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W. V. Good, C. Hou, A. M. Norcia, M. W. Pettet, A. Madan; Effect of Grade I and II Intraventricular Hemorrhage on Visuocortical Functioning. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3169.
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Grade III/IV intraventricular hemorrhage is a major cause of adverse neurological outcome. However, the effect of milder hemorrhage (grade I/II) IVH on neurological outcome is less clearly defined. Here we measured Sweep Visual Evoked Potential (SVEP) responses to determine if infants with grade I or II IVH, as detected by head ultrasound, had visual function changes compared to age-matched infants with normal head ultrasounds.
A total of 72 very low birthweight (<1500g) infants were examined, either with grade I or II IVH (n=20) or without IVH (n=52) as detected by head ultrasound. SVEP exams were conducted between 5 and 7 month corrected age. The two groups were similar for gestational age, birthweight, and post-conceptional age at the time of examination. Infants with any > Stage II ROP or Plus disease were excluded. Contrast sensitivity, grating acuity, and vernier acuity were measured using swept-parameter visual evoked potentials. Thresholds and response amplitudes across swept-parameters in two groups were compared.
Grade I or II IVH infants showed higher (worse) individual-averaged vernier thresholds than control infants (1.01 IVH vs 0.58 arcmin, p<0.001), while contrast and grating thresholds showed no difference. SVEP response amplitudes to swept contrast, spatial frequency and vernier-offset stimuli were significantly lower in infants with grade I or II IVH than in infants with no IVH.
SVEP response amplitudes to a wide range of contrast, spatial frequency and vernier offset values are decreased in infants with grade I or II IVH compared to controls and vernier offset thresholds are elevated. These physiological changes indicate that milder germinal matrix hemorrhages (grade I/II IVH) are associated with functional deficits when measured at 5-7 months corrected age. Longterm deleterious effects of Grade I and II IVH on vision or development are unknown, and are under investigation.
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