Consonant-vowel Syllables Research Articles

Cross-Linguistic Nasalance Comparisons: A Review of Speech Sample Sets and Preliminary Consideration of Effect of Lexical Tone.

Nasalance is an acoustic representation of perceived nasality with proven clinical and research utility. Its validity is contingent on appropriate speech sample sets and distinct normative databases based on known impact factors such as language and phonetic environment, but little is known about the potential effects of lexical tone on nasalance. Its use in international cross-linguistic studies necessitates definition and added considerations of speech sampling protocol. Part I. A methodological review was undertaken using PRISMA (2020), the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist for evaluating risk of bias, and calculation of effect sizes and/or visual displays using tables showing grouping of similar data for synthesis of findings. Part II. A pilot study explored the effect of lexical tone on nasalance in Cantonese, a lexical tone language. Part I. 17 studies met the inclusion criteria. In addressing possible confounders and minimizing risk of bias, 13 studies were assigned an overall quality rating of (+) acceptable and the remaining 4, a high rating (++). For the 9-word string, there was a (non-clinical) difference of 3-5% between Swedish and Brazilian-Portuguese, and a moderate effect size for age (d=0.49); for the consonant-vowel syllables set (CV set), clinical differences across languages were identified for adults, and between 5-10% for children and adolescents. Part II. The pilot study showed a significant effect of lexical tone on nasalance where nasalance for the high-level tone 1 was significantly higher than that for high-rising tone 2, low-rising tone 5, and low-falling tone 4. There is a need for further evidence from other languages, including tonal languages, to better define the evidence and speech methodology of international cross-linguistic nasalance studies.

Subthalamic nucleus neurons encode syllable sequence and phonetic characteristics during speech.

Speech is a complex behavior that can be used to study unique contributions of the basal ganglia to motor control in the human brain. Computational models suggest that the basal ganglia encode either the phonetic content or the sequence of speech elements. To explore this question, we investigated the relationship between phoneme and sequence features of a spoken syllable triplet and the firing rate of subthalamic nucleus (STN) neurons recorded during the implantation of deep brain stimulation (DBS) electrodes in individuals with Parkinson's disease. Patients repeated aloud a random sequence of three consonant-vowel (CV) syllables in response to audio cues. Single-unit extracellular potentials were sampled from the sensorimotor STN; a total of 227 unit recordings were obtained from the left STN of 25 subjects (4 females). Of these, 113 (50%) units showed significant task-related increased firing and 53 (23%) showed decreased firing (t test relative to inter-trial period baseline, P < 0.05). Linear regression analysis revealed that both populations of STN neurons encode phoneme and sequence features of produced speech. Maximal phoneme encoding occurred at the time of phoneme production, suggesting efference copy- or sensory-related processing, rather than speech motor planning (-50 ms and +175 ms relative to CV transition for consonant and vowel encoding, respectively). These findings demonstrate that involvement of the basal ganglia in speaking includes separate single unit representations of speech sequencing and phoneme selection in the STN.NEW & NOTEWORTHY Speech is a unique human behavior that requires dynamic execution of precisely timed and coordinated movements, resulting in intelligible vocalizations. Here, we demonstrate that activity of individual neurons in the subthalamic nucleus (STN) of the basal ganglia encode syllable sequence order and phoneme identity during a speech production task. These findings advance our understanding of neural substrates of human speech and shed light on potential involvement of the STN in complex human behaviors.

Enhancing analysis of diadochokinetic speech using deep neural networks

Diadochokinetic speech tasks (DDK) involve the repetitive production of consonant-vowel syllables. These tasks are useful in detecting impairments, differential diagnosis, and monitoring progress in speech-motor impairments. However, manual analysis of those tasks is time-consuming, subjective, and provides only a rough picture of speech. This paper presents several deep neural network models working on the raw waveform for the automatic segmentation of stop consonants and vowels from unannotated and untranscribed speech. A deep encoder serves as a features extractor module, replacing conventional signal processing features. In this context, diverse deep learning architectures, such as convolutional neural networks (CNNs) and large self-supervised models like HuBERT, are applied for the extraction process. A decoder model uses derived embeddings to identify frame types. Consequently, the paper studies diverse deep architectures, ranging from linear layers, LSTM, CNN, and transformers. These architectures are assessed for their ability to detect speech rate, sound duration, and boundary locations on a dataset of healthy individuals and an unseen dataset of older individuals with Parkinson’s Disease. The results reveal that an LSTM model performs better than all other models on both datasets and is comparable to trained human annotators.

