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Divya Narayanan, Han Cheng, Rosa Tang, Laura Frishman; Reproducibility of Multifocal Visual Evoked Potential (mfVEP) in Normal and Multiple Sclerosis (MS) Eyes. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5131. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To establish reproducibility of mfVEP amplitude and latency measures for use in longitudinal studies
mfVEP was recorded twice with 60-sector pattern reversal dartboard stimuli (VERIS 5.1) in 29 normal subjects (age 28.1±8.1 yrs) and 23 MS patients (age 38.4±9.5 yrs, MS duration 6.6±8.0 yrs). Mean time interval between 2 visits was 14±9 days for normals; 16±8 days for MS. For MS eyes with a history of optic neuritis (ON), time since last ON was > 6 months. In each visit two 7 min recordings were obtained and averaged for each eye. Customized software  was used to calculate response amplitude (logSNR) and latency (ms) for global (mean logSNR or median latency for 60 sectors) and 9 regional measures. For a typical MS-ON eye, global logSNR is about 0.4 (vs 0.6 in normals) and latency is prolonged by 12 ms (normal implicit time = 100 ms).  One eye of each subject was randomly selected for analysis. Reproducibility of mfVEP was evaluated by intraclass correlation coefficient (ICC), and test retest variability (TRV) which is 1.96 times within subject standard deviation.  ICC ≥ 0.75 is considered as good agreement. Intravisit TRV was determined by comparing the two 7 min recordings from the 1st visit.
For global amplitude, normal and MS eyes had the same intervisit ICC (0.93) and TRV (0.10 logSNR). For global latency, the intervisit ICC was 0.89 in normals and 0.95 in MS; intervisit TRV was 2.6 ms in normals and 5.4 ms in MS. Regional intervisit TRV ranged from 0.10 to 0.15 logSNR for amplitude in normals and MS; and for latency, 3.1 to 6 ms in normals and 5.7 to 8.4 ms in MS. About 60% of the intervisit amplitude variability and 80% of latency were reflected in intravisit variability (intravisit TRV: 0.06 for amplitude in both groups; 2.1 ms in normals and 4.8 ms for latency in MS).
mfVEP amplitude and latency have good reproducibility. TRVs for amplitude are similar in normals and MS. TRV for latency in MS eyes was about two times that in normals. Intravisit variability predicts intervisit variability. mfVEP can be used as a reliable tool to detect progression in MS patients. 1. Hood DC and Greenstein VC. 2003. Prog Retin Eye Res 22: 201-251; 2. Laron M et al. 2010. Mult Scler 16:412-426; 3. Bland JM and Altman DG. 1996. BMJ 313:744.
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