High test-retest reliability of checkerboard reversal visual evoked potentials (VEP) over 8 months.
OBJECTIVE
The inter-individual variation in the shape of a visual evoked potential (VEP) is large even for simple stimuli. We compared the inter-individual variation in VEP waveform to the intra-individual stability.


METHODS
We recorded VEP with checkerboard stimulation in 10 women aged 19-29years in two sessions. We determined the latencies and the peak-to-peak amplitude of N75 and P100. As a new approach in VEP research, we regressed VEP waveforms pairwise onto each other and calculated a t-value between all sessions. The maximal t-value was taken to indicate recognition for all 19 comparisons performed with one session. The recognition rate was cross-validated in a generalized linear regression model (GLM).


RESULTS
The number of sessions correctly matched to the correct subject was 19 of 20 (true positives) leading to a sensitivity of 95.0% with confidence interval [75.1% 99.9%] for the method. The number of true negatives was 359 of 360 leading to a specificity of 99.7% [98.5% 100.0%].


CONCLUSIONS
The VEP waveform shows high intra-individual stability compared to the inter-individual variation in healthy women.


CONCLUSIONS
With a new statistical approach the effect of external factors on the VEP waveform can now be contrasted against the normal variability over time in longitudinal studies.
Sarnthein
Johannes
J
Neurochirurgische Klinik, UniversitätsSpital Zürich, CH-8091 Zürich, Switzerland. johannes.sarnthein@usz.ch
Andersson
Maria
M
Zimmermann
Michael B
MB
Zumsteg
Dominik
D
D000328:Adult; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D015203:Reproducibility of Results; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult