Notched-noise precursors improve detection of low-frequency amplitude modulation

Almishaal, Ali A.; Bidelman, Gavin M.; Jennings, Skyler G.

doi:10.1121/1.4973912

Cited by 18 publications

(32 citation statements)

References 64 publications

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“…Here, monaural AM detection thresholds were measured for probes at two temporal positions in simultaneous ipsilateral, contralateral and bilateral noise. The present stimulus design is thus different from that of Almishaal et al (2017). Nonetheless, the present AM detection thresholds for 70 dB SPL carriers and ipsilateral BBN (the stimuli and condition most similar to any of those explored by Almishaal et al 2017) were 2.8 dB better in the late than in the early condition.…”

Section: Comparison With Earlier Studiesmentioning

confidence: 47%

“…Assuming that the MOCR is involved to some extent in the present temporal effects on AM detection, the present results indicate that the MOCR may also help by enhancing AM cues. This idea is supported by recent evidence that cochlear implant users show better speech-in-noise intelligibility with a binaural sound coding strategies inspired by the MOCR than with standard strategies (Lopez-Poveda 2015;Lopez-Poveda et al 2016, 2017. It remains uncertain, however, to what extent this intelligibility improvement is actually due to the MOCR-inspired strategy enhancing AM cues per se or to other concomitant benefits (see the Discussion in Lopez-Poveda et al 2016).…”

Section: Discussionmentioning

confidence: 88%

“…The present study was motivated by the hypothesis that the MOCR may facilitate the detection of AM in simultaneous noise. To our knowledge, only Almishaal et al (2017) have investigated a related hypothesis. They measured AM detection thresholds for a narrow-band noise AM carrier centered at 5 kHz as a function of carrier level in the presence and in the absence of a 200 ms, 40 dB sound pressure level (SPL) ipsilateral notched noise precursor.…”

Section: Introductionmentioning

confidence: 99%

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Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral, Contralateral and Bilateral Noise

Marrufo-Pérez

Eustaquio-Martín

López-Bascuas

et al. 2018

JARO

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The amplitude modulations (AMs) in speech signals are useful cues for speech recognition. Several adaptation mechanisms may make the detection of AM in noisy backgrounds easier when the AM carrier is presented later rather than earlier in the noise. The aim of the present study was to characterize temporal adaptation to noise in AM detection. AM detection thresholds were measured for monaural (50 ms, 1.5 kHz) pure-tone carriers presented at the onset ('early' condition) and 300 ms after the onset ('late' condition) of ipsilateral, contralateral, and bilateral (diotic) broadband noise, as well as in quiet. Thresholds were 2-4 dB better in the late than in the early condition for the three noise lateralities. The temporal effect held for carriers at equal sensation levels, confirming that it was not due to overshoot on carrier audibility. The temporal effect was larger for broadband than for low-band contralateral noises. Many aspects in the results were consistent with the noise activating the medial olivocochlear reflex (MOCR) and enhancing AM depth in the peripheral auditory response. Other aspects, however, indicate that central masking and adaptation unrelated to the MOCR also affect both carrier-tone and AM detection and are involved in the temporal effects.

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Section: Comparison With Earlier Studiesmentioning

confidence: 47%

Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral, Contralateral and Bilateral Noise

Marrufo-Pérez

Eustaquio-Martín

López-Bascuas

et al. 2018

JARO

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“…For NH listeners, the noise level was fixed at 60 dB sound pressure level (SPL). This level was chosen because broadband noise at this level is capable of activating the MOCR without activating the middle-ear muscle reflex (Lilaonitkul and Guinan, 2009;Aguilar et al, 2013;Mishra and Lutman, 2014), a factor that could have confounded the results. For CI users, the noise level was set at Ϫ25 dB full scale (FS), where 0 dB FS corresponds to a signal with peak amplitude at unity.…”

