Introduction: The purpose of speech audiometry is to extend the diagnostics of central auditory processes. First audiometric tests were monaural tests introduced in the fifties by Bocca and Calearo to diagnose Central Auditory Processing Disorders (CAPD). Monaural tests are characterized by low redundancy, which allows for deciphering a given word or phrase only if the amount of accessible information exceeds a required minimum. Until now, a new monaural filtered speech test has been drawn up at the Department of Phoniatrics and Audiology. The purpose of the research was to draw up and assess the effectiveness of monaural low redundancy tests, in which the acoustic signal has been compressed or noise has been added.
Materials and method: 35 people with normal hearing, aged 16-60, have been examined. The test material included: a compressed speech test, in which the speech signal has been accelerated by 25% with the use of Cool Edit Pro 2.0; the pauses between the words have not been shortened a speech-in-noise test, in which the noise has been added with the use of Cool Edit Pro 2.0. The signal/noise ratio has been set at the level of 10 dB. The examination has been conducted at three different volume levels: 25, 35 and 45 dB.
Conclusions: Best results have been achieved at the volume level of 45 dB (above hearing threshold); There were differences in results at volume levels 25 dB and 35 dB in compressed speech test and at volume level 25 dB in speech in noise. Both tests have shown the influence of age on the test result which suggests undiagnosed CAPD among people (with normal hearing) aged over 55.