Dichotic listening to musical chords: background and preliminary data.

One test of dichotic listening utilizing nonverbal stimuli is included on the VA-CD Tonal and Speech Materials for Auditory Perceptual Assessment, Disc 1.0. It is a test using three tone complexes that meet the definition of musical chords. The dichotic chords were included as a complement to the three dichotic speech procedures on the VA disc because musical chords may depend on right hemisphere brain function in a manner at least related to the way speech depends on left hemisphere organization/activity. Normative data were obtained from 120 normal-hearing listeners at nine testing centers in the United States. The three tone chords were presented dichotically under two onset time conditions, simultaneous and 90-msec onset time stagger, and three presentation levels, 70, 80, and 90 dB SPL. In general, subjects could identify the dichotically presented chords about 60 percent of the time in each ear. In addition, onset time relationships and presentation levels did not greatly affect accuracy. Overall, subject performance was similar to that noted by others and at levels that should allow lesion effects to be sought.