Biomedical subjects

A Fourcin

Publications and source records attributed to A Fourcin.

6 recordsLinked to original sources

PubMed1992

Speech pattern hearing aids for the profoundly hearing impaired: speech perception and auditory abilities.

A family of prototype speech pattern hearing aids for the profoundly hearing impaired has been compared to amplification. These aids are designed to extract acoustic speech patterns that convey essential phonetic contrasts, and to match this information to residual receptive abilities. In the first study, the presentation of voice fundamental frequency information from a wearable SiVo (sinusoidal voice) aid was compared to amplification in 11 profoundly deafened adults. Intonation reception was often better, and never worse, with fundamental frequency information. Four subjects scored more highly in audio-visual consonant identification with fundamental frequency information, five performed better with amplified speech, and two performed similarly under these two conditions. Five of the 11 subjects continued use of the SiVo aid after the tests were complete. A second study examined a laboratory prototype compound speech pattern aid, which encoded voice fundamental frequency, amplitude envelope, and the presence of voiceless excitation. In five profoundly deafened adults, performance was better in consonant identification when additional speech patterns were present than with fundamental frequency alone; the main advantage was derived from amplitude information. In both consonant identification and connected discourse tracking, performance with appropriately matched compound speech pattern signals was better than with amplified speech in three subjects, and similar to performance with amplified speech in the other two. In nine subjects, frequency discrimination, gap detection, and frequency selectivity were measured, and were compared to speech receptive abilities with both amplification and fundamental frequency presentation. The subjects who showed the greatest advantage from fundamental frequency presentation showed the greatest average hearing losses, and the least degree of frequency selectivity. Compound speech pattern aids appear to be more effective for some profoundly hearing-impaired listeners than conventional amplifying aids, and may be a valuable alternative to cochlear implants.

Adult↗

PubMed1991

Development of phonetic labeling in hearing-impaired children.

The development of labeling ability of an unselected group of 16 severely to profoundly hearing-impaired children was assessed over a period of 4 years, using synthetic speech pattern tests of increasing acoustic complexity. Detailed results are presented for six children matched in pairs in terms of their average pure-tone thresholds. All children showed progress in their ability to label at least some of the contrasts. Development was usually seen for the vowel contrast before the more complex initial consonant voicing contrast. Rate of development was not closely related to average pure-tone thresholds.

Child↗

PubMed1990

The effects of two different speech-coding strategies on voice fundamental frequency control in deafened adults.

Control of voice fundamental frequency (Fx) during reading of a standard passage was assessed for four profoundly deafened adults receiving auditory feedback in one of two conditions: (i) with an extended low-frequency response amplifying aid; (ii) with the SiVo aid, which provided only Fx information. A third condition, where the subjects were unaided, was also included. For each feedback condition, quantitative analyses of laryngograph recordings were used to provide measures of Fx mode, 90% Fx range and the regularity of vocal fold vibration. In baseline unaided recordings, three subjects (S1, S2 and S4) showed some aspects of Fx control outside the normal range, while the other (S3) had appropriate Fx control. In the three subjects with impaired control, simplified Fx feedback led to better control than feedback from amplified speech. In two of these subjects, these differences were statistically significant. S3, who showed unimpaired Fx control, did not show any changes in Fx control under the different feedback conditions. Although the patterns of data were different in the individual subjects, simplified Fx feedback led to either improved or unimpaired control of Fx relative to speech feedback or to not feedback. These findings have important implications for speech-processing strategies implemented in hearing aids and cochlear implants, where the effects of different speech-coding strategies on production have been largely ignored.

Adult↗

PubMed1990

Prospects for speech pattern element aids.

A brief discussion is given of new hearing aids which are based on the use of speech pattern elements. Their operation essentially involves the reduction of the complex acoustic structure of the original speech signal into simpler sets of perceptually clear components which are then encoded for maximally relevant presentation to the listener. This approach has four primary features which may contribute crucially to future advances. First, by providing for external analysis, reduced or even non-existent ability in the impaired ear can be palliated. Second, by the selection of appropriate elements of the original speech signal, the stimulation can be tailored so that it matches the residual auditory ability--psychophysical and cognitive--of the deaf person. Third, the speech, language, and also environmental needs of the individual adult or developing child can be met in structured ways. Fourth, the use of selective pattern sensitive analysis methods makes it possible in practice to provide a degree of in-built immunity to domestic and working acoustic environments.

Adult↗

PubMed1987

A microprocessor-based acoustic hearing aid for the profoundly impaired listener.

We have found that the larynx-frequency pattern of speech presented as a sinusoid can be of greater communicative value to profoundly hearing-impaired people than the complete acoustic signal. The presence of higher harmonics can give poorer labelling of isolated intonation contrasts and often minimal gain in segmental spectrally-based distinctions. These observations have led to the development of a practical, body-worn, pattern-processing hearing aid that uses a microprocessor to sense the (analogue-processed) speech fundamental frequency, transform it into an appropriate amplitude and frequency region, and generate digitally the required output sinusoid. Our findings have important implications for the design of other signal-processing hearing aids in demonstrating that a simplification of speech can lead to enhanced speech receptive abilities in persons with impaired hearing.

Adult↗

PubMed1984

Speech pattern element stimulation in electrical hearing.

A sensation of hearing is provided for the otherwise totally deaf adult by the use of an electrode arrangement, placed external to the cochlea, which provides only larynx frequency speech pattern information. This is normally obtained by acoustic analysis and is presented so that, although its pattern is preserved, its physical form is matched to the patient's auditory capacity. Speech-receptive improvement has been shown using interactive synthetic speech techniques, video-recorded lipreading tests, and interactive conversational-type presentations. Speech production skills are also enhanced by self-monitoring, and examples of voice range improvement and jitter reduction are given. The particular electrode system used is especially suitable for promontory stimulation in adult patients without a tympanic membrane. The work as a whole is relevant, however, to the design of other conservative prostheses for both deaf adults and children.

Acoustic Stimulation↗