| Abstract: | The patterns of perceptual asymmetry elicited by dichotic speech and complex pitch stimuli were evaluated in a group of 28 normal, right-handed subjects. As in previous studies, between 70 and 75% of the subjects showed a right-ear advantage for speech and left-ear advantage for pitch. However, less than half of the subjects (46%) showed the expected pattern on both tests. It is argued that the assumption of symmetrical, contralateral auditory pathway superiority during dichotic stimulation is only appropriate in roughly half of the dextral population. In the remaining half, significant subcortical asymmetries and/or a lack of contralateral advantage appear to be present. The assessment of complementary cortical functions should provide a way to reduce the confounding of cortical and subcortical contributions to auditory perceptual asymmetries, and thus provide a more accurate behavioral index of brain organization. |
