Multifocal frequency-doubling pattern visual evoked responses to dichoptic stimulation.
OBJECTIVE
To examine the feasibility of a multifocal visual evoked potential (mfVEP) binocularly, using a variant of the multifocal frequency-doubling (FD) pattern-electroretinogram (MFP).


METHODS
Stimuli were presented in both monocular and dichoptic conditions at eight visual field locations/eye. The incommensurate stimulus frequencies ranged from 15.45 to 21.51 Hz. Five stimulus conditions differing in spatial frequency and orientation were examined for three viewing conditions. The resulting 15 stimulus conditions were examined in 16 normal subjects who repeated all conditions twice.


RESULTS
Several significant independent effects were identified. Response amplitudes were reduced for dichoptic viewing (by 0.85 times, p<4 x 10(-11)); offset by increases in responses for between eye differences of one octave of spatial frequency: lower (1.15 times, 0.1 cpd); higher (1.29 times, 0.4 cpd), both p<1.8 x 10(-7). Crossed orientations produced significant effects upon response phase (p=0.023) but not amplitude (p=0.062).


CONCLUSIONS
The results indicated that dichoptic evoked potentials using multifocal frequency-doubling illusion stimuli are practical. The use of crossed orientation, or differing spatial frequencies, in the two eyes reduced binocular interactions.


CONCLUSIONS
The results indicate a method wherein several spatial or temporal and frequencies per visual field region can be tested in reasonable time using a multifocal VEP using spatial frequency-doubling stimuli.
ARC Centre of Excellence in Vision Science, CVS, Research School of Biology, Australian National University, Acton, Canberra, ACT 0200, Australia; Department of Biomedical Science, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 53300 Kuala Lumpur, Malaysia.
Yanti
Y
Rosli
ARC Centre of Excellence in Vision Science, CVS, Research School of Biology, Australian National University, Acton, Canberra, ACT 0200, Australia. Electronic address: ted.maddess@anu.edu.au.
T
T
Maddess
ARC Centre of Excellence in Vision Science, CVS, Research School of Biology, Australian National University, Acton, Canberra, ACT 0200, Australia.
A
A
Dawel
ARC Centre of Excellence in Vision Science, CVS, Research School of Biology, Australian National University, Acton, Canberra, ACT 0200, Australia.
A C
AC
James
D000328:Adult; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D015348:Vision, Binocular / Q000502:physiology; D055815:Young Adult