Tone-syllable synchrony in Mandarin: New evidence and implications

Recent research has shown evidence based on a minimal contrast paradigm that consonants and vowels are articulatorily synchronized at the onset of the syllable. What remains less clear is the laryngeal dimension of the syllable, for which evidence of tone synchrony with the consonant-vowel syllable has been circumstantial. The present study assesses the precise tone-vowel alignment in Mandarin Chinese by applying the minimal contrast paradigm. The vowel onset is determined by detecting divergence points of F2 trajectories between a pair of disyllabic sequences with two contrasting vowels, and the onsets of tones are determined by detecting divergence points of f0 trajectories in contrasting disyllabic tone pairs, using generalized additive mixed models (GAMMs). The alignment of the divergence-determined vowel and tone onsets is then evaluated with linear mixed effect models (LMEMs) and their synchrony is validated with Bayes factors. The results indicate that tone and vowel onsets are fully synchronized. There is therefore evidence for strict alignment of consonant, vowel and tone as hypothesized in the synchronization model of the syllable. Also, with the newly established tone onset, the previously reported ‘anticipatory raising’ effect of tone now appears to occur within rather than before the articulatory syllable. Implications of these findings will be discussed.

An auditory perspective on phonological development in infancy.

The auditory system encodes the phonetic features of languages by processing spectro-temporal modulations in speech, which can be described at two time scales: relatively slow amplitude variations over time (AM, further distinguished into the slowest <8-16 Hz and faster components 16-500 Hz), and frequency modulations (FM, oscillating at higher rates about 600-10 kHz). While adults require only the slowest AM cues to identify and discriminate speech sounds, infants have been shown to also require faster AM cues (>8-16 Hz) for similar tasks. Using an observer-based psychophysical method, this study measured the ability of typical-hearing 6-month-olds, 10-month-olds, and adults to detect a change in the vowel or consonant features of consonant-vowel syllables when temporal modulations are selectively degraded. Two acoustically degraded conditions were designed, replacing FM cues with pure tones in 32 frequency bands, and then extracting AM cues in each frequency band with two different low-pass cut- off frequencies: (1) half the bandwidth (Fast AM condition), (2) <8 Hz (Slow AM condition). In the Fast AM condition, results show that with reduced FM cues, 85% of 6-month-olds, 72.5% of 10-month-olds, and 100% of adults successfully categorize phonemes. Among participants who passed the Fast AM condition, 67% of 6-month-olds, 75% of 10-month-olds, and 95% of adults passed the Slow AM condition. Furthermore, across the three age groups, the proportion of participants able to detect phonetic category change did not differ between the vowel and consonant conditions. However, age-related differences were observed for vowel categorization: while the 6- and 10-month-old groups did not differ from one another, they both independently differed from adults. Moreover, for consonant categorization, 10-month-olds were more impacted by acoustic temporal degradation compared to 6-month-olds, and showed a greater decline in detection success rates between the Fast AM and Slow AM conditions. The degradation of FM and faster AM cues (>8 Hz) appears to strongly affect consonant processing at 10 months of age. These findings suggest that between 6 and 10 months, infants show different developmental trajectories in the perceptual weight of speech temporal acoustic cues for vowel and consonant processing, possibly linked to phonological attunement.

Assessing Speech Audibility via Syllabic-Rate Neural Responses in Adults and Children With and Without Hearing Loss.

An objective method for assessing speech audibility is essential to evaluate hearing aid benefit in children who are unable to participate in hearing tests. With consonant-vowel syllables, brainstem-dominant responses elicited at the voice fundamental frequency have proven successful for assessing audibility. This study aimed to harness the neural activity elicited by the slow envelope of the same repetitive consonant-vowel syllables to assess audibility. In adults and children with normal hearing and children with hearing loss wearing hearing aids, neural activity elicited by the stimulus /su∫i/ or /sa∫i/ presented at 55-75 dB SPL was analyzed using the temporal response function approach. No-stimulus runs or very low stimulus level (15 dB SPL) were used to simulate inaudible conditions in adults and children with normal hearing. Both groups of children demonstrated higher response amplitudes relative to adults. Detectability (sensitivity; true positive rate) ranged between 80.1 and 100%, and did not vary by group or stimulus level but varied by stimulus, with /sa∫i/ achieving 100% detectability at 65 dB SPL. The average minimum time needed to detect a response ranged between 3.7 and 6.4 min across stimuli and listener groups, with the shortest times recorded for stimulus /sa∫i/ and in children with hearing loss. Specificity was >94.9%. Responses to the slow envelope of non-meaningful consonant-vowel syllables can be used to ascertain audible vs. inaudible speech with sufficient accuracy within clinically feasible test times. Such responses can increase the clinical usefulness of existing objective approaches to evaluate hearing aid benefit.

