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Kabdebon C, Fló A, de Heering A, Aslin R. The power of rhythms: how steady-state evoked responses reveal early neurocognitive development. Neuroimage 2022; 254:119150. [PMID: 35351649 PMCID: PMC9294992 DOI: 10.1016/j.neuroimage.2022.119150] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 12/17/2022] Open
Abstract
Electroencephalography (EEG) is a non-invasive and painless recording of cerebral activity, particularly well-suited for studying young infants, allowing the inspection of cerebral responses in a constellation of different ways. Of particular interest for developmental cognitive neuroscientists is the use of rhythmic stimulation, and the analysis of steady-state evoked potentials (SS-EPs) - an approach also known as frequency tagging. In this paper we rely on the existing SS-EP early developmental literature to illustrate the important advantages of SS-EPs for studying the developing brain. We argue that (1) the technique is both objective and predictive: the response is expected at the stimulation frequency (and/or higher harmonics), (2) its high spectral specificity makes the computed responses particularly robust to artifacts, and (3) the technique allows for short and efficient recordings, compatible with infants' limited attentional spans. We additionally provide an overview of some recent inspiring use of the SS-EP technique in adult research, in order to argue that (4) the SS-EP approach can be implemented creatively to target a wide range of cognitive and neural processes. For all these reasons, we expect SS-EPs to play an increasing role in the understanding of early cognitive processes. Finally, we provide practical guidelines for implementing and analyzing SS-EP studies.
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Affiliation(s)
- Claire Kabdebon
- Laboratoire de Sciences Cognitives et Psycholinguistique, Département d'études cognitives, ENS, EHESS, CNRS, PSL University, Paris, France; Haskins Laboratories, New Haven, CT, USA.
| | - Ana Fló
- Cognitive Neuroimaging Unit, CNRS ERL 9003, INSERM U992, CEA, Université Paris-Saclay, NeuroSpin Center, Gif/Yvette, France
| | - Adélaïde de Heering
- Center for Research in Cognition & Neuroscience (CRCN), Université libre de Bruxelles (ULB), Brussels, Belgium
| | - Richard Aslin
- Haskins Laboratories, New Haven, CT, USA; Department of Psychology, Yale University, New Haven, CT, USA
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Assessment of Human Visual Acuity Using Visual Evoked Potential: A Review. SENSORS 2020; 20:s20195542. [PMID: 32998208 PMCID: PMC7582995 DOI: 10.3390/s20195542] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/16/2020] [Accepted: 09/25/2020] [Indexed: 01/23/2023]
Abstract
Visual evoked potential (VEP) has been used as an alternative method to assess visual acuity objectively, especially in non-verbal infants and adults with low intellectual abilities or malingering. By sweeping the spatial frequency of visual stimuli and recording the corresponding VEP, VEP acuity can be defined by analyzing electroencephalography (EEG) signals. This paper presents a review on the VEP-based visual acuity assessment technique, including a brief overview of the technique, the effects of the parameters of visual stimuli, and signal acquisition and analysis of the VEP acuity test, and a summary of the current clinical applications of the technique. Finally, we discuss the current problems in this research domain and potential future work, which may enable this technique to be used more widely and quickly, deepening the VEP and even electrophysiology research on the detection and diagnosis of visual function.
