Age norms for monocular grating acuity measured by sweep-VEP in the first three years of age

Salomão, Solange Rios; Ejzenbaum, Fábio; Berezovsky, Adriana; Sacai, Paula Yuri; Pereira, Josenilson Martins

doi:10.1590/s0004-27492008000400002

Cited by 30 publications

(39 citation statements)

References 19 publications

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“…The existing data have been obtained using fixed spatiotemporal (ST) frequencies to elicit the VEP, and these indicate that the binocular motion subsystem underlying the DMA matures (symmetricizes) earlier for low spatiotemporal frequencies (e.g., Norcia, 2004;Norcia, Hamer, & Orel-Bixler, 1990a). A natural approach to more efficient mapping of the spatiotemporal domain of the DMA would be to take advantage of the swept-parameter VEP, as used extensively to study grating acuity, contrast sensitivity, motion responses, and vernier responses in infants and adults (Almoqbel, Leat, & Irving, 2008;Chen et al, 2005;Hamer et al, 1989;Hou et al, 2007;Norcia et al, 1989Norcia et al, , 1999Norcia et al, 1990b;Norcia & Tyler, 1985;Oliveira et al, 2004;Salomão, Ejzenbaum, Berezovsky, Sacai, & Pereira, 2008;Tyler, Apkarian, Levi, & Nakayama, 1979). The present study introduces a stimulus paradigm in which, for a given temporal frequency, a grating undergoing 90deg oscillatory displacements is swept in SF.…”

Section: A New Paradigm For Mapping the Spatiotemporal Development Ofmentioning

confidence: 99%

The Jitter Spatial Frequency Sweep VEP: a new paradigm to study spatiotemporal development of pattern- and motion-processing mechanisms in human infants

Hamer¹,

Norcia²

2009

Psychol. Neurosci. (Online)

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We introduce a new VEP paradigm-the Jitter Spatial Frequency (JSF) Sweep VEP-that permits efficient mapping of the spatiotemporal tuning of the developmental motion asymmetry (DMA). Vertical sinewave gratings undergoing 90 o horizontal oscillatory displacements (6 or 10 Hz) were presented while their SF was swept over 2 to 5 octaves during each VEP trial. JSF sweep VEPs were recorded from 28 infants (8-43 weeks), and symmetric (second-harmonic, F2) and asymmetric (F1) components of the VEP were measured. JSF sweeps can provide four useful estimates: (1,2) the high-SF cutoff of F1 and F2 responses estimates the spatial resolution of direction-selective (DS) and non-DS mechanisms, respectively; (3) the low-SF cutoff for F1 estimate the SF-boundary between mature (F1 absent) and immature (F1 present) DS mechanisms; and (4) the F1 high-SF cutoff estimates the lower velocity limit of cortical DS cells. For 6 Hz, the low-SF F1 cutoffs increased two times faster than traditional (contrast-reversal) VEP grating acuity (0.5 vs ~0.25 octaves/month), and twice that of the high-SF F1 and F2 cutoffs. This implies that no single mechanism can account for the DMA at both low and high SFs. At 10 Hz, the DMA exhibited no significant development, consistent with slower maturation of DS mechanisms at higher ST frequencies. The F2 high-SF cutoffs were higher than F1 at both 6 and 10 Hz, suggesting higher spatial resolution for non-DS (pattern) vs DS (motion) mechanisms. Finally, the lower velocity limit of the DS mechanisms decreased from ~2 deg/sec at 8 weeks, to 0.75 deg/sec at 33 weeks, similar to analogous limits for direction-of-motion identification in adults (~0.5-1 deg/sec), and close to prior VEP estimates in infants (0.6 deg/sec).

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Section: A New Paradigm For Mapping the Spatiotemporal Development Ofmentioning

confidence: 99%

The Jitter Spatial Frequency Sweep VEP: a new paradigm to study spatiotemporal development of pattern- and motion-processing mechanisms in human infants

Hamer¹,

Norcia²

2009

Psychol. Neurosci. (Online)

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“…This group of children (GA <33 weeks) were also the only ones with neurological deficits, but statistical analysis showed that this did not affect the finding of reduced CS. The authors acknowledge their small sample size and potential lack of power in their analyses, but as their acuity values were similar to published normative data 28 it is plausible that thyroid levels have little or no impact on visual acuity. However, neurodevelopmental measures at 5 years of age have been shown to be associated with neonatal hypothyroxinaemia.…”

Section: Reduced Visual Acuitymentioning

confidence: 63%

Preterm birth: the ophthalmic consequences

O’Connor

2011

British and Irish Orthoptic Journal

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Aim: There is a growing body of evidence evaluating the outcomes following preterm birth. Continued evaluation is essential to determine the impact of new treatments, which can affect many areas of development. Therefore this review aims to provide an evidence-based update on the ophthalmic sequelae of preterm birth. Methods: A literature search of databases was performed, focusing on publications from the last 3 years. Results: New treatments are being developed to prevent severe vision loss due to retinopathy of prematurity (ROP), but as they are so new no longterm data are available. The development of new imaging techniques has allowed detailed analysis of the visual pathway, with changes in the posterior visual pathway identified and linked to visual function. Deficits of visual function in the preterm population extend beyond visual acuity, affecting functional ability in many ways, even in the presence of a normal visual acuity response. Strabismus rates continue to be increased but do not appear to have changed in recent years. Overall the literature agrees that preterm birth affects a range of ophthalmic outcomes, but there continues to be a lack of consensus as to what follow-up care is required. Conclusions: Children born preterm are at continued risk of developing a range of ophthalmic sequelae but new techniques are being applied to determine their aetiology. Novel treatments for ROP have shown promise in reducing severe visual impairments, but many questions remain regarding the nature of more subtle deficits of visual functions and how they should be identified.

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“…Dados normativos obtidos em outro laboratório por vários motivos não podem ser utilizados como parâmetros de normalidade já que raramente os laboratórios de eletrofisiologia usam exatamente o mesmo equipamento para aquisição das respostas, havendo configurações, marcas e modelos diferentes (18) . Ocorrem também diferenças nos eletrodos utilizados (14) , bem como diferenças raciais da amostra estudada e também da experiência da equipe em realizar o exame justificando assim necessidade de dados normativos próprios tanto para o PERG como para outros exames eletrofisiológicos (21)(22)(23)(24)(25)(26) .…”

Section: Discussionunclassified