The effect of speech presentation level on measurement of auditory acclimatization to amplified speech.

A systematic improvement in auditory performance over time, following a change in the acoustic information available to the listener (that cannot be attributed to task, procedural or training effects) is known as auditory acclimatization. However, there is conflicting evidence concerning the existence of auditory acclimatization; some studies show an improvement in performance over time while other studies show no change. In an attempt to resolve this conflict, speech recognition abilities of 16 subjects with bilateral sensorineural hearing impairments were measured over a 12-week period following provision of a monaural hearing instrument for the first time. The not-fitted ear was used as the control. Three presentation levels were used representing quiet, normal, and raised speech. The results confirm the presence of acclimatization. In addition, the results show that acclimatization is evident at the higher presentation levels but not at the lowest.