Three-channel Lissajous' trajectory of human auditory brain stem evoked potentials

By simultaneously recording from 3 orthogonal electrode montages, and plotting the 3 voltage-time records on three-dimensional voltage-voltage-voltage coordinates, a spatial Lissajous' trajectory is obtained. This 3-Channel Lissajous' Trajectory (3CLT) represents the simultaneous voltage values from 3 independent montages and, assuming a uniform volume conductor, it includes all the information required for calculation of the dipole equivalent of surface-recorded activity. In 3CLT time is not explicitly graphed, but is implied as motion along the trajectory. Thanks to the small distribution of the generators of BAEPs, relative to their distance from the recording electrodes, 3CLT of BAEPs holds the promise of summarizing all activity from the surface. Comparing 3CLT of BAEPs to left vs. right ear stimulation has confirmed the lateralization of components I and III, but has also shown lateralization for the other components, which detailed surface mapping studies had overlooked. 3CLT may offer a more sensitive, yet less cumbersome, alternative to detailed surface mapping of BAEPs. The full promise of 3CLT can only be evaluated after quantitative indices of the trajectory are developed.