TECHNICAL ASPECTS OF STIMULUS PRESENTATION THROUGH THE HEARING AID FOR ASSR RECORDING

Bronyakin SA, Belov OA,  Tavartkiladze GA.

National Research Centre for Audiology and Hearing Rehabilitation, Moscow,Russia.

Recently objective methods are widely used for hearing threshold determination as well as for the evaluation of the results of hearing aid fitting and speech processor programming in CI users.

The main goal of our study was to evaluate the usefulness of ASSR registration for the objective verification of the gain parameters in patients using hearing aids (HA).

The ASSR registration was performed in patients with HA based on the Gennum platform with the use of AUDERA device. The automatic algorithm based on phase coherence technique for the response detection was applied at frequencies of 500, 1000, 2000 and 4000 Hz.

The amplitude-modulated stimulus was presented (i) to the HA microphone located in the soundproof room and (ii) through the audio input of the HA. For the second condition the appropriate calibration was performed. Stimulation level was precisely adjasted to produce equal HA output level for both conditions. The second approach was developed due to multiple problems existing with free-field quality in conventional (not soundproof) rooms.

In both stimulus presentation conditions the amplitude characteristics as well as modulated tone spectrum were analysed at each frequency at the input and the output of HA.

The results obtained suggest that the described approach could be used for objective measures of HA amplification parameters in patients with hearing loss.

Email: gtavartkiladze@audiology.ru