Relationship between IDDSI Flow Test and Consistometric Measures for Consistency Classification - An Examination of Thickened Liquids Prepared Using Starch-Based and Xanthan Gum-Based Thickening Agents.

INTRODUCTION: Consistency of liquid food plays an important role in managing patients with dysphagia, which can be objectively evaluated by using IDDSI Flow Test and consistometry. The present study established the relationship between IDDSI Flow Test and consistometric measures, and examined the measurement limitations of each test associated with thickened liquids prepared using starch-based and xanthan gum-based thickening agents. METHODS: Thirteen thickened liquid samples of consistency ranging from IDDSI Level 1 (mildly thick) to Level 3 (moderately thick) were prepared using starch-based and xanthan gum-based thickeners. IDDSI Flow Test and consistometric measures were obtained and analyzed using correlation and regression. RESULTS: A strong correlation was observed between both tests. Regression analyses revealed a linear and a quadratic relationship between IDDSI Flow Test and consistometric measurements, respectively. CONCLUSION: Starch-based and xanthan gum-based thickeners exhibited different relationships between IDDSI Flow Test and consistometric measurements. Findings allow easy conversion and adaptation of consistometric measures to the IDDSI framework, which renders the use of consistometry in the clinical settings as a complementary quantitative measurement of liquid consistency to IDDSI Flow Test.

An acoustic study of Cantonese alaryngeal speech in different speaking conditions.

Esophageal (ES) speech, tracheoesophageal (TE) speech, and the electrolarynx (EL) are common methods of communication following the removal of the larynx. Our recent study demonstrated that intelligibility may increase for Cantonese alaryngeal speakers using clear speech (CS) compared to their everyday "habitual speech" (HS), but the reasoning is still unclear [Hui, Cox, Huang, Chen, and Ng (2022). Folia Phoniatr. Logop. 74, 103-111]. The purpose of this study was to assess the acoustic characteristics of vowels and tones produced by Cantonese alaryngeal speakers using HS and CS. Thirty-one alaryngeal speakers (9 EL, 10 ES, and 12 TE speakers) read The North Wind and the Sun passage in HS and CS. Vowel formants, vowel space area (VSA), speaking rate, pitch, and intensity were examined, and their relationship to intelligibility were evaluated. Statistical models suggest that larger VSAs significantly improved intelligibility, but slower speaking rate did not. Vowel and tonal contrasts did not differ between HS and CS for all three groups, but the amount of information encoded in fundamental frequency and intensity differences between high and low tones positively correlated with intelligibility for TE and ES groups, respectively. Continued research is needed to understand the effects of different speaking conditions toward improving acoustic and perceptual characteristics of Cantonese alaryngeal speech.

Acoustic characteristics associated with liquid swallowing sounds of different bolus consistencies in young healthy adults.

BACKGROUND: Cervical auscultation has been used clinically as an augmentative procedure for swallow examination. Despite its frequent use for screening and preliminary assessment of swallowing, the usefulness of cervical auscultation is controversial due to a lack of sufficient research, particularly in quantifying swallowing sounds. AIMS: To document the acoustic characteristics of normal swallowing sound associated with swallowing bolus of different consistencies among younger healthy adults. METHODS & PROCEDURES: A total of 30 healthy young adult participants swallowed 5 ml thickened liquids of four different consistencies (slightly thick, mildly thick, moderately thick and extremely thick) prepared using a starch-based commercial thickener, and the corresponding swallowing sounds were recorded using a wireless accelerometric stethoscope. An array of acoustic measures including duration of swallowing sound (DSS), duration to peak intensity (DPI), frequency at peak intensity (FPI), peak intensity (PI), average intensity (AI), and difference between peak and average intensity (DPAI) values associated with the swallowing signals were obtained. OUTCOMES & RESULTS: In general, increased durational measures of the swallowing sounds were associated with an increase in bolus consistency. Intensity measures including PI, AI and DPAI were found to be stable across different consistencies. The change in FPI did not appear to be particularly meaningful due to its high variability. In addition, no significant differences were observed between men and women. CONCLUSIONS & IMPLICATIONS: Swallow sounds associated with different bolus consistencies could be quantified and used to differentiate consistencies. The present findings could serve as a reference for future swallowing research of normal and dysphagic population. WHAT THIS PAPER ADDS: What is already known on the subject Cervical auscultation using traditional stethoscope has been used as part of an informal clinical swallow examination by practitioners. Validity of cervical auscultation is controversial, possibly due to the lack of normative data on swallow sounds. What this paper adds to existing knowledge The present study explored the possibility of using wireless accelerometric stethoscopy for cervical auscultation for dysphagia screening. Acoustic profiles of swallow sounds associated with boluses of different consistencies in healthy individuals were examined. What are the potential or actual clinical implications of this work? Findings contribute to our knowledge about the acoustic characteristics of swallow sounds of boluses of different consistencies in healthy young individuals. The study provides normative clinical data on cervical auscultation using wireless accelerometric stethoscope for normal swallow.

How Accurate Are the Consistency Labels Used in Hong Kong? An Objective Study of the Consistency of Thickened Liquids Using International Dysphagia Diet Standardisation Initiative and Consistometric Measurements.

OBJECTIVES: The present study objectively examined the consistency (thickness) of labels that are used in Hong Kong for the population with dysphagia using an International Dysphagia Diet Standardisation Initiative (IDDSI) flow test and Bostwick consistometric measurements. METHODS: Liquids were prepared by thickening water to achieve 4 consistency labels (slightly thick, mildly thick, medium thick, and extra thick) according to manufacturer's instructions, employing 2 types of thickening products that are used in Hong Kong, i.e., starch based and gum based. For each consistency label prepared using each thickening product, the IDDSI flow test and consistometric measurements were obtained and compared. RESULTS: The results showed that the actual thickness of liquids was highly dependent on the type of thickener (starch based vs. gum based) used. Thickened liquids prepared using the starch-based thickener were generally thinner than the actual value at a lower concentration. CONCLUSION: Though prepared strictly following the manufacturer's instructions, the thickened liquids fail to faithfully correlate with the standardized norms established according to the IDDSI framework and the objective consistometric measurement using a Bostwick consistometer. Therefore, caution must be exercised when administering a thickened diet following the manufacturer's instructions for patients with dysphagia.

Articulatory Contact Pressure during Bilabial Plosive Production in Esophageal and Tracheoesophageal Speech.

OBJECTIVES: The present study investigated the articulatory contact pressure during the production of bilabial plosives by esophageal (ES), tracheoesophageal (TE), and laryngeal speakers. METHODS: The peak contact pressure (PCP) during bