1
|
Saad A, Turgut F, Sommer C, Becker M, DeBuc D, Barboni M, Somfai GM. The Use of the RETeval Portable Electroretinography Device for Low-Cost Screening: A Mini-Review. Klin Monbl Augenheilkd 2024; 241:533-537. [PMID: 38653305 DOI: 10.1055/a-2237-3814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Electroretinography (ERG) provides crucial insights into retinal function and the integrity of the visual pathways. However, ERG assessments classically require a complicated technical background with costly equipment. In addition, the placement of corneal or conjunctival electrodes is not always tolerated by the patients, which restricts the measurement for pediatric evaluations. In this short review, we give an overview of the use of the RETeval portable ERG device (LKC Technologies, Inc., Gaithersburg, MD, USA), a modern portable ERG device that can facilitate screening for diseases involving the retina and the optic nerve. We also review its potential to provide ocular biomarkers in systemic pathologies, such as Alzheimer's disease and central nervous system alterations, within the framework of oculomics.
Collapse
Affiliation(s)
- Amr Saad
- Ophthalmology, Stadtspital Zürich Triemli, Zürich, Switzerland
| | - Ferhat Turgut
- Ophthalmology, Stadtspital Zürich Triemli, Zürich, Switzerland
- Ophthalmology, Gutblick, Pfäffikon, Switzerland
| | - Chiara Sommer
- Ophthalmology, Stadtspital Zürich Triemli, Zürich, Switzerland
| | - Matthias Becker
- Ophthalmology, Stadtspital Zürich Triemli, Zürich, Switzerland
| | - Delia DeBuc
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, United States
| | - Mirella Barboni
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Gabor Mark Somfai
- Ophthalmology, Stadtspital Zürich Triemli, Zürich, Switzerland
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
2
|
Han KJ, Moon H, Woo JM, Min JK. USING RETeval SYSTEM FLICKER ELECTRORETINOGRAPHY FOR EVALUATION OF DENSE VITREOUS HEMORRHAGE. Retina 2022; 42:73-79. [PMID: 34292221 DOI: 10.1097/iae.0000000000003263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine whether the RETeval electroretinography (ERG) system can be used to evaluate eyes with dense vitreous hemorrhage (VH). METHODS This retrospective case series study included 69 eyes of 69 patients with acute dense VH. Flicker ERGs were recorded by the RETeval system, an ERG device with adhesive skin electrodes. We evaluated the flicker ERG amplitudes in eyes with VH and the ratio of the VH eye amplitudes compared with the fellow eye amplitudes for each VH cause. RESULTS In patients with rhegmatogenous retinal detachment, the amplitude ratios were extremely low (0.08 ± 0.03). To detect rhegmatogenous retinal detachment, the area under the receiver operating characteristic curve was 0.977 (95% confidence interval, 0.943-1.000) (best rhegmatogenous retinal detachment cutoff value, 0.14; sensitivity, 100.0%; and specificity, 95.4%). The flicker ERG amplitude was not significantly correlated with the initial visual acuity (ρ = -0.189, P = 0.120) but was positively correlated with the postoperative visual acuity in eyes with VH (ρ = -0.328, P = 0.006). CONCLUSION The RETeval ERG system was found to be a useful diagnostic option in situations where dense VH precluded fundus examination or posterior vitreous detachment was indistinguishable from rhegmatogenous retinal detachment.
Collapse
Affiliation(s)
- Kyu Jin Han
- Department of Ophthalmology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | | | | | | |
Collapse
|
3
|
Kawai M, Himeno T, Shibata Y, Hirai N, Asada‐Yamada Y, Asano‐Hayami E, Ejima Y, Kasagi R, Nagao E, Sugiura‐Roth Y, Nakai‐Shimoda H, Nakayama T, Yamada Y, Ishikawa T, Morishita Y, Kondo M, Tsunekawa S, Kato Y, Nakamura J, Kamiya H. Neuroretinal dysfunction revealed by a flicker electroretinogram correlated with peripheral nerve dysfunction and parameters of atherosclerosis in patients with diabetes. J Diabetes Investig 2021; 12:1236-1243. [PMID: 33210835 PMCID: PMC8264400 DOI: 10.1111/jdi.13465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/05/2020] [Accepted: 11/15/2020] [Indexed: 11/28/2022] Open
Abstract
AIMS/INTRODUCTION Diabetic polyneuropathy (DPN) develops in the early stage of diabetes. However, no common diagnostic protocol has yet been established. Here, to verify that the flicker electroretinogram using a hand-held device can detect the early dysfunction of the peripheral nervous system in patients with diabetes, we investigated the correlation between the progression of DPN and neuroretinal dysfunction. MATERIALS AND METHODS In total, 184 participants with type 1 or 2 diabetes underwent a flicker electroretinogram (ERG) using a hand-held device RETeval™ and nerve conduction study. Participants were also evaluated for intima-media thickness, ankle-brachial index, toe brachial index and brachial-ankle pulse wave velocity. Parameters of the nerve conduction study were used to diagnose the severity according to Baba's classification. A multiple regression analysis was used to examine the associations of ERG parameters with the severity of DPN categorized by Baba's classification. Diagnostic properties of the device in DPN were evaluated using a receiver operating characteristic curve. RESULTS A multiple regression model to predict the severity of DPN was generated using ERG. In the model, moderate-to-severe DPN was effectively diagnosed (area under the receiver operating characteristic curve 0.692, sensitivity 56.5%, specificity 78.3%, positive predictive value 70.6%, negative predictive value 66.1%, positive likelihood ratio 2.60, negative likelihood ratio 0.56). In the patients without diabetic retinopathy, the implicit time and amplitude in ERG significantly correlated with the parameters of the nerve conduction study, brachial-ankle pulse wave velocity and intima-media thickness. CONCLUSIONS Electroretinogram parameters obtained by the hand-held device successfully predict the severity of DPN. The device might be useful to evaluate DPN.
Collapse
Affiliation(s)
- Miyuka Kawai
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Tatsuhito Himeno
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yuka Shibata
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
- Department of LaboratoryThe Medical Clinic of Aichi Medical UniversityNagoyaJapan
- Department of Clinical LaboratoryAichi Medical University HospitalNagakuteJapan
| | - Nobuhiro Hirai
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yuriko Asada‐Yamada
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Emi Asano‐Hayami
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yohei Ejima
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Rina Kasagi
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Eriko Nagao
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yukako Sugiura‐Roth
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Hiromi Nakai‐Shimoda
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Takayuki Nakayama
- Department of Clinical LaboratoryAichi Medical University HospitalNagakuteJapan
| | - Yuichiro Yamada
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Takahiro Ishikawa
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yoshiaki Morishita
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Masaki Kondo
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Shin Tsunekawa
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Yoshiro Kato
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Jiro Nakamura
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| | - Hideki Kamiya
- Division of DiabetesDepartment of Internal MedicineAichi Medical University School of MedicineNagakuteJapan
| |
Collapse
|
4
|
Kim K, Kim HJ, Zhang H, Park W, Meyer D, Kim MK, Kim B, Park H, Xu B, Kollbaum P, Boudouris BW, Lee CH. All-printed stretchable corneal sensor on soft contact lenses for noninvasive and painless ocular electrodiagnosis. Nat Commun 2021; 12:1544. [PMID: 33750806 PMCID: PMC7943761 DOI: 10.1038/s41467-021-21916-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 12/17/2020] [Indexed: 02/03/2023] Open
Abstract
Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes. The corneal sensor is integrated with soft contact lenses via an electrochemical anchoring mechanism in a seamless manner that ensures its mechanical and chemical reliability. Thus, the resulting device enables the high-fidelity recording of full-field electroretinogram signals in human eyes without the need of topical anesthesia or a speculum. The device, superior to clinical standards in terms of signal quality and comfortability, is expected to address unmet clinical needs in the field of ocular electrodiagnosis.
Collapse
Affiliation(s)
- Kyunghun Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ho Joong Kim
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Haozhe Zhang
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Woohyun Park
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Dawn Meyer
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Min Ku Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Bongjoong Kim
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Heun Park
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Baoxing Xu
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA.
| | - Pete Kollbaum
- School of Optometry, Indiana University, Bloomington, IN, USA.
| | - Bryan W Boudouris
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA.
- Department of Chemistry, Purdue University, West Lafayette, IN, USA.
| | - Chi Hwan Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA.
