Electrophysiological assessment of contrast sensitivity in human infants.
Contrast sensitivity functions (CSF's) were measured for a group of 6-month-old infants using the visual evoked potential (VEP). Sine-wave luminance gratings were counterphase modulated at 12 contrast reversals per s and simultaneously swept in contrast. Each contrast sweep lasted 10 s, spanning a range of 0.5 to 40% contrast in 19 equal logarithmic steps. The amplitude and phase of the response at the second harmonic were determined by a discrete Fourier transform. Contrast thresholds were estimated from a linear extrapolation to zero-amplitude of the VEP amplitude vs. log-contrast function. Contrast sensitivity was found to be nearly adult-like at 1 c/deg, but was not yet mature at higher spatial frequencies.
D002657:Child Development; D004056:Differential Threshold; D004594:Electrophysiology; D005074:Evoked Potentials, Visual; D006801:Humans; D007223:Infant; D010775:Photic Stimulation / Q000379:methods; D014785:Vision, Ocular / Q000502:physiology*