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R C Beattie

Publications and source records attributed to R C Beattie.

54 records · Page 3Linked to original sources
PubMed1981

Bone-conducted speech: intelligibility functions and threshold force levels for spondees.

Threshold force values for spondees were obtained for thirty-six subjects with normal hearing using the Radioear B-70-AA and B-71 bone vibrators, which were coupled to the head with a Radioear P-3333 headband. Measurements were made on a Bruel & Kjaer model 4930 artificial mastoid. In addition to the 1000 Hz calibration tone preceding the spondees, speech noise and white noise were dubbed on the tape at the same level as the tone. Since the results indicated similar threshold force levels for both vibrators, the data from the B-70-AA and B-71 were pooled. These values in dB re 1 micro Newton are 53.2 dB for 1000 Hz, 56.8 dB with white noise, and 62.4 dB using speech noise. Any of these three calibrating signals appear appropriate when delivering speech to the B-70-AA or B-71 bone vibrators. Another purpose of this study was to establish normal speech intelligibility functions for the CID W-22 test using the B-71 vibrator. Sixteen subjects with normal hearing were tested at sensation levels (SLs) ranging from 0 to 34 dB. The results showed that intelligibility scores ranged from about 15 percent at 0 dB SL to 95 percent at 34 dB SL, and that the slope of the intelligibility function systematically decreased with increasing intensity. These findings are typical of speech intelligibility functions obtained via air conduction.

Adult↗
PubMed1979

Effects of speech materials on the loudness discomfort level.

Clinicians have used speech stimuli when measuring the loudness discomfort level (LDL) to determine the upper intensity limit for test stimulus presentation, and to select the saturation sound pressure level for an individual's hearing aid. Because little research has investigated the effects of speech stimuli on the LDL, this study was undertaken to compare LDLs using six commercially available speech materials on 120 normally hearing listeners. Our comparisons showed no significant differences between the mean scores for any of the speech stimuli. These findings suggest that any differences in the mean LDLs among studies probably are not attributable to the speech stimuli. The intrasession reliability of LDL measurement was also assessed using a modified method of limits procedure with 2-dB increments and instructions stressing initial discomfort. It was concluded that examiners probably could attain a high degree of reliability by simply averaging the results of two ascending trials, because 95% of these test/retest differences did not exceed 6 dB. Our findings were integrated with previous studies in terms of: (1) test stimuli; (2) listener experience; (3) instructional set; and (4) psychophysical method. This discussion points to many unanswered questions and concludes that the LDL should be interpreted very cautiously. Moreover, it is suggested that the stimuli selected for LDL measurement should reflect the examiner's purpose.

Acoustic Stimulation↗
PubMed1978

Half-list speech discrimination measures in hearing aid evaluations.

The usefulness of half-list speech discrimination tests for evaluating hearing aids was assessed. Test and retest speech discrimination scores (SDSs) were obtained from 23 adults with moderate hearing impairment using four preselected hearing aids. Reliability coefficients were generally lower for half-lists than for full-lists, and the rankings of the hearing aids on the basis of SDSs were less consistent for the half-lists than for the full-lists. Individual subject differences between half-list SDSs were 10% or greater in more than one third of the cases. It was concluded that half-lists derived from the NU-6 full-lists should not be used to differentiate among hearing aids.

Adult↗
PubMed1977

A comparison of the Auditec of St. Louis cassette recordings of NU-6 and CID W-22 on a normal-hearing population.

Articulation functions were generated on a normal-hearing population with the Auditec of St. Louis cassette recordings of the NU-6 and CID W-22 speech discrimination tests. Both tests were similar and yielded slopes of about 4.4%/dB. Each gave a speech discrimination score of approximately 95% at 32 dB SL. Speech reception thresholds were obtained with monitored live voice and yielded good test-retest consistency. Speech thresholds were about 9 dB better than the ANSI (1969) specifications.

Adult↗
PubMed1976

Reliability of monosyllabic discrimination tests in white noise for differentiating among hearing aids.

