- AUDIOLOGY JAPAN (ISSN:03038106)
- vol.29, no.1, pp.35-42, 1986-02-28 (Released:2010-04-30)
A series of studies on human auditory laterality suggested the presence of a switching mechanism in human brainstem that automatically transmits auditory signals to either the right or the left hemisphere, depending upon the physical properties of the sound.The purpose of this study was to identify physical parameters that determine this laterality.Some environmental and artificial sounds for which the hemispheric dominance had been previously clarified by both Tsunoda's method and the auditory evoked potential method, were analyzed by analog and digital signal processing techniques.As the results, in normal Japanese, the right hemisphere was found to be dominant for the sounds with the following physical characteristics:(1) single formant (or formant-like structure) or simple (logarithmic) attenuation in higher frequency ranges.(2) two or more formants (or formant-like structures) in harmonic relations.(3) small pitch fluctuations and rich harmonic structures, particularly, when sounds consist only of harmonic tones.