PURPOSE: The visual evoked potential (VEP) is a frequently used noninvasive measurement of visual function. However, high-amplitude variability has limited its potential for evaluating axonal damage in both laboratory and clinical research. This study was conducted to improve the reliability of VEP amplitude measurement in rats by using electroencephalogram (EEG)-based signal correction. METHODS: VEPs of Sprague-Dawley rats were recorded on three separate days within 2 weeks. The original VEP traces were normalized by EEG power spectrum, which was evaluated by Fourier transform. A comparison of intersession reproducibility and intersubject variability was made between the original and corrected signals. RESULTS: Corrected VEPs showed lower amplitude intersession within-subject SD (Sw), coefficient of variation (CoV), and repeatability (R(95)) than the original signals (P < 0.001). The intraclass correlation coefficient (ICC) of the corrected traces (0.90) was also better than the original potentials (0.82). For intersubject variability, the EEG-based normalization improved the CoV from 44.64% to 30.26%. A linear correlation was observed between the EEG level and the VEP amplitude (r = 0.71, P < 0.0001). CONCLUSIONS: Underlying EEG signals should be considered in measuring the VEP amplitude. In this study, a useful technique was developed for VEP data processing that could also be used for other cortical evoked potential recordings and for clinical VEP interpretation in humans.
PURPOSE: The visual evoked potential (VEP) is a frequently used noninvasive measurement of visual function. However, high-amplitude variability has limited its potential for evaluating axonal damage in both laboratory and clinical research. This study was conducted to improve the reliability of VEP amplitude measurement in rats by using electroencephalogram (EEG)-based signal correction. METHODS: VEPs of Sprague-Dawley rats were recorded on three separate days within 2 weeks. The original VEP traces were normalized by EEG power spectrum, which was evaluated by Fourier transform. A comparison of intersession reproducibility and intersubject variability was made between the original and corrected signals. RESULTS: Corrected VEPs showed lower amplitude intersession within-subject SD (Sw), coefficient of variation (CoV), and repeatability (R(95)) than the original signals (P < 0.001). The intraclass correlation coefficient (ICC) of the corrected traces (0.90) was also better than the original potentials (0.82). For intersubject variability, the EEG-based normalization improved the CoV from 44.64% to 30.26%. A linear correlation was observed between the EEG level and the VEP amplitude (r = 0.71, P < 0.0001). CONCLUSIONS: Underlying EEG signals should be considered in measuring the VEP amplitude. In this study, a useful technique was developed for VEP data processing that could also be used for other cortical evoked potential recordings and for clinical VEP interpretation in humans.
Authors: Yuyi You; Vivek K Gupta; Nitin Chitranshi; Brittany Reedman; Alexander Klistorner; Stuart L Graham Journal: J Vis Exp Date: 2015-07-29 Impact factor: 1.355
Authors: David A Houlden; Chantal A Turgeon; Thomas Polis; John Sinclair; Stuart Coupland; Pierre Bourque; Martin Corsten; Amin Kassam Journal: J Clin Monit Comput Date: 2014-06 Impact factor: 2.502
Authors: Nisha S Pulimood; Wandilson Dos Santos Rodrigues; Devon A Atkinson; Sandra M Mooney; Alexandre E Medina Journal: J Neurosci Date: 2017-06-12 Impact factor: 6.167
Authors: Kalina Makowiecki; Andrew Garrett; Vince Clark; Stuart L Graham; Jennifer Rodger Journal: Transl Vis Sci Technol Date: 2015-04-28 Impact factor: 3.283