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Hamilton R, Bach M, Heinrich SP, Hoffmann MB, Odom JV, McCulloch DL, Thompson DA. VEP estimation of visual acuity: a systematic review. Doc Ophthalmol 2020; 142:25-74. [PMID: 32488810 PMCID: PMC7907051 DOI: 10.1007/s10633-020-09770-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 05/05/2020] [Indexed: 01/23/2023]
Abstract
Purpose Visual evoked potentials (VEPs) can be used to measure visual resolution via a spatial frequency (SF) limit as an objective estimate of visual acuity. The aim of this systematic review is to collate descriptions of the VEP SF limit in humans, healthy and disordered, and to assess how accurately and precisely VEP SF limits reflect visual acuity. Methods The protocol methodology followed the PRISMA statement. Multiple databases were searched using “VEP” and “acuity” and associated terms, plus hand search: titles, abstracts or full text were reviewed for eligibility. Data extracted included VEP SF limits, stimulus protocols, VEP recording and analysis techniques and correspondence with behavioural acuity for normally sighted healthy adults, typically developing infants and children, healthy adults with artificially degraded vision and patients with ophthalmic or neurological conditions. Results A total of 155 studies are included. Commonly used stimulus, recording and analysis techniques are summarised. Average healthy adult VEP SF limits vary from 15 to 40 cpd, depend on stimulus, recording and analysis techniques and are often, but not always, poorer than behavioural acuity measured either psychophysically with an identical stimulus or with a clinical acuity test. The difference between VEP SF limit and behavioural acuity is variable and strongly dependent on the VEP stimulus and choice of acuity test. VEP SF limits mature rapidly, from 1.5 to 9 cpd by the end of the first month of life to 12–20 cpd by 8–12 months, with slower improvement to 20–40 cpd by 3–5 years. VEP SF limits are much better than behavioural thresholds in the youngest, typically developing infants. This difference lessens with age and reaches equivalence between 1 and 2 years; from around 3–5 years, behavioural acuity is better than the VEP SF limit, as for adults. Healthy, artificially blurred adults had slightly better behavioural acuity than VEP SF limits across a wide range of acuities, while adults with heterogeneous ophthalmic or neurological pathologies causing reduced acuity showed a much wider and less consistent relationship. For refractive error, ocular media opacity or pathology primarily affecting the retina, VEP SF limits and behavioural acuity had a fairly consistent relationship across a wide range of acuity. This relationship was much less consistent or close for primarily macular, optic nerve or neurological conditions such as amblyopia. VEP SF limits were almost always normal in patients with non-organic visual acuity loss. Conclusions The VEP SF limit has great utility as an objective acuity estimator, especially in pre-verbal children or patients of any age with motor or learning impairments which prevent reliable measurement of behavioural acuity. Its diagnostic power depends heavily on adequate, age-stratified, reference data, age-stratified empirical calibration with behavioural acuity, and interpretation in the light of other electrophysiological and clinical findings. Future developments could encompass faster, more objective and robust techniques such as real-time, adaptive control. Registration International prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), registration number CRD42018085666.
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Affiliation(s)
- Ruth Hamilton
- Department of Clinical Physics and Bioengineering, Royal Hospital for Children, NHS Greater Glasgow and Clyde, Glasgow, UK. .,College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Michael Bach
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sven P Heinrich
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - J Vernon Odom
- Departments of Ophthalmology and Neuroscience, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Daphne L McCulloch
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Dorothy A Thompson
- The Department of Clinical and Academic Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,University College London Great Ormond Street Institute of Child Health, London, UK
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Similarities and differences between behavioral and electrophysiological visual acuity thresholds in healthy infants during the second half of the first year of life. Doc Ophthalmol 2017; 134:99-110. [PMID: 28220265 DOI: 10.1007/s10633-017-9576-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 02/09/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE Behavioral and electrophysiological methods for visual acuity estimation typically correlate well in children and adult populations, but this relationship remains unclear in infants, particularly during the second half of the first year of life. It has been suggested that the agreement between both methods mostly relies on age and/or subjective acuity factors. The present study aimed at comparing acuity thresholds obtained with both approaches in a sample of healthy infants in a relatively narrow age range, that is 6-10 months old. METHODS Acuity thresholds were assessed in 61 healthy infants aged between 6 and 10 months using the Teller acuity cards (TAC) and sweep visual evoked potentials (sVEP). The TAC stimuli (stationary vertical gratings displayed on laminated cards) ranged from 0.31 to 38 cycles per degree (cpd). The TAC acuity threshold was estimated according to the highest spatial frequency scored by the experimenter as seen by the infant. The sVEP stimuli (high-contrast vertical gratings counter-phased at 12 reversals/s) ranged from 13.5 to 1 cpd. sVEP were recorded at Oz and acuity threshold was estimated using regression linear fitting. RESULTS Considering the entire sample, sVEP acuity thresholds (8.97 ± 2.52 cpd) were significantly better than TAC scores (5.58 ± 2.95 cpd), although the difference was within 1 octave for 64% of the infants. Neither Pearson nor intra-class correlations between the two methods were significant (0.18 and 0.03, respectively). While age at assessment was not related to any dependent variable (TAC, sVEP, sVEP-TAC difference score), subjective (behavioral) acuity was found to underlie the difference between the two methods. The difference between sVEP and TAC scores decreased as a function of subjective acuity, and at the highest subjective acuity level (>10 cpd), TAC acuity slightly exceeded sVEP acuity. CONCLUSIONS The superiority of sVEP acuity often reported in the literature was evident in our infant sample when subjective acuity (TAC) was low or moderate, but not when it was high (>10 cpd). The relationship between the two estimation methods was not dependent on age, but on subjective acuity.