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
5
|
Deng X, Li Z, Zeng P, Wang J, Liang J, Lan Y. A Diagnostic Model for Screening Diabetic Retinopathy Using the Hand-Held Electroretinogram Device RETeval. Front Endocrinol (Lausanne) 2021; 12:632457. [PMID: 33912134 PMCID: PMC8074966 DOI: 10.3389/fendo.2021.632457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/11/2021] [Indexed: 11/13/2022] Open
Abstract
PURPOSE To construct a proper model to screen for diabetic retinopathy (DR) with the RETeval. METHOD This was a cross-sectional study. Two hundred thirty-two diabetic patients and seventy controls were recruited. The DR risk assessment protocol was performed to obtain subjects' DR risk score using the RETeval. Afterwards, the receiver operating characteristic (ROC) curve was used to determine the best cutoff for diagnosing DR. Random forest and decision tree models were constructed. RESULTS With increasing DR severity, the DR score gradually increased. When the DR score was used to diagnose DR, the ROC curve had an area under the curve of 0.881 (95% confidence interval: 0.836-0.927, P < 0.001), with a best cutoff value of 22.95, a sensitivity of 74.3% (95 CI: 66.0%~82.6%), and a specificity of 90.6% (95 CI: 83.7% ~94.8%). The top four risk factors selected by the random forest were used to construct the decision tree for diagnosing DR, which had a sensitivity of 93.3% (95% CI: 86.3%~97.0%) and a specificity of 80.3% (95% CI: 72.1% ~86.6%). CONCLUSIONS The DR risk assessment protocol combined with the decision tree model was innovatively used to evaluate the risk of DR, improving the sensitivity of diagnosis, which makes this method more suitable than the current protocol for DR screening.
Collapse
Affiliation(s)
- Xiaowen Deng
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zijing Li
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Peng Zeng
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jing Wang
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jiaqi Liang
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yuqing Lan
- Department of Ophthalmology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Yuqing Lan,
| |
Collapse
|
6
|
Abstract
OBJECTIVE The information derived from the electroretinogram (ERG), especially with regard to local areas of retinal dysfunction or therapeutic rescue, can be enhanced by an increased understanding of the relationship between local retinal current sources and local ERG potentials measured at the cornea. A critical step in this direction is the development of a robust bioelectric field model of the ERG. METHODS A finite-element model was created to simulate ERG potentials at the cornea resulting from physiologically relevant transretinal currents. A magnetic resonance image of a rat eye was segmented to define all major ocular structures, tissues were assigned conductivity values from the literature. The model was optimized to multi-electrode ERG (meERG) data recorded in healthy rat eyes, and validated with meERG data from eyes with experimental lesions in peripheral retina. RESULTS Following optimization, the simulated distribution of corneal potentials was in good agreement with measured values; residual error was comparable to the average difference of individual eyes from the measured mean. The model predicted the corneal potential distribution for eight eyes with experimental lesions with similar accuracy, and a measure of pre- to post-lesion changes in corneal potential distribution was well correlated with the location of the lesion. CONCLUSION An eye model with high anatomical accuracy was successfully validated against a robust dataset. SIGNIFICANCE This model can now be used for optimization of ERG electrode design, and to support functional mapping of the retina from meERG data via solving the inverse bioelectric source problem.
Collapse
|
7
|
Abstract
Electroretinography (ERG) is important for functional diagnostics of the retina. Types of information about retinal function obtainable by ERG differ depending on recording conditions, e.g., a combination of light stimulus and adaptation. In terms of stimulation, single-flash and flicker stimuli are frequently used because response properties have been well investigated, allowing an assessment of fundamental retinal functionality; for example, how photoreceptors and bipolar cells, including signal transmission between them, are affected under pathological conditions. Usually, ERGs are recorded with a nonzero lower cutoff frequency of amplifiers to avoid certain artifacts, and additionally, responses are averaged over time so that non-event-related signals are cancelled out. However, the improved signal quality is associated with a loss of information. Especially in steady-state flicker ERG, information about the absolute baseline of recordings is missing because the prestimulus baseline is not included on the recording trace as well as because a zero response is obtained in all cases in which the signal baseline stays constant for a sufficient amount of time. In other words, it is impossible to tell from the conventional flicker ERG whether a zero signal is obtained under conditions of maximal or no excitation of the visual system. In this chapter, we describe a direct current ERG protocol (featuring a lower cutoff frequency of zero) with repetitive single flashes mimicking conventional flicker that contains a defined onset. Using this recording protocol, it is possible to assess not only the absolute excitatory level of the retina but also the development of steady-state responses from the single flash response.
Collapse
Affiliation(s)
- Naoyuki Tanimoto
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Kiel, Germany.
| | - Mathias W Seeliger
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| |
Collapse
|
8
|
Abstract
The electroretinogram (ERG) represents the biopotential that is produced by the retina in response to a light stimulus. To date, it remains the best diagnostic tool to objectively evaluate the functional integrity of the normal or diseased retina. In the following pages we briefly review the necessary requirements in order to record and analyze the conventional clinical ERG.
Collapse
Affiliation(s)
- Mathieu Gauvin
- Department of Ophthalmology & Neurology-Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, 1001 Boul. Décarie, Glen Site, Block E, Montreal, QC, Canada, H4A 3J1
| | - Allison L Dorfman
- Department of Ophthalmology & Neurology-Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, 1001 Boul. Décarie, Glen Site, Block E, Montreal, QC, Canada, H4A 3J1
| | - Pierre Lachapelle
- Department of Ophthalmology & Neurology-Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, 1001 Boul. Décarie, Glen Site, Block E, Montreal, QC, Canada, H4A 3J1.
| |
Collapse
|
9
|
Abstract
Electroretinography is a crucial assay for studying the function and the functional integrity of the retina. The mouse is an important animal model for studying the retinal neurons and circuitries. In addition, it is often used as animal model for human retinal disorders. Therefore, a good understanding of the procedures in animal handling, of the methods for data analysis and of the requirements for stimulators and for the data acquisition equipment is of importance. Here, the currently most common methods and materials for in vivo electroretinography in the mouse are discussed.
Collapse
Affiliation(s)
- Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.
| | - Naoyuki Tanimoto
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Kiel, Germany
| |
Collapse
|
10
|
McInturff SP, Buchser WJ. A portable device for recording evoked potentials, optimized for pattern ERG. BIOMED ENG-BIOMED TE 2015; 61:69-76. [PMID: 26536572 DOI: 10.1515/bmt-2015-0042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 09/30/2015] [Indexed: 11/15/2022]
Abstract
Recording evoked potentials in un-anesthetized animals and people is a powerful technique to non-invasively measure the function of neurons. As such, the primary output neurons of the eye can be assessed by the pattern electroretinogram (PERG). Currently, electro-physiologic setups to perform PERG or related recordings are costly, complicated, and non-portable. Here, we design a simple steady-state PERG system, based off an Arduino board. The amplifier is built on a shield that fits over a microcontroller board, an Arduino, which digitizes the signal and sends it to a computer that presents stimuli then records and analyzes the evoked potentials. We used the device to record PERG accurately with a sensitivity as low as half a microvolt. The device has also been designed to implement other evoked potential recordings. This simple device can be quickly constructed and used for experiments in moving systems. Additionally, this device can be used to expose students in underserved areas to research technology that they would otherwise not have access to.
