Biomedical subjects

J E Preminger

Publications and source records attributed to J E Preminger.

4 recordsLinked to original sources

PubMed1998

Selective visual masking in speechreading.

Using digital video technology, selective aspects of a face can be masked by identifying the pixels that represent it and then, by adjusting the gray levels, effectively eliminate that facial aspect. In groups of young adults with normal vision and hearing, consonant-viseme recognition was measured for closed sets of vowel-consonant-vowel disyllables. In the first experiment viseme recognition was measured while the tongue and teeth were masked and while the entire mouth was masked. The results showed that masking of the tongue and teeth had little effect on viseme recognition, and when the entire mouth was masked, participants continued to identify consonant visemes with 70% or greater accuracy in the /a/ and /(ball)/ vowel contexts. In the second experiment, viseme recognition was measured when the upper part of the face and the mouth were masked and when the lower part of the face and the mouth were masked. The results showed that when the mouth and the upper part of the face were masked, performance was poor, but information was available to identify the consonant-viseme /f/. When the mouth and the lower part of the face were masked, viseme recognition was quite poor, but information was available to discriminate the consonant-viseme /p/ from other consonant visemes.

Adult↗

PubMed1995

Quantifying the relation between speech quality and speech intelligibility.

The purpose of the present research was to examine the relation between speech quality and speech intelligibility. Speech quality measurements were made using continuous discourse and a category rating procedure for the following dimensions: intelligibility, pleasantness, loudness, effort, and total impression. Measurements were made using a group of listeners with normal hearing for a set of stimulus conditions in which intelligibility varied, and for a set of stimulus conditions in which intelligibility was held constant near 100%. When ratings were made for a set of stimulus conditions in which intelligibility was allowed to vary (a) intersubject reliability was high (i.e., different listeners interpreted the dimensions in a similar manner); and (b) the speech quality dimensions of intelligibility, effort, and loudness were indistinguishable. When ratings were made for a set of stimulus conditions in which intelligibility was held constant (a) intersubject reliability was reduced, indicating that different listeners interpreted the dimensions in different ways; (b) most listeners rated each dimension differently, indicating that the dimensions were unique; and (c) across listeners, no single dimension was highly correlated with total impression. These results can be used in order to examine the relation between speech quality and speech intelligibility.

Adult↗

PubMed1995

Measurement of speech quality as a tool to optimize the fitting of a hearing aid.

The purpose of the present research was to develop a theoretical basis for the adjustment of hearing aid frequency response based on speech quality measurements. Speech quality measurements were made using continuous discourse and a category rating procedure for the following dimensions: intelligibility, pleasantness, loudness, effort, noisiness, and total impression. Speech quality ratings were obtained from a group of listeners with hearing loss who wore hearing aids. The stimulus conditions simulated hearing aid frequency response alterations within a frequency response range where intelligibility was held constant at or near 100%. The subject ratings revealed that (a) different listeners interpreted the individual dimensions in different ways; (b) within listeners, most of the dimensions were unique; that is, they were rated differently; and (c) across listeners, pleasantness was the dimension most highly correlated with total impression.

Adult↗

PubMed1994

Is useful speech information carried by fibers with high characteristic frequencies?

It has been proposed that auditory-nerve fibers with characteristic frequencies (CFs) above the speech-frequency range are important in speech perception when the signal-to-noise ratio in the speech frequency range is low [S. Greenberg, J. Phon. 16, 139-149 (1988)]. If this is true, then it might be expected that recognition of speech at low signal-to-noise ratios would worsen with the addition of high-pass noise sufficiently intense to mask information in high-CF fibers. This hypothesis was tested for closed-set recognition of vowels and spondees. Recognition was measured as a function of signal-to-noise ratio in speech-shaped noise, with and without an intense high-pass noise. The addition of high-pass noise did not degrade vowel recognition. Spondee recognition decreased with the addition of the high-pass noise at the highest levels of the speech-shaped noise. However, this same decrease was seen when the spondees were low-pass filtered to simulate downward spread of masking by the high-pass noise. This indicates that the decrease in spondee recognition with high-pass noise was due to masking of information in fibers with CFs in the speech range. Overall, these results suggest that fibers whose CFs are above the speech range are not necessary for speech perception in noise or in quiet.

Adult↗