The distributions of amplitudes and latencies of the auditory brainstem responses (ABRs) were studied in 6 normal adult subjects, with 15 electrodes being placed on the mid-coronal scalp region and 8 electrodes on the mid-sagittal scalp region in each subject. Wave I appeared as a negative deflection at the ipsilateral mastoid to a monaural stimulus and as a positive deflection at the vertex. The polarity inversion was accounted for by the “near-field” nature of the recording. The amplitudes of waves II to V were somewhat varied with different electrode locations over the scalp. A gradual prolongation of latencies of waves II, III and V were seen at the ipsilateral mastoid. The latency shifts may be caused by the spatial and temporal summations of several neural generators. As the spatial amplitude differences between adjacent electrode sites were not large, two-dimensional maps obtained by the interpolation method may be considered to accurately represent the distribution of these potentials over the scalp.