Collapse
|
11
|
KAMIO Y, SAKAI N, SAMESHIMA T, TAKAHASHI G, KOIZUMI S, SUGIYAMA K, NAMBA H. Usefulness of intraoperative monitoring of visual evoked potentials in transsphenoidal surgery. Neurol Med Chir (Tokyo) 2014; 54:606-11. [PMID: 25070017 PMCID: PMC4533496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/10/2014] [Indexed: 03/22/2024] Open
Abstract
Postoperative visual outcome is a major concern in transsphenoidal surgery (TSS). Intraoperative visual evoked potential (VEP) monitoring has been reported to have little usefulness in predicting postoperative visual outcome. To re-evaluate its usefulness, we adapted a high-power light-stimulating device with electroretinography (ERG) to ascertain retinal light stimulation. Intraoperative VEP monitoring was conducted in TSSs in 33 consecutive patients with sellar and parasellar tumors under total venous anesthesia. The detectability rates of N75, P100, and N135 were 94.0%, 85.0%, and 79.0%, respectively. The mean latencies and amplitudes of N75, P100, and N135 were 76.8 ± 6.4 msec and 4.6 ± 1.8 μV, 98.0 ± 8.6 msec and 5.0 ± 3.4 μV, and 122.1 ± 16.3 msec and 5.7 ± 2.8 μV, respectively. The amplitude was defined as the voltage difference from N75 to P100 or P100 to N135. The criterion for amplitude changes was defined as a > 50% increase or 50% decrease in amplitude compared to the control level. The surgeon was immediately alerted when the VEP changed beyond these thresholds, and the surgical manipulations were stopped until the VEP recovered. Among the 28 cases with evaluable VEP recordings, the VEP amplitudes were stable in 23 cases and transiently decreased in 4 cases. In these 4 cases, no postoperative vision deterioration was observed. One patient, whose VEP amplitude decreased without subsequent recovery, developed vision deterioration. Intraoperative VEP monitoring with ERG to ascertain retinal light stimulation by the new stimulus device was reliable and feasible in preserving visual function in patients undergoing TSS.
Collapse
Affiliation(s)
- Yoshinobu KAMIO
- Department of Neurosurgery, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| | - Naoto SAKAI
- Department of Neurosurgery, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| | - Tetsuro SAMESHIMA
- Department of Neurosurgery, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| | - Goro TAKAHASHI
- Department of Otolaryngology, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| | - Shinichiro KOIZUMI
- Department of Neurosurgery, Seirei Mikatahara General
Hospital, Hamamatsu, Shizuoka
| | - Kenji SUGIYAMA
- Department of Neurosurgery, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| | - Hiroki NAMBA
- Department of Neurosurgery, Head and Neck Surgery,
Hamamatsu University School of Medicine, Hamamatsu, Shizuoka
| |
Collapse
|
12
|
Guthrie MJ, Kang-Mieler JJ. Dual electroretinogram/nitric oxide carbon fiber microelectrode for direct measurement of nitric oxide in the in vivo retina. IEEE Trans Biomed Eng 2013; 61:611-9. [PMID: 24043366 DOI: 10.1109/tbme.2013.2281541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nitric oxide (NO) plays an important physiological role in normal and pathological retinas. Intraretinal NO concentrations have not been directly measured due to lack of NO electrodes capable of determining their location in the retina. The microelectrodes described here allow recording of the intraretinal electroretinogram (ERG) and NO concentration from the same location, with ERGs used to determine retinal depth. Double-barreled electrodes were constructed with one barrel serving as a reference/voltage recording barrel and the other containing a Nafion-coated carbon fiber used to detect NO amperometrically. Nafion coating imparted a high selectivity for NO versus ascorbic acid (2000:1). In vivo rodent experiments demonstrated that the electrodes could record intraretinal ERGs and NO current with minimal retinal thickness deformation (9%), allowing for retinal NO depth profile measurements. Comparison of NO depth profiles under control conditions and under nitric oxide synthase (NOS) inhibition by 5 mM L-NG-Nitroarginine methyl ester (L-NAME) verified that the recorded current was attributable to NO. NO concentrations from control profiles ( n = 4) were 2.37 ± 0.34 μM at the choroid and 1.12 ± 0.14 μM at the retinal surface. NO concentrations from L-NAME profiles ( n = 4) were significantly lower at 0.83 ± 0.15 μM at the choroid ( p = 0.006) and 0.27 ± 0.04 μM at the retinal surface ( p = 0.001). Localized regions of increased NO (100-400 nM) were seen in the inner retina under control conditions but not after L-NAME. The dual ERG-NO electrode may be a valuable tool in evaluating the role of NO in normal and diseased retinas.
Collapse
|
13
|
Herbik A, Hölzl GC, Reupsch J, Hoffmann MB. Differential effects of optic media opacities on mfERGs and mfVEPs. Clin Neurophysiol 2013; 124:1225-31. [PMID: 23352815 DOI: 10.1016/j.clinph.2012.11.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/21/2012] [Accepted: 11/28/2012] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To assess different effects of image degradation that could result from optic media opacities on multifocal retinal (mfERG) and cortical responses (mfVEP). METHODS Monocular flash-mfERGs and pattern-reversal mfVEPs were recorded. MfERG-P1 amplitudes and implicit times and mfVEP root-mean-square values (RMS) and delays were compared for different filter conditions (none, 8% luminance, 50% luminance, 50% luminance plus blur) in a total of ten participants with normal vision. RESULTS Reducing stimulus luminance down to 50% and 8% reduced mfERG amplitudes to 86% and 42%, respectively, with no significant effect on mfVEP amplitude. Implicit times were increased for mfERGs by 0.9 ms and 6.0 ms, respectively, and for mfVEPs by 1.0 ms and 6.3 ms, respectively. For '50% luminance plus blur' mfERG amplitudes were significantly reduced centrally and enhanced peripherally and delayed by 1.3 ms. MfVEPs were reduced close to noise level independent of eccentricity. CONCLUSIONS Degradation of the retinal image is a potential source of discrepancies between mfERGs and mfVEPs. Image blur suppresses the mfVEP at all locations and changes mfERG topography, resulting in a selective loss of central responses. SIGNIFICANCE Considering optic media opacities is of importance for the correct interpretation of mfERG and mfVEP recordings, particularly in elderly patients.
Collapse
Affiliation(s)
- A Herbik
- Visual Processing Laboratory, Ophthalmology, Otto-von-Guericke-University, Magdeburg, Germany
| | | | | | | |
Collapse
|
14
|
Kaid T, Matsunag M, Hanaya J, Nakamura Y, Ohtani S, Miyat K, Kondo M. [Comparison between subtraction skin electrodes and corneal-contact electrodes in flash electroretinograms]. Nippon Ganka Gakkai Zasshi 2013; 117:5-11. [PMID: 23424970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PURPOSE To compare electroretinogram (ERG) responses measured with a skin electrode with those from a corneal-contact electrode in healthy adults. METHOD Sixty two eyes of 31 healthy adults (8 men and 23 women) were enrolled (mean age 34.0 +/- 8.1 years). ERG responses for full-field and single flash stimuli was recorded with skin electrodes and corneal-contact electrodes. Morphology of the ERG waveform, a-wave and b-wave amplitudes, b/a ratios, and a-wave and b-wave implicit times were compared between the two electrode measurements. Correlations between the two measurements were also examined. RESULTS All features of the ERG waveform were identifiable using the skin electrodes. In the skin electrode ERGs, a-wave and b-wave amplitudes, and the b/a ratios were smaller (p<0.001) and the a-wave and b-wave implicit times were shorter (p<0.001) than those in the corneal-contact electrode ERGs. The B-wave amplitudes, b/a ratios and the a-wave and b-wave implicit times showed significant correlations between the two electrodes (p<0.01). In 16 eyes the OP4 was detected as the b-wave. CONCLUSION The skin electrode ERG had shorter amplitudes and shorter implicit times than the corneal electrode ERGs, but corresponded well in its morphology to the corneal-contact electrode ERGs. Skin electrodes ERG would be useful for the examination of child patients and patients with corneal diseases. Further study is required for clinical application.
Collapse
|
15
|
Moayed AA, Hariri S, Choh V, Bizheva K. In vivo imaging of intrinsic optical signals in chicken retina with functional optical coherence tomography. Opt Lett 2011; 36:4575-7. [PMID: 22139247 DOI: 10.1364/ol.36.004575] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Visually evoked intrinsic optical signals (IOSs) were measured in vivo for the first time to our knowledge from all retina layers of the chicken retina with a combined functional optical coherence tomography and electroretinography (ERG) system. IOS traces were recorded from a small volume in the retina with 3.5 μm axial resolution and 7 ms time resolution. Comparison of the IOS and ERG traces shows a correlation between the positive and negative IOS measured from different retinal layers and the timing of the a and b waves in the ERG recording.