Reaction time for correct identification of vowels in consonant-vowel syllables and of vowel segments.

Reaction times for correct vowel identification were measured to determine the effects of intertrial intervals, vowel, and cue type. Thirteen adults with normal hearing, aged 20-38 years old, participated. Stimuli included three naturally produced syllables (/ba/ /bi/ /bu/) presented whole or segmented to isolate the formant transition or static formant center. Participants identified the vowel presented via loudspeaker by mouse click. Results showed a significant effect of intertrial intervals, no significant effect of cue type, and a significant vowel effect-suggesting that feedback occurs, vowel identification may depend on cue duration, and vowel bias may stem from focal structure.

Preliminary Speech Perception Performance Profiles of School-Age Children With Childhood Apraxia of Speech, Speech Sound Disorder, and Typical Development.

Limited research exists assessing speech perception in school-age children with speech sound disorder (SSD) and childhood apraxia of speech (CAS); despite early evidence that speech perception may lead to error-prone motor planning/programming. In this study, we examine speech perception performance in school-age children with and without speech production deficits. Speech perception was assessed using the Wide Range Acoustic Accuracy Scale to determine the just-noticeable difference in discrimination for three consonant-vowel syllable contrasts (/bɑ/-/wɑ/, /dɑ/-/gɑ/, /ɹɑ/-/wɑ/), each varying along a single acoustic parameter for seven children with CAS with rhotic errors, seven children with SSD with rhotic errors, and seven typically developing (TD) children. Findings revealed statistically significant mean differences between perceptual performance of children with CAS when compared to TD children for discrimination of /ɹɑ/-/wɑ/ contrasts. Large effect sizes were also observed for comparisons of /ɹɑ/-/wɑ/ contrasts between children with CAS, SSD, and TD peers. Additionally, large effect sizes were observed for /dɑ/-/gɑ/ contrasts between children with CAS and SSD and TD children despite nonsignificant mean differences in group performance. Overall, mean outcome scores suggest that school-age children with CAS and persistent rhotic errors demonstrated less accurate speech perception skills relative to TD children for the /ɹɑ/-/wɑ/ contrasts. However, the relatively small sample sizes per group limit the extent to which these findings may be generalized to the broader population.

Speech production real-time MRI at 0.55 T.

To demonstrate speech-production real-time MRI (RT-MRI) using a contemporary 0.55T system, and to identify opportunities for improved performance compared with conventional field strengths. Experiments were performed on healthy adult volunteers using a 0.55T MRI system with high-performance gradients and a custom 8-channel upper airway coil. Imaging was performed using spiral-based balanced SSFP and gradient-recalled echo (GRE) pulse sequences using a temporal finite-difference constrained reconstruction. Speech-production RT-MRI was performed with three spiral readout durations (8.90, 5.58, and 3.48 ms) to determine trade-offs with respect to articulator contrast, blurring, banding artifacts, and overall image quality. Both spiral GRE and bSSFP captured tongue boundary dynamics during rapid consonant-vowel syllables. Although bSSFP provided substantially higher SNR in all vocal tract articulators than GRE, it suffered from banding artifacts at TR > 10.9 ms. Spiral bSSFP with the shortest readout duration (3.48 ms, TR = 5.30 ms) had the best image quality, with a 1.54-times boost in SNR compared with an equivalent GRE sequence. Longer readout durations led to increased SNR efficiency and blurring in both bSSFP and GRE. High-performance 0.55T MRI systems can be used for speech-production RT-MRI. Spiral bSSFP can be used without suffering from banding artifacts in vocal tract articulators, provide better SNR efficiency, and have better image quality than what is typically achieved at 1.5 T or 3 T.

