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Roger Wing-hong Li, Marion Hastings Edwards, Brian Brown; Variation in Vernier Evoked Cortical Potential with Age. Invest. Ophthalmol. Vis. Sci. 2001;42(5):1119-1124.
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purpose. To investigate the effects of age on transient vernier visual evoked
potential (VEP) and vernier acuity estimated by extrapolation.
methods. Transient vernier VEPs were examined in normal subjects aged 20 to 75
years. Vernier offsets were presented for the first 350 msec of the
stimulus period, and the segments were then realigned in the following
400 msec. The six vernier offsets used were 20, 40, 60, 80, 100, and
140 seconds of arc. Averaging for each offset setting produced vernier
VEP waveforms, for which amplitude and latency of visual evoked
response and background electroencephalographic (EEG) noise level were
determined. Extrapolation of the function relating signal-to-noise
ratio and log vernier offset to a ratio of 1.0 resulted in an estimate
of vernier acuity.
results. Amplitude of vernier VEP waveforms was significantly reduced in
subjects more than 60 years of age, and the latency to the first
negative peak was progressively prolonged with increasing age. There
was no statistically significant change in electroencephalographic
(EEG) noise with advancing age. VEP vernier acuity was significantly
degraded in the 61- to 75-year age group. These results are parallel to
recent psychophysical findings that alignment performance is worse in
older persons than in younger ones.
conclusions. The present findings provide the first electrophysiological evidence of
age-related cortical degeneration associated with vernier processing.
Reduced neural activity probably contributes to the loss of vernier
acuity with advancing age. Also provided are the first normative data
for subjects of different ages for vernier VEP and VEP vernier acuity.
Moreover, the present study has demonstrated that vernier VEP is
sensitive to neural changes and therefore may be applied in clinical
situations to evaluate the integrity of the visual
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