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A Boothroyd

Publications and source records attributed to A Boothroyd.

52 records · Page 3Linked to original sources
PubMed1988

Perception of speech pattern contrasts from auditory presentation of voice fundamental frequency.

The perception of phonologically significant speech pattern contrasts was measured in normally hearing subjects who were presented with F0 contours alone, speechreading alone, and the two in combination. For the suprasegmentals and final consonant voicing, perception in the combined condition was dominated by F0. For the vowel, consonant place, and final consonant continuance contrasts, perception in the combined condition was dominated by vision. For initial consonant voicing and continuance, however, there was clear evidence of interaction between F0 and speechreading. Here, the combined score was higher than either of the single-modality scores, and also higher than could be predicted on the assumption that the auditory and visual channels act as statistically independent channels of information.

Adult↗
PubMed1988

Tactile presentation of voice fundamental frequency as an aid to the speechreading of sentences.

In two experiments, the perception of words in sentences was measured by speechreading with and without tactile presentation of voice fundamental frequency (F0). The first experiment involved normally hearing subjects and two kinds of tactile display of F0: (1) a spatial, multichannel display; and (2) a temporal, single-channel display. Mean performance with the tactile displays was found to be slightly, but significantly, better than speechreading alone, but no significant difference was found between the two displays. The second experiment involved hearing-impaired subjects and only the spatial, multi-channel display of F0. For all three subjects, after extended training, speechreading performance was significantly better with the addition of the tactile display than by speechreading alone. The improvement amounted to reductions of word recognition error of 24, 33, and 50% in the three subjects.

Adult↗
PubMed1988

A wearable multichannel tactile display of voice fundamental frequency.

This paper describes a wearable sensory aid that provides the deaf with tactually encoded information about intonation. Fundamental frequency is represented as both place and rate of vibration in a linear array of solenoids. Pitch extraction is accomplished through low-pass filtering and peak detection. A microcomputer is used to measure pitch period, which in turn determines which of the solenoids is actuated. By comparing consecutive periods, the system discriminates against random, noise-related inputs. The device is switchable between 1-, 8-, and 16-channel operation. The electronics package is contained in a case that may be worn on a belt. The solenoid array is worn on the forearm. The system is powered by five, rechargeable lithium cells and runs for at least 6 hours between charges. Proposed developments include the incorporation of digital pitch extraction methods and the option to use the spatial output dimension to encode speech parameters other than fundamental frequency.

Deafness↗
PubMed1988

Mathematical treatment of context effects in phoneme and word recognition.

Percent recognition of phonemes and whole syllables, measured in both consonant-vowel-consonant (CVC) words and CVC nonsense syllables, is reported for normal young adults listening at four signal-to-noise (S/N) ratios. Similar data are reported for the recognition of words and whole sentences in three types of sentence: high predictability (HP) sentences, with both semantic and syntactic constraints; low predictability (LP) sentences, with primarily syntactic constraints; and zero predictability (ZP) sentences, with neither semantic nor syntactic constraints. The probability of recognition of speech units in context (pc) is shown to be related to the probability of recognition without context (pi) by the equation pc = 1 - (1-pi)k, where k is a constant. The factor k is interpreted as the amount by which the channels of statistically independent information are effectively multiplied when contextual constraints are added. Empirical values of k are approximately 1.3 and 2.7 for word and sentence context, respectively. In a second analysis, the probability of recognition of wholes (pw) is shown to be related to the probability of recognition of the constituent parts (pp) by the equation pw = pjp, where j represents the effective number of statistically independent parts within a whole. The empirically determined mean values of j for nonsense materials are not significantly different from the number of parts in a whole, as predicted by the underlying theory. In CVC words, the value of j is constant at approximately 2.5. In the four-word HP sentences, it falls from approximately 2.5 to approximately 1.6 as the inherent recognition probability for words falls from 100% to 0%, demonstrating an increasing tendency to perceive HP sentences either as wholes, or not at all, as S/N ratio deteriorates.

Adult↗
PubMed1988

Spatial, tactile presentation of voice fundamental frequency as a supplement to lipreading: results of extended training with a single subject.

An adult with a severe, postlingually-acquired, sensorineural, hearing loss was given 2 hours a week of training in the perception of connected discourse by lipreading, supplemented by voice fundamental frequency (Fo), encoded as locus of vibratory stimulation of the forearm. Three, 3-week blocks of training in the supplemented condition were interspersed with 1-week periods of training by lipreading alone. Training was conducted via a computer-controlled, interactive video system, using a semi-automated connected discourse tracking procedure. Performance was measured as the percentage of words correctly recognized on the first presentation of new sentence material. Scores by lipreading alone averaged approximately 65 percent and remained essentially constant over the 13 weeks of training. Scores under the supplemented condition rose from 65 percent at the beginning of the study to 85 percent at the end. The final supplemented score represented roughly a 50 percent reduction of error rate, when compared with lipreading alone. Performance with the tactile supplement was not as good as with auditorily presented Fo, but was better than has previously been reported in the literature. These data provide evidence to support the notion that subjects can learn to integrate novel tactile codes with the visual stimulus during the lipreading of connected speech.

