@inproceedings {Verhulst1815_2016,
	year = {2016},
	author = {Verhulst, Sarah and Jagadeesh, Anoop and Mauermann, Manfred and Ernst, Frauke},
	title = {Amplitude-Modulation Detection in Noise: Relation to Subcomponents of Peripheral Hearing Loss},
	booktitle = {Assoc. Res. Otolaryng. MidWinter Meeting (ARO)},
	URL = {http://c.ymcdn.com/sites/www.aro.org/resource/resmgr/Abstract_Archives/UPDATED_2016_ARO_Abstract_Bo.pdf},
	abstract = {and aging can reduce the number and types of auditorynerve
fibers responsible for a robust coding of sound to the
auditory brainstem. Even though a temporal coding deficit
associated with auditory-nerve and brainstem processing
has been linked to degraded amplitude-modulation detection
in listeners with normal audiometric thresholds, it is not clear
how these supra-threshold hearing deficits interact with the
outer-hair-cell-loss component of hearing loss. As listeners
with elevated audiometric thresholds likely suffer from a
mixture of peripheral pathologies, it is important to understand
which of the hearing deficits is perceptually more dominant in
specific listening conditions.
The present study separated cochlear mechanical hearing
deficits derived from DPOAE growth functions from brainstem
coding fidelity measures (ABR and EFR) in listeners with
normal and mildly-sloping audiograms, and compared
these metrics to psychoacoustic amplitude-modulation (AM)
detection performance. Specifically, we adopted a differential
paradigm in which we tested how badly various types of
masking noises impact AM detection performance. The fixedlevel
wideband noise masker condition was designed to
inform about how auditory filter widening and coding fidelity
impact AM detection performance. In the second, narrowband
masker (40Hz), condition, we expected performance to be
limited by temporal coding fidelity within a single auditory
filter.
AM detection thresholds to 65 and 70 dB SPL, 100-Hzmodulated
4-kHz pure tones were measured in 18 listeners
in the quiet and two masker conditions. Two stimulus
configurations were considered for the elevated-threshold
group: in the first, stimulus levels were adjusted according
to equal sensation level (SL); in the second, stimulus levels
were kept constant. AM detection performance in quiet was
similar for both the elevated-threshold and normal-threshold
group when stimuli were presented at equal SL. For that
same condition, AM thresholds were significantly more
robust against the broadband noise in the elevated-threshold
group. However, for the fixed level condition, AM detection
was significantly worse in the elevated-threshold group and
the broadband noise degraded AM detection more in the
normal-hearing group. The narrowband masker impacted
both groups similarly in the equal SL condition, but had nearly
no effect on the elevated-threshold group when stimuli were
presented at fixed levels. We are currently further relating the
psychoacoustic results to the recorded physiological metrics
to elucidate which subcomponents of peripheral hearing loss
are responsible for AM detection performance in the different
masker conditions.
Funding
DFG Cluster of Excellence EXC 1077/1 "Hearing4all"}
}