Phase-locking of auditory-nerve discharges to sinusoidal electric stimulation of the cochlea

Dynes, Scott; Delgutte, Bertrand

doi:10.1016/0378-5955(92)90011-b

Cited by 112 publications

(82 citation statements)

References 37 publications

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“…The difference between the two means is highly significant (p<0.001, two-sided permutation test for difference in means). These values of dynamic range are comparable to those observed with pure-tone stimulation in a normal ear (Sachs and Abbas, 1974), and considerably larger than the dynamic ranges observed with sinusoidal electric stimulation without a DPT (van den Honert and Stypulkovsky, 1987;Hartmann et al, 1990;Dynes and Delgutte, 1992). In contrast, transient DPT responders have useful dynamic ranges as low as 10 dB, more in line with electric dynamic ranges reported in the literature.…”

Section: Threshold and Dynamic Rangesupporting

confidence: 71%

“…Because the median DPT level in these experiments was 6 dB re: 1 mA (see Table I in Litvak et al, 2003b), the peak amplitude of the modulation waveform was typically only 4 μA at threshold. This is much lower than singleunit thresholds reported for low-frequency sinusoidal electric stimulation, which are typically tens or hundreds of μA (Parkins and Colombo, 1987;Hartmann et al, 1990;Dynes and Delgutte, 1992). Thus the introduction of a DPT is highly effective in improving thresholds for sustained responders.…”

Section: Threshold and Dynamic Rangementioning

confidence: 60%

“…Such double-peaked period histograms are not observed for acoustic stimulation above 1000 Hz (Johnson, 1980). Interval histograms are also highly abnormal, demonstrating a tendency for spikes to occur at regular intervals, even for highfrequency (>1000 Hz) stimulation (Parkins, 1989;Dynes and Delgutte, 1992). In some cases, ANFs fire exactly on every other cycle or even at higher multiples of the stimulus period (Javel, 1990;Javel and Shepherd, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Improved temporal coding of sinusoids in electric stimulation of the auditory nerve using desynchronizing pulse trains

Litvak

Delgutte

Eddington

2003

The Journal of the Acoustical Society of America

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Rubinstein et al. [Hearing Res. 127, 108-118 (1999)] suggested that the representation of electric stimulus waveforms in the temporal discharge patterns of auditory-nerve fiber (ANF) might be improved by introducing an ongoing, high-rate, desynchronizing pulse train (DPT). To test this hypothesis, activity of ANFs was studied in acutely deafened, anesthetized cats in response to 10-min-long, 5-kpps electric pulse trains that were sinusoidally modulated for 400 ms every second. Two classes of responses to sinusoidal modulations of the DPT were observed. Fibers that only responded transiently to the unmodulated DPT showed hyper synchronization and narrow dynamic ranges to sinusoidal modulators, much as responses to electric sinusoids presented without a DPT. In contrast, fibers that exhibited sustained responses to the DPT were sensitive to modulation depths as low as 0.25% for a modulation frequency of 417 Hz. Over a 20-dB range of modulation depths, responses of these fibers resembled responses to tones in a healthy ear in both discharge rate and synchronization index. This range is much wider than the dynamic range typically found with electrical stimulation without a DPT, and comparable to the dynamic range for acoustic stimulation. These results suggest that a stimulation strategy that uses small signals superimposed upon a large DPT to encode sounds may evoke temporal discharge patterns in some ANFs that resemble responses to sound in a healthy ear.

