Possibilities of spatial hearing testing in occupational medicine

Dysfunctions of the organ of hearing are a significant limitation in the performance of occupations that require its full efficiency (vehicle driving, army, police, fire brigades, mining). Hearing impairment is associated with poorer understanding of speech and disturbed sound localization that directly affects the worker's orientation in space and his/her assessment of distance and location of other workers or, even most importantly, of dangerous machines. Testing sound location abilities is not a standard procedure, even in highly specialized audiological examining rooms. It should be pointed out that the ability to localize sounds which are particularly loud, is not directly associated with the condition of the hearing organ, but is rather considered an auditory function of a higher level. Disturbances in sound localization are mainly associated with structural and functional disturbances of the central nervous system and occur also in patients with normal hearing when tested with standard methods. The article presents different theories explaining the phenomenon of sound localization, such as interaural differences in time, interaural differences in sound intensity, monaural spectrum shape and the anatomical and physiological basis of these processes. It also describes methods of measurement of disturbances in sound localization which are used in Poland and around the world, also by the author of this work. The author analyzed accessible reports on sound localization testing in occupational medicine and the possibilities of using such tests in various occupations requiring full fitness of the organ of hearing.