Directional Hearing, Three Different Test-Methods

Abstract

The sound localization ability in normal hearing subjects has been tested with three different methods: 1. free field test in anechoic chamber utilizing pure tones of 500 Hz, according to Nordlund (1963) 2. tests with headphones in dichotic presentation and variable electronic delay line unit, 3. the stethoscope test according to Groen (1969). The free field-test measures the subject's ability to detect interaural phase-time and intensity differences. For the last 10 years this test has been in regular clinical routine use and proved valuable in the diagnosis of retrocochlear lesions. The drawback of this test is that it requires an anechoic room. Localization tests over headphones utilizing an electronic delay line and dichotic presentation might be a good substitute for detecting interaural phases or time differences. The simpler stethoscope test served the same purpose. In order to classify the merits of the three tests they were carried out on one—hundred normal hearing subjects. The results revealed ...