Collapse
Affiliation(s)
- Alireza Akhlagh Moayed
- Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | | | | | | |
Collapse
|
16
|
Spiridonov IN, Rezvykh SV, Orlov IN. [Electrode equipment for electroretinography]. Med Tekh 2011:5-10. [PMID: 21574475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
17
|
Harimoto T, Takei K, Kawano T, Ishihara A, Kawashima T, Kaneko H, Ishida M, Usui S. Enlarged gold-tipped silicon microprobe arrays and signal compensation for multi-site electroretinogram recordings in the isolated carp retina. Biosens Bioelectron 2010; 26:2368-75. [PMID: 21093247 DOI: 10.1016/j.bios.2010.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 09/29/2010] [Accepted: 10/11/2010] [Indexed: 11/18/2022]
Abstract
In order to record multi-site electroretinogram (ERG) responses in isolated carp retinae, we utilized three-dimensional (3D), extracellular, 3.5-μm-diameter silicon (Si) probe arrays fabricated by the selective vapor-liquid-solid (VLS) growth method. Neural recordings with the Si microprobe exhibit low signal-to-noise (S/N) ratios of recorded responses due to the high-electrical-impedance characteristics of the small recording area at the probe tip. To increase the S/N ratio, we designed and fabricated enlarged gold (Au) tipped Si microprobes (10-μm-diameter Au tip and 3.5-μm-diameter probe body). In addition, we demonstrated that the signal attenuation and phase delay of ERG responses recorded via the Si probe can be compensated by the inverse filtering method. We conclude that the reduction of probe impedance and the compensation of recorded signals are useful approaches to obtain distortion-free recording of neural signals with high-impedance microelectrodes.
Collapse
Affiliation(s)
- Tetsuhiro Harimoto
- Department of Electronic and Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Moayed AA, Hariri S, Hyun C, Doran B, Kraft TW, Boyd S, Bizheva K. Combined optical coherence tomography and electroretinography system for in vivo simultaneous morphological and functional imaging of the rodent retina. J Biomed Opt 2010; 15:040506. [PMID: 20799773 DOI: 10.1117/1.3475489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A combined ultrahigh resolution optical coherence tomography (UHROCT) and a electroretinography (ERG) system is presented for simultaneous imaging of the retinal structure and physiological response to light stimulation in the rodent eye. The 1060-nm UHROCT system provides approximately 3x5 microm (axialxlateral) resolution in the rat retina and time resolution of 22 micros. A custom-designed light stimulator integrated into the UHROCT imaging probe provides light stimuli with user-selected color, duration, and intensity. The performance of the combined system is demonstrated in vivo in healthy rats, and in a rat model of drug-induced outer retinal degeneration. Experimental results show correlation between the observed structural and physiological changes in the healthy and degenerated retina.
Collapse
|
19
|
Krakau CE, Ohman R. An apparatus for ERG recording adaptable to the slit lamp microscope [proceedings]. Acta Ophthalmol 2009:9-10. [PMID: 184681 DOI: 10.1111/j.1755-3768.1975.tb01201.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
20
|
|
21
|
Gjötterberg M. Double flash human electroretinogram with special reference to the oscillatory potentials and the early phase of dark adaptation: a normative study. Acta Ophthalmol 2009; 52:291-304. [PMID: 4406860 DOI: 10.1111/j.1755-3768.1974.tb00379.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
22
|
Knave B, Nilsson SE, Lunt T. The human electroretinogram: DC recordings at low and conventional stimulus intensities. Description of a new method for clinical use. Acta Ophthalmol 2009; 51:716-26. [PMID: 4801167 DOI: 10.1111/j.1755-3768.1973.tb08265.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
23
|
Shamshinova AM, Seidova SFG. [Optimization of a recording procedure of a multifocal electroretinogram]. Vestn Oftalmol 2009; 125:13-17. [PMID: 19284094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The paper presents a procedure and conditions for recording multifocal electroretinogram (mfERG), its origin, and factors influencing small-signal ERG. The optimal conditions of ERG extraction using the existing method are appraised and indications for its use in ophthalmological care defined. The results of comparing the new types of electrodes developed in Russia for ERG recording and a DTL electrode included in the ISCEV guidelines are presented.
Collapse
|
24
|
Oyamada MK, Dotto PDF, Abdalla M. [Technical factors that influence multifocal electroretinogram (mfERG) recording]. Arq Bras Oftalmol 2007; 70:713-7. [PMID: 17906773 DOI: 10.1590/s0004-27492007000400027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Accepted: 11/07/2006] [Indexed: 11/21/2022] Open
Abstract
PURPOSE To describe the main intervening factors observed during the acquisition and analysis of multifocal electroretinogram (mfERG), that could affect the recorded signal, the obtained responses and their analysis. METHODS The error factors observed during the acquisition of 100 sequential multifocal electroretinogram tests, in the period of May to July, 2005 were analyzed. The examinations of multifocal electroretinogram were carried out in agreement with international guideline recommendations, taking into account the established parameters of equipment, with 61 elements, and visual angle of 30 degrees. All patients had been submitted to complete ophthalmologic examination, excluding those with inadequate transparency of ways, flat corneas and those incapable to visualize a central fixation target. RESULTS The intervening factors, that could cause artifacts and errors in the interpretation of the obtained results, observed and corrected during the acquisition of multifocal electroretinogram were: eccentric or poor fixation, eye movements, orbicular contraction, cervical muscle contraction, inadequate transparency of the corneal electrode, electrode displacement, lens support decentralization, inadequate viewing distance in patients with high refractive errors, eye height inadequacy in relation to the center of the screen, electrical noise in 60 HZ frequency and electromagnetic field and high impedances. Excessive use of filters in wave processing for noise and artifact removal can interfere with the analysis of the obtained results. CONCLUSION Simple observational cares during signal acquisition are of significant importance to ensure accuracy of the topographical electroretinogram information, good waveform morphology and low noise level register. Through their ready correction, the correct and adjusted analysis of the amplitude and of implicit time of peaks N1, P1 and N2 is reliable. Digital smooth system with specific frequency peak removal supply waves with more defined morphology with lower amplitude reduction than other available resources.
Collapse
Affiliation(s)
- Maria Kiyoko Oyamada
- Departamento de Oftalmologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
| | | | | |
Collapse
|
25
|
Yoshii M, Nagasaka E, Yanashima K, Hayashi H. [Verification of multifocal electroretinogram Veris III system for clinical problems]. Nippon Ganka Gakkai Zasshi 2007; 111:722-7. [PMID: 17907466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
PURPOSE To verify the usefulness of the Veris III system, which is said to be problematic in clinical applications for recording multifocal electroretinograms (mfERG) by an ophthalmologist. METHODS A test wave was input to the system and the data were analyzed using Veris Science software. The items tested were overlapping, spatial averaging, combination procedures, and emission properties of the cathode ray tube (CRT) monitor (B 4). RESULTS Overlapping was not observed under the standard stimulus conditions. The data resulting from both spatial averaging and combination procedures coincided with the theoretical calculated data defined by both procedures. Analysis of the emission properties of the CRT monitor showed that it took 85 mu seconds from the beginning to the end of the bright emission. CONCLUSIONS No clinical problems were found in the M-sequence program, the spatial averaging procedure, or the combination procedure using several test waves. It is necessary to pay attention to the configuration of pattern stimulation on the CRT monitor (B 4), because it has a very steep emission during a very short time.
Collapse
Affiliation(s)
- Masaru Yoshii
- Eye Clinic, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | | | | | | |
Collapse
|
26
|
Beeler P, Barthelmes D, Sutter FK, Helbig H, Fleischhauer JC. Comparison of performance and patient satisfaction of two types of ERG electrodes. Klin Monbl Augenheilkd 2007; 224:265-8. [PMID: 17458789 DOI: 10.1055/s-2007-962856] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND An age-controlled comparison concerning patient satisfaction and electrical performance of microfibres (DTL) and rigid contact lens (Henkes) corneal ERG electrodes was carried out. METHODS 36 test persons underwent complete ophthalmological examination and were equally distributed into 3 age groups. Electroretinograms were recorded according to ISCEV standards. Randomly, in one eye a Henkes electrode was used and in the other eye a DTL electrode. Amplitudes of a- and b-waves and implicit times were measured and compared for the two electrode types. RESULTS 34 of 36 test persons preferred DTL electrodes. Electrical performance concerning b-wave amplitudes was comparable. Statistically significant differences were detected only for scotopic combined cone-rod stimulation in the age groups 20 - 40 and 41 - 60 years between the different electrodes. Other recordings did not show differences. A statistically significant reduction of signal amplitudes with age was detected for scotopic isolated rod signals and combined cone-rod signals. Significance level was p < 0.05. No conjunctival or corneal erosions were found after ERG recordings for either electrode. CONCLUSIONS Electrical performance is comparable between electrodes. For scotopic stimulations age was a significant influencing factor for signal amplitude and should be respected for normative values. DTL electrodes were preferred by the vast majority of patients. No adverse clinical effects were observed for either electrode. DTL electrodes should be preferred due to hygienic reasons (single use) and patient comfort.
