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Biomedical subjects

J L Danhauer

Publications and source records attributed to J L Danhauer.

48 records · Page 3Linked to original sources
PubMed1977

Normal-hearing subjects' perception of speech through one-third octave bands.

Perceptual features of consonants were investigated from normally-hearing Ss' confusions of stimuli perceived through one-third-octave bands; 12 Ss were paid to respond to CVs consisting of 17 consonants, each paired with the vowels /i, a, u/ and filtered through one-third-octave bands centered at 0.5, 1, 2, 3.15 and 4 kc/s and one critical band (500 c/s wide) centered at 3.15 kc/s. An earlier cursory analysis of distinctive features in these data (Chari, N.C.A., Herman, G. and Danhauer, J.L. "Perception of one-third octave-band filtered speech." J. Acoust. Soc. Am., 1977, 61, 576-580) showed that while place features were severely affected by the filtering, manner and voicing features were not. The data were submitted in the present study to INDSCAL for a more a-posteriori investigation of the features and their weights by the Ss. Results showed some differences in the features and their weights across the various filter bands, but that they were similar to those found earlier for hearing-impaired Ss having losses corresponding to frequency cut-offs in this study.

Adult↗
PubMed1976

INDSCAL analysis of perceptual judgments for 24 consonants via visual, tactile, and visual-tactile inputs.

Twenty-four normal-hearing subjects received CV stimuli of uni- and bisensory inputs through the visual (speechreading), tactile (touch), and visual-tactile (speechreading and touch) modalities. Stimuli were presented via either a videotape monitor or a tactile vibrator or both. The purposes were to investigate the contribution of the tactile modality in uni- and bisensory conditions, and to analyze consonantal substitution errors to find perceptual features utilized by the subjects in their decision-making processes. The subjects' consonantal perceptions were phonetically transcribed and submitted to INDSCAL analysis which yielded mainly a four-dimensional solution. The interpretations of these dimensions were primarily closed bilabial, easy to see/hard to see, voiced/voiceless, and front/back place. Additional features were retrieved, but occurred less consistently.

Analysis of Variance↗
PubMedDate not supplied

Features from normal and sensorineural listeners' nonsense syllable test errors.

Identification errors for initial consonants of consonants-vowels-consonants-vowels from lists A and B of the Nonsense Syllable Test were analyzed for 10 normal-hearing and 8 sensorineural hearing-impaired listeners. The Nonsense Syllable Test stimuli were presented binaurally through earphones at 6 increasing sensation levels. Listeners' verbal responses were recorded and transcribed, converted to symmetric confusion matrices, and submitted to analysis of individual differences scaling for symmetrical matrices. Results from 2- through 5-dimensional analyses revealed that voicing, place of articulation, frication, and sibilancy were the salient features used by both listener types in their perceptions of the initial consonants. Findings suggest that consideration of composition of the stimulus set is important when assessing a listener's response to specific speech discrimination tests.

Adult↗
PubMedDate not supplied

SSW test performance-intensity functions for hearing-impaired adults.

The present study investigated the effects of intensity on hearing-impaired adults' performance on the Staggered Spondaic Word (SSW) test. Fifteen adults having mild-to-moderate cochlear hearing losses were administered the 40-item SSW test which was subdivided into four groups of ten items each, and presented at different intensity levels (20, 30, 40, and 50 dB SL re the three-frequency, pure-tone average). Subjects' responses were used to generate performance-intensity functions. Scores were analyzed for overall, competing, and noncompeting conditions. No significant differences were found for these hearing-impaired listeners' performance for items presented at the standard 50 dB and those at the low sensation levels.

Adult↗
PubMedDate not supplied

Older persons' performance on auditory, visual, and auditory-visual presentations of the Edgerton and Danhauer Nonsense Syllable Test.

The speech sound discrimination abilities of 15 normal-hearing and 15 sensorineural hearing-impaired subjects between 55 and 65 years of age were assessed using videotaped presentations of the Nonsense Syllable Test (NST). Stimuli were presented in auditory (A), visual (V), and auditory-visual (AV) modes. All subjects received the stimuli in two trials for each presentation mode; hearing-impaired subjects were unaided for the first, and wore their own hearing aids for the second. Responses were transcribed phonemically and were scored by the phoneme method. Intra- and interjudge reliability was greater than 90%. Mean phoneme discrimination scores were plotted for each group across the three presentation modes. The results revealed that: both groups' performance improved from V to A to AV modes, but differences were apparent in the amount of increase across modes within each group; the NST differentiated between groups in the A and AV modes, but not in the V mode; the NST identified "poor" speechreaders in each group under both V and AV conditions; and consonant errors in the V mode formed seven homophenous categories based on place of articulation. The NST can be a useful screening test in auditory rehabilitation to distinguish those hearing-impaired persons who naturally take advantage of visual cues from those who do not.

