Cutaneous senses for detection and localization of environmental sound sources: a review and tutorial

A review and tutorial on the potential use of the skin for sound localization are presented. Some basic physical and psychophysical properties are reviewed; special properties and phantom perceptions associated with cutaneous stimulation are presented; experiments by Békésy, Gescheider, Frost, Richardson and Weisenberger on different instrumentation for/and results on localization of sound sources with skin stimulation are analysed. The best results have been obtained using intensity differences between two vibrators. Sound source localization precision approaching that of the auditory sense in quiet surroundings has been obtained, particularly when free head movements are allowed. Significant results have also been obtained with temporal differences, provided the natural sound delay between the ears is increased to fit the coding characteristics of the skin. As yet, no portable equipment has been designed and tested in realistic environments.