Reliability of intensity dependence of auditory-evoked potentials

Intensity dependence of auditory-evoked potentials (IAEP) is a suggested indicator of serotonergic neurotransmission. In contrast to its clinical renaissance, the reliability of IAEP has only been examined in a few studies, most of which are limited due to the possibly confounding effects of age and gender. Therefore, the present study examines different reliabilities of various IAEP parameterizations while controlling for age and gender.

Auditory-evoked potentials were recorded from 166 students. Of these 37 women and 25 men were retested after three weeks.

Test-retest and odd-even reliabilities were remarkable at Cz in both females (r=.88/.86) and males (r=.82/.79). Reliabilities were higher in women, higher with linear than median slopes and best at Cz. Bisection of sweep number, split-half reliability, the second run, and lower intensities revealed lower reliabilities.

Reliabilities at Cz can reach the same level as previously reported by dipole-source-localization methods, if sufficient sweep number and linear slopes are applied.

Based on theoretical arguments and current data, the continued use of the easy and rapidly done single-channel IAEP is suggested, although ideally in combination with multi-channel source-localization methods. This would be seminal for a drafted program standardizing IAEP to further improve its clinical utility.