Abstract
Purpose::
To evaluate the responses in the multifocal visual evoked potential (mfVEP) from different cortical areas in normal subjects in order to identify the crossed and uncrossed visual pathways.
Methods::
Normal subjects were examined with mfVEP (VERIS). Twenty healthy subjects, 16-60 years (mean age of 40 years) and best corrected visual acuity of 20/20 were examined with mfVEP (VERIS) for interpretation of the normal cortical response. The 60 segment dartboard visual stimulus was displayed on a screen in the IR camera for a more stable adjustment of the equipment and better control of the fixation during the recording. A two channel registration system was used to assess responses from the left and the right visual cortex during the same stimulation.
Results::
The mfVEP demonstrated high signal-to-noise ratio (SNR) in the paracentral field corresponding to the uncrossed and crossed visual pathways. The amplitudes from the visual pathways demonstrated significant higher amplitudes from the right cortex comparing to the left cortex (p=0.03 and p=0.009).
Conclusions::
With two lateral registration channels, the responses significantly correlate to the different visual pathway.Further evaluation of the visual pathway comparing the uncrossed and crossed pathway from both eyes demonstrated significantly higher amplitude from the right cortex compared to the left cortex in the responses with the highest signal-to-noise ratio (SNR). This has not been described previously and may be of major importance for better understanding and analyzing the cortical response in the mfVEP.
Keywords: electrophysiology: clinical • neuro-ophthalmology: optic nerve • visual cortex