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B Delgutte

Publications and source records attributed to B Delgutte.

4 recordsLinked to original sources
PubMed1992

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

The activity of auditory-nerve fibers was recorded in anesthetized cats in response to sinusoidal electric stimuli applied through a bipolar electrode pair inserted about 5 mm into the cochlea through the round window. The synchronization index was calculated from period histograms for frequencies ranging from 0.2 to over 10 kHz. The stimulus artifact was largely eliminated through the use of differential micropipettes and an adaptive digital filter. Measured synchronization indices were many times larger than the indices that could be attributed to the residual stimulus artifact. Synchronization indices at each stimulus frequency varied considerably from fiber to fiber, even in the same animal. The dependence of synchrony on stimulus frequency was also variable, decreasing monotonically in some fibers and nonmonotonically in others. The average electric synchronization index for all fibers did not fall as steeply with frequency as does the average synchrony for acoustic stimuli. The finding of significant phase locking to electric stimuli well above 1 kHz suggests that the poor frequency discrimination of cochlear-implant recipients for single-channel stimulation above this frequency may be due to the inability of the central processor to make effective use of the available phase-locking information for monaural stimulation.

Acoustic Stimulation↗
PubMed1978

Technique for the perceptual investigation of F0 contours with application to French.

Two experimental techniques were used in this study: (1) an analysis of F0 contours of French sentences containing words likely to express the speaker's attitude (modals, negative, adverbs, quantifiers) and (2) listeners' judgements of the naturalness of synthetic sentences in which the F0 contour was systematically manipulated. The F0 contours were characterized by schematic patterns [J. Vaissière Res. Lab. Electron., Q. Prog. Report No. 115, MIT, 251-262 (1975)]. For all the sentences that were studied, the configurations of patterns frequently observed in the analyzed corpus were judged most natural when synthesized. This result suggests that the features of the F0 contours most relevant to naturalness are preserved in the pattern representation. Three types of patterns were distinguished: (1) a prominent, demarcative pattern (P2); (2) A PROMINENT, NOndemarcative pattern (PE); (3) nonprominent, nondemarcative patterns, A P2 pattern often occurred at the end of a syntactic constituent. Listeners' judgements showed that a P2 at the end of a syntactic constituent is rarely required for naturalness, but a P2 in contradiction to syntax causes unnaturalness. Prominent patterns (P2 or PE) often occurred on negatives, adverbs, and quantifiers. However, the presence or absence of a prominent pattern on these words does not affect naturalness.

Attitude↗
PubMedDate not supplied

Fundamental considerations in designing auditory implants.

The usual premise underlying developmental work on cochlear prostheses as prospective cures for profound deafness is that the auditory nerve can be electrically stimulated in such a manner that communicative skills can be developed or maintained. Physiologic recordings from single fibers in the cat's auditory nerve and attempts to model these responses have generated a description of how the auditory nerve codes complex sounds such as speech. This work suggests that certain minimal cues might have to be present at the level of the auditory nerve in order that adequate discrimination of specific speech signals can take place. The prospects for achieving a useful prosthesis in the near future will be evaluated in terms of what can be expected from current attempts to code the artificial stimulation properly.

Acoustic Stimulation↗