[Pattern-reversal visual evoked potential abnormalities in patients with defined multiple sclerosis].

INTRODUCTION Multiple sclerosis is an idiopathic demyelinating disease that may affect the optic nerve leading to acute unilateral visual loss, which could be observed by means of evoked visual potential (VEP). This exam is much valued for studying prechiasmatic visual paths in multiple sclerosis. PURPOSE To analyze the findings of pattern reversal VEP in patients with prior diagnosis of multiple sclerosis and to compare them to visual acuity. METHODS Twenty-four patients with a definite diagnosis of multiple sclerosis were submitted to pattern reversal VEP from October 2001 to March 2007. RESULTS In P100 component response, at 15' and 1 degree stimuli, 19 eyes presented latency response up to 115 ms in both stimuli, which coincided in 6 eyes with latency response between 116 and 135 ms; 11 eyes had a latency response higher than 135 ms, and four eyes did not respond to stimuli. Correlating visual acuity with P100 latency for 15', in Pearson r correlation, r=0.85 with p=0.000000123, and for 1 degree, r = 0.87 with p=0.0000000338. CONCLUSION Approximately 60.4% of patients presented abnormalities. However, the correlation between the P100 latency (15' and 1 degree) and visual acuity was statistically significant; therefore the better the visual acuity, the better the response to stimuli of the pattern-reversal VEP.