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C Speaks

Publications and source records attributed to C Speaks.

At least 19 recordsLinked to original sources
PubMed2000

Subjective vs. objective intelligibility of sentences in listeners with hearing loss.

The relation between rated intelligibility and correct key word repetitions of sentences was examined in listeners with normal hearing and listeners with hearing loss. Ten lists of 10 CID sentences were arranged in two randomly ordered groups. Listeners were asked to complete two tasks: (1) rate the intelligibility of 50 sentences on a scale of 0 to 100%, and (2) repeat each of the 50 sentences, which were scored as the number of key words repeated correctly. Sentences were presented at five signal-to-noise ratios. The start level for sentence presentation was established using the method of adjustment and the Revised Speech Intelligibility Rating passages. Correlations of rated intelligibility and correct repetition were 0.85 for listeners with normal hearing and 0.86 for listeners with hearing loss. This study confirms the earlier work of Speaks, Parker, Harris, and Kuhl (1972), and the findings demonstrate that listeners with hearing loss preserve the ability to rate the intelligibility of speech.

Adolescent↗
PubMed1994

A Revised Speech Intelligibility Rating (RSIR) test: listeners with normal hearing.

Two experiments were conducted to examine the intelligibility of 72 passages of connected discourse prepared by Cox and McDaniel in their development of the Speech Intelligibility Rating (SIR) test. Intelligibility was assessed with a method-of-adjustment (MOA) procedure in which listeners adjusted the level of a multi-talker babble until they could just understand 50% of a passage; the measure of intelligibility was the signal-to-babble ratio, dB S/B. The objective was to develop a Revised Speech Intelligibility Rating (RSIR) test that would comprise a large number of equivalent passages that produce reliable intelligibility measures. In experiment 1, the S/B ratio was based on the overall root-mean-square (rms) levels of speech and babble, as represented by the average level of frequent peaks observed on a VU meter. Across all 72 passages, mean intelligibility was -1.43 dB S/B, and the measure of intelligibility for 42 passages was within +/- 0.5 dB of the overall mean for all 72 passages. In experiment 2, the S/B ratio was based on long-term rms levels of speech and babble measured in 16 one-third-octave bands, with center frequencies from 160 to 5000 Hz. In an effort to achieve greater equivalence in intelligibility among passages, the overall rms level of each passage was attenuated by the difference between SB16-band for an individual passage and S/B16-band for a reference passage. Mean intelligibility across all 72 passages was -8.06 dB, and the measure of intelligibility was within +/- 0.5 dB of the overall mean for 64 of the 72 passages. For those 64 passages, the 95% critical difference for five MOAs was 0.72 dB, which corresponds to an estimated percentage critical difference of 10.8%.

Acoustic Stimulation↗
PubMed1993

Intelligibility of selected passages from the Speech Intelligibility Rating (SIR) test.

Two experiments were conducted to examine the intelligibility of 12 of the 72 passages of connected discourse prepared by Cox and McDaniel (1984, 1989) in the development of the Speech Intelligibility Rating (SIR) test. Intelligibility was assessed with a method-of-adjustment procedure in the presence of two maskers. One was a multi-talker babble with a variable S/N ratio environment that yields intelligibility scores that are potentially level-dependent because of the almost inevitable difference in speech intensity from passage to passage. The second was a signal-correlated noise with a constant S/N ratio environment that provides scores that are essentially level-independent. Two homogeneous subsets of nine passages each were identified that yield equivalent intelligibility scores. The outcome underscores the value of incorporating a signal-correlated noise masker that yields scores that are relatively unaffected by small differences in signal level among passages.

Adult↗
PubMed1992

Relative ear advantage and element duration.

Lauter [J. Acoust. Soc. Am. 71, 701-707 (1982)] reported that although the magnitude and direction of the absolute ear advantage for speech and nonspeech sound sets presented dichotically varies considerably among listeners, consistent patterns of a relative ear advantage (EArel) across sound sets are preserved from listener to listener. She further claimed that EArel appeared to be related to the duration of elements that composed a sequence. The existence of EArel is investigated for four sound sets: CV nonsense syllables and pitch patterns that were composed of 50-, 80-, or 120-ms tones. The paradigm was target monitoring, a Yes/No task in which listeners attended to only one ear and listened for the presence of a target signal. The results failed to confirm that listeners have a consistent relative ear advantage related to element duration for nonspeech sound sets.

Acoustics↗
PubMed1991

Interpretation of outcome on dichotic listening tests following stroke.

The historical basis for interpretation of the dichotic listening performance of aphasic patients is presented. Most studies agree with respect to outcome; aphasic patients as a group tend to have ear advantages (EAs) that are shifted to the left relative to non-brain-damaged listeners. Studies disagree as to whether this difference reflects a shift toward right hemisphere dominance for language processing or a "contralateral ear lesion effect." Emphasis is placed on the most recent additions to the literature, including discussion of factors that affect the accuracy with which lesions can be localized. The conclusion reached is that variables other than dominance determine the direction of ear advantage for many aphasic listeners.

Auditory Pathways↗
PubMed1989

Effects of decision variables on stimulus dominance in dichotic listening.

