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Biomedical subjects

P W Shields

Publications and source records attributed to P W Shields.

8 recordsLinked to original sources
PubMed2001

Intelligibility, subjective ratings and completion time scores using the FAAF test with hearing-impaired subjects and noisy reverberant environments.

A series of experiments have been performed with the primary aim of assessing the performance of a signal-processing algorithm for a possible future hearing aid application. As part of this work the four alternative auditory feature (FAAF) test was used to obtain a quantitative assessment of speech intelligibility and a subjective assessment of speech quality. This paper reports results of experiments using normal hearing (NH) subjects that provide partial verification of the FAAF test originators' prior work. Also reported are intelligibility score, mean opinion score (MOS) and completion time data obtained by use of the

Adult↗
PubMed2001

Improvements in intelligibility of noisy reverberant speech using a binaural subband adaptive noise-cancellation processing scheme.

This article reports on the performance of an adaptive subband noise cancellation scheme, which performs binaural preprocessing of speech signals for a hearing-aid application. The multi-microphone subband adaptive (MMSBA) signal processing scheme uses the least mean squares (LMS) algorithm in frequency-limited subbands. The use of subbands enables a diverse processing mechanism to be employed, splitting the two-channel wide-band signal into smaller frequency-limited subbands, which can be processed according to their individual signal characteristics. The frequency delimiting used a linear- or cochlear-spaced subband distribution. The effect of the processing scheme on speech intelligibility was assessed in a trial involving 15 hearing-impaired volunteers with moderate sensorineural hearing loss. The acoustic material consisted of speech and speech-shaped noise signals, generated using simulated and real-room acoustic environments, at signal-to-noise ratios (SNRs) in the range -6 to +3 dB. The results show that the MMSBA scheme delivered average speech intelligibility improvements of 11.5%, with a maximum of 37.25%, in noisy reverberant conditions. There was no significant reduction in mean speech intelligibility due to processing, in any of the test conditions.

Acoustics↗
PubMed1977

Further observations on mandibular anaesthesia.

Recent studies have emphasized that none of the accepted intraoral landmarks used in the conventional mandibular block technique is completely reliable, nor can they presage those instances in which the lingula presents an obstruction to the needle pathway. An answer to this problem is suggested by the use of extraoral landmarks to assist in estimating the height and expected depth of needle penetration. The importance of palpating for the anterior border of the medial pterygoid muscle deep in the pterygotemporal depression is reaffirmed.

Anesthesia, Dental↗