Consonant Recognition Tests Research Articles

Face Masks Impact Auditory and Audiovisual Consonant Recognition in Children With and Without Hearing Loss.

Teachers and students are wearing face masks in many classrooms to limit the spread of the coronavirus. Face masks disrupt speech understanding by concealing lip-reading cues and reducing transmission of high-frequency acoustic speech content. Transparent masks provide greater access to visual speech cues than opaque masks but tend to cause greater acoustic attenuation. This study examined the effects of four types of face masks on auditory-only and audiovisual speech recognition in 18 children with bilateral hearing loss, 16 children with normal hearing, and 38 adults with normal hearing tested in their homes, as well as 15 adults with normal hearing tested in the laboratory. Stimuli simulated the acoustic attenuation and visual obstruction caused by four different face masks: hospital, fabric, and two transparent masks. Participants tested in their homes completed auditory-only and audiovisual consonant recognition tests with speech-spectrum noise at 0 dB SNR. Adults tested in the lab completed the same tests at 0 and/or −10 dB SNR. A subset of participants from each group completed a visual-only consonant recognition test with no mask. Consonant recognition accuracy and transmission of three phonetic features (place of articulation, manner of articulation, and voicing) were analyzed using linear mixed-effects models. Children with hearing loss identified consonants less accurately than children with normal hearing and adults with normal hearing tested at 0 dB SNR. However, all the groups were similarly impacted by face masks. Under auditory-only conditions, results were consistent with the pattern of high-frequency acoustic attenuation; hospital masks had the least impact on performance. Under audiovisual conditions, transparent masks had less impact on performance than opaque masks. High-frequency attenuation and visual obstruction had the greatest impact on place perception. The latter finding was consistent with the visual-only feature transmission data. These results suggest that the combination of noise and face masks negatively impacts speech understanding in children. The best mask for promoting speech understanding in noisy environments depend on whether visual cues will be accessible: hospital masks are best under auditory-only conditions, but well-fit transparent masks are best when listeners have a clear, consistent view of the talker’s face.

Speech perception in noise in children with dyslexia: Does speech sound disorder matter?

The aim of this observational cohort study with a control group is to compare consonant perception skills in quiet and in noise in children with typical language and learning development and in children with dyslexia, with and without Speech Sound Disorder (SSD). Three groups were included: A control group of twenty children with normal reading abilities and typical language development, twelve children with dyslexia and typical language development and thirteen children with dyslexia and SSD. All subjects received a consonant recognition test in three different listening conditions (quiet, + 10 and 0 Signal-to-Noise Ratio). In all test conditions, children with dyslexia and SSD had significantly lower consonant recognition scores than the control group and the children with dyslexia and typical language development (p< .0001). The poorer performances observed in children with dyslexia and SSD may be explained by impaired phonological processing underlying both conditions.

The Effectiveness of Communication-Oriented Pronunciation Instruction and Students&amp;apos; Perception

The purpose of this study is intended to empirically examine whether or not communication-oriented pronunciation teaching affects the English segmental and suprasegmental pronunciation improvements of Korean college learners, as well as their English speaking ability. The students who participated in this study were 26 college students, all of whom were taking an English pronunciation clinic course at a local university. Three types of pre and post-tests were conducted to find out how communication-oriented pronunciation teaching influenced the learners’ pronunciation. Namely, tests of consonant and vowel sound recognition, reading aloud tests, and picture description tests.&lt;br/&gt;First, a total of 40 questions were given as pre-and post-pronunciation recognition evaluations to find out how accurately the students perceived the sounds of consonants and vowels. In addition, the students’ voices were recorded as they read dialogue readings both before and after the evaluation, in order to examine the degree of improvement of the segmental and suprasegmental features. Finally, the students were asked to describe certain pictures before and after the course to see if there were any beneficial effects regarding their pronunciation of English.&lt;br/&gt;The findings showed that communication-oriented activities led to significant improvements, but only on the consonant recognition tests, not on the tests with vowels. The results from the reading aloud tests also demonstrated that the communication-oriented activities helped students to improve suprasegmental elements, such as stress, intonation, and rhythm. Moreover, there was a significant improvement in the speaking ability of the students, from which I can infer that communication-oriented activities have a positive effect on improving the students’ suprasegmentals, as well as their speaking ability.