Section: Methodsmentioning

confidence: 99%

Adaptation to Noise in Human Speech Recognition Unrelated to the Medial Olivocochlear Reflex

2018

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Sensory systems constantly adapt their responses to the current environment. In hearing, adaptation may facilitate communication in noisy settings, a benefit frequently (but controversially) attributed to the medial olivocochlear reflex (MOCR) enhancing the neural representation of speech. Here, we show that human listeners ( = 14; five male) recognize more words presented monaurally in ipsilateral, contralateral, and bilateral noise when they are given some time to adapt to the noise. This finding challenges models and theories that claim that speech intelligibility in noise is invariant over time. In addition, we show that this adaptation to the noise occurs also for words processed to maintain the slow-amplitude modulations in speech (the envelope) disregarding the faster fluctuations (the temporal fine structure). This demonstrates that noise adaptation reflects an enhancement of amplitude modulation speech cues and is unaffected by temporal fine structure cues. Last, we show that cochlear implant users ( = 7; four male) show normal monaural adaptation to ipsilateral noise. Because the electrical stimulation delivered by cochlear implants is independent from the MOCR, this demonstrates that noise adaptation does not require the MOCR. We argue that noise adaptation probably reflects adaptation of the dynamic range of auditory neurons to the noise level statistics. People find it easier to understand speech in noisy environments when they are given some time to adapt to the noise. This benefit is frequently but controversially attributed to the medial olivocochlear efferent reflex enhancing the representation of speech cues in the auditory nerve. Here, we show that the adaptation to noise reflects an enhancement of the slow fluctuations in amplitude over time that are present in speech. In addition, we show that adaptation to noise for cochlear implant users is not statistically different from that for listeners with normal hearing. Because the electrical stimulation delivered by cochlear implants is independent from the medial olivocochlear efferent reflex, this demonstrates that adaptation to noise does not require this reflex.

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“…Using a short-duration (50 ms), narrowband-noise carrier centered on 5000 Hz and off-frequency noise to minimize the effects of the spread of excitation, Almishaal et al (2017) measured AM detection as a function of carrier level to test the hypothesis that AM detection declines with increasing carrier level, as predicted from BM compression. Consistent with their hypothesis, AM detection declined as carrier level increased from 45 to 65 dB sound pressure level (SPL).…”

Section: Introductionmentioning

confidence: 99%

Amplitude modulation detection with a short-duration carrier: Effects of a precursor and hearing loss

Jennings

Chen

Fultz

et al. 2018

The Journal of the Acoustical Society of America

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This study tests the hypothesis that amplitude modulation (AM) detection will be better under conditions where basilar membrane (BM) response growth is expected to be linear rather than compressive. This hypothesis was tested by (1) comparing AM detection for a tonal carrier as a function of carrier level for subjects with and without cochlear hearing impairment (HI), and by (2) comparing AM detection for carriers presented with and without an ipsilateral notched-noise precursor, under the assumption that the precursor linearizes BM responses. Average AM detection thresholds were approximately 5 dB better for subjects with HI than for subjects with normal hearing (NH) at moderate-level carriers. Average AM detection for low-to-moderate level carriers was approximately 2 dB better with the precursor than without the precursor for subjects with NH, whereas precursor effects were absent or smaller for subjects with HI. Although effect sizes were small and individual differences were noted, group differences are consistent with better AM detection for conditions where BM responses are less compressive due to cochlear hearing loss or due to a reduction in cochlear gain. These findings suggest the auditory system may quickly adjust to the local soundscape to increase effective AM depth and improve signal-to-noise ratios.

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Notched-noise precursors improve detection of low-frequency amplitude modulation

Cited by 18 publications

References 64 publications

Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral, Contralateral and Bilateral Noise

Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral, Contralateral and Bilateral Noise

Adaptation to Noise in Human Speech Recognition Unrelated to the Medial Olivocochlear Reflex

Amplitude modulation detection with a short-duration carrier: Effects of a precursor and hearing loss

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