TY - JOUR
T1 - Multifocal visual evoked potentials are influenced by variable contrast stimulation in MS
AU - Frohman, Audrey R.
AU - Schnurman, Zane
AU - Conger, Amy
AU - Conger, Darrel
AU - Beh, Shin C
AU - Greenberg, Benjamin
AU - Sutter, Erich
AU - Calabresi, Peter A.
AU - Balcer, Laura J.
AU - Frohman, Teresa C.
AU - Frohman, Elliot
N1 - Funding Information:
A. Frohman, Z. Schnurman, A. Conger, D. Conger, and S. Beh report no disclosures. B. Greenberg has received grants from the Guthy Jackson Charitable Foundation, Accelerated Cure Project, and Ampliummune. He has received consulting fees from Diogenix, Sanofi Aventis, and the Greater Good Foundation. He also holds an equity position in Diogenix. He has received speaker honoraria from Serono, the MS Association of America, the National MS Society, and the American Academy of Neurology. E. Sutter holds an equity position in Electrodiagnostic Imaging. P. Calabresi has provided consultation services to Novartis, EMD-Serono, Teva, Biogen-IDEC; and has received grant support from EMD-Serono, Teva, Biogen-IDEC, Genentech, Bayer, Abbott, and Vertex. L. Balcer has received honoraria for consulting on development of visual outcomes for MS trials from Biogen-Idec and Bayer. She is on a clinical trial advisory board for Biogen-Idec. T. Frohman has received speaker fees from Biogen Idec and TEVA. E. Frohman has received speaking and consulting fees from Biogen Idec, TEVA Neuroscience, Acorda, Bayer, and Novartis. He has received consulting fees from Biogen Idec, TEVA Neuroscience, Acorda, Novartis, and Abbott Laboratories. Go to Neurology.org for full disclosures.
PY - 2012/8/21
Y1 - 2012/8/21
N2 - Objective: To test the hypothesis that patients with multiple sclerosis (MS) with intereye asymmetry on low contrast letter acuity, and thickness of the retinal nerve fiber layer (RNFL), would exhibit corresponding changes in cortical timing and amplitude responses on pattern reversal multifoca visual evoked potentials (mfVEP), contingent upon variable stimulus contrast. Methods: In a cross-sectional study, we investigated a cohort of 11 normal subjects and 40 patients with MS, 21 of whom had a history of acute optic neuritis (MS-AON) with an intereye asymmetry with respect to RNFL thickness, and on low contrast letter acuity performance. Pattern reversal mfVEP was performed at high (100%), low (33.3%), and very low (14.2%) Michelson-contrast levels. Results: Compared to baseline measures at 100% contrast, the mean amplitude of the mfVEP was reduced in MS-AON eyes, upon pattern-reversal stimulation at the 2 lower contrast levels (p < 0.0001). With respect to changes in timing responses, the intereye asymmetry was increased in the MS-AON patients upon lower contrast pattern-reversal stimulation (p < 0.0001 for 33.3% compared to 100%, and p < 0.001 for 14.2% compared to 100%). The fellow eye in 12 (57%; p < 0.001) of the patients with an abnormal eye, and a history of AON, revealed abnormal amplitude and timing responses upon low contrast stimulation (signifying unmasking of occult damage). Conclusions: Our findings support the hypothesis that mfVEP metric abnormalities are contingent upon contrast magnitude during pattern reversal stimulation. Further, this paradigm was capable of unmasking occult abnormalities in a significant number of apparently unaffected eyes.
AB - Objective: To test the hypothesis that patients with multiple sclerosis (MS) with intereye asymmetry on low contrast letter acuity, and thickness of the retinal nerve fiber layer (RNFL), would exhibit corresponding changes in cortical timing and amplitude responses on pattern reversal multifoca visual evoked potentials (mfVEP), contingent upon variable stimulus contrast. Methods: In a cross-sectional study, we investigated a cohort of 11 normal subjects and 40 patients with MS, 21 of whom had a history of acute optic neuritis (MS-AON) with an intereye asymmetry with respect to RNFL thickness, and on low contrast letter acuity performance. Pattern reversal mfVEP was performed at high (100%), low (33.3%), and very low (14.2%) Michelson-contrast levels. Results: Compared to baseline measures at 100% contrast, the mean amplitude of the mfVEP was reduced in MS-AON eyes, upon pattern-reversal stimulation at the 2 lower contrast levels (p < 0.0001). With respect to changes in timing responses, the intereye asymmetry was increased in the MS-AON patients upon lower contrast pattern-reversal stimulation (p < 0.0001 for 33.3% compared to 100%, and p < 0.001 for 14.2% compared to 100%). The fellow eye in 12 (57%; p < 0.001) of the patients with an abnormal eye, and a history of AON, revealed abnormal amplitude and timing responses upon low contrast stimulation (signifying unmasking of occult damage). Conclusions: Our findings support the hypothesis that mfVEP metric abnormalities are contingent upon contrast magnitude during pattern reversal stimulation. Further, this paradigm was capable of unmasking occult abnormalities in a significant number of apparently unaffected eyes.
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UR - http://www.scopus.com/inward/citedby.url?scp=84866073359&partnerID=8YFLogxK
U2 - 10.1212/WNL.0b013e3182661edc
DO - 10.1212/WNL.0b013e3182661edc
M3 - Article
C2 - 22815550
AN - SCOPUS:84866073359
SN - 0028-3878
VL - 79
SP - 797
EP - 801
JO - Neurology
JF - Neurology
IS - 8
ER -