Influence of Upper Frequency Boundary on Consonant Perception in Normal Hearing and Cochlear Implant Adults

Purpose: Although some studies argue that it is worthy for cochlear implant (CI) users to have frequency information above 3,000 Hz for consonant recognition, it is not clear whether CI patients make use of this information, especially in Korean. In this experiment, we tested whether consonant recognition in CI patients depended on the utilization of information from 3,000 to 8,000 Hz. Methods: We conducted consonant recognition tests in Korean [3 syllable structures: vowel-consonant-vowel (VCV), consonant-vowel (CV), and vowelconsonant (VC)] pronounced by one male and one female speakers for 3 normal hearing (NH) and 3 CI adults with 9 low-pass filtering frequency conditions. Results: Both groups showed decreased correction scores as cut-off frequency getting lower. CI subjects scored twice errors to NH subjects across frequency conditions. The cut-off frequency of 1,500 Hz brought a significant decrease of consonant recognition. Consonants in VCV syllable recognized better than VC and CV syllable in both groups. Fricatives and affricates in the manner of articulation and alveolar and palatal in the place of articulation are the ones that benefit from high frequency coding. Alveolar plosive sounds were most difficult sounds in both groups and this confirms previous studies of consonant recognition in Korean. Conclusion: NH and CI groups demonstrated poorer consonant recognition as cut-off frequency decreased with relatively large decrements of CI group. The information above 3,000 Hz conveys little information for consonant recognition in the normal and CI subjects while some CI subjects utilized information up to 6,000 Hz. There were large individual differences, particularly in CI group.

Effects of Vowel Context on the Recognition of Initial and Medial Consonants by Cochlear Implant Users

Scores on consonant-recognition tests are widely used as an index of speech-perception ability in cochlear implant (CI) users. The consonant stimuli in these tests are typically presented in the /alpha/ vowel context, even though consonants in conversational speech occur in many other contexts. For this reason, it would be useful to know whether vowel context has any systematic effect on consonant recognition in this population. The purpose of the present study was to compare consonant recognition for the /alpha, i/, and /u/ vowel contexts for consonants presented in both initial (Cv) and medial (vCv) positions. Twenty adult CI users with one of three different implanted devices underwent consonant-confusion testing. Twelve stimulus conditions that differed according to vowel context (/alpha, i, u/), consonant position (Cv, vCv), and talker gender (male, female) were assessed in each subject. Mean percent-correct consonant-recognition scores were slightly (5 to 8%) higher for the /alpha/ and /u/ vowel contexts than for the /i/ vowel context for both initial and medial consonants. This general pattern was observed for both male and female talkers, for subjects with better and poorer average consonant-recognition performance, and for subjects using low, medium, and high stimulation rates in their speech processors. In contrast to the mean data, many individual subjects demonstrated large effects of vowel context. For 10 of 20 subjects, consonant-recognition scores varied by 15% or more across vowel contexts in one or more stimulus conditions. Similar to the mean data, these differences generally reflected better performance for the /alpha/ and /u/ vowel contexts than for the /i/ vowel context. An analysis of consonant features showed that overall performance was best for the voicing feature, followed by the manner and place features, and that the place feature showed the strongest effect of vowel context. Vowel-context effects were strongest for the six consonants /d, j, n, k, m/, and /l/. For three of these consonants (/j, n, k/), the back vowels /alpha/ and /u/ produced substantially (30 to 35%) higher mean scores than the front vowel /i/. For each of the remaining three consonants, a unique pattern was observed in which a different single vowel produced substantially higher scores than the others. Several additional consonants (/s, g, w, b/, and /d/) showed strong context effects in either the initial consonant or medial consonant position. Overall, voiceless stop, nasal, and glide-liquid consonants showed the strongest effects of vowel context, whereas the voiceless fricative and voiceless affricate consonants were least affected. Consistent with the feature analysis, a qualitative assessment of phoneme errors for the six key consonants indicated that vowel-context effects stem primarily from changes in the number of place-of-articulation errors made in each context. Vowel context has small but significant effects on consonant-recognition scores for the "average" CI listener, with the back vowels /alpha/ and /u/ producing better performance than the front vowel /i/. In contrast to the average results, however, the effects of vowel context are sizable in some individual subjects. This suggests that it may be beneficial to assess consonant recognition using two vowels, such as /alpha/ and /i/, which produce better and poorer performance, respectively. The present results underscore previous findings that poor transmission of spectral speech cues limits consonant-recognition performance in CI users. Spectral cue transmission may be hindered not only by poor spectral resolution in these listeners but also by the brief duration and dynamic nature of consonant place-of-articulation cues.