Adult↗
PubMed1987

Effect of two approaches to auditory training on speech recognition by hearing-impaired adults.

Twenty adults with mild to moderate sensorineural hearing impairments were given three tests of speech recognition: the CUNY Nonsense Syllable Test (NST), the low predictability items of the Revised Speech Perception in Noise (RSPIN) test, and the high predictability items of the RSPIN test. They were tested on four occasions: at the beginning of the study, after one month of "no treatment," after a month of intensive auditory training, and after a further month of "no treatment." During the treatment period, 10 of the subjects spent all of the time on activities involving sentence perception and perceptual strategy while the other 10 spent half of the time on activities involving consonant recognition. A small, but statistically significant increase in speech recognition performance on the high probability material was observed in both groups subsequent to training, but the effect of training method was not significant. In addition, the gains achieved were not lost in the month following the end of training. The findings suggest that the benefits of auditory training were found in an increased use of sentence context as an aid to word recognition.

Aged↗
PubMed1986

Lipreading with tactile supplements.

Lipreading performance, after brief training, was measured in two normal subjects, as the percentage of words recognized in sets of unrelated sentences. Three receptive conditions were used: lipreading alone, lipreading plus a single-channel tactile display of fundamental frequency (temporal only), and lipreading plus a multichannel, tactile, spatial display of fundamental frequency (temporal-spatial). After training, performance with tactile supplements was better than without, but it was not possible to conclude that either of the tactile displays was better than the other. During training, a significant correlation between performance and session number was found for the temporal-spatial display only.

Female↗
PubMed1985

Evaluation of speech production of the hearing impaired: some benefits of forced-choice testing.

The speech production performance of 16 hearing-impaired subjects (thresholds 82-110 dB HL) was measured using both experienced and inexperienced listeners. Four types of measure were obtained: score on a forced-choice test requiring the production of eight segmental contrasts, recognition probability for phonemes produced in consonant-vowel-consonant (CVC) words, recognition probability for CVC words produced in a simple carrier phrase, and recognition probability for words produced in sentence context. The experienced listeners gave higher scores than did the inexperienced listeners, but the magnitude of the effect decreased with decreasing linguistic redundancy in the test material, falling to only 1.3 percentage points for the forced-choice test. The pattern of performance across the eight contrasts of the forced-choice test changed significantly from subject to subject. Performance on the contrast test accounted for 70% of the variance in the scores on the sentence test. The results demonstrate that forced-choice tests can be used to provide speech production measures that are virtually independent of listener experience, that provide analytic detail about an individual's production of phonetic contrasts, and that are reasonably predictive of the intelligibility of speech produced in more natural communicative settings.

Adolescent↗
PubMed1984

Auditory perception of speech contrasts by subjects with sensorineural hearing loss.

The goal of these studies was to find out how much of the acoustical information in amplified speech is accessible to children with varying degrees of sensorineural hearing loss. Context-varying, forced-choice tests of speech perception were presented, without feedback on performance, to orally trained subjects with better ear, three-frequency average hearing losses in the range 55-123 dB HL. As expected, average performance fell with increasing hearing loss. The values of hearing loss at which scores fell to 50% (after correction for chance) were 75 dB HL for consonant place; 85 dB HL for initial consonant voicing; 90 dB HL for initial consonant continuance; 100 dB HL for vowel place (front-back); 105 dB HL for talker sex; 115 dB HL for syllable pattern; and in excess of 115 dB HL for vowel height. Performance on the speech contrast tests was significantly correlated with the intelligibility of the subjects' own speech and with the open-set recognition of phonemes in monosyllabic words, even when pure-tone threshold was held constant.

Adolescent↗
PubMed1976

Assessment of nasalization in the speech of deaf children.

Nasality is widely recognized as a problem in the speech of many deaf people. This paper describes one approach to the assessment of nasalization and to the development of visual aids to assist in training of velopharyngeal control. The approach involves detection of the velopharyngeal opening during voiced sounds by means of a small accelerometer attached to the nose, and presentation of the accelerometer output on a computer-controlled visual display. The display may be used as a training aid, or for the purpose of analyzing either recorded or live speech. Objective data are presented on some of the properties of the accelerometer output for the speech of people with normal hearing and of a number of children whose hearing is severely impaired. These data show inadequate velopharyngeal control, particularly improper nasalization of certain vowels, for a significant number of the deaf children. For a group of the hearing-impaired children, subjective judgments of the adequacy of velopharyngeal control and of other speech attributes were obtained. Correlations among these judgments and relations between judgments of adequacy of velopharyngeal control and the objective measures of nasalization are shown. Some comments are made on the development of procedures for the training of velopharyngeal control using the display as an aid.

Acoustics↗