Randomized long interstimuli interval flash-VEP and SSEP

Randomized long interstimuli interval stimulations are recommended in the literature for the examination of different evoked potentials because of the probable effects of habituation and of contingent negative variation on the wave form, especially of its late components. The results of (randomly stimulated) SSEP and Flash-VEP elicited with randomized ISI of 3 to 5 seconds were analysed and normative values for these EP's were given. The results were compared with the latency data in the literature where fixed and short ISI were used. The comparison suggests that in cases where for practical reasons the time consuming (randomized long ISI) stimulation is not possible regular stimulation with interstimulus interval of somewhat more than one second also gives satisfactory results.