In spite of criticism, monosyllabic discrimination tests are widely employed for hearing aid selection. The current study was designed to investigate the following questions: (1) How reliable is aided speech discrimination of monosyllables in a background of white noise? (2) Can differences among hearing aids be reliably demonstrated by measuring intelligibility of monosyllables in a background of white noise? and (3) Do hearing aids interact with hearing loss? Twenty subjects with mild-moderate sensorineural hearing losses participated in two experimental sessions. Four hearing aids were evaluated using the NU-6 monosyllables in a background of white noise (s/n = +20 dB). Since the standard deviation of the test-retest differences was 6%, differences between aids were not considered significant unless they exceeded 12%. An interaction between subjects and hearing aids was found; that is, the best aid for one person was not the best for all. Measuring monosyllabic word intelligibility in a background of white noise does not reliably identify a single best aid. However, one or more inferior aids were consistently eliminated in 80% of the subjects.

Aged↗
PubMed1975

Relative intelligibility of the CID spondees as presented via monitored live voice.

Using three speakers and 75 subjects, a 7.90dB range in the relative intelligibility of the Central Institute for the Deaf (CID) spondees was found when they were presented via monitored live voice. This range is consistent with previous research and is considered unnecessarily large and detrimental to the efficiency and precision of the speech reception threshold (SRT) test. The exclusive use of 18 words that have a mean range of 1.5 dB is suggested. The slope of the 3l-item spondee articulation function is 12 percent per decibel and is slightly steeper than previous research using the CID W-1 recorded spondees. The slope for the suggested 18-item test is also about 12 percent per decibel. For the 36-item test the mean speech detection threshold (SDT) was 6.6 dB sound pressure level (SPL) and the mean SRT was 14.2 db SPL. The 7.6-dB difference between the two speech measures is consistent with previous research but the SRT is about 6 dB better than the 20 dB SPL recommended by ANSI 1969. For the suggested 18-item test, the mean SRT was 14.5 dB SPL, which was 7.9 dB above SDT. When the 18-item test is used, average normal hearing can be expected to be about 5.5 dB better than specified by ANSI 1969.

Adult↗
PubMedDate not supplied

Loudness discomfort levels of hearing-impaired listeners using speech material.

This study was undertaken to: (1) investigate the effects of speech materials on the loudness discomfort level (LDL); (2) assess the intrasession stability among three LDL trials; and (3) examine the relationships between the speech LDL and the pure-tone and spondee thresholds. Ninety-six adults with mild-to-moderate sensorineural hearing loss were tested. Findings showed little or no difference among five commercially available speech materials. Thus, it was concluded that differences in speech materials do not comprise a major source of variability among studies when comparing mean LDL data. Group means may, however, obscure significant individual variations in LDL's that result from differing speech materials. Considerable LDL variability among listeners with similar thresholds was found, suggesting an intolerably high error rate for predictive purposes.

Auditory Threshold↗
PubMedDate not supplied

Effects of a competing message on the speech comfortable loudness level for two instructional sets.

The effects of a competing message on the speech comfortable loudness level (CLL) was compared for two instructional sets in 2 conditions of quiet and in the presence of a four-talker babble competing message. Kopra and Blosser's (24) instructions were selected to sample the middle of the CLL range, whereas Lucker et al.'s (27) instructions sampled the upper limit of the CLL range. Two groups of 12 normal-hearing subjects were tested using a method of adjustment. The results indicated no significant differences between the initial and final CLL's in quiet. However, data for each instructional set showed that the CLL's obtained with Lucker et al.'s phraseology (97.8 dB SPL) was significantly higher than with Kopra and Blosser's instructions (75.2 dB SPL). The four-talker babble served to raise the CLL, although less effect was observed on the upper limit of the CLL range than for the middle portion of this range. The clinical implications of these findings are discussed.

Acoustic Stimulation↗
PubMedDate not supplied

Practice effects of a four-talker babble on the synthetic sentence identification test.

This investigation was designed to : (1) collect normative data on a commercially available recording of the Synthetic Sentence Identification (SSI) test mixed with a four-talker (FT) competitor at several message-to-competition ratios (MCRs), and (2) assess the effects of practice on SSI-FT performance at each MCR. Sixteen normal-hearing subjects responded to a total of 140 sentences during four trials at MCRs ranging from -6 to +4 dB. The results showed a marked learning effect, especially at the more favorable MCRs; approximately 60 practice sentences were required to ensure stable SSI scores. The clinical implications of these findings are discussed.

