629.pd

ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update)

This document developed by the International Society for Clinical Electrophysiology of Vision (ISCEV) provides guidance for calibration and verification of stimulus and recording systems specific to clinical electrophysiology of vision. This guideline provides additional information for those using ISCEV Standards and Extended protocols and supersedes earlier Guidelines. The ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update) were approved by the ISCEV Board of Directors 01, March 2023

Factors influencing the magnitude of recall-anticipation method learning difference in paired-associate learning

Digitized by Kansas Correctional Industrie

Locating vep equivalent dipoles in magnetic resonance images

Pattern-reversal and diffuse flash visual evoked potentials (VEPs) were obtained from 4 normal adults. A spatio-temporal dipole model was used to determine the location of the hypothetical equivalent dipoles consistent with the scalp distribution of the VEPs. Equivalent dipoles representing ERG and VEP activity were placed within 3-D magnetic resonance images of the brain. Most of the localization error appeared to be due to inadequate sampling of the potential field in frontal and occipital areas by the 10-20 system of electrode placement. Locating electrophysiologic dipoles within magnetic resonance images of brain structure allows evaluation of dipole localization techniques. © 1995 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted