Interactive fitting of multiple algorithms implemented in the same digital hearing aid

The main purpose of this study is to examine the applicability of an adaptive and interactive optimization strategy to fine-tune three hearing-aid algorithms simultaneously: dynamic compression, temporal signal enhancement, and noise reduction. The optimal combination of these three algorithms was determined by a multidirectional pattern search with an adaptive step size. Additionally, we applied a round-robin procedure to validate the results of the optimization procedure. For both procedures the listeners were asked to compare two consecutive, differently processed sentences in continuous and fluctuating background noises on speech intelligibility. Ten hearing-impaired and four normal-hearing subjects participated. The reliability and consistency of the multidirectional pattern search was low, especially for the fluctuating noise condition. The results of the round-robin procedure did not correspond closely with the pattern search results. These findings suggest that the current implementation of a multidirectional optimization procedure has not yet proven to be applicable for the necessary individual fine tuning of complex signal processing strategies, when the objective is to maximize speech intelligibility.

[1]  G Keidser.  The Relationship Between Listening Conditions and Alternative Amplification Schemes for Multiple Memory Hearing Aids , 1995, Ear and hearing.

[2]  F K Kuk,et al.  Relative satisfaction for frequency responses selected with a simplex procedure in different listening conditions. , 1993, Journal of speech and hearing research.

[3]  F K Kuk,et al.  Effect of hearing aid experience on preferred insertion gain selection. , 1996, Journal of the American Academy of Audiology.

[4]  S. C. Purdy,et al.  FIABILITE, SENSIBILITE ET VALIDITE DU JUGEMENT DE L'INTELLIGIBILITE DE LA PAROLE OBTENUES PAR ESTIMATION DE LA GRANDEUR, ESTIMATION CATEGORIELLE ET COMPARAISON PAR PAIRES CHEZ DES SUJETS AGES , 1992 .

[5]  D D Dirks,et al.  Preferred frequency response for two- and three-channel amplification systems. , 1993, Journal of rehabilitation research and development.

[6]  T Houtgast,et al.  Method for the selection of sentence materials for efficient measurement of the speech reception threshold. , 1999, The Journal of the Acoustical Society of America.

[7]  H Levitt,et al.  Effect of compression ratio in a slow-acting compression hearing aid: paired-comparison judgments of quality. , 1994, The Journal of the Acoustical Society of America.

[8]  Wouter A Dreschler,et al.  UvA-DARE ( Digital Academic Repository ) Methodological aspects of an adaptive multidirectional pattern search to optimize speech perception using three hearing-aid algorithms , 2004 .

[9]  Comparison of preferred frequency gain settings obtained with category rating and modified simplex procedure. , 1996, Journal of the American Academy of Audiology.

[10]  H Levitt,et al.  An evaluation of three adaptive hearing aid selection strategies. , 1987, The Journal of the Acoustical Society of America.

[11]  P. Moran.  On the method of paired comparisons. , 1947, Biometrika.

[12]  H Levitt,et al.  Effect of release time in compression hearing aids: paired-comparison judgments of quality. , 1995, The Journal of the Acoustical Society of America.

[13]  F K Kuk,et al.  The reliability of a modified simplex procedure in hearing aid frequency-response selection. , 1992, Journal of speech and hearing research.

[14]  D Byrne.  Effects of frequency response characteristics on speech discrimination and perceived intelligibility and pleasantness of speech for hearing-impaired listeners. , 1986, The Journal of the Acoustical Society of America.

[15]  J. Punch,et al.  Listener-assessed intelligibility of hearing aid-processed speech. , 1977, Journal of the American Auditory Society.

[16]  D D Dirks,et al.  Subjective Judgments of Speech Clarity Measured by Paired Comparisons and Category Rating , 1997, Ear and hearing.

[17]  C V Pavlovic,et al.  Reliability, sensitivity and validity of magnitude estimation, category scaling and paired-comparison judgements of speech intelligibility by older listeners. , 1992, Audiology : official organ of the International Society of Audiology.

[18]  Etienne Parizet,et al.  Paired comparison listening tests and circular error rates , 2002 .

[19]  G Keidser,et al.  Candidates for Multiple Frequency Response Characteristics , 1995, Ear and hearing.

[20]  S ZERLIN,et al.  A new approach to hearing-aid selection. , 1962, Journal of speech and hearing research.

[21]  G A Studebaker,et al.  Paired comparison judgments of relative intelligibility in noise. , 1982, The Journal of the Acoustical Society of America.