The number of spectral channels required for speech recognition depends on the difficulty of the listening situation

Shannon, Robert V.; Fu, Qiuyun; Galvin, John J.

doi:10.1080/03655230410017562

Cited by 225 publications

(204 citation statements)

References 19 publications

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“…The AMI offers the crucial advantage over the ABI in that it can be surgically implanted under direct visual exposure of the target region, without brain distortions caused by tumors in NF2 patients, and with less risks of damaging critical brainstem structures and cranial nerves. Our results demonstrate that the AMI is safe for human use and provides different loudness, pitch, temporal, and directional percepts, features that have shown to be important for speech perception (Pfingst et al, 1983;Shannon et al, 1995;Nelson et al, 1996;Friesen et al, 2001) and more complex sound processing (Smith et al, 2002;Shannon et al, 2004;Kidd et al, 2005). Furthermore, the AMI can provide performance levels at least comparable with the ABI in NF2 patients, particularly when stimulating the ICC.…”

Section: Sound Localizationmentioning

confidence: 69%

Electrical Stimulation of the Midbrain for Hearing Restoration: Insight into the Functional Organization of the Human Central Auditory System

Lim¹,

Lenarz²,

Joseph³

et al. 2007

J. Neurosci.

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The cochlear implant can restore speech perception in patients with sensorineural hearing loss. However, it is ineffective for those without an implantable cochlea or a functional auditory nerve. These patients can be implanted with the auditory brainstem implant (ABI), which stimulates the surface of the cochlear nucleus. Unfortunately, the ABI has achieved limited success in its main patient group [i.e., those with neurofibromatosis type 2 (NF2)] and requires a difficult surgical procedure. These limitations have motivated us to develop a new hearing prosthesis that stimulates the midbrain with a penetrating electrode array. We recently implanted three patients with the auditory midbrain implant (AMI), and it has proven to be safe with minimal movement over time. The AMI provides loudness, pitch, temporal, and directional cues, features that have shown to be important for speech perception and more complex sound processing. Thus far, all three patients obtain enhancements in lip reading capabilities and environmental awareness and some improvements in speech perception comparable with that of NF2 ABI patients. Considering that our midbrain target is more surgically exposable than the cochlear nucleus, this argues for the use of the AMI as an alternative to the ABI. Fortunately, we were able to stimulate different midbrain regions in our patients and investigate the functional organization of the human central auditory system. These findings provide some insight into how we may need to stimulate the midbrain to improve hearing performance with the AMI.

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Section: Sound Localizationmentioning

confidence: 69%

Electrical Stimulation of the Midbrain for Hearing Restoration: Insight into the Functional Organization of the Human Central Auditory System

Lim¹,

Lenarz²,

Joseph³

et al. 2007

J. Neurosci.

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“…A promising avenue of research lies in linking cross-species differences in the physiological organization of the auditory system to observed differences in the use of auditory cues. Further research manipulating spectral shape and pitch salience of tone sequences, for example using noisevocoding or sinusoidal-vocoding, which allow control over spectral resolution while removing versus preserving pitch cues, respectively (54,55), will help researchers understand species differences in auditory sequence recognition.…”

Section: Discussionmentioning

confidence: 99%

Songbirds use spectral shape, not pitch, for sound pattern recognition

Bregman

Patel

Gentner

2016

Proc. Natl. Acad. Sci. U.S.A.

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Humans easily recognize "transposed" musical melodies shifted up or down in log frequency. Surprisingly, songbirds seem to lack this capacity, although they can learn to recognize human melodies and use complex acoustic sequences for communication. Decades of research have led to the widespread belief that songbirds, unlike humans, are strongly biased to use absolute pitch (AP) in melody recognition. This work relies almost exclusively on acoustically simple stimuli that may belie sensitivities to more complex spectral features. Here, we investigate melody recognition in a species of songbird, the European Starling (Sturnus vulgaris), using tone sequences that vary in both pitch and timbre. We find that small manipulations altering either pitch or timbre independently can drive melody recognition to chance, suggesting that both percepts are poor descriptors of the perceptual cues used by birds for this task. Instead we show that melody recognition can generalize even in the absence of pitch, as long as the spectral shapes of the constituent tones are preserved. These results challenge conventional views regarding the use of pitch cues in nonhuman auditory sequence recognition.absolute pitch | songbirds | comparative cognition | pitch processing | pattern perception

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“…With simulations and normal-hearing subjects, as many as ten channels are needed to reach asymptotic performance (for difficult tests) using a CIS-like processor . Other investigators have found that even more channels are needed for asymptotic performance, especially for difficult tests such as identification of vowels or recognition of speech presented in competition with noise or a multi-talker babble (Friesen et al, 2001;Shannon et al, 2004). For example, Friesen et al (2001) found that identification of vowels for listeners with normal hearing continued to improve with the addition of channels in the acoustic simulations up to the tested limit of 20 channels, for vowels presented in quiet and at progressively worse S/Ns out to and including +5 dB.…”

Section: Likely Limitations Imposed By Present Electrode Designs and mentioning

confidence: 99%

Cochlear implants: A remarkable past and a brilliant future

2008

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The aims of this paper are to (i) provide a brief history of cochlear implants; (ii) present a status report on the current state of implant engineering and the levels of speech understanding enabled by that engineering; (iii) describe limitations of current signal processing strategies and (iv) suggest new directions for research. With current technology the "average" implant patient, when listening to predictable conversations in quiet, is able to communicate with relative ease. However, in an environment typical of a workplace the average patient has a great deal of difficulty. Patients who are "above average" in terms of speech understanding, can achieve 100% correct scores on the most difficult tests of speech understanding in quiet but also have significant difficulty when signals are presented in noise. The major factors in these outcomes appear to be (i) a loss of low-frequency, fine structure information possibly due to the envelope extraction algorithms common to cochlear implant signal processing; (ii) a limitation in the number of effective channels of stimulation due to overlap in electric fields from electrodes, and (iii) central processing deficits, especially for patients with poor speech understanding. Two recent developments, bilateral implants and combined electric and acoustic stimulation, have promise to remediate some of the difficulties experienced by patients in noise and to reinstate low-frequency fine structure information. If other possibilities are realized, e.g., electrodes that emit drugs to inhibit cell death following trauma and to induce the growth of neurites toward electrodes, then the future is very bright indeed.

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The number of spectral channels required for speech recognition depends on the difficulty of the listening situation

Cited by 225 publications

References 19 publications

Electrical Stimulation of the Midbrain for Hearing Restoration: Insight into the Functional Organization of the Human Central Auditory System

Electrical Stimulation of the Midbrain for Hearing Restoration: Insight into the Functional Organization of the Human Central Auditory System

Songbirds use spectral shape, not pitch, for sound pattern recognition

Cochlear implants: A remarkable past and a brilliant future

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