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N van Son

Publications and source records attributed to N van Son.

4 recordsLinked to original sources
PubMed1997

SICONA: the development of signal conditioning communication aids for the severely hearing impaired.

Project SICONA endeavours to satisfy the specific needs of the severely hearing impaired. A complex system is introduced, consisting of several speech processing modules to achieve an improvement of the communication ability within the target group. The basic methods are improving the S/N-ratio by multichannel wireless FM transmission, enhancing weak consonants and second formant information and transposing the unvoiced fricative /s/ into the residual hearing area. Single case studies indicate the effectiveness of the proposed methods; improved reception of speech features within the F2 range and successful integration of the replacement /s/ could be shown. Practical useability is achieved by introducing wireless coupling between the miniaturized (SMD technology, ASIC) system components.

Conditioning, Psychological↗
PubMed1993

Auditory pattern perception in the profoundly hearing impaired and lipreading of Dutch phonemes.

Successful rehabilitation of the profoundly hearing impaired by means of a speech-processing hearing aid requires integration of auditory and visual speech information. In two studies we investigated (1) which perceptual dimensions play a role in processing various auditory patterns by profoundly hearing-impaired subjects, and (2) which Dutch consonants and vowels can be identified by the average lipreader. One of the important cues in auditory pattern discrimination seems to be the presence of temporal fluctuations (beats) in the signal, resulting from two closely placed frequency components. However, this feature is confounded with the perception of loudness. A second cue used by some subjects is the presence of high-frequency peaks. In lipreading, at least three groups of consonants and three vowel groups may be distinguished; phonemes within a group cannot be discriminated from each other. Important features for both consonants and vowels are degree of lip opening and lip activity (movement or rounding). These results suggest how the auditory speech signal might be coded so as to provide supplementary information to speechreading.

Acoustic Stimulation↗
PubMedDate not supplied

The perception of complex harmonic patterns by profoundly hearing-impaired listeners.

In providing profoundly hearing-impaired persons with processed speech through a signal-processing hearing aid, it is important that the new speech code matches their auditory capacities. This processing capacity for auditory information was investigated in this study. In part 1, the subjects' ability to judge similarities among 8 different but related harmonic complexes was studied. The patterns contained different numbers of harmonics to a 125-Hz fundamental frequency; the harmonics had been spread over the spectrum in various ways. The perceptual judgments appeared to be based on a temporal cue, beat strength, and a spectral cue, related to the balance of high and low frequency components. In part 2, three sets of synthetic vowels were presented to the subjects. Each vowel was realized by summing harmonically related in-phase sinusoids at two formant frequencies. The sets differed in the number of sinusoids per formant: 1, 2 or 3. It was found that the subjects used spectral cues and vowel length for differentiating among the vowels. The overall results show the limited but perhaps usable ability of the profoundly impaired ear to handle spectral information. Implications of these results for the development of signal-processing hearing aids for the profoundly hearing impaired are discussed.

Acoustic Stimulation↗