S. Tobimatsu et al., NORMAL VARIABILITY OF THE AMPLITUDE AND PHASE OF STEADY-STATE VEPS, Electroencephalography and clinical neurophysiology. Evoked potentials, 100(3), 1996, pp. 171-176
The present study quantifies the amplitude and phase variability of st
eady-state VEPs (S-VEPs) and compares this variability between subject
s and between individual runs. The S-VEPs were recorded repeatedly in
14 normal subjects with varying spatial and temporal frequencies of si
nusoidal gratings; 6 spatial frequencies (range 0.5-8.0 c/deg) with 3
temporal frequencies (4, 6 and 8 Hz) were used. A total of 75 response
s were averaged and analyzed by the Fourier method, Four recordings we
re obtained in each spatio-temporal combination. In general, the phase
data showed small inter- and intrasubject variability. As anticipated
, the amplitude data showed a large degree of intersubject variability
, although the intrasubject variability was very small. In addition, i
n some stimulus conditions the inter- and intrasubject variability inc
reased, which thus suggested the existence of an optimal spatio-tempor
al combination. Therefore, these stimulus parameters should be taken i
nto consideration when S-VEPs are applied in clinical practice.