Previous Work

Companies We Have Provided Service To:

Since 2002, NAL has completed studies for the following organisations (listed alphabetically):

Arnang Pty Ltd, Australia
Australian Hearing
Bernafon AG, Switzerland
Commercial Television Australia
GN ReSound, Denmark
CTO through HörCentrum, Germany
Office of Hearing Services, Australia
Phonak AG, Switzerland
Siemens Hearing Instruments, Germany
VAST Audio Pty Ltd, Australia
Work Safe, Victoria


Titles of Previous Contracted Work:


  • Evaluation of the Alaska real-time signal processing chip.

    Dillon H, Keidser G, O'Brien A and Silberstein H (2003). Sound quality comparisons of advanced hearing aids. Hearing Journal, 56(4):30-40.
  • Subjective assessment of loudness characteristics of typical television programme material.
  • Compression parameters for severe to profound hearing loss.

    Keidser G, Dillon H, Dyrlund O, Carter L and Hartley D (2007). Preferred compression ratios in the low and high frequencies by the moderately severe to severe-profound population. Journal of the American Academy of Audiology, 18(1):17-33.

    Convery E, Keidser G and Carter L (2008). Transitioning hearing aid users with severe or profound hearing loss from linear to non-linear amplification: Three case studies. Australian & New Zealand Journal of Audiology, 30(1):73-85.

    Keidser G, Hartley D and Carter L (2008). Long-term usage of modern signal processing by listeners with severe or profound hearing loss: A retrospective survey. American Journal of Audiology, 17(2):136-146.

    Convery E, Keidser G. (2010) User preferences for amplification for adults with severe and profound hearing loss. ENT and Audiology News 18(6): 78-80.
  • Impact of three types of signal processing in hearing aids on the horizontal localisation performance.

    Keidser G, Rohrseitz K, Dillon H, Hamacher V, Carter L, Rass U and Convery E (2006). The effect of multi-channel wide dynamic range compression, noise reduction, and directional microphone on horizontal localisation performance in hearing aid wearers. International Journal of Audiology, 45(10):563-579.
  • Evaluation of a prototype temporary earmould with various vent size.
  • Impact of gain mismatch on the horizontal localisation performance.

    Keidser G, Convery E, Hamacher V (2011) Gain mismatch and horizontal localization performance. Hearing Journal 64(2):26,30,32-33.
  • Preference for direct or amplified low-frequency sound.

    Keidser G, Carter L, Chalupper J and Dillon H (2007). Effect of low-frequency gain and venting effects on the benefit derived from directionality and noise reduction in hearing aids. International Journal of Audiology, 46(10):554-568.
  • Relate hearing loss to hearing aid benefit.
  • Evaluation of a transient noise reduction algorithm.

    Keidser G, O’Brien A, Latzel M and Convery E (2007). Evaluation of a transient noise reduction algorithm. Hearing Journal, 60(2): 29,32,34,38-39.
  • International levels of service for children with hearing impairment.
  • Gain adaptation in new hearing aid users.

    Keidser G, O’Brien A, Carter L, McLelland M and Yeend I (2008). Variation in preferred gain with experience for hearing aid users. International Journal of Audiology, 47(10):621-635.
  • The effect of frequency-specific directionality on horizontal localisation and sound quality.

    Keidser G, O’Brien A, Hain Jens-Uwe, McLelland M, Yeend I (2009) The effect of frequency-dependent microphone directionality on horizontal localisation performance in hearing aid users. International Journal of Audiology 48(11):789-803.
  • Learning volume control: Best classification system and benefit.
  • Verifying the hearing aid output level using environmental sounds.

    Kiessling J, Keidser G, Bentler R and Mueller M (2009). The Output Verification Test – a step towards a tool to clinically verify the output of hearing instruments. Hearing Review, 16(4):12-19.

    Keidser G, Bentler R, Kiessling J (2010) A multi-site evaluation of a proposed test for verifying hearing aid maximum output. International Journal of Audiology 49(1):14-23.

    Keidser G, Convery E, Kiessling J, Bentler R (2009) Is the hearing instrument to blame when things get really noisy? Hearing Review 16(8):12-19.
  • In-situ audiometry; reliability and validity.

    O’Brien A, Keidser G, Yeend I, Hartley L, Dillon H (2010)Validity and reliability of in-situ air conduction thresholds measured through a hearing aid coupled to closed and open instant-fit tips. International Journal of Audiology 49(12): 868-76.
  • The effect of asymmetric directionality on speech recognition in noise.
  • The effect of frequency compression on horizontal localisation and speech recognition in noise.

    O'Brien A, Yeend I, Hartley L, Keidser G, Nyffeler M (2010) Evaluation of frequency compression and high-frequency directionality. Hearing Journal 63(8):32,34-37.
  • The perceptibility, acceptability, and benefit of transitioning to new gain targets in experienced hearing aid wearers with moderately severe to profound hearing loss.

    Convery E, Keidser G (2011) Transitioning hearing aid users with severe and profound loss to a new gain/frequency response: benefit, perception, and acceptance. Journal of the American Academy of Audiology 22(3):168-180.