Stimulus dominance occurs when one member of a dichotic pair is identified more accurately than the other member. The contribution that attentional factors, listener biases, and other nonsensory variables make to stimulus dominance was assessed by comparison of scores obtained in a conventional two-ear monitoring task with scores obtained in a yes/no target-monitoring task. The target-monitoring paradigm is an application of signal detection theory to dichotic listening that allows calculation of d', a measure of perceptual sensitivity. Patterns of dominance for the two paradigms were very similar, which indicates that nonsensory factors had little influence in determining those patterns.

Adult↗
PubMed1989

Comparison of target monitoring and two-ear monitoring dichotic listening procedures.

The dichotic listening performance of 40 listeners was assessed for consonant-vowel (CV) nonsense syllables with two procedures. One was a conventional two-ear monitoring task in which listeners attended to both ears and provided two responses for each pair of syllables. The ear advantage was described by % RE-% LE. The second was target monitoring, a yes/no task in which listeners attended to only one ear and listened for the presence of a target syllable. That procedure provided both hit and false alarm rates for each ear, and the ear advantage was described by P(C)maxRE-P(C)maxLE, which is insensitive to decision variables. Although both procedures yielded mean right-ear advantages (REA), the mean REA of +7.5% with two-ear monitoring was significantly different from the mean REA of +2.6% with target monitoring. In addition, although 62% of the listeners had a significant REA with the conventional procedure, only 40% had a significant REA with target monitoring. Decision variables, which are not controlled with conventional dichotic testing methods, may contribute to the ear advantage as it is described frequently in the literature.

Adult↗
PubMed1987

Effects of simulated conductive hearing loss on dichotic listening performance for digits.

This experiment assessed conditions under which simulated conductive hearing loss would affect performance on a digit dichotic test. Losses were simulated by insertion of EAR plugs, and each subject served as his/her own control. Performance for left ear plugged and right ear plugged conditions was compared with performance in a normal hearing condition (neither ear plugged). Conductive losses did not affect dichotic performance at test intensities 12 dB above the "knees" of monotic performance-intensity functions for the plugged ears (95% correct points) but did affect dichotic performance for some listeners at intensities that were within 8 dB of the monotic knees.

Acoustic Stimulation↗
PubMed1986

Longitudinal dichotic listening patterns for aphasic patients. II. Relationship with lesion variables.

Dichotic listening scores and information on lesion size and location were obtained for aphasic patients. All patients had a reduction in dichotic scores at 1 month postonset of symptoms, but some patients returned to normal levels of performance by 6 months postonset. Lesion location was the main determinant of patterns of performance. Right ear scores from the dichotic digit test closely reflected the presence or absence of lesions involving Heschl's gyrus. What appeared to be an effect of lesion volume was confounded by the relationship between increasing lesion volume and a greater likelihood of damage to Heschl's gyrus.

Adult↗
PubMed1986

Longitudinal dichotic listening patterns for aphasic patients. III. Relationship to language and memory variables.

Longitudinal dichotic scores were obtained for aphasic patients for whom extensive language and memory data were also available. Severity of language impairments was related to ear advantage, but this occurred because larger lesions yielded more severe language impairments and were more likely to involve Heschl's gyrus. Extent of language recovery was not related to changes in ear dominance. Relationships that occurred generally supported a functional-anatomical interpretation which stressed the importance of the integrity of the posterior superior temporal lobe to performance both on dichotic tests and on specific language or memory tests.

Adult↗
PubMed1985

Effects of stimulus material on the dichotic listening performance of patients with sensorineural hearing loss.

Dichotic listening scores were obtained from 27 patients with sensorineural hearing loss in response to four dichotic speech tests: digits, vowel words, consonant words, and CV nonsense syllables. Monotic performance-intensity functions for each ear were defined with the CV syllables, and the four dichotic tests were administered at an intensity that produced asymptotic monotic performance for both ears with the CV syllables. Four blocks of 30 pairs of items per block were presented for each dichotic test, which produced 240 responses per test for each patient. Reliable differences among left-ear scores, right-ear scores, performance level, and the ear advantage were observed among the four tests. The digit test appeared to be most promising for assessing central auditory function when the patient had a sensorineural hearing loss because performance for the digits was only slightly affected by the peripheral loss.

Adult↗
PubMed1984

Application of theory of signal detection to dichotic listening.

Listener performance during dichotic listening to CV nonsense syllables was assessed with a Yes/No target-monitoring task that provides both hit and false alarm information. The ear advantage was described by a metric, P(C)maxRE - P(C)maxLE, that is relatively insensitive to a listener's criterion or bias toward "yes" or "no" responses. One half of the listeners in two experiments had a significant right-ear advantage. The potential influence of listener criterion on measures of the ear advantage in conventional dichotic listening experiments is discussed.

Adult↗
PubMed1983

Peripheral hearing loss: implications for clinical dichotic listening tests.

