Optimization of Frequency Lowering Algorithms for Getting the Highest Speech Intelligibility Improvement by Hearing Loss Simulation

Systems-Level Quality Improvement
Part of the following topical collections:
  1. Systems-Level Quality Improvement


High frequency hearing loss is a growing problem for both children and adults. To overcome this impairment, different frequency lowering methods (FLMs) were tried from 1930s, however no satisfaction was provided up to now. In this study, for getting higher speech intelligibility, eight combinations of FLMs which were designed originally were tried with simulated sounds onto normal hearing subjects. These improvements were calculated by the difference with standard hearing aid method, amplification. High frequency hearing loss was simulated with the combined suprathreshold effects. An offline study was carried out for each subject for determining the significant methods used in modified rhyme test (MRT) (Subjective measure for intelligibility). Significant methods were determined according to their speech intelligibility index (SII) (Objective measure for intelligibility). All different cases were tried under four noisy environments and a noise free environment. Twelve hearing impaired subjects were simulated by hearing loss simulation (HLS). MRT was developed for Turkish language as a first time. As the results of improvements, total 71 cases were statistically significant for twelve subjects. Eighty-three percent success of FLMs was achieved against amplification for being an alternative method of amplification in noisy environments. For four subjects, all significant methods gave higher improvements than amplification. As conclusion, specific method recommendations for different noisy environments were done for each subject for getting more speech intelligibility.


Frequency lowering algorithms Speech intelligibility Modified rhyme test Simulated hearing loss High frequency hearing loss 


  1. 1.
    Bench, J., and Bamford, J., Speech-hearing tests and the spoken language of hearing-impaired children. Academic, London, 1979.Google Scholar
  2. 2.
    Ching, T. Y., Dillon, H., and Byrne, D., Speech recognition of hearing impaired listeners: predictions from audibility and the limited role of high-frequency amplification. J. Acoust. Soc. Am. 103:1128–1140, 1998.CrossRefGoogle Scholar
  3. 3.
    Hogan, C. A., and Turner, C. W., High-frequency audibility: benefits for hearing-impaired listeners. J. Acoust. Soc. Am. 104(1):432–441, 1998.CrossRefGoogle Scholar
  4. 4.
    Murray, N. B., and Byrne, D., Performance of hearing impaired and normal hearing listeners with various high frequency cut-offs in hearing aids. Aust. J. Audiol. 8:21–28, 1986.Google Scholar
  5. 5.
    Fowler, E. P., A method for the early dedection of otosclerosis. Arch. Otolaryngol. 24:731–741, 1936.CrossRefGoogle Scholar
  6. 6.
    Baer, T., Moore, B. C., and Kluk, K., Effects of low pass filtering on the intelligibility of speech in noise for people with and without dead regions at high frequencies. J. Acoust. Soc. Am. 112:1133–1144, 2002.CrossRefGoogle Scholar
  7. 7.
    Moore, B. C. J., and Glasberg, B. R., A model of loudness perception applied to cochlear hearing loss. Audit. Neurosci. 3:289–311, 1997.Google Scholar
  8. 8.
    Vickers, D. A., Baer, T., and Moore, B. C. J., Effects of lowpass filtering on speech intelligibility for listeners with dead regions at high frequencies. Br. J. Audiol. 35:148–149, 2001.Google Scholar
  9. 9.
    Robinson, J. D., Baer, T., and Moore, B. R. C., Using transposition to improve consonant discrimination and detection for listeners with severe high-frequency hearing loss. Int. J. Audiol. 46:293–308, 2007.CrossRefGoogle Scholar
  10. 10.
    Simpson, A., Frequency-lowering devices for managing high-frequency hearing loss: a review. Trends Amplif. 13(2):87–106, 2009.CrossRefGoogle Scholar
  11. 11.
    House, A. S., Williams, C. E., Hecker, M. H. L., and Kryter, K. D., Articulation testing methods: consonantal differentiation with a closed response set. J. Acoust. Soc. Am. 37:158–166, 1965.CrossRefGoogle Scholar
  12. 12.
    ANSI-S3.5, American national standard methods for the calculation of the speech intelligibility index. American National Standards Institute, Inc, New York, 1997.Google Scholar
  13. 13.
    Moore, B. C. J., Glasberg, B. R., and Vickers, D. A., Simulation of the effects of loudness recruitment on the intelligibility of speech in noise. Br. J. Audiol. 29:131–143, 1995.CrossRefGoogle Scholar
  14. 14.
    Nejime, Y., and Moore, B. C. J., Simulation of the effect of threshold elevation and loudness recruitment combined with reduced frequency selectivity on the intelligibility of speech in noise. J. Acoust. Soc. Am. 102:603–615, 1997.CrossRefGoogle Scholar
  15. 15.
    Palaz, H., Bicil, Y., Kanak, A., and Dogan, M. U., New Turkish intelligibility test for assessing speech communication systems. J. Speech Commun. 47:411–423, 2005.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Computer Engineering, Engineering FacultyGazi UniversityAnkaraTurkey
  2. 2.Informatics InstituteMiddle East Technical UniversityAnkaraTurkey

Personalised recommendations