Reproducibility of multifocal visual evoked potential and traditional visual evoked potential in normal and multiple sclerosis eyes.

PURPOSE: To establish reproducibility of multifocal visual evoked potential (mfVEP) and traditional pattern-reversal VEP (tVEP) in normals and relapsing-remitting multiple sclerosis (RRMS).

METHODS

mfVEP (60-sector dartboard) was recorded twice within a month in 40 normals and 40 RRMS patients [25 eyes with last optic neuritis (ON) ≥6 months, 34 non-ON]. mfVEP amplitude and latency (ms) were calculated as mean logSNR and median relative latency, respectively, for all 60 sectors (global) and 9 regions. tVEP was recorded (15', 60' and 120' checks) in subsets of 34 normals and 30 RRMS patients. tVEP N75-P100 amplitude (µV) and P100 latency (ms) were obtained. Reproducibility was evaluated using intraclass correlation coefficient (ICC) and test-retest variability (TRV). ICC ≥ 0.75 was considered good.

RESULTS

ICCs for global and regional mfVEP were >0.80 in all groups. ICCs for tVEP were >0.75 for all except latency in ON (0.52-0.68). For mfVEP or tVEP, TRV for amplitude was similar among all groups; TRV for latency (ms) was larger in ON (5.3 for mfVEP global, 10.3 for 60' tVEP) compared with non-ON (3.1, 8.3) and normal (2.3, 5.7) (p < 0.05 for all). When tVEP was analyzed using similar methods as mfVEP (logSNR and relative latency), mfVEP global measures showed better ICC and TRV than tVEP in all groups.

CONCLUSIONS

mfVEP and tVEP showed good reproducibility in normals and RRMS. TRV for mfVEP latency was larger in ON than normal or non-ON. mfVEP global latency's TRV was about half the respective values for tVEP in all groups, due to averaging of multiple responses.