A multidimensional characterization of the neurocognitive architecture underlying age-related temporal speech processing

Healthy aging is often associated with speech comprehension difficulties in everyday life situations despite a pure-tone hearing threshold in the normative range. Drawing on this background, we used a multidimensional approach to assess the functional and structural neural correlates underlying age-related temporal speech processing while controlling for pure-tone hearing acuity. Accordingly, we combined structural magnetic resonance imaging and electroencephalography, and collected behavioral data while younger and older adults completed a phonetic categorization and discrimination task with consonant-vowel syllables varying along a voice-onset time continuum. The behavioral results confirmed age-related temporal speech processing singularities which were reflected in a shift of the boundary of the psychometric categorization function, with older adults perceiving more syllable characterized by a short voice-onset time as /ta/ compared to younger adults. Furthermore, despite the absence of any between-group differences in phonetic discrimination abilities, older adults demonstrated longer N100/P200 latencies as well as increased P200 amplitudes while processing the consonant-vowel syllables varying in voice-onset time. Finally, older adults also exhibited a divergent anatomical gray matter infrastructure in bilateral auditory-related and frontal brain regions, as manifested in reduced cortical thickness and surface area. Notably, in the younger adults but not in the older adult cohort, cortical surface area in these two gross anatomical clusters correlated with the categorization of consonant-vowel syllables characterized by a short voice-onset time, suggesting the existence of a critical gray matter threshold that is crucial for consistent mapping of phonetic categories varying along the temporal dimension. Taken together, our results highlight the multifaceted dimensions of age-related temporal speech processing characteristics, and pave the way toward a better understanding of the relationships between hearing, speech and the brain in older age.

Simulating vocal learning of spoken language: Beyond imitation

Computational approaches have an important role to play in understanding the complex process of speech acquisition, in general, and have recently been popular in studies of vocal learning in particular. In this article we suggest that two significant problems associated with imitative vocal learning of spoken language, the speaker normalisation and phonological correspondence problems, can be addressed by linguistically grounded auditory perception. In particular, we show how the articulation of consonant–vowel syllables may be learnt from auditory percepts that can represent either individual utterances by speakers with different vocal tract characteristics or ideal phonetic realisations. The result is an optimisation-based implementation of vocal exploration – incorporating semantic, auditory, and articulatory signals – that can serve as a basis for simulating vocal learning beyond imitation.

The influence of phoneme contexts on adaptation in vowel‐evoked envelope following responses

Repeated stimulus presentation leads to neural adaptation and consequent amplitude reduction in vowel‐evoked envelope following responses (EFRs)—a response that reflects neural activity phase‐locked to envelope periodicity. EFRs are elicited by vowels presented in isolation or in the context of other phonemes such as consonants in syllables. While context phonemes could exert some forward influence on vowel‐evoked EFRs, they may reduce the degree of adaptation. Here, we evaluated whether the properties of context phonemes between consecutive vowel stimuli influence adaptation. EFRs were elicited by the low‐frequency first formant (resolved harmonics) and middle‐to‐high‐frequency second and higher formants (unresolved harmonics) of a male‐spoken /i/ when the presence, number and predictability of context phonemes (/s/, /a/, /∫/ and /u/) between vowel repetitions varied. Monitored over four iterations of /i/, adaptation was evident only for EFRs elicited by the unresolved harmonics. EFRs elicited by the unresolved harmonics decreased in amplitude by ~16–20 nV (10%–17%) after the first presentation of /i/ and remained stable thereafter. EFR adaptation was reduced by the presence of a context phoneme, but the reduction did not change with their number or predictability. The presence of a context phoneme, however, attenuated EFRs by a degree similar to that caused by adaptation (~21–23 nV). Such a trade‐off in the short‐ and long‐term influence of context phonemes suggests that the benefit of interleaving EFR‐eliciting vowels with other context phonemes depends on whether the use of consonant‐vowel syllables is critical to improve the validity of EFR applications.

Comparisons of auditory brainstem response elicited by compound click-sawtooths sound and synthetic consonant-vowel /da/

The auditory brainstem response to complex sounds (cABR) could be evoked using speech sounds such as the 40 ms synthetic consonant-vowel syllable /da/ (CV-da) that was commonly used in basic and clinical research. cABR consists of responses to formant energy as well as the energy of fundamental frequency. The co-existence of the two energy makes cABR a mixed response. We introduced a new stimulus of click-sawtooths (CSW) with similar time-lock patterns but without formant or harmonic energy. Ten young healthy volunteers were recruited and the cABRs of CV-da and CSW of their 20 ears were acquired. The response latencies, amplitudes, and frequency-domain analytic results were compared pairwisely between stimuli. The response amplitudes were significantly greater for CSW and the latencies were significantly shorter for CSW. The latency-intensity functions were also greater for CSW. For CSW, adjustments of energy component can be made without causing biased changes to the other. CSW may be used in future basic research and clinical applications.

