creating sound value TM The perceptibility, acceptability, and benefit of transitioning to new gain targets in experienced hearing aid wearers with moderately severe to profound hearing loss Elizabeth Convery and Gitte Keidser National Acoustic Laboratories and the HEARing CRC Audiology Australia’s XIX National Conference, May 2010, Sydney creating sound value TM

Introduction severe and profound hearing loss long-term hearing aid users reluctant to alter amplification characteristics retain older technology for longer adapt to frequency response with +LF and –HF gain ↓ speech understanding due to upward spread of masking full-time hearing aid users highly reliant on amplification

creating sound value TM Introduction technology currently available to meet HF gain requirements of people with severe and profound hearing loss –increased bandwidth –more sophisticated feedback cancellers best way to introduce new amplification characteristics? –gradual introduction shown to be successful for introducing multichannel WDRC (Kuk 2001, Kuk et al. 2003, Keidser et al. 2007)

creating sound value TM to investigate the effect of a gradual change in gain/frequency response on experienced hearing aid users with moderately severe to profound loss Objective – do they accept the – do they benefit – is the transition change? objectively, subjectively? perceptually disturbing?

creating sound value TM 23 experienced hearing aid users PTA ≥ 60 dB HL devices set to match gain/frequency response of participants’ own devices for a 65 dB SPL input Method wore the Siemens Artis 2 SP for 15 weeks “mimic fit”

creating sound value TM Results – mimic fit vs NAL-RP overfit in mid frequencies re: NAL-RP underfit in high frequencies re: NAL-RP

creating sound value TM Method Exp group Control group age = 68 yrs PTA = 79 dB HL 50% 25% NAL-RP 75% Week 15 Week 12 Week 9 Week 6 Week 3 mimic fit age = 64 yrs PTA = 79 dB HL Week 1 PC SD LS Q SD LS Q SD LS Q SD LS Q SD LS Q Subjective tests: paired comparison, questionnaire Objective tests: speech discrimination, loudness scaling PC

creating sound value TM no significant change in any of these factors over time, or between groups: –perception of loudness, sound quality, speech intelligibility, own voice volume –overall performance rating –presence and degree of perceptual disturbance Results – subjective feedback experimental participants were accepting of the gradual change to their amplification characteristics, and did not experience greater perceptual disturbance than control participants

creating sound value TM speech discrimination Results – objective tests performance of control participants improved over time - acclimatisation or learning effect experimental group participants had greater difficulty as settings reached the NAL-RP prescription Interaction between group and time p =

creating sound value TM loudness scaling Results – objective tests experimental group tended to find mid-level sounds softer over time than did control participants Interaction between group and time p = 0.44

creating sound value TM mimic fit program preferred to NAL-RP overall Results – paired comparison suggest that experimental participants did undergo some adaptation to the new settings during the 15-week study period control group maintained or slightly increased their preference for mimic fit between weeks 1 and 15 experimental group showed a lesser preference for mimic fit at week 15 than at week 1 p = 0.09

creating sound value TM evidence in support of gain transition not perceptually disturbing to participants participants not aware of changes to loudness, speech understanding, sound quality less preference for original settings after 15 weeks evidence that does not support transition decline in speech discrimination performance Conclusions  individual variation longer increment intervals?

creating sound value TM Gain transition... –only initiate transition if there is a compelling reason risk of TTS/PTS due to overamplification poorer than expected speech discrimination re: pure tone thresholds complaints about sound quality –ensure an appropriate transition goal –monitor speech discrimination over time be prepared to stop, or delay, transition if performance decrements are observed Clinical recommendations or no? yes yes, BUT

creating sound value TM Acknowledgements creating sound value TM This research was financially supported by the HEARing CRC established and supported under the Australian Government’s Cooperative Research Centres Program from the National Acoustic Laboratories Anna O’Brien, Margot McLelland, Ingrid Yeend, Megan Gilliver, Vivian Fabricatorian, Pamela Jackson, Emma van Wanrooy, Elizabeth Beach from Siemens Audiologische Technik Simone Siltmann, Dirk Junius