Comparison of two signal processing strategies using consonant recognition tests

(2004). Comparison of two signal processing strategies using consonant recognition tests. Cochlear Implants International: Vol. 5, No. sup1, pp. 38-40.

Comparison of two signal processing strategies using consonant recognition tests

Comparison of two signal processing strategies using consonant recognition tests

Articulation index predictions for hearing-impaired listeners with and without cochlear dead regions

Vickers, Moore, and Baer [J. Acoust. Soc. Am. 110, 1164–1175 (2001)] reported that hearing-impaired subjects with cochlear “dead regions” benefited from amplification of frequencies up to an octave above the estimated edge frequency of the dead region, but not beyond, whereas hearing-impaired subjects without dead regions did show benefit beyond this boundary. Dead regions are thought to have no functioning inner hair cells. Vickers et al. indicated that a clinical test for detecting dead regions would provide supplementary information that is important for hearing aid fitting. Furthermore, they suggested that the articulation index (AI) may overestimate the potential benefit of amplification for listeners with dead regions because the AI does not account for the presence of dead regions. To evaluate their claims, we conducted an AI analysis [H. Fletcher, Speech and Hearing in Communication (Van Nostrand, New York, 1953); H. Fletcher and R. H. Galt, J. Acoust. Soc. Am. 22, 89–151 (1950)]. Results show that the AI is generally accurate in predicting the consonant recognition test scores of Vickers et al.’s subjects irrespective of the presence/absence of dead regions. This suggests that audiogram differences account for the observed performance differences; it was not necessary to invoke dead regions to explain the speech test results. The results of the AI analysis are sufficiently accurate to call in to question whether a clinical test for dead regions would offer additional predictive information.

ミトコンドリア脳筋症例に対する人工内耳

Kearns-Sayre syndrome (KSS) is one of a mitochondrial disease characterized by progressive eye disorders, such as pigmentary retinopathy, and complete heart blockage. A recent study revealed that the etiology of this syndrome involves sporadic large scale rearrangements of mitochondrial DNA. Other neurologic symptoms are frequently associated with this syndrome, and hearing loss is the other main symptom. At the age of 37 years, this female patient began to suffer progressive hearing loss, and eventually became completely deaf. MRI imaging showed diffuse, abnormally high signals in the brain white matter, in T2-weighted images. Further neurological examination revealed eye abnormalities, and a genetic analysis confirmed a diagnosis of KSS. In this case, no sensory agnosia or other focal signs of disorder in the brain cortex were found, and the electrophysical criteria for cochlear implant were fulfilled. Cochlear implantation was performed on May 19, 1995. Post-operatively, the patient underwent vowel and consonant recognition tests. The patients scored well with an accuracy of 75% for vowels and 36% for consonants. The accuracy of vowel and consonant recognition with lip reading was elevated to 100% and 72%, respectively. Sound recognition in this patient seemed to be quite high compared to that reported in other implanted patients. The excellent results obtained in this KSS patient suggest pure neural deafness, and raise the possibility of cochlear involvement in this condition.

The mechanism of speech perception in patients with a multichannel cochlear implant

The mechanism of speech perception in patients with a multichannel cochlear implant was investigated by administering vowel, consonant, and speech recognition tests, and comparing sound spectrograms with the activities recorded from the cochlear implant electrodes. Vowel recognition was found to be adequate, but consonant recognition was poor. Although the cochlear hair cells of such patients are known to be functionally damaged, the cochlear nerve was found to have the capacity to characterize frequency. The signals from the implanted device were very simple compared with those from the normal cochlea; however, the patients could nevertheless understand speech well after cochlear implantation.