Collapse
Affiliation(s)
- P Beeler
- Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland
| | | | | | | | | |
Collapse
|
27
|
Dudgeon SM, Keating D, Parks S. Simultaneous structural and functional imaging of the macula using combined optical coherence tomography ophthalmoscope and multifocal electroretinogram. J Opt Soc Am A Opt Image Sci Vis 2007; 24:1394-401. [PMID: 17429485 DOI: 10.1364/josaa.24.001394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Multimodal imaging (MMI) is a new imaging technique that combines an electrophysiological test (multifocal electroretinogram) with an optical coherence tomography ophthalmoscope. MMI allows the two technologies to operate simultaneously yet independently to provide accurate correlation of macular structure and function at multiple sites. Preliminary work with MMI in patients with macular holes showed that functional deficits existed beyond the geographical area of structural alterations and that macular hole size did not always correlate with the severity of functional loss. Functional information may therefore be important when assessing prognosis in these patients. We envisage that MMI may prove a useful new tool in the assessment of many macular pathologies.
Collapse
Affiliation(s)
- Sinead M Dudgeon
- ElectroDiagnostic Imaging Unit, Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, UK
| | | | | |
Collapse
|
28
|
Bolbecker AR, Lewis AR, Swan AA, Carlson K, Fleet JR, Beck KE, Wasserman GS. Stable bellows cup electrode demonstrates low-frequency properties of long-term electroretinographic recordings in the Limulus lateral eye. J Neurosci Methods 2007; 159:252-60. [PMID: 16949159 DOI: 10.1016/j.jneumeth.2006.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 07/18/2006] [Accepted: 07/19/2006] [Indexed: 10/24/2022]
Abstract
Conventional methods have long been used to record electroretinograms (ERGs) from the surface of the lateral eye of Limulus, the horseshoe crab. But, using these methods, the convexity of this eye has sometimes led to electrode problems that deterred acceptance of the validity of unexpected and unfamiliar phenomena. To deal with the electrode problem, a new gel/bellows cup electrode has been devised which was created from a small bellows suction cup. Coated with a recording gel and positioned by a massive apparatus arrangement, it maintains a secure connection to the convexity of the lateral eye for many days without requiring any attention after its placement. This new electrode has now been used for thousands of hours of ERG research during which crabs have often been left undisturbed in the apparatus for many days. This new method has revealed the existence of a novel low-frequency phenomenon demonstrated by the occurrence of noise-like fluctuations in successive ERGs. The frequency of these fluctuations is low relative to the properties of the ERG itself. Several converging tests of this new electrode system indicated that this new phenomenon is not an artifact but rather a genuine expression of endogenous bioelectric events.
Collapse
Affiliation(s)
- Amanda R Bolbecker
- Sensory Coding Laboratory, Department of Psychological Sciences, Purdue University, 703 Third Street, West Lafayette, IN 47907-2081, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Sasaki S, Yamashita H, Yagi K, Iwaki Y, Kimura M. Full-field ERGs obtained using a contact lens electrode with built-in high intensity white light-emitting diodes in beagle dogs can be applied to toxicological assessments. Toxicol Lett 2006; 166:115-21. [PMID: 16872762 DOI: 10.1016/j.toxlet.2006.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 06/08/2006] [Accepted: 06/08/2006] [Indexed: 11/29/2022]
Abstract
We investigated full-field ERGs in beagle dogs using a contact lens electrode with built-in LED. Experiment 1 was performed to determine the appropriate conditions for stimulus intensity and background illumination. We found that full-field ERGs could be recorded under the following conditions: stimulus intensity: -2.5logcd*s/m(2) in rod responses (RRs), 1.2logcd*s/m(2) in maximal responses (MRs), oscillatory potentials (OPs), cone responses (CRs), 30-Hz flicker responses (FRs), and background illumination: more than 25cd/m(2) in CRs and FRs. Experiment 2 was performed to apply full-field ERGs in beagle dogs to the detection of retinal toxicities. A dog was given one 30mg/kg dose of sodium iodate (NaIO(3)) intravenously. ERGs were recorded before administration and 1, 3, 5, 8, 24h, 7 and 14 days after administration of NaIO(3). The RRs disappeared completely at 1h when MRs and OPs decreased. On the other hand, CRs and FRs were recorded even at 8h. All responses disappeared at 24h. These findings indicate that retinal toxicity by NaIO(3) is first expressed in rods, followed by cones. These results suggest that full-field ERGs in beagle dogs using an LED contact lens can be used to evaluate toxic effects on rods and cones separately, with the potential to prove more useful than conventional methods for toxicological assessments of developing pharmaceuticals, and can be applied to it.
Collapse
Affiliation(s)
- Shoji Sasaki
- Toxicology Laboratory, Medicinal Development Research Laboratories, Taisho Pharmaceutical Co., Ltd., 403 Yoshino-Cho 1, Kita-Ku, Saitama-Shi, Saitama 331-9530, Japan.
| | | | | | | | | |
Collapse
|
30
|
Abstract
Electroretinographic (ERG) investigations are conventionally performed by using corneal or conjunctival recording electrodes. Both types have to be placed in contact with the eye, resulting invasive and providing discomfort for the patient. This paper presents a simple technique to detect ERG potentials non-invasively. It relies on the use of a conducting liquid between the eye and an external conductor, which actually derives the ocular potential without any ocular contact. These elements are the basic components of a new type of ERG electrode, referred to as Carpi-Tomei (CT) electrode. The paper describes the assembly of prototype samples of the new electrode. Preliminary testing assessed the feasibility of the proposed non-invasive technique.
Collapse
Affiliation(s)
- F Carpi
- Interdepartmental Research Centre E Piaggio, University of Pisa, School of Engineering, via Diotisalvi, Pisa, Italy.
| | | |
Collapse
|
31
|
Abstract
The scotopic ERG recorded in response to a focal stimulus has a double b-wave. The first wave results from direct focal stimulation of the retina, and the second originates in the peripheral retina in response to scattered light. The aim of this study was to assess two possible protocols for the isolation of the focal rod response, namely 'Subtraction' and 'Background Adaptation' techniques. The Subtraction technique involved the recording of a full-field response, which matched the b-wave elicited by intraocular light scatter, and the subtraction of this full-field response from the initial trace to isolate the focal component. In the Background Adaptation technique an adapting surround was used to suppress the response from the peripheral retina. Focal rod responses were isolated with both techniques. However, the Background Adaptation technique was found to more reliably elicit a focal response with a measurable a-wave, and was also considerably less time consuming than the Subtraction technique.
Collapse
Affiliation(s)
- Alison Binns
- School of Optometry and Vision Sciences, Cardiff University, Wales, UK.
| | | |
Collapse
|
32
|
Mentzer AE, Eifler DM, Montiani-Ferreira F, Tuntivanich N, Forcier JQ, Petersen-Jones SM. Influence of Recording Electrode Type and Reference Electrode Position on the Canine Electroretinogram. Doc Ophthalmol 2006; 111:95-106. [PMID: 16514491 DOI: 10.1007/s10633-005-4517-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2005] [Indexed: 11/28/2022]
Abstract
Electroretinography is commonly used to assess the functional integrity of the retina. There are many external variables that can influence the electroretinographic waveforms recorded, and it is important to be aware of these so as not to misinterpret their effects as abnormalities in retinal function. In this study we examined the effect of three different recording electrodes on the ERGs recorded from normal dogs. A bipolar Burian-Allen lens, a monopolar Dawson Trick Litzkow (DTL) fiber electrode, and a monopolar ERG-Jet lens electrode were compared. The effect of altering the distance of the reference electrode from the eye was also examined; using the ERG-Jet lens electrode, the ERG was recorded with the reference electrode placed over the zygomatic arch at 1, 3 and 5 cm caudal to the lateral canthus. The ERGs recorded with the bipolar Burian-Allen lens had significantly lower amplitudes, higher a-wave thresholds and a shallower initial a-wave slope, than those recorded by the two monopolar electrodes. Positioning the reference electrode further from the eye resulted in significantly higher amplitudes. Naka-Rushton fitting and calculation of retinal sensitivity (K) gave significantly different results between the Burian-Allen lens and ERG-Jet lens electrode with the reference electrode 5 cm from the lateral canthus. These results demonstrate that recording electrode type and distance of the reference electrode from the eye significantly affect the ERG tracings of the dog, and may alter the assessment of retinal function that can therefore be derived. Results obtained using these three different types of electrodes cannot be directly compared.
