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Roman Blanco, Consuelo Perez-Rico, LLuisa Rubio, Maribel Roldan, Lucía Ayuso; Evaluation of visual function in patients with Clinical Isolated Syndrome using multifocal visual evoked potentials and optic coherence tomography. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5736.
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© ARVO (1962-2015); The Authors (2016-present)
To assess mfVEP amplitude and latency changes over time in Clinical Isolated Syndrome (CIS) patients with and without a history of optic neuritis (ON).
MfVEP was recorded with 60-sector pattern-reversal dartboard stimuli (VERIS). Customized software was used to calculate response amplitude (logSNR), latency (ms) and probability plots (Hood & Greenstein 2003). Stratuts OCT 3000 (Carl Zeiss Meditec, inc. CA) was used to acquire retinal nerve fiber layer measurements (RNFL). Twenty four patients had mfVEP at 3, 12 and 24 months after CIS diagnosis. Eleven patients had a history of ON (ON group) and thirteen did not (no-ON group). Bland Altman plots were constructed for each group to examine an eye’s change in mean amplitude and median latency between visits. Logistic regressions were performed accounting for age and within-patient and inter-eye correlations.
The percentage of conversion from CIS to definite MS after follow-up in the ON group was 18,1% and 36.3% at 3m and 12m respectively while in the no-ON group, conversion rate was 54.1% and 77 % at 3 and 12 months respectively. Abnormal LCR and MRI at the time of diagnosis were significantly correlated with the risk of developing MS (McDonald's criteria, 2005) at one year. 64.2 % of eyes without ON history were identified as having abnormal amplitudes and 42.8 % showed abnormal latencies at the time of diagnosis. In this sense, an abnormal mfVEP in the no-ON group was significantly correlated with a high risk of developing MS before twelve months. Retinal nerve fiber layer thickness (total and temporal) was significantly reduced in the optic coherence tomography in the ON-group while the no-ON group did not show any significant thinning in the retina structure. Overall, OCT detected significantly fewer optic nerve changes in the clinically affected eyes in comparison with mfVEP.
MfVEP amplitude and latency measures indicate long-term longitudinal changes in visual function in CIS patients with no clinical ON and it's associated with high-risk of developing MS. Our findings parallel those of brain MRI studies suggesting that neuronal degeneration occurs somewhat independently of axonal loss and is more closely tied to disability.
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