Adult↗
PubMedDate not supplied

Relationship between the calibration tone and speech volume unit (VU) levels for some commercially available test tapes.

The relationship between the calibration tone and speech volume unit (VU) levels for nine commercially recorded speech tests was studied. Two procedures were used. In procedure 1, experienced clinicians reported observations of four different audiometer VU meters responding to six commercially available speech tests. Differences in magnitude estimates among judges were usually about 1 dB or less. Peak VU level deviations from the zeroed calibration tone were within +/- 1.5 VU except for the Fulton Lewis Jr. recording, which varied by about -4.8 VU. In procedure 2, a video system was used to recorded precisely VU meter responses to clinical speech materials. Differences between the calibration tones and speech levels were similar to those obtained using multiple observers. Statistically significant (p less than or equal to 0.01) differences were found between the speech levels of the commercial test recordings.

Audiometry↗
PubMedDate not supplied

Frequency-specific auditory brainstem responses in adults with sensorineural hearing loss.

The purpose of this study was to investigate the prediction of pure tone thresholds from auditory brainstem response (ABR) thresholds to tone bursts in noise using two formulae: (1) a correction factor based on the average difference between pure tone thresholds and ABR thresholds, and (2) a regression equation describing the relationship between pure tone thresholds and ABR thresholds. Twenty subjects with mild to moderate sensorineural hearing loss were tested with tone bursts having 1 millisecond rise-plateau-fall times in highpass noise (500 Hz) and notch noise (1000, 2000, and 4000 Hz). The data revealed that the pure tone-ABR threshold difference systematically decreased as frequency increased. Mean differences were approximately 25 dB at 500 Hz and 1000 Hz, 15 dB at 2000 Hz, and 10 dB at 4000 Hz. Using these correction factors, approximately 90 per cent of pure tone thresholds were predicted within +/- 10 dB at 2000 Hz and 4000 Hz, and within +/- 20 dB at 500 Hz and 1000 Hz. Similar results were found using the regression formulae. The results suggest that ABR thresholds to tone bursts in noise may provide valuable information on the auditory sensitivity and audiometric configuration of difficult-to-test patients.

Aged↗
PubMedDate not supplied

Effects of relative levels of the primary tones on distortion product otoacoustic emissions in normal-hearing subjects.

This study investigated the effects of the relative levels of the two primary tones, L1 and L2, on the amplitude of distortion product otoacoustic emissions (2F1-F2). Testing was conducted with a commercially available system for measuring DPOAEs (Grason-Stadler, GSI-60). The intensity of the lowest primary tone (L1) remained constant at 75, 65, 55 or 45 dB SPL while L2 varied over a 20 dB range around L1, i.e. L1-L2 was -5, 0, 5, 10 or 15 dB. For example, when L1 was 75 dB SPL, L2 was presented at 80, 75, 70, 65 or 60 dB SPL. Thirty normal-hearing women were presented with 11 pairs of primary tones having geometric means ranging from 531 Hz to 5531 Hz. A constant F2:F1 ratio of 1.21 was used. The results revealed that when L1 was 75 dB SPL, the largest distortion products were observed across all frequencies for the 0 dB condition (L1=75 dB; L2=75 dB) and -5 dB condition (L1=75 dB; L2=80 dB). When L1 was 65 dB SPL, the largest DPs were obtained across all frequencies for the 5 dB condition (L1=65 dB; L2=60 dB). For L1=55 dB SPL, the largest DPs were obtained across all frequencies for the 5 dB (L1=55 dB; L2=50 dB) and 10 dB (L1=55 dB; L2=45 dB) conditions. No mean DP differences were observed among relative levels (-5 dB to 15 dB) when L1 was 45 dB SPL; however, the 15 dB condition (L1=45 dB; L2=30 dB) at 5531 Hz resulted in fewer identifiable responses than the other relative levels.

Acoustic Stimulation↗
PubMedDate not supplied

An investigation of the Auditec of St. Louis recordings of the Central Institute for the Deaf spondees.