Collapse
Affiliation(s)
- Alice E Mentzer
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | | | | | | | | | | |
Collapse
|
33
|
Kim CBY, VerHoeve JN, Kaufman PL, Nork TM. Effects of reference electrode location on monopolar-derived multifocal electroretinograms in cynomolgus monkeys. Doc Ophthalmol 2006; 111:113-25. [PMID: 16514493 DOI: 10.1007/s10633-005-4781-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2005] [Indexed: 10/25/2022]
Abstract
The purpose of this study is to determine the effect of reference electrode location on the multifocal electroretinographic waveform. Multifocal electroretinograms (mfERGs) were recorded from 20 ocularly normal cynomolgus monkeys. The corneal electrode was an ERG-jet referenced to an ipsilaterally (outer canthus) situated subdermal needle electrode and to the contralateral corneal electrode. Testing was monocular and recordings from both montages were obtained simultaneously. The stimulus array consisted of 103 equal-sized hexagonal elements, which subtended +/-44 degrees about the central visual axis. Mean luminance of the display was 100 cd/m2. First-order (K1) and second-order (first slice) kernels (K2.1) of the mfERG were grouped in (a) 4 rings, representing the central 56 degrees of visual field and (b) in 15-element quadrants. The mfERG waveform measures included amplitude, implicit time, and root mean square (RMS) of the oscillatory potentials (OP) and response waveform. K1 and K2.1 ring and quadrant amplitudes were larger with the contralateral than with the ipsilateral reference, but more notably signal-to-noise ratios (S:N) of the response waveform were always larger with the ipsilateral reference. Implicit times were longer for the contralateral than ipsilateral reference montage. K1 and K2.1 implicit times in males were longer than in females. Quadrant groupings revealed generally larger K1 and K2.1 amplitudes in nasal than in temporal retina.
Collapse
Affiliation(s)
- Charlene B Y Kim
- Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, WI 53792-3220, USA.
| | | | | | | |
Collapse
|
34
|
Abstract
The scotopic ERG recorded in response to a focal stimulus has a double b-wave. The first wave results from direct focal stimulation of the retina, and the second originates in the peripheral retina in response to scattered light. The aim of this study was to assess two possible protocols for the isolation of the focal rod response, namely 'Subtraction' and 'Background Adaptation' techniques. The Subtraction technique involved the recording of a full-field response, which matched the b-wave elicited by intraocular light scatter, and the subtraction of this full-field response from the initial trace to isolate the focal component. In the Background Adaptation technique an adapting surround was used to suppress the response from the peripheral retina. Focal rod responses were isolated with both techniques. However, the Background Adaptation technique was found to more reliably elicit a focal response with a measurable a-wave, and was also considerably less time consuming than the Subtraction technique.
Collapse
Affiliation(s)
- Alison Binns
- School of Optometry and Vision Sciences, Cardiff University, Wales, UK.
| | | |
Collapse
|
35
|
Maehara S, Osawa A, Itoh N, Wakaiki S, Tsuzuki K, Seno T, Kushiro T, Yamashita K, Izumisawa Y, Kotani T. Detection of cone dysfunction induced by digoxin in dogs by multicolor electroretinography. Vet Ophthalmol 2005; 8:407-13. [PMID: 16359364 DOI: 10.1111/j.1463-5224.2005.00415.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is difficult to detect discrete cone function with the present conventional electroretinography (ERG) examination. In this study, we developed contact electrodes with a built-in color (red (644 nm), green (525 nm), or blue (470 nm)) light source (color LED-electrode), and evaluated an experimental model of digoxin in the dog. First, 17 normal Beagle dogs were used to determine which electrode works well for color ERG measurement on dogs. Then, color ERG was performed on seven normal Beagle dogs at various points during a 14-day period of digoxin administration. A single daily dose of 0.0125 mg/kg/day, which is within the recommended oral maintenance dosage range for dogs, was administered orally for 2 weeks. Ophthalmic examination, measurement of plasma concentration of digoxin, and color ERG examination were performed. On first examination, amplitudes of all responses were significantly (P < 0.01) lower with the red, than with the blue and green electrodes during ERG recording. In ERG using the red electrode, the standard deviation was large. According to these preliminary results, the red electrode was not used in the experimental dog model with digoxin. In the digoxin administrated animals, no significant change was observed in the ophthalmic examination findings. The digoxin level increased steadily throughout the dosing period but was always within the therapeutic range for dogs. In rod ERG, no abnormalities were detected with any electrode. In standard combined ERG, decreased amplitude of the a-wave was detected with every electrode. In single flash cone ERG, prolongation of implicit time was detected by color ERG with the blue and green electrodes. In 30-Hz flicker ERG, decreased amplitude was detected only by color ERG with the blue electrode. The decreased amplitude and prolonged implicit time recovered after termination of digoxin administration. Cone dysfunction induced by digoxin in the dog was revealed by multicolor ERG using blue and green LED-electrodes. Multi-color ERG was useful for detecting cone type-specific dysfunction in the dog.
Collapse
Affiliation(s)
- Seiya Maehara
- Department of Companion Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Demontis GC, Sbrana A, Gargini C, Cervetto L. A simple and inexpensive light source for research in visual neuroscience. J Neurosci Methods 2005; 146:13-21. [PMID: 15935218 DOI: 10.1016/j.jneumeth.2005.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Revised: 01/07/2005] [Accepted: 01/10/2005] [Indexed: 11/22/2022]
Abstract
Investigating the properties of light responsive neurons and their networks requires appropriate control of stimulus parameters, such as intensity, spectral composition, spatial and temporal profile. In the present paper, we describe how to build a simple, versatile and low-cost light source for use in visual neuroscience. The light source is a InGaN-based ultrabright light-emitting diode (LED), which may generate conventional light flashes as well as a variety of time varying stimuli to be used in quantitative studies of the visual system. In particular, with this instrument one may generate light stimuli sinusoidally modulated in time at frequencies ranging from 0.05 to 50 Hz, with less than 1% harmonic distortion at a contrast exceeding 85%. The relationship between applied voltage and energy emitted by the source is linear over an intensity range that exceeds 4.5 log-units, up to the full suppression of the light-sensitive currents in mammalian rods. The light source has minimal space requirement and does not generate appreciable radiating heat and hum, allowing its use for single cell work "in vitro" as well as for "in vivo" recording of the electroretinogram (ERG).
Collapse
Affiliation(s)
- Gian Carlo Demontis
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, I-56126 Pisa, Italy.
| | | | | | | |
Collapse
|
37
|
Schmah M, Horn E. Neurophysiological long-term recordings in space: experiments Scorpi and Scorpi-T. Gravit Space Biol Bull 2005; 18:95-6. [PMID: 16038102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Michael Schmah
- University of Ulm, Gravitational Physiology, Ulm, Germany
| | | |
Collapse
|
38
|
Guarino I, Loizzo S, Lopez L, Fadda A, Loizzo A. A chronic implant to record electroretinogram, visual evoked potentials and oscillatory potentials in awake, freely moving rats for pharmacological studies. Neural Plast 2005; 11:241-50. [PMID: 15656271 PMCID: PMC2567048 DOI: 10.1155/np.2004.241] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Electroretinogram (ERG), widely used to
study the pharmacological effects of drugs in
animal models (e.g., diabetic retinopathy), is
usually recorded in anesthetized rats. We report
here a novel simple method to obtain chronic
implantation of electrodes for simultaneous
recording at the retinal and cortical levels in
freely moving, unanesthetized animals. We
recorded cortical (VEPs) and retinal (ERGs)
responses evoked by light (flash) stimuli in
awake rats and compared the results in the
same rats anesthetized with urethane (0.6
mg/kg) before and after the monocular administration
of scopolamine methyl bromide (1‰solution). We also compared the retinal
responses with those derived from a classic acute
corneal electrode. Anesthesia induced consistent
changes of several VEP and ERG parameters
like an increase of both latency and amplitude.