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Section: Threshold and Dynamic Rangesupporting

confidence: 71%

Section: Threshold and Dynamic Rangementioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved temporal coding of sinusoids in electric stimulation of the auditory nerve using desynchronizing pulse trains

Litvak

Delgutte

Eddington

2003

The Journal of the Acoustical Society of America

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“…Thus, introducing ongoing temporal changes in the stimulus seems to cause a recovery from binaural adaptation in CI listeners. Possible reasons for the excessive form of the binaural adaptation effect could be the high degree of phase locking and across-fiber synchrony in the neural response to electric stimulation (18)(19)(20)(21)(22). Introducing artificial randomness into the stimulus may reduce the amount of periodicity in the neural response and consequently avoid binaural adaptation.…”

Section: Discussionmentioning

confidence: 99%

Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

Laback

Majdak

2008

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

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Interaural time difference (ITD) arises whenever a sound outside of the median plane arrives at the two ears. There is evidence that ITD in the rapidly varying fine structure of a sound is most important for sound localization and for understanding speech in noise. Cochlear implants (CIs), neural prosthetic devices that restore hearing in the profoundly deaf, are increasingly implanted to both ears to provide implantees with the advantages of binaural hearing. CI listeners have been shown to be sensitive to fine structure ITD at low pulse rates, but their sensitivity declines at higher pulse rates that are required for speech coding. We hypothesize that this limitation in electric stimulation is at least partially due to binaural adaptation associated with periodic stimulation. Here, we show that introducing binaurally synchronized jitter in the stimulation timing causes large improvements in ITD sensitivity at higher pulse rates. Our experimental results demonstrate that a purely temporal trigger can cause recovery from binaural adaptation. Thus, binaurally jittered stimulation may improve several aspects of binaural hearing in bilateral recipients of neural auditory prostheses.binaural adaptation ͉ cochlear implant ͉ fine structure ͉ lateralization ͉ localization I nteraural time difference (ITD) arises whenever a sound source outside the median plane arrives at the two ears and provides important information on the sound's lateral position. ITD occurs both in the rapidly varying fine structure and in the slowly varying envelope of the signal. There is evidence that ITD in the fine structure of a sound is most important for sound localization (1, 2) and for understanding speech in noise (3, 4). Listeners bilaterally supplied with cochlear implants (CIs) have been shown to be sensitive to fine structure ITD, but their sensitivity disappears at a pulse rate of a few hundred pulses per second (5-8). This is in contrast to normal hearing (NH) listeners, who are sensitive to ITD in the fine structure up to much higher frequencies (9, 10). The CI listeners' limitation in the ability to process fine structure ITD information at higher rates is disadvantageous with respect to speech coding where such high rates are required.In this study, we present a method of electric stimulation that improves CI listeners' sensitivity to fine structure ITD at higher pulse rates. The method is based on previous findings on the limitation in ITD perception at higher modulation rates in NH listeners.In studies with NH listeners, it has been observed that the sensitivity to ITD information degrades with increasing modulation rate of a high-frequency carrier signal (11,12). By using filtered pulse trains, it was shown (11, 13) that, as pulse rate increases, increasing the stimulus duration yields a smaller improvement of ITD sensitivity than would be expected from a model based on optimum integration of ITD information across time (11). This effect has been referred to as binaural adaptation. Binaural adaptation has such a strong effect...

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“…This suggests that rates of >1200 pps per channel are needed to effectively code the voice pitch range up to 300 Hz. On the other hand studies examining neural responses to electrical stimulation in animals have shown that at rates above >800 pps/ch, there is poorer phase locking and less effective entrainment of neurons due to refractory effects being more dominant (Parkins, 1989;Dynes &Delgutte, 1992). It is therefore simplistic to assume that a higher stimulation rate alone will necessarily result in more effective transfer of temporal information in the auditory system.…”

Section: Stimulation Rate Effects On Speech Perceptionmentioning

confidence: 97%

Cochlear Implant Stimulation Rates and Speech Perception

Arora¹

2012

Modern Speech Recognition Approaches With Case Studies

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Phase-locking of auditory-nerve discharges to sinusoidal electric stimulation of the cochlea

Cited by 112 publications

References 37 publications

Improved temporal coding of sinusoids in electric stimulation of the auditory nerve using desynchronizing pulse trains

Improved temporal coding of sinusoids in electric stimulation of the auditory nerve using desynchronizing pulse trains

Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

Cochlear Implant Stimulation Rates and Speech Perception

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