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Valtenice de Cassia R. Franca, Russell D. Hamer, Dora F. Ventura, Marcelo F. Costa; Sweep VEP (sVEP) Evaluation the Effect Of Fetal Growth Restriction (FGR) On Early Contrast Sensitivity Development In Fullterm Brazilian Newborns. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5724.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the effect of FGR on contrast sensitivity (CS) development using the sweep visual evoked potential (sVEP) In fullterm Brazilian newborns.
42 fullterm (≥37 weeks gestation) infants, 6 - 24 weeks postnatal age, were tested. 14 were FGR (birthweights < 10th percentile), and 28 control (CNTL) had normal birthweights. Infants had no genetic abnormalities. Mothers did not smoke, drink alcohol or use drugs. sVEP: 0.5 c/deg sinusoidal luminance gratings (161 cd/m2 mean luminance) phase-reversing at 6 Hz were swept logarithmically from low to high contrast. Threshold contrast was estimated by extrapolating the 2nd harmonic amplitude to 0 microV. Peak amplitude (Apk), peak signal-to-noise ratio (SNRpk), and phase at the peak (PHpk) were also recorded.
Young (6-10 weeks) FRG infants had significantly lower CS than CNTLs (Mann-Whitney U, p=0.007). The groups did not have significantly different Apk or SNRpk. The high-SNR phase advanced rapidly between 6 and 18 weeks by 270 deg and 263 deg for the FGR and CNTL groups , respectively, corresponding to decreases in apparent latency of ~5.2 and 5.1 ms/week.
Infants born with signs of Fetal Growth Restriction manifest losses in low spatial frequency CS in the early postnatal weeks during a period when CS normally increases rapidly toward adult levels (Norcia et al., Vis Res 30,1475, 1990). It appears that the rate of development of phase, or apparent neural latency, is not affected by FGR during the first few postnatal months. Whether FGR affects subsequent development will be evaluated as data are collected from infants at older ages.
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