In particular, the analysis of the variation of
latency, amplitude, and spectral content of
rapid oscillatory potentials could be important
for a functional evaluation of the visual system
in unanesthetized versus anesthetized animals.
Collapse
Affiliation(s)
- Irene Guarino
- Istituto Superiore di Sanità, Via Regina Elena 299, Roma 00161, Italy
- University of Salerno, Department of Pharmaceutical Sciences, via Ponte Don Melillo, Fisciano (Salerno) 84084, Italy
| | - Stefano Loizzo
- Istituto Superiore di Sanità, Via Regina Elena 299, Roma 00161, Italy
| | - Luisa Lopez
- Istituto Superiore di Sanità, Via Regina Elena 299, Roma 00161, Italy
- Child Neurology Unit, University of Rome Tor Vergata, Center for Developmental Disabilities, via Anagnina Nuova 13, Grottaferrata 00046, Italy
| | - Antonello Fadda
- Istituto Superiore di Sanità, Via Regina Elena 299, Roma 00161, Italy
| | - Alberto Loizzo
- Istituto Superiore di Sanità, Via Regina Elena 299, Roma 00161, Italy
- *Alberto Loizzo:
| |
Collapse
|
39
|
Szlyk JP, Vajaranant TS, Rana R, Lai WW, Pulido JS, Paliga J, Blair NP, Seiple W. Assessing Responses of the Macula in Patients with Macular Holes using a New System Measuring Localized Visual Acuity and the mfERG. Doc Ophthalmol 2005; 110:181-91. [PMID: 16328926 DOI: 10.1007/s10633-005-4313-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2005] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate acuity and multifocal electroretinogram (mfERG) responses from the macula in affected and unaffected fellow eyes of patients with macular holes. METHODS We tested 10 eyes with macular hole and 10 fellow eyes from 11 patients. We measured local visual acuity thresholds at 27 discrete locations within 21 degrees diameter using the Functional Fundus Imaging System (FFIS), a psychophysical system that measures visual acuity as a function of visual field location, and local ERG responses within 45 degrees diameter using the mfERG. RESULTS In the affected eyes, the mean FFIS visual acuity thresholds were significantly elevated within the central 21 degrees diameter area, compared to a group of control eyes. No significant differences were found between the acuities of the fellow eyes compared to those of the control group. The amplitudes of the first positive peak of the mfERG were reduced in the central 7.8 degrees in affected eyes. In the central 2 degrees , 4 out of 10 affected eyes showed non-measurable ERG signals. The remaining six eyes showed significantly reduced mean amplitudes, but not delayed implicit times, when compared to the control group. For the fellow eyes, the mean amplitudes of the mfERG and implicit times did not differ from the means of the control eyes. CONCLUSIONS Both local psychophysical and electrophysiological testing demonstrated retinal dysfunction extending beyond the site of the macular holes in some patients (three of the patients had central mfERG amplitudes falling within the normal range).
Collapse
Affiliation(s)
- Janet P Szlyk
- Research and Development Service, Jesse Brown Department of Veterans Affairs Medical Center, Chicago, IL, USA
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
PURPOSE Compare electroretinogram (ERG) responses to full-field stimuli recorded with corneal-contact and skin electrodes in healthy children and adults. METHOD ERGs were recorded independently in two laboratories in children (aged 4-14 years) and adults (aged 20-62 years). A Burian-Allen (BA) electrode were used to test both children and adults in one laboratory. A Gold Foil (GF) electrode was used to test adults and skin electrodes to test children and adults in the other laboratory. Responses were recorded to full-field stimuli similar to those specified in the ISCEV Standard. Dark-adapted responses were also recorded over a 5 log unit range of stimulus energies. RESULTS All ISCEV rod and cone responses were recorded in every subject with skin electrodes as well as with eye-contact electrodes. BA and GF amplitudes and latencies were similar for the majority of ISCEV responses. The waveform morphology of rod and cone skin electrode responses was similar to corneal electrode responses in children and adults. GF electrode responses were on average 4 to 5 times larger than skin electrode responses recorded in the same laboratory. After scaling skin electrode responses by 4.5 the distribution of response amplitudes was found to be similar to that for the eye-contact electrodes in both children and adults. Dark-adapted responses were recorded to all stimulus intensities in every subject with each type of electrode. B-wave S-R functions were evaluated by fitting the Naka-Rushton equation. Vmax was similar for BA and GF electrode responses and this was about 4 times greater than for skin electrode responses. Log (sigma) was similar for GF and skin electrodes but these differed significantly from the BA electrode. Vmax and log(sigma) were similar in adults and children for BA and skin electrode responses. CONCLUSION ERGs to full-field stimuli can be recorded successfully with either eye-contact or skin electrodes.
Collapse
Affiliation(s)
- Keith Bradshaw
- Vision Science, Ophthalmology Department, Addenbrooke's Hospital, Cambridge, UK.
| | | | | |
Collapse
|
41
|
Maehara S, Itoh N, Itoh Y, Wakaiki S, Tsuzuki K, Seno T, Kushiro T, Yamashita K, Izumisawa Y, Kotani T. Electroretinography Using Contact Lens Electrode with Built-In Light Source in Dogs. J Vet Med Sci 2005; 67:509-14. [PMID: 15942136 DOI: 10.1292/jvms.67.509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m(2)/sec (6,000 cd/m(2), 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m(2)/sec (80 cd/m(2), 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function.
Collapse
Affiliation(s)
- Seiya Maehara
- Department of Companion Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Affiliation(s)
- Michael F Marmor
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA 94305-5308, USA.
| | | | | | | |
Collapse
|
43
|
Abstract
To compare the recording characteristics of the DTL fiber and Jet contact lens electrodes, ERG responses were recorded from 20 normal subjects using the ISCEV standard clinical protocol. In each subject, the DTL electrode was placed in the right eye and the Jet contact lens in the left eye after 30 min of dark-adaptation. After presenting standard dark- and light-adapted stimuli, each response was analyzed for a- and b-wave amplitude and implicit time. Each subject was then asked to rate the comfort of each electrode. Responses recorded with the DTL are larger and faster for the dark-adapted dim white and red flashes. In contrast, the Jet electrode records larger responses for the dark-adapted standard flash and light-adapted flashes. Of these differences, only the standard flash is statistically significant. However, overall the DTL electrode has greater variability than the Jet electrode across all recordings. The DTL and Jet electrodes cannot be used interchangeably as demonstrated by a Bland and Altman analysis of agreement. Thus, separate normative values need to be collected for each type of electrode to accurately assess retinal function. Based on the comfort assessment of the two electrodes, the subjects preferred the DTL electrode over the Jet electrode. Due to the superior comfort level of the DTL and its similarities to the Jet contact lens electrode in ERG recordings, the DTL electrode appears to be a good alternative to the Jet electrode in routine clinical testing when used with the appropriate normative values.
Collapse
Affiliation(s)
- Hang Yin
- Emory University, Atlanta, GA, USA
| | | |
Collapse
|
44
|
Abstract
The electroretinogram (ERG) is routinely used to study retinal physiology in the clinic and in research. Due to their outstanding properties, contact lens electrodes (CLEs) are widely used for ERG recordings. Though the procedures for ERG recordings in mice are similar to those used in humans and larger vertebrates, use of CLEs in the mouse has been limited because of difficulties involved with the manufacturing of small contact lenses. We describe a simple instrument and method for manufacturing contact lenses and CLEs for stable ERG recordings in mice. The instrument operates like a hole-punch and is based on slip joint pliers incorporating a ball bearing on one jaw and forming plate on the other. These CLEs are simple to manufacture, inexpensive and provide stable, long-term recordings of corneal ERGs in mice. With minor modifications, these CLEs could be made for other small animals such as rats or fish.
