Acclimatization effect in speech recognition: evaluation without hearing aids.

Background: After the adaptation of hearing aids, an improvement in speech understanding is expected to occur, called acclimatization.

Aim: To determine the effect of acclimatization in sentences recognition threshold, for the conditions of silence (SRTQ) and noise (SRTN), in new users of hearing aids, evaluated prior to and after acclimatization, without the use of the hearing aids.

Method: Participants were 40 individuals, aged between 28 and 78 years, with mild to moderate sensorineural hearing loss. Tests were conducted in three sessions: prior to the adaptation of the hearing aids, fourteen days and three months later.The Portuguese Sentences Lists test in free field was used for testing, and the SRTQ and SRTN were obtained (with noise level settled at 65 dB A). Results were expressed through the signal/noise ratios.

Results: The mean values for the SRTQ in the 1st, 2nd and 3rd sessions were 54.43, 51.71 and 52.22 dB A respectively,. The mean signal/noise ratios for the 1st, 2nd and 3rd sessions were 1.67, 0.30 and -0.03 dB A. When comparing the results obtained between the testing sessions, a statistically significant difference was observed between the 1st and 2nd sessions, and between the 1st and 3rd sessions for the values obtained in the testing conditions of silence and noise.

Conclusion: There was a progressive reduction of sentences recognition thresholds and signal/noise ratios indicating an improvement in performance even when assessing the individuals without the hearing aids. This improvement can be related to the effect of acclimatization.