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Spatial release from masking deficits in hearing-impaired people: Is inadequate audibility the problem?

Helen Glyde1,2,3, Jörg Buchholz 1,2, Lillian Nielsen 2, Virginia Best 1,2, Harvey Dillon 1,2, Sharon Cameron 1,2, & Louise Hickson 1,3

1. HEARing CRC, 2. National Acoustic Laboratories, 3. University of Queensland

XXXII World Congress of Audiology, Brisbane, 2014

• Spatially separating speech from distracting noise typically results in improved speech understanding.

• Referred to as spatial release from masking (SRM)

• SRM can be measured clinically using the Listening in Spatialized Noise – Sentences Test (LiSN-S)

Background

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• Previous research suggested SRM declines with hearing loss.

Background

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Sp

atia

l re

leas

e f

rom

mas

kin

g (

dB

)

Glyde et al (2013)

Why?

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• Poor temporal resolution?

• Poor frequency resolution?

• Inadequate audibility?

• To determine whether inadequate audibility could explain the apparent relationship between SRM and hearing loss.

Aim

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Method

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Hearing status Amplification Participants Mean age (range)

Simulated hearing-impairment

NAL-RP n = 12 33.6 yrs (25 – 47)

NAL-RP + 25 %NAL-RP + 50 %

n = 16 28.8 yrs (18 – 53)

Normal hearing n = 96 (Cameron et al. 2011)

31.9 yrs (18 – 60)

Hearing impairment

NAL-RP n = 16 (Glyde et al. 2013)

73.1 yrs (39 – 87)

NAL-RP + 25 %NAL-RP + 50 %

n = 16 68.8 yrs (21 – 80)

Same Voice - 0° Condition

Same Voice - ±90° Condition

Sp

atia

l Re

lea

se

F

rom

Ma

sk

ing

Method

Low cue

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Method

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Results – Objective analysis

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Results - Data

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• Sig. improvement in SRM with increase in audibility (p ranging from < 0.001 to 0.047)

• NH performance remains sig. better than HI performance at all levels of audibility (p ranging from 0.001 to 0.011)

HI group

Sim. HI group

Conclusion

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• Inadequate audibility explains the majority of the difference in SRM measured between NH and HI adults.

• Improving audibility allows HI adults to gain greater benefit from spatial separation.

• An amplification strategy which increases audibility but is practical for use in everyday life may improve speech understanding in noise.

Acknowledgements

creating sound valueTM

This research was financially supported by the HEARing CRC established and supported under the Australian Government’s Cooperative Research Centres Program.

Thanks for listening