Abstract
Purpose: :
To establish age assorted normal values for visual evoked potentials with isoluminant blue on yellow stimulation and examine the maturation of the waveforms with increasing age.
Methods: :
44 healthy subjects underwent VEP testing with an isoluminant blue checkerboard stimulus on a yellow background presented on a CRT monitor (Roland Consult, Brandenburg, Germany). The subjects were divided in 4 age groups: <20 years (10 subjects, mean age 12±3), 20-40 (14 subjects, mean age 29±6), 40-60 (9 subjects, mean age 51±4) and >60 (11 subjects, mean age 68±5).
Results: :
The responses showed a triphasic course with a first positive "P1", a negative "N" , and a second positive "P2" peak. The latencies of P1 showed the following development throughout the four age groups: 124±15 ms, 98±33 ms, 99±3 ms and 101±9 ms. The latencies of "N" were: 189±24 ms, 157±41 ms, 147±27 ms and 151±10 ms. The latencies of the second positive component "P2" had no noticeable age dependence and a mean latency of 289±57 ms.
Conclusions: :
In addition to the previously described biphasic negative - positive characteristic of the blue on yellow VEP we recognized a preceding positive peak with our stimulation setting. Because of the similar development of the latency maturation of this "P1" peak compared to the known negative component "N", especially the significantly longer latencies of the <20 age group relative to the older groups, which is not typical for luminance contrast on/off VEPs, we believe that this peak is a genuine blue specific chromatic component and not an artifact of an unintended luminance contrast.
Keywords: electrophysiology: clinical • visual development • color vision