Multifocal Visual Evoked Potential in Normal Subjects

ABSTRACT

PURPOSE: To introduce the clinical utility of multifocal visual evoked potential (mfVEP) and to assess the waveform from normal Korean subjects. METHODS: mfVEP with 4 channel recording was performed using the RETIscan(R) system (Roland Consult, Wiesbaden, Germany) for 25 eyes of 25 normal subjects. Amplitudes and implicit times were obtained from ring-shaped 6 areas and 4 sectors. To investigate the false-positive ratio of the examination, stimuli were given with one-half of the CRT monitor completely covered and the results were compared. RESULTS: Amplitudes of P1, N2 were larger in the central 10degrees area than other areas (p<0.001). Amplitudes were reduced and implicit times were prolonged on peripheral areas. P1 amplitudes were larger in the inferior field. Waves with large amplitudes by noise were recorded in 13.7% of covered areas. CONCLUSIONS: mfVEP is useful tool to detect local optic nerve damage and rule out the non-organic cause of visual field defect. However, mfVEP results are difficult to interpret due to noise and poor patient cooperation. Standardization of mfVEP is necessary for its application.