Syllable-Initial Phonemes Affect Neural Entrainment to Consonant-Vowel Syllables.

Neural entrainment to speech appears to rely on syllabic features, especially those pertaining to the acoustic envelope of the stimuli. It has been proposed that the neural tracking of speech depends on the phoneme features. In the present electroencephalography experiment, we examined data from 25 participants to investigate neural entrainment to near-isochronous stimuli comprising syllables beginning with different phonemes. We measured the inter-trial phase coherence of neural responses to these stimuli and assessed the relationship between this coherence and acoustic properties of the stimuli designed to quantify their “edginess.” We found that entrainment was different across different classes of the syllable-initial phoneme and that entrainment depended on the amount of “edge” in the sound envelope. In particular, the best edge marker and predictor of entrainment was the latency of the maximum derivative of each syllable.

AUDIOWIZUALNA PERCEPCJA MOWY W OBUUSZNYCH I ROZDZIELNOUSZNYCH WARUNKACH SŁUCHOWYCH

BackgroundSpeech perception is multisensory, relying on auditory as well as visual information from the articulators. Watching articulatory gestures which are either congruent or incongruent with the speech audio can change the auditory percept, indicating that there is a complex integration of auditory and visual stimuli. A speech segment is comprised of distinctive features, notably voice onset time (VOT) and place of articulation (POA). Understanding the importance of each of these features for audiovisual (AV) speech perception is critical. The present study investigated the perception of AV consonant-vowel (CV) syllables with various VOTs and POAs under two conditions: diotic incongruent and dichotic congruent.Material and methodsAV stimuli comprised diotic and dichotic CV syllables with stop consonants (bilabial /pa/ and /ba/; alveolar /ta/ and /da/; and velar /ka/ and /ɡa/) presented with congruent and incongruent video CV syllables with stop consonants. There were 40 righthanded normal hearing young adults (20 females, mean age 23 years, &lt;i&gt;SD&lt;/i&gt; = 2.4 years) and 20 males (mean age 24 years, &lt;i&gt;SD&lt;/i&gt; = 2.1 years) who participated in the experiment.ResultsIn the diotic incongruent AV condition, short VOT (voiced CV syllables) of the visual segments were identified when auditory segments had a CV syllable with long VOT (unvoiced CV syllables). In the dichotic congruent AV condition, there was an increase in identification of the audio segment when the subject was presented with a video segment congruent to either ear, in this way overriding the otherwise presented ear advantage in dichotic listening. Distinct visual salience of bilabial stop syllables had greater visual influence (observed as greater identification scores) than velar stop syllables and thus overrode the acoustic dominance of velar syllables.ConclusionsThe findings of the present study have important implications for understanding the perception of diotic incongruent and dichotic congruent audiovisual CV syllables in which the stop consonants have different VOT and POA combinations. Earlier findings on the effect of VOT on dichotic listening can be extended to AV speech having dichotic auditory segments.

The onset of voice onset time: Measuring the emergent timing of laryngeal and oral gestures in early speech development

Voicing contrasts in stop consonants are predominantly signaled by manipulation of voice onset time (VOT), the relative timing of oral and laryngeal gestures responsible for the release of the oral constriction and the onset of phonation. VOT is usually measured from the acoustic signal and defined by the time between the stop consonant burst and the following glottal period. Although this works well in adult speech, the same measure can be problematic when applied to child vocalizations. Infant productions of closant-vocant sequences perceived as consonant-vowel syllables by adults often do not exhibit full closure and are voiced throughout. Traditional measures of VOT cannot then be employed, even though evidence from the acoustic signal can still be used to deduce the presence and timing of precursors of the oral and laryngeal gestures from which adult voicing contrasts later emerge. This study illustrates these issues using data derived from home audio recordings made monthly from birth to three years as part of a large-scale, longitudinal study of infant vocal development. New methods for measuring VOT are proposed, using the relative amplitude, frequency and phase of the harmonics in the acoustic signal to infer the timing of underlying articulatory gestures.

Effects of Spectral Shaping on Speech Auditory Brainstem Responses to Stop Consonant-Vowel Syllables.

