Roberto Santangelo1,2, Valerio Castoldi1,2, Raffaele D'Isa1, Silvia Marenna1,2, Su-Chun Huang1,2, Marco Cursi1, Giancarlo Comi1,2, Letizia Leocani3,4. 1. Department of Neurology and Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy. 2. University Vita-Salute San Raffaele - IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy. 3. Department of Neurology and Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy. letizia.leocani@hsr.it. 4. University Vita-Salute San Raffaele - IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy. letizia.leocani@hsr.it.
Abstract
PURPOSE: Visual evoked potentials (VEPs) are a powerful tool to evaluate nervous conduction along the visual pathways, both in humans and in animal models. Traditionally, epidural screw electrodes are used to record VEPs in preclinical research. Here we tested the feasibility in the preclinical setting of the same noninvasive technique used for clinical VEP acquisition, by using epidermal cup electrodes with no surgical procedures. METHODS: Monocular flash VEPs were recorded bilaterally under sevoflurane anesthesia once a week for 6 weeks in 14 dark Agouti rats, 7 with implanted epidural screws and 7 with epidermal 6 mm Ø Ag/AgCl cups. RESULTS: VEP traces obtained with the two techniques were morphologically comparable. There were no significant differences in latency of the main visual component between screw-recorded VEPs (sVEPs) and cup-recorded VEPs (cVEPs). Amplitude values with epidermal cups were significantly lower than those with epidural screws. Both techniques provided latencies and amplitudes which were stable over time. Furthermore, with regard to latency both methods ensured highly repeatable measurements over time, with epidermal cups even providing slightly better results. On the other hand, considering amplitudes, cVEPs and sVEPs provided fairly acceptable repeatability. CONCLUSIONS: Epidermal cup electrodes can provide comparable results to those obtained with the "gold standard" epidural screws, while representing a simpler and less invasive technique to test nervous conduction along the visual pathways in the preclinical setting.
PURPOSE: Visual evoked potentials (VEPs) are a powerful tool to evaluate nervous conduction along the visual pathways, both in humans and in animal models. Traditionally, epidural screw electrodes are used to record VEPs in preclinical research. Here we tested the feasibility in the preclinical setting of the same noninvasive technique used for clinical VEP acquisition, by using epidermal cup electrodes with no surgical procedures. METHODS: Monocular flash VEPs were recorded bilaterally under sevoflurane anesthesia once a week for 6 weeks in 14 dark Agouti rats, 7 with implanted epidural screws and 7 with epidermal 6 mm Ø Ag/AgCl cups. RESULTS: VEP traces obtained with the two techniques were morphologically comparable. There were no significant differences in latency of the main visual component between screw-recorded VEPs (sVEPs) and cup-recorded VEPs (cVEPs). Amplitude values with epidermal cups were significantly lower than those with epidural screws. Both techniques provided latencies and amplitudes which were stable over time. Furthermore, with regard to latency both methods ensured highly repeatable measurements over time, with epidermal cups even providing slightly better results. On the other hand, considering amplitudes, cVEPs and sVEPs provided fairly acceptable repeatability. CONCLUSIONS: Epidermal cup electrodes can provide comparable results to those obtained with the "gold standard" epidural screws, while representing a simpler and less invasive technique to test nervous conduction along the visual pathways in the preclinical setting.
Authors: Graham E Holder; Gastone G Celesia; Yozo Miyake; Shozo Tobimatsu; Richard G Weleber Journal: Clin Neurophysiol Date: 2010-06-16 Impact factor: 3.708
Authors: Sharmila Vaz; Torbjörn Falkmer; Anne Elizabeth Passmore; Richard Parsons; Pantelis Andreou Journal: PLoS One Date: 2013-09-09 Impact factor: 3.240