Reliability of the Promontory Stimulation Test for the Preoperative Evaluation of Cochlear Implants: A Comparison with the Round Window Stimulation Test

The electrical stimulatory threshold of the preoperative promontory stimulation test (PST) was compared with the postoperative threshold of the electrode following cochlear implantation. Postoperative results from warble-tone audiometry, the vowel recognition test, the consonant recognition test, and the speech tracking test, which employed a speech processor, were similarly evaluated. In certain patients who responded insufficiently to the PST, an exploratory tympanotomy under local anesthesia was performed prior to cochlear implantation, and stimulatory threshold was measured with an electrode placed directly on the round window [round window stimulation test (RWST)]. No correlation was found between the PST results and the postoperative performance of the cochlear implant. The RWST was determined to be better than the PST in the evaluation of cochlear implant performance.

Improved information transfer of phoneme features with a multiple-electrode cochlear implant.

The spectral maxima sound processor (SMSP), recently developed at the University of Melbourne, has been shown to provide improved speech discrimination in quiet and in noise for subjects using the Mini System 22 cochlear implant when compared with commercially available speech processors, including the Mini Speech Processor (MSP) [C. M. McKay and H. J. McDermott, J. Acoust. Soc. Am. 89, 1959 (1991)]. The ability of five subjects to perceive phoneme features using the SMSP has been compared with their ability using the MSP. Information transfer analysis has been applied to the results of open-set CNC word tests and closed-set vowel and consonant recognition tests. Phoneme features studied were consonant manner and place of articulation and voicing, vowel duration, formant frequencies, and formant transitions. The results show an overall improvement in the perception of all phoneme features, with large improvements seen in perception of consonant place of articulation. This consonant feature has been perceived poorly relative to other consonant features with all previous speech processors used with this implant. Further development of the SMSP is being guided by the results of this analysis.

Relationship between consonant recognition and subjective ratings of hearing aids

The relationships between consonant recognition performance and subjective ratings (using continuous discourse and nonsense syllables as stimuli) of speech understanding, listening comfort, quality, noise interference and overall liking were examined in quiet and in noise using hearing-impaired subjects and seven different hearing aids. Correlations among the subjective scales varied depending on test conditions and test stimuli. Scores on the speech understanding and overall liking scales correlated moderately with scores on a consonant-recognition test presented in noise and when syllables were used as the materials for judgments. The overall liking scale (for a hearing aid) correlated with all other subjective scales and consonant recognition performance. However, the relative contribution of each subjective scale to overall liking varied depending on test conditions and test materials.

Training influences on visual consonant and sentence recognition.

Visual consonant and sentence reception were compared in three groups of 10 normal-hearing young adult subjects including a Training group that received 14 hours of videotaped analytic visual consonant recognition training with 100% feedback concerning the correctness of their responses, a Pseudotraining group that received the same treatment as the Training group with the exception that they were not given any information about whether their responses were correct or not, and a Control group. While all three groups scored significantly higher on the post-treatment visual consonant recognition test, there was no significant difference between the Training group and the Pseudotraining group in terms of improvement scores. Furthermore, none of the groups improved in their ability to recognize visually presented sentence length material. These results are discussed in terms of the development of task-specific performance skills.

Long-term effects of multichannel cochlear implant usage.

A major concern regarding multichannel (multi-electrode) cochlear prosthesis usage has been the possibility of long-term deleterious physiological effects such as the degeneration of spiral ganglion cells, neuronal degeneration, and new bone formation. These effects, if present, would become evident in the deterioration of hearing sensation and performance of the cochlear implant recipient on a battery of audiologic tests. To date, five patients using the Australian multi-electrode multichannel cochlear implant have undergone a 1-year evaluation of the device. The assessment includes a check of electrical threshold and comfort levels for each electrode, sound field pure tone and speech thresholds, the MAC battery, vowel and consonant recognition tests, and speech tracking tasks. All results were compared to those obtained postoperatively following stimulation and a 3-month training period. Results to date have shown no deterioration in implant functioning in all patients tested. Periodic extensive monitoring of all implant recipients is advocated in order to evaluate the possibility of long-term effects.