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5
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Vesely P. Contribution of sVEP visual acuity testing in comparison with subjective visual acuity. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2015; 159:616-21. [PMID: 25690522 DOI: 10.5507/bp.2015.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 01/15/2015] [Indexed: 11/23/2022] Open
Abstract
AIMS Visual acuity determination is an important task in ophthalmology and optometry practices. Visual acuity can be examined objectively or subjectively. The objective examination method, sVEP, allows for quick objective measurements of patient's visual acuity. Previous studies have not demonstrated the repeatability of this objective sVEP method. This study aims to evaluate the sVEP method and compare it to a subjective method. METHODS AND RESULTS The sample was divided into two groups. For the first group, visual acuity was measured with sVEP and Snellen methods on only one patient twelve times. In the second group, visual acuity was measured twice with sVEP followed twice with the Snellen method with Landolt's rings and logMAR modification on 32 non-pathological patients. Results showed significant differences between average values of visual acuity obtained with both methods (sVEP and Snellen) in both samples (T-test, P < 0.01; Wilcoxon test, P = 0.02 in second group). In the second group, significant correlations between repeated sVEP measurements (Spearman test, P < 0.05, r = 0.69) were found but no significant correlation between average sVEP measurement and average Snellen measurement (Spearman test, P > 0.05, r = 0.15) was found. CONCLUSION Objective measurement of visual acuity with sVEP is a valid and reliable method, but is recommended only when it is not possible to use a subjective method for measuring visual acuity, e.g. children, patients with mental retardation or simulating/dissimulating patients.
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Affiliation(s)
- Petr Vesely
- Department of Optometry and Orthoptics, Faculty of Medicine, Masaryk University, Brno and Department of Ophthalmology and Optometry, St. Anne's University Hospital in Brno, Czech Republic
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Effects of sweep VEP parameters on visual acuity and contrast thresholds in children and adults. Graefes Arch Clin Exp Ophthalmol 2010; 249:613-23. [DOI: 10.1007/s00417-010-1469-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 06/08/2010] [Accepted: 07/17/2010] [Indexed: 10/19/2022] Open
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Lesmes LA, Lu ZL, Baek J, Albright TD. Bayesian adaptive estimation of the contrast sensitivity function: the quick CSF method. J Vis 2010; 10:17.1-21. [PMID: 20377294 PMCID: PMC4439013 DOI: 10.1167/10.3.17] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 11/10/2009] [Indexed: 11/24/2022] Open
Abstract
The contrast sensitivity function (CSF) predicts functional vision better than acuity, but long testing times prevent its psychophysical assessment in clinical and practical applications. This study presents the quick CSF (qCSF) method, a Bayesian adaptive procedure that applies a strategy developed to estimate multiple parameters of the psychometric function (A. B. Cobo-Lewis, 1996; L. L. Kontsevich & C. W. Tyler, 1999). Before each trial, a one-step-ahead search finds the grating stimulus (defined by frequency and contrast) that maximizes the expected information gain (J. V. Kujala & T. J. Lukka, 2006; L. A. Lesmes et al., 2006), about four CSF parameters. By directly estimating CSF parameters, data collected at one spatial frequency improves sensitivity estimates across all frequencies. A psychophysical study validated that CSFs obtained with 100 qCSF trials ( approximately 10 min) exhibited good precision across spatial frequencies (SD < 2-3 dB) and excellent agreement with CSFs obtained independently (mean RMSE = 0.86 dB). To estimate the broad sensitivity metric provided by the area under the log CSF (AULCSF), only 25 trials were needed to achieve a coefficient of variation of 15-20%. The current study demonstrates the method's value for basic and clinical investigations. Further studies, applying the qCSF to measure wider ranges of normal and abnormal vision, will determine how its efficiency translates to clinical assessment.