Acoustic Stimulation↗
PubMedDate not supplied

Effects of noise on NST and NU 6 stimuli.

This study determined how normal-hearing listeners' performance on a nonsense syllable test (NST) was affected by three noise competitors, and how these responses differed from those on the standard NU 6 meaningful word test. Twenty young adult listeners heard the stimuli via earphones and provided verbal responses to the NST and NU 6 items in competition with: white noise, multitalker noise, and white noise which was amplitude modulated by the multitalker noise, each at a 0 dB signal-to-noise ratio. Responses were scored on a whole-word (all-or-none) basis. Statistical analyses revealed that listeners' performance was always poorer on the NST than on the NU 6 regardless of competitor type; and that scores were better in the multitalker noise followed by white noise and amplitude modulated white noise. These data and those from earlier studies indicate that the NST is sufficiently difficult in quiet that it may not warrant testing in noise.

Adolescent↗
PubMedDate not supplied

Consonant perception by normals in conditions of filtering.

Consonant perception was investigated for 120 normal-hearing adults who listened to 16 consonants in a phrase context and made similarity judgements of 256 diadic stimulus pairs on a 9-point equal-appearing interval scale. Stimuli were presented at subjects' most comfortable listening levels in 3 low-pass filtered and one nonfiltered conditions. Subjects' ratings were converted to 16 X 16 full symmetric similarity matrices and submitted to INDSCAL analyses. Results revealed perceptual features common to all groups, as well as group-specific features (i.e., sibilancy, stop/continuancy, and place for nonfiltered; plosive and place for 4000-Hz low-pass; stop/continuancy and place for 2000-Hz low-pass; and voicing and stop/continuancy for 500-Hz low-pass). These results were similar to those found earlier for hearing-impaired subjects having sensorineural losses compatible with these frequency cut-offs.

Attention↗
PubMedDate not supplied

Relation between formant frequencies and optimal octaves in vowel perception.

The purpose of this study was to investigate the relation between the traditional concept of formant frequencies and the controversial concept of optimal octaves in the perception of the vowels/i, a, u/. The vowels (produced by a male speaker of General American English) were filtered through eight bandwidths (80-160, 160-315, 315-630, 630-1,250, 1,250-2,500, 2,500-5,000, 5,000-10,000, and 10,000-20,000 Hz) and presented to two groups of subjects. One group performed similarity ratings on pairs of filtered and nonfiltered stimuli; the other identified the individual filtered and nonfiltered vowels. The optimal bandwidths derived from the data of the two groups were compared to the formant frequencies of our speaker, to those reported in the literature, and to the optimal octaves published earlier by other authors. The results showed that there were specific bandwidths which allowed for correct perception and identification of each vowel, and that these bandwidths were compatible with both the optimal octaves and the formant frequencies reported in the literature for each vowel.

Auditory Perception↗
PubMedDate not supplied

Bone conduction speech audiometry in normal subjects.

The present study was designed to investigate: (1) the relationship among bone conduction (BC) pure tone averages, BC speech reception thresholds (SRTs), and BC speech detection thresholds for normal subjects; (2) short term reliability of BC SRTs; and (3) characteristics of the articulation functions for spondees obtained by bone conduction. Twenty-five normal-hearing young adults participated. The data revealed that BC SRT-pure tone average and SRT-speech detection threshold relationships are essentially the same as for air conduction. A comparison of the articulation functions for air conduction and BC revealed no practical difference between the two modes of stimulus presentation.

Adult↗
PubMedDate not supplied

Modified rhyme test and synthetic sentence identification test scores of normal and hearing-impaired subjects listening in multitalker noise.

Articulation functions were established for 35 normal hearing, 6 flat sensorineural, and 6 high frequency sloping sensorineural hearing-impaired subjects using the modified rhyme test (MRT) and synthetic sentence identification test (SSIT) in three message competition ratios (MCRs) of multitalker noise. An analysis of variance revealed significant differences between tests, subject groups, presentation conditions, and interactions between variables. Post hoc analyses revealed that SSIT functions were not significantly different among groups, and that MRT functions were different for each group. The MRT and SSIT were found to be two significantly different tests, each taxing different areas of discrimination. Results suggest that both tests can be used clinically with various MCRs of multitalker noise, but that the poorest MCR for each test does not aid in defining discrimination abilities.

Acoustic Stimulation↗