Purpose:
VEP peak latency has found to be a better indicator of visual development than amplitude (Sokol and Jones, 1979; Tello et al, 2010). In this study, two latencies were measured in phase, orientation, and direction VEPs.
Methods:
The three visual stimuli were tested in 61 adults at 1- 16 r/s and 136 infants (age 7-79 weeks) at 2-8 r/s. In addition to measuring its peak transient latencies at 1-3 r/s, apparent latencies from the gradient of phase against reversal rates were also calculated in steady-state recording at 1- 16 r/s.
Results:
For the transient peak latencies, infants showed similar orientation and direction responses while adults had similar phase and orientation latencies. Both adults and infants had similar orientation and direction calculated latencies that are significantly longer than their respective peak latencies. While the transient latencies of the three stimuli merged at around 20 weeks, the calculated latencies of orientation and direction merged at about 30 weeks of age.
Conclusions:
The transient peak latencies of phase, orientation, and direction VEPs showed similar developmental trends. Phased based calculated latency, however, reflected different timing of cortical feedback loops. Their implications will be further explored.
Keywords: electrophysiology: non-clinical • visual development: infancy and childhood • visual development