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Affiliation(s)
- Luis Andres Lesmes
- Vision Center Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA.
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Almoqbel F, Leat SJ, Irving E. The technique, validity and clinical use of the sweep VEP. Ophthalmic Physiol Opt 2008; 28:393-403. [PMID: 18761477 DOI: 10.1111/j.1475-1313.2008.00591.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vision scientists have concentrated on studying two visual functions when it comes to assessing the sensory visual development in human: visual acuity and contrast sensitivity. The methods used to measure these visual functions can be either behavioral or electrophysiological. A relatively new technique for measuring the visual acuity and contrast sensitivity electrophysiologically is the sweep visual evoked potential (sVEP). This paper is a review of the literature on the sVEP technique: stimulus parameters, threshold determination, validity and reliability of sVEP are discussed. Different studies using the sVEP to study the development of visual acuity, contrast sensitivity, and vernier acuity are presented. Studies have demonstrated that the sVEP is a potentially important tool for assessing visual acuity and contrast sensitivity in non-verbal individuals with disorders affecting their visual system.
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Affiliation(s)
- Fahad Almoqbel
- School of Optometry, University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1, Canada.
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9
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Abstract
Uma das funções visuais mais estudadas durante os primeiros anos de vida é a acuidade visual. A acuidade visual reflete a capacidade do sistema visual em discriminar detalhes de um objeto. Em bebês e pacientes não-verbais, utiliza-se a avaliação da acuidade visual de resolução de grades. Neste artigo, são mostrados os diferentes métodos de medida da acuidade de grades disponíveis para uso em clínica, juntamente com dados de desenvolvimento normal dessa função.
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Seiple W, Holopigian K, Clemens C, Greenstein VC, Hood DC. The multifocal visual evoked potential: An objective measure of visual fields? Vision Res 2005; 45:1155-63. [PMID: 15707924 DOI: 10.1016/j.visres.2004.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Revised: 10/21/2004] [Accepted: 11/09/2004] [Indexed: 11/22/2022]
Abstract
We examined the effects of inter-modal attention and mental arithmetic on Humphrey visual field sensitivity and multifocal visual evoked potential (mfVEP) amplitude. Four normally sighted subjects (ages ranging from 24 to 58 years) participated in this study. Monocular visual field sensitivity was measured under two conditions: (1) standard testing condition and (2) while the subject performed a Paced Auditory Serial Addition Task (PASAT). Monocular mfVEPs were recorded in response to a 60-sector stimulus. The checkerboard pattern in each sector was contrast reversed according to a binary m-sequence. mfVEPs were recorded under two conditions: (1) standard testing conditions and (2) while the subject performed a PASAT. We found that, when compared to the no-task condition, all subjects had locations of significantly reduced Humphrey visual field sensitivities when performing the PASAT. In contrast, there were no significant decreases in mfVEP amplitude in any sector for any of the subjects while performing the PASAT. Our findings indicate that divided attention and ongoing mental processes did not affect the mfVEP. Therefore, the mfVEP provides an objective measure of visual field function that may be useful for some patients with unreliable automated static perimetry results.
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Affiliation(s)
- William Seiple
- Department of Ophthalmology, New York University School of Medicine, BEL 5N15, 550 First Avenue, New York, NY 10016, USA.
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11
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Chapter 11 Assessment of vision in infants and young children. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1567-4231(09)70208-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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12
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Abstract
Young infants can distinguish red from green without brightness cues which shows that neural pathways processing color information (the 'red-green' color-opponent pathway) are functional early in life. There is some doubt over whether the 'blue-yellow' pathway is functional in young infants. Here, we show that infants behave like tritanopic adults until 2-3 months post-term age. By 3-4 months, infants distinguish tritan stimuli, and therefore, the 'blue-yellow' pathway must be functional by that age. Our sweep visual evoked potentials to identical stimuli, however, are not significantly above noise levels, in disagreement with the behavioral responses. We discuss several possible explanations for the discrepancy.
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Affiliation(s)
- Catherine M Suttle
- School of Optometry, University of California, Berkeley, CA 94720-2020, USA.