This experiment assessed the extent to which a peripheral hearing loss may confound interpretation of dichotic listening test results in assessment of central auditory deficit. A normal-hearing listener was tested monotically and dichotically with CV nonsense syllables in two conditions. In one, an EAR plug was inserted in the auditory canal to simulate a unilateral conductive hearing loss. In the second, no plus was inserted. Syllables were presented with equal intensity to the two ears for dichotic testing and testing was conducted at several different intensities. With the plug inserted, both magnitude and direction of percent ear advantage varied with test intensity even when monotic speech recognition scores exceeded 95% for both ears. When dichotic tests are used to assess central auditory deficit in patients with peripheral hearing loss, we recommend that the test intensity be at least 10 dB from both the lower and upper knees of monotic performance-intensity functions.

Dichotic Listening Tests↗
PubMed1983

Effects of talker and of listener bias on stimulus dominance in dichotic listening.

Stimulus dominance, wherein a higher score occurs for one member of a pair of syllables presented dichotically, was investigated in two experiments. The first examined effects due to talker. Six stop consonant-vowel syllables were spoken by two talkers. The pattern of stimulus dominance was not significantly different for the two talkers, and stimulus dominance was not related to articulatory feature-sharing categories. The second experiment investigated whether stimulus dominance reflects a true perceptual superiority of one syllable over another or whether attentional strategies or biases by listeners contribute to the outcome. Syllables were spoken by a single talker. For one group of listeners, tendencies to attend selectively to one ear or the other were uncontrolled. For the second group, maximum performance could be achieved only by attending exclusively to the monitored ear. The magnitude and frequency of stimulus dominance was significantly smaller with the single-ear monitoring task, but ear dominance was unaffected.

Adolescent↗
PubMed1982

Statistical properties of responses to dichotic listening with CV nonsense syllables.

Twenty-four listeners received 20 dichotic listening runs of 30 pairs of natural CV nonsense syllables per run. Left- and eight-ear responses are represented by two partially overlapping normal distributions with equal variance. Observed ear advantages across listening runs are also distributed normally. The means of the distribution of ear advantage are listener specific, but the standard deviations are 10.8% +/- 2.5. The origin of reversals in direction of ear advantage among listening runs is statistical--a small mean/sigma ratio--and approximately six listening runs (180 listening trials) are required to achieve a split-half reliability coefficient of + 0.90.

Dominance, Cerebral↗
PubMed1981

Stimulus dominance in dichotic listening.

Twenty-four listeners received 20 dichotic-listening runs of natural stop-vowel syllables. Listeners marked two responses for each of 30 pairs of syllables per run, which yielded 480 pairs of responses for each of the 30 pairs of syllables. The principal analysis focused on "stimulus dominance" wherein a significantly higher score occurs for one of the competing syllables in a pair regardless of the ear to which that syllable is presented. With 30 pairs of syllables, there were 15 possible instances of stimulus dominance; 11 were observed. The voicing feature was contrasted for 9 of the 15 pairs. Seven of those pairs resulted in significantly higher scores (dominance) for the voiceless stop than for the voiced, one resulted in a higher score for the voiced member of the pair, and for one pair the scores for the two members were essentially the same. Stimulus dominance cannot, however, be characterized sufficiently as a dominance of voiceless over voiced stops; three of the six pairs in which voicing was shared also produced significant stimulus dominance. Stimulus dominance for a given pair of syllables may interact with, and in some cases override, the ear advantage. Of the 30 pairs of syllables, 11 produced a significant right ear advantage (REA), 9 produced a significant left ear advantage (LEA), and for 10 pairs the ear advantage was not significantly different from zero. For a specific pair of syllables, the direction of ear with, and in some cases override, the ear advantage. Of the 30 pairs of syllables, 11 produced a significant right ear advantage (REA), 9 produced a significant left ear advantage (LEA), and for 10 pairs the ear advantage was not significantly different from zero. For a specific pair of syllables, the direction of ear with, and in some cases override, the ear advantage. Of the 30 pairs of syllables, 11 produced a significant right ear advantage (REA), 9 produced a significant left ear advantage (LEA), and for 10 pairs the ear advantage was not significantly different from zero. For a specific pair of syllables, the direction of ear advantage usually corresponded to the ear that received the dominant syllable.

Adolescent↗
PubMed1981

Effects of stimulus material on the dichotic listening performance of aphasic patients.

Sixteen aphasic patients were given five different verbal dichotic listening tests. The differences among results obtained on a digit test, a high-contrast word test (perception of either vocalic or consonantal information was sufficient for accurate responses), and a vowel-word test (perception of vocalic information was required for accurate responses) were not significant. However, a consonant-word test resulted in significant decreases in both left- and right-ear scores and an increase in the performance levels, and the magnitude of difference scores between ears was limited by low levels of performance for the majority of patients. Attempts to identify relations between patterns of performance on dichotic listening tests and radiographic evidence of lesion location were most profitable when they involved the right-ear (RE) scores on the digit test. The discontinuity in the distribution of these scores corresponded to the presence of absence of damage to the geniculo-temporal system. That is, when the geniculo-temporal system was spared, the RE scores exceeded 75% correct, whereas damage to the geniculo-temporal system was associated with RE scores of less than 50% correct.

Adult↗