Spectral shaping is employed by hearing aids to make consonantal information, such as formant transitions, audible for listeners with hearing loss. How manipulations of the stimuli, such as spectral shaping, may alter encoding in the auditory brainstem has not been thoroughly studied. The aim of this study was to determine how spectral shaping of synthetic consonant-vowel (CV) syllables, varying in their second formant (F2) onset frequency, may affect encoding of the syllables in the auditory brainstem. We employed a repeated measure design. Sixteen young adults (mean = 20.94 years, 6 males) and 11 older adults (mean = 58.60 years, 4 males) participated in this study. Speech-evoked auditory brainstem responses (speech-ABRs) were obtained from each participant using three CV exemplars selected from synthetic stimuli generated for a /ba-da-ga/ continuum. Brainstem responses were also recorded to corresponding three CV exemplars that were spectrally shaped to decrease low-frequency information and provide gain for middle and high frequencies according to a Desired Sensation Level function. In total, six grand average waveforms (3 phonemes [/ba/, /da/, /ga/] X 2 shaping conditions [unshaped, shaped]) were produced for each participant. Peak latencies and amplitudes, referenced to prestimulus baseline, were identified for 15 speech-ABR peaks. Peaks were marked manually using the program cursor on each individual waveform. Repeated-measures analysis of variances were used to determine the effects of shaping on the latencies and amplitudes of the speech-ABR peaks. Shaping effects produced changes within participants in ABR latencies and amplitudes involving onset and major peaks of the speech-ABR waveform for certain phonemes. Specifically, data from onset peaks showed that shaping decreased latency for /ga/ in older listeners, and decreased amplitude onset for /ba/ in younger listeners. Shaping also increased the amplitudes of major peaks for /ga/ stimuli in both groups. Encoding of speech in the ABR waveform may be more complex and multidimensional than a simple demarcation of source and filter information, and may also be influenced by cue intensity and age. These results suggest a more complex subcortical encoding of vocal tract filter information in the ABR waveform, which may also be influenced by cue intensity and age.

Sensitivity of Vowel-Evoked Envelope Following Responses to Spectra and Level of Preceding Phoneme Context.

Vowel-evoked envelope following responses (EFRs) could be a useful noninvasive tool for evaluating neural activity phase-locked to the fundamental frequency of voice (f0). Vowel-evoked EFRs are often elicited by vowels in consonant-vowel syllables or words. Considering neural activity is susceptible to temporal masking, EFR characteristics elicited by the same vowel may vary with the features of the preceding phoneme. To this end, the objective of the present study was to evaluate the influence of the spectral and level characteristics of the preceding phoneme context on vowel-evoked EFRs. EFRs were elicited by a male-spoken /i/ (stimulus; duration = 350 msec), modified to elicit two EFRs, one from the region of the first formant (F1) and one from the second and higher formants (F2+). The stimulus, presented at 65 dB SPL, was preceded by one of the four contexts: /∫/, /m/, /i/ or a silent gap of duration equal to that of the stimulus. The level of the context phonemes was either 50 or 80 dB SPL, 15 dB lower and higher than the level of the stimulus /i/. In a control condition, EFRs to the stimulus /i/ were elicited in isolation without any preceding phoneme contexts. The stimulus and the contexts were presented monaurally to a randomly chosen test ear in 21 young adults with normal hearing. EFRs were recorded using single-channel electroencephalogram between the vertex and the nape. A repeated measures analysis of variance indicated a significant three-way interaction between context type (/∫/, /i/, /m/, silent gap), level (50, 80 dB SPL), and EFR-eliciting formant (F1, F2+). Post hoc analyses indicated no influence of the preceding phoneme context on F1-elicited EFRs. Relative to a silent gap as the preceding context, F2+-elicited EFRs were attenuated by /∫/ and /m/ presented at 50 and 80 dB SPL, as well as by /i/ presented at 80 dB SPL. The average attenuation ranged from 14.9 to 27.9 nV. When the context phonemes were presented at matched levels of 50 or 80 dB SPL, F2+-elicited EFRs were most often attenuated when preceded by /∫/. At 80 dB SPL, relative to the silent preceding gap, the average attenuation was 15.7 nV, and at 50 dB SPL, relative to the preceding context phoneme /i/, the average attenuation was 17.2 nV. EFRs elicited by the second and higher formants of /i/ are sensitive to the spectral and level characteristics of the preceding phoneme context. Such sensitivity, measured as an attenuation in the present study, may influence the comparison of EFRs elicited by the same vowel in different consonant-vowel syllables or words. However, the degree of attenuation with realistic context levels exceeded the minimum measurable change only 12% of the time. Although the impact of the preceding context is statistically significant, it is likely to be clinically insignificant a majority of the time.