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13
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Suttle CM, Banks MS, Candy TR. Does a front-end nonlinearity confound VEP acuity measures in human infants? Vision Res 2001; 40:3665-75. [PMID: 11116168 DOI: 10.1016/s0042-6989(00)00208-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The visual evoked potential is commonly used to estimate visual acuity in infants. The stimulus used is temporally modulated in order to drive the cortical response. Here it is proposed that distortion products generated by a front-end nonlinearity may contaminate the acuity estimate. Specifically, the nonlinearity might convert temporal modulation of a high spatial frequency grating into apparent whole-field flicker. Thus, the VEP may reflect an artifactual response to a high spatial frequency that is not resolved at the cortical level. If this were the case, one could null or attenuate the flicker response by adding whole-field flicker to the grating stimulus. We looked for such nulling effects in 18 infants aged 6-17 weeks. No consistent evidence was found for the nulling effect, so it was concluded that infant VEP acuity estimates are not significantly contaminated by the hypothesized distortion product.
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Affiliation(s)
- C M Suttle
- School of Optometry, University of California, Berkeley, CA, USA.
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14
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Candy TR, Banks MS. Use of an early nonlinearity to measure optical and receptor resolution in the human infant. Vision Res 1999; 39:3386-98. [PMID: 10615503 DOI: 10.1016/s0042-6989(99)00035-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We measured the resolution of the optics and receptoral processes in human infants. To do so, we recorded visual-evoked potentials (VEPs) to sampled sinewave gratings, stimuli that generate highly visible distortion products at a nonlinearity early in the retina. We varied the spatial frequency content of the stimulus to determine the frequencies that can be transmitted through the optics and receptors and thereby generate distortion products. Data were collected from adults and 2- to 7-month-old infants. The results indicated that the resolution of the infants' optical/receptoral processes was within a factor of two of adults' even at the earliest ages tested. These first stages of processing, therefore, do not explain infants' poor performance in many visual tasks, or restrict the types of visual stimuli affecting more central mechanisms that undergo experience-dependent development.
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Affiliation(s)
- T R Candy
- School of Optometry, University of California at Berkeley, USA.
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15
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Candy TR, Crowell JA, Banks MS. Optical, receptoral, and retinal constraints on foveal and peripheral vision in the human neonate. Vision Res 1998; 38:3857-70. [PMID: 10211379 DOI: 10.1016/s0042-6989(98)00080-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We examined the properties of the foveal, parafoveal, and near peripheral cone lattice in human neonates. To estimate the ability of these lattices to transmit the information used in contrast sensitivity and visual acuity tasks, we constructed ideal-observer models with the optics and photoreceptors of the neonatal eye at retinal eccentricities of 0, 5, and 10 degrees. For ideal-observer models limited by photon noise, the eye's optics, and cone properties, contrast sensitivity was higher in the parafovea and near periphery than in the fovea. However, receptor pooling probably occurs in the neonate's parafovea and near periphery as it does in mature eyes. When we add a receptor-pooling stage to the models of the parafovea and near periphery, ideal acuity is similar in the fovea, parafovea, and near periphery. Comparisons of ideal and real sensitivity indicate that optical and receptoral immaturities impose a significant constraint on neonatal contrast sensitivity and acuity, but that immaturities in later processing stages must also limit visual performance.
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Affiliation(s)
- T R Candy
- School of Optometry, University of California, Berkeley 94720-2020, USA.
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16
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Balaban MT, Dannemiller JL. Age differences in responses to temporally modulated patterns at 6 and 12 weeks. Infant Behav Dev 1992. [DOI: 10.1016/0163-6383(92)80005-f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Abstract
Forced-choice preferential-looking (FPL) and pattern-visual-evoked potential (VEP) acuity tests were conducted with 42 children with bilateral moderate to severe visual impairment (age, 4 months to 9 years). Within this group of children, FPL acuity testing was more successful than VEP acuity testing (98% versus 64%). Mean FPL acuity was better than mean VEP acuity (20/155 vs 20/290, P less than .002). For the children who completed both FPL and VEP acuity tests, an acuity difference score (FPL minus VEP) was derived, and compared to difference scores based on normative data. Significant differences were found between visually impaired (VI) and control difference scores (P less than .001). Difference scores of VI were larger than and opposite in sign to the control scores. Rating scores of visual behaviors supported the concurrent validity of the FPL acuities (P = .01), but not the VEP acuities.