The Auditec of St. Louis recordings of the Central Institute for the Deaf spondees were investigated with normal hearing subjects and found to have an unnecessarily large range of audibility. Consequently, an 18-item test with greater homogeneity of audibility was proposed. Articulation function slopes of about 10% per decibel were obtained with both the 18- and 36-item tests. The articulation function of the 18-item test did not reflect its improved homogeneity. The mean speech reception threshold was 5 dB better than ANSI-1969 specifications, and speech detection threshold was found to be 9 dB better than speech reception threshold. A derived speech reception threshold can be obtained by adding 5 dB to the lowest threshold at which any spondee is identified.

Academies and Institutes↗
PubMedDate not supplied

Comparison of speech detection and spondee thresholds and half- versus full-list intelligibility scores with MLV and taped presentations of NU-6.

Several speech audiometric measurements were made on 212 ears with mild sensorineural hearing loss. An 8-dB difference between speech detection and spondee thresholds was observed, which is the same relationship that has been found in normal ears. No significant differences in speech discrimination scores (SDS's) were observed when NU-6 was administered via monitored live voice (MLV) and the Auditec recordings. Although our data support the use of MLV testing, verification with a standardized recording should be considered when unusually poor SDS's are obtained. Half-list and full-list SDS's were analyzed for both taped and MLV presentation modes. This analysis showed that both the MLV and taped stimuli exhibited very similar variability and that about 96% of the half-list scores were within 6% of the full-list scores. The clinician should be cautious, however, because 4% of the ears had half-list/full-list discrepancies ranging from 8 to 14% and differences as large as 28% have been reported by Raffin and Thornton (1977). Furthermore, variability between half-list and full-list SDS's varies as a function of intelligibility impairment, being least for scores approaching the extremes of 0 and 100% and greatest for scores in the 30 to 70% range. Finally, our data suggest that half-list testing can be an effective screening procedure to determine it full-list testing is advisable.

Acoustic Stimulation↗
PubMedDate not supplied

Loudness discomfort level for speech: comparison of two instructional sets for saturation sound pressure level selection.

This study was undertaken to compare the speech loudness discomfort levels (LDL's) with two instructional sets which have been proposed for saturation sound pressure level selection of hearing aids. The phraseology recommended by McCandless and by Berger was presented to normal-hearing and hearing-impaired listeners. The normal-hearing subjects obtained mean LDL's of 94.6 and 111.9 dB SPL for these respective instructions, which was statistically significant. The hearing-impaired listeners also showed LDL's with Berger's instructions (114.7 dB SPL) to be significantly higher than with McCandless' instructional set (109.3 dB SPL). Consequently, this investigation suggests that these two instructional sets may lead to substantially different saturation sound pressure levels. Further studies are needed to determine the most appropriate phraseology for LDL measurement, including the assessment of speech intelligibility at various saturation sound pressure levels. Another instructional set was constructed which (1) includes an explanation to patients of the purpose and importance of the test, (2) requests listeners to indicate the upper level they are "willing" to listen as opposed to the level they are "able" to listen, (3) instructs patients to search thoroughly around their LDL before making a final judgment, and (4) contains a statement that the LDL should be made with the understanding that the speech could be listened to for a period of time. Whatever instructions are used, clinicians are advised to interpret their LDL's very cautiously until validational studies are available.

Adolescent↗
PubMedDate not supplied

Reliability of the Tillman-Olsen procedure for determination of spondee threshold using recorded and live voice presentations.

This study investigated the reliability of the Tillman-Olsen procedure for establishing the spondee threshold (ST). Monitored live voice (MLV) and the Auditec of St. Louis recordings of the Central Institute for the Deaf spondees were used as stimuli. Ninety-five percent of 96 normal hearing subjects had test-retest STs within 5 dB and no subject varied more than 8 dB. Although these results represent good short term reliability for the Tillman-Olsen procedure, repeatability is no better than that produced by other procedures. Thresholds obtained by MLV were as reliable as the recorded spondees. It was concluded that recorded spondees offer no advantages over MLV testing for the experienced clinician. The recorded presentation gave STs that are very close to the normative value for speech specified by ANSl-1969. Live voice testing showed STs 4.7 dB better than when the Auditec recordings were used.

Adolescent↗
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↗