Time‐intensity envelope cues for consonant recognition

A primary source of perceptual information for the cochlear implant user in the time‐intensity envelope of the speech waveform. The purpose of this study was to estimate the amount and type of information for consonant recognition potentially available in the time‐intensity envelope of speech. The experimental stimuli were generated from the time‐intensity envelopes of 19 /aCa/ utterances (C = /p, t, k, b, d, g, f, θ, s, ∫, v, ð, z, ȝ, m, n, r, l, j/), spoken by a male talker. The envelopes were obtained by full‐wave rectifying and low‐pass filtering the speech waveforms at 2000, 200, and 20 Hz. These envelopes were used to multiply noise with a 3‐kHz bandwidth, producing three sets of envelope stimuli with identical, flat spectra that differed in the amount of time‐varying in their amplitude envelopes. The unprocessed speech waveforms and the three sets of envelope stimuli were presented to 12 normal‐hearing subjects in blocked, closed‐set consonant recognition tests. Individual and group confusion matrices from each test were submitted to multidimensional scaling analyses (SINDSCAL) and information transmission analyses (SINFA). The results of these analyses revealed that three different envelope features account for most of the consonant information in the time‐intensity envelope of speech.

A parametric representation and a clustering method for phoneme recognition--Application to stops in a CV environment

A new method of representing phonemic categories and determining their standard values from a training sample distribution is presented. It is an essential part of a phoneme recognition system aiming at speaker-independent speech recognition. The phonemic value of a short-duration speech signal of up to 50 ms is represented by a matrix composed of acoustic parameters. Standard phonemic categories (SPC's) are defined by a combination of several simple potential functions in this matrix space. The potential function set, as well as its number, is determined automatically by the proposed method. Processing is primarily by algebraic operation and is formulated according to an analogy to particle dynamics. The method is applied to voiceless and voiced stop consonant sets spoken by twelve speakers. The relationship between the classification rate and the number of SPC's is investigated under several initial conditions. Stop consonant recognition tests in CV-syllables are made using derived SPC sets irrespective of following vowels. Recognition rates for the utterances of four speakers not included among the twelve speakers used for training were 84 percent for voiceless and 81 percent for voiced stops.

Intelligibility and ratings of digitally coded speech

An experiment has been performed to investigate perceptual effects of digital encoding of speech. The aim was to gain information about the influence on intelligibility and subjective quality of three distortions: bandwidth reduction, peak clipping, and amplitude quantization. Allowing two levels of each distortion, we produced eight encoders encompassing all possible combinations of the three impairments. By means of a consonant recognition test (CRT) and a category-rating test, twelve subjects provided intelligibility and rating data about each encoder. The results show that the effect of multiple distortions is not, in general, the sum of effects of individual distortions and that the distortions influence intelligibility and subjective quality differently. For example, with respect to consonant recognition, quantization and clipping reinforce one another; occurring together they cause more recognition errors than the sum of the errors caused by the two distortions occurring individually. On the other hand, the effects of quantization and clipping on subjective quality are essentially additive.

Introduction to the Consonant-Recognition Test

A test of speech intelligibility called the Consonant Recognition Test has been developed and evaluated. Designed to use human subjects in conjunction with a digital computer as a precision laboratory tool for diagnostic analysis of speech communication systems, this test appears to combine the attributes of simplicity, efficiency of testing, sensitivity, and diagnostic ability to an extent not previously attained by intelligibility tests. To minimize the effects of speaker differences and to permit one to use conveniently a large number of speakers, nine speakers were rotated or “multiplexed” in the recorded version of the lists so that each list contained a sample of the nine voices. Experiments comparing the consonant recognition test to the Fairbanks rhyme test have demonstrated that the consonant recognition test requires less than 75% of the time for test administration and is about 18% more sensitive, while still providing an extensive diagnostic analysis of the systems under evaluation.