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Affiliation(s)
- M C Bane
- Retina Foundation of the Southwest, Dallas, TX 75231
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18
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Suter S, Suter PS, Crow C. Infant and adult grating acuity estimated by VEPs and heart-rate change. Infant Behav Dev 1991. [DOI: 10.1016/0163-6383(91)90028-q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
The development of visual motion mechanisms has been studied in infants with a visual evoked potential (VEP) technique which isolates responses from directionally-selective mechanisms. In adults, the amplitude of this directional VEP increased with velocity up to a maximum at 15-20 deg/sec, and then declined with further increases in velocity. In a group of infants tested longitudinally, directional responses were first found at a median age of 74 days with a stimulus velocity of 5 deg/sec, and 90 days with a velocity of 20 deg/sec; this age difference was statistically significant. Initially, VEP amplitudes were significantly greater at 5 deg/sec than at 20 deg/sec. By the end of the longitudinal study, there was no significant difference in amplitudes at the two velocities. In a second group of infants, simultaneous recording of VEPs and electrooculograms indicated that eye movements tracking the stimulus were not a significant factor in the development of the directional VEP. It is concluded that the development of directional selectivity starts at low velocities, and extends to higher velocities with age.
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Affiliation(s)
- J Wattam-Bell
- Department of Experimental Psychology, University of Cambridge, U.K
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20
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Gottlob I, Fendick MG, Guo S, Zubcov AA, Odom JV, Reinecke RD. Visual acuity measurements by swept spatial frequency visual-evoked-cortical potentials (VECPs): clinical application in children with various visual disorders. J Pediatr Ophthalmol Strabismus 1990; 27:40-7. [PMID: 2324917 DOI: 10.3928/0191-3913-19900101-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous studies have indicated that visual acuities of normal infants can be estimated with good accuracy using swept spatial frequency visual-evoked-potentials (VECPs). In this report we describe acuity measurements obtained with this technique from 304 examinations performed on 135 children having various visual disorders. When possible, two or more different stimulation frequencies (8, 12, 15 or 24 contrast reversals/sec) were used in each patient, and three to eight sweep VECPs were obtained from each patient under each simulation and recording condition. High correlation coefficients (0.94 - 0.96) between the acuity estimated on each patient from either the single sweep giving the best visual acuity (BSS) or from vector averages (VeA) of the EEG data obtained from several sweeps confirmed previous findings in normal infants. We also found high correlation coefficients among BSS recorded at different temporal frequencies (0.79-0.97) and among comparisons of BSS or VeA acuity to optotype visual acuity (0.6-0.89). Children with clinically undetectable optokinetic responses showed lower visual acuity estimated by BSS than those who demonstrated optokinetic nystagmus. We conclude that the sweep VECP is a valid method, giving estimates of acuity which correlate well with optotype acuity and correspond well to other clinical findings, and that it can be useful in the clinical management of nonverbal patients.
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Affiliation(s)
- I Gottlob
- Foerderer Eye Movement Center for Children, Wills Eye Hospital, Philadelphia, PA 19107
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21
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Swanson WH, Birch EE. Infant spatiotemporal vision: dependence of spatial contrast sensitivity on temporal frequency. Vision Res 1990; 30:1033-48. [PMID: 2392833 DOI: 10.1016/0042-6989(90)90113-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Effects of temporal frequency on infant spatial contrast sensitivity were studied with forced-choice preferential looking, using localized 1.0 and 0.35 c/deg grating patches. Between 4 and 8 months, contrast sensitivity at 1.0 c/deg increased significantly at 8-17 Hz but showed little change at 2-4 Hz, so temporal tuning became increasingly bandpass with age. At 4 months, temporal tuning was lowpass at 1.0 c/deg and bandpass at 0.35 c/deg. Control data on adults indicate that the differences between the infant and adult data cannot be accounted for solely by reduced photoreceptor density and quantal catch, and suggest developmental changes in tuning and/or relative sensitivities of spatiotemporal mechanisms.
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Affiliation(s)
- W H Swanson
- Retina Foundation of the Southwest, Dallas, TX 75231
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