Abstract
Purpose :
To evaluate the intra-session and inter-session repeatability of short-duration transient visual evoked potentials (SD-tVEP) in normal adults over 40 years of age.
Methods :
Inclusion criteria were adults over age 40yrs with best corrected distance acuity of 20/40 or better in each eye. Exclusion criteria were history of ocular disease or surgery other than cataract extraction, and neurologic disorders that could affect the VEP, including epilepsy and stroke. Subjects underwent three consecutive SD-tVEP examinations using the Diopsys NOVA fixed protocol. All examination procedures were carried out in accordance with manufacturer recommendations. To assess inter-session repeatability 9 subjects returned on another day for repeat examination.
Results :
A total of 45 subjects were recruited. Mean±SD age: 53±9yrs (range: 40-84yrs). 69% of subjects were female and 80% were non-white. Mean within-subject coefficients of variation (CV) for P100 amplitude (A) were 23% and 19% for low contrast (10%, Lc) and high contrast (85%, Hc) stimuli, respectively. The CV for P100 latency (L) were 3% Hc and 6% Lc. Coefficients of reproducibility (CR) and relative repeatability ([CR/µ]*100, RR) OD were LcA: ±10.88µV (113%), HcA: ±14.37 µV (111%), LcL: ±29.37ms (26%), and HcL: ±23.69ms (22%). CR and RR values OS were LcA: ±11.21µV (118%), HcA: ±12.47 µV (99%), LcL: ±30.34ms (27%), and HcL: ±20.15ms (19%). Inter-session RR values (OD/OS) were LcA: 137%/234%; HcA: 243%/346%; LcL: 72%/101%; and HcL: 22%/51%. Between session intraclass correlation coefficients (ICC) generally improved when the means of 3 exams were analyzed compared to first exams only. (FIGURE)
Conclusions :
SD-tVEP demonstrated good intra-session and inter-session repeatability in these healthy older adults, with L being more repeatable than A. Inter-session amplitude repeatability improved by averaging multiple exams. These results are consistent with reported SD-tVEP repeatability in primarily white normal young adults (Tello, et. al. Doc Ophthalmol, 2010;1120:219).
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.