Temporal processing deficit in children with attention-deficit/hyperactivity disorder: An online assessment.

ObjectiveTemporal processing deficits were found among children with attention-deficit/hyperactivity disorder (ADHD). The present study aims to develop an online temporal processing assessment that can be conducted remotely, and the sensitivity of the test was assessed on a group of children with ADHD.MethodsA total of 188 children were recruited, including 94 typically developing (TD) children, and 94 children with ADHD. The online assessment consists of two temporal-order judgment (TOJ) tasks. One task used tone pairs presented with two interstimulus intervals (ISIs) (305ms and 40ms). Another task used pairs of consonant-vowel (CV) syllables with 20 varying ISI levels. Participants were asked to determine the sequence of the sound pairs.ResultsThe results showed that ADHD children were less accurate (ISI 305ms: M = 83.90%; ISI 40ms: M = 66.28%) than TD children (ISI 305ms: M = 89.36%; ISI 40ms: M = 77.16%) in the tone task. Similarly, ADHD children showed a higher ISI passing threshold (M = 283.64ms) than TD children (M = 199.76ms) and higher accuracy in the CV task. Hierarchical binary logistic regression suggested a model to predict ADHD children using accuracy in ISI 40ms in the tone task and ISI passing threshold in the CV task. Receiver operating characteristic (ROC) analysis yielded a sensitivity of 75.58% and a specificity of 51.11%.ConclusionADHD children showed temporal processing deficits of both tones and CVs. The online assessment may be a valid tool for differentiating ADHD children from TD children.

Development and Evaluation of a Language-Independent Test of Auditory Discrimination for Referrals for Cochlear Implant Candidacy Assessment.

Objectives:The purpose of this study was to (1) develop a Language-independent Test of Auditory Discrimination (LIT-AD) between speech sounds so that people with hearing loss who derive limited speech perception benefits from hearing aids (HAs) may be identified for consideration of cochlear implantation and (2) examine the relationship between the scores for the new discrimination test and those of a standard sentence test for adults wearing either HAs or cochlear implants (CIs).Design:The test measures the ability of the listener to correctly discriminate pairs of nonsense syllables, presented as sequential triplets in an odd-one-out format, implemented as a game-based software tool for self-administration using a tablet computer. Stage 1 included first a review of phonemic inventories in the 40 most common languages in the world to select the consonants and vowels. Second, discrimination testing of 50 users of CIs at several signal to noise ratios (SNRs) was carried out to generate psychometric functions. These were used to calculate the corrections in SNR for each consonant-pair and vowel combination required to equalize difficulty across items. Third, all items were individually equalized in difficulty and the overall difficulty set. Stage 2 involved the validation of the LIT-AD in English-speaking listeners by comparing discrimination scores with performance in a standard sentence test. Forty-one users of HAs and 40 users of CIs were assessed. Correlation analyses were conducted to examine test–retest reliability and the relationship between performance in the two tests. Multiple regression analyses were used to examine the relationship between demographic characteristics and performance in the LIT-AD. The scores of the CI users were used to estimate the probability of superior performance with CIs for a non-CI user having a given LIT-AD score and duration of hearing loss.Results:The LIT-AD comprises 81 pairs of vowel–consonant–vowel syllables that were equalized in difficulty to discriminate. The test can be self-administered on a tablet computer, and it takes about 10 min to complete. The software automatically scores the responses and gives an overall score and a list of confusable items as output. There was good test–retest reliability. On average, higher LIT-AD discrimination scores were associated with better sentence perception for users of HAs (r = −0.54, p <0.001) and users of CIs (r = −0.73, p <0.001). The probability of superior performance with CIs for a certain LIT-AD score was estimated, after allowing for the effect of duration of hearing loss.Conclusions:The LIT-AD could increase access to CIs by screening for those who obtain limited benefits from HAs to facilitate timely referrals for CI candidacy evaluation. The test results can be used to provide patients and professionals with practical information about the probability of potential benefits for speech perception from cochlear implantation. The test will need to be evaluated for speakers of languages other than English to facilitate adoption in different countries.