Collapse
Affiliation(s)
- Botir T Sagdullaev
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY 40292, USA.
| | | | | |
Collapse
|
45
|
Schipper J, Ridder GJ, Arapakis I, Gellrich NC, Spetzger U, Maier W. [Neurophysiologic intraoperative monitoring to preserve cranial nerve function in base of skull surgery]. HNO 2004; 52:897-907. [PMID: 15067412 DOI: 10.1007/s00106-004-1074-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Neurophysiologic intraoperative monitoring (NIM) has gone through a renaissance since the advent of computer technology. Currently, both motor and sensory cranial nerves, including the IInd and VIIIth cranial nerves, can be intraoperatively controlled by means of small and mobile systems. PATIENTS AND METHODS In order to estimate the value of NIM using the new generation of computer systems, we analyzed the records of 379 patients who underwent skull base surgery since 1996. These comprised NIM of the IInd, VIIth, VIIIth cranial nerves in most cases and of the IXth, Xth, XIth, and XIIth cranial nerves in selected cases. RESULTS Whereas 72% of these cases demonstrated changes in the recorded intraoperative NIM signals, only 29% of them gave evidence of either clinical or electrophysiological neural function alterations during the postoperative follow-up. CONCLUSIONS NIM is the only available system capable of providing the surgeon with instant intraoperative neural status-related feedback.
Collapse
Affiliation(s)
- J Schipper
- Interdisziplinäres Zentrum für Schädelbasis- und Craniofaciale Chirurgie am Universitätsklinikum Freiburg.
| | | | | | | | | | | |
Collapse
|
46
|
Mohan Ram LS, Jalali S, Roopa Reddy PS, Rao VS, Das T, Nutheti R. Safety and efficacy evaluation of a new electrode (the LVP electrode) part I. Pattern ERG pilot study. Doc Ophthalmol 2004; 107:171-7. [PMID: 14661907 DOI: 10.1023/a:1026303905863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have designed a less expensive, non-corneal ERG electrode. Named as the LVP electrode, this new disposable electrode was found safe and reliable for pattern ERG recordings.
Collapse
Affiliation(s)
- L S Mohan Ram
- Smt. Kannuri Santhamma Retina Vitreous Center, L V Prasad Eye Institute, Hyderabad, India
| | | | | | | | | | | |
Collapse
|
47
|
Porciatti V, Ventura LM. Normative data for a user-friendly paradigm for pattern electroretinogram recording. Ophthalmology 2004; 111:161-8. [PMID: 14711729 PMCID: PMC2760457 DOI: 10.1016/j.ophtha.2003.04.007] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2003] [Accepted: 04/11/2003] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To provide normative data for a user-friendly paradigm for the pattern electroretinogram (PERG) optimized for glaucoma screening (PERGLA). DESIGN Prospective nonrandomized case series. PARTICIPANTS Ninety-three normal subjects ranging in age between 22 and 85 years. METHODS A circular black-white grating of 25 degrees visual angle, reversing 16.28 times per second, was presented on a television monitor placed inside a Ganzfeld bowl. The PERG was recorded simultaneously from both eyes with undilated pupils by means of skin cup electrodes taped over the lower eyelids. Reference electrodes were taped on the ipsilateral temples. Electrophysiologic signals were conventionally amplified, filtered, and digitized. Six hundred artifact-free repetitions were averaged. The response component at the reversal frequency was isolated automatically by digital Fourier transforms and was expressed as a deviation from the age-corrected average. The procedure took approximately 4 minutes. MAIN OUTCOME MEASURES Pattern electroretinogram amplitude ( micro V) and phase (pi rad); response variability (coefficient of variation [CV] = standard deviation [SD] / mean x 100) of amplitude and phase of 2 partial averages that build up the PERG waveform; amplitude ( micro V) of background noise waveform, obtained by multiplying alternate sweeps by +1 and -1; and interocular asymmetry (CV of amplitude and phase of the PERG of the 2 eyes). RESULTS On average, the PERG has a signal-to-noise ratio of more than 13:1. The CVs of intrasession and intersession variabilities in amplitude and phase are lower than 10% and 2%, respectively, and do not depend on the operator. The CV of interocular asymmetries in amplitude and phase are 9.8+/-8.8% and 1.5+/-1.4%, respectively. The PERG amplitude and phase decrease with age. Residuals of linear regression lines have normal distribution, with an SD of 0.1 log units for amplitude and 0.019 log units for phase. Age-corrected confidence limits (P<0.05) are defined as +/-2 SD of residuals. CONCLUSIONS The PERGLA paradigm yields responses as reliable as the best previously reported using standard protocols. The ease of execution and interpretation of results of PERGLA indicate a potential value for objective screening and follow-up of glaucoma.
Collapse
|
48
|
Abstract
PURPOSE To characterize the cone electroretinograms (ERGs) elicited by chromatic stimuli obtained from a newly-developed contact lens electrode with built-in light-emitting diodes (LEDs) emitting different colors. METHODS Cone ERGs were recorded from normal subjects with a contact lens electrode with built-in blue (430 nm), red (644 nm), and white LEDs. These LEDs have a wide range of luminance intensities (3 log units), and can be used as either the background illumination or the stimulus in any combination. The stimulus duration was fixed at 1 ms. For comparison, cone ERGs were recorded with Ganzfeld color flash stimuli using Wratten color filters on a bright white background. RESULTS With a bright background illumination provided by the white LED (2.0 log cd/m2), the blue LED stimulus elicited an ERG with two positive peaks similar to that recorded with conventional Ganzfeld blue flashes. The peak time of the early b-wave was 24 to 28 ms, and that of the later one was 43 to 48 ms, and these values were identical to the L,M-cone and S-cone b-wave, respectively, elicited by Ganzfeld flashes. The ERGs elicited by the red LED lacked the second peak. CONCLUSION These results indicate that the S-cone and L,M-cone ERGs can be recorded simultaneously under the same background with this contact lens electrode. This relatively simple technique can be used to examine the human S-cone system in a routine clinical setting.
Collapse
Affiliation(s)
- Mieko Tsuruoka
- Department of Ophthalmology, Toho University Sakura Hospital, Sakura, Japan
| | | | | | | |
Collapse
|
49
|
Mohan Ram LS, Jalali S, Faheemuddin S, Das T, Nutheti R. Safety and efficacy evaluation of a new ERG electrode (the LVP electrode) part II. Flash ERG pilot study. Doc Ophthalmol 2003; 107:179-83. [PMID: 14661908 DOI: 10.1023/a:1026301422701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A new disposable, non-contact electrode (LVP electrode) was evaluated for use in recording flash ERG. A comparison of DTL and LVP electrodes showed reproducible waveforms for all components analysed. There was a good correlation obtained between the DTL and LVP electrodes. The LVP electrode is safe, less expensive and has less movement of the fiber due to its rigidity.
Collapse
Affiliation(s)
- L S Mohan Ram
- Smt. Kannuri Santhamma Retina Vitreous Center, L V Prasad Eye Institute, Hyderabad, India
| | | | | | | | | |
Collapse
|
50
|
Rudolph G, Kalpadakis P, Bechmann M, Haritoglou C, Kampik A. Scanning laser ophthalmoscope-evoked multifocal ERG (SLO-mfERG) in patients with macular holes and normal individuals. Eye (Lond) 2003; 17:801-8. [PMID: 14528241 DOI: 10.1038/sj.eye.6700502] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIMS A scanning laser ophthalmoscope (SLO) has been used for multifocal electroretinography (mf ERG) measurements under simultaneous fundus monitoring. The aim of this study was to prove if the SLO-mfERG measurement reflects reliably the clinically registered underlying disease, and to demonstrate the importance of its main advantage, fixation monitoring. METHODS In all, 10 patients with macular hole stage II/III were included in the study, and 19 normal individuals served as the control group. The mf ERG device was combined with an SLO, which was used both as a stimulus and trigger unit as well as a fundus-monitoring system. Monitoring of the fundus was guaranteed by an infrared laser (780 nm). The stimulus matrix consisted of 61 hexagonal elements, covering 24 degrees of the posterior pole. We examined both, patients with macular holes and healthy individuals. RESULTS Compared to normal controls, patients with a macular hole (Gass stage III) showed a significant decrease in response density in the centre of the stimulus array, which correlated well with the morphological alteration observed by clinical examination. However, variation of response density of the central hexagonal area has been proved to be high. CONCLUSIONS SLO-mfERG is a feasible and reliable new technique to investigate macular function under simultaneous fundus control. The main advantage is that control of fixation can be used in order to obtain more reliable results that correlate well with visible fundus abnormalities such as in patients with macular holes. However, further investigations have to be performed in order to overcome sufficiently the problem of fixation instability.
Collapse
Affiliation(s)
- G Rudolph
- Eye Clinic, Ludwig-Maximilians-University Munich, Germany.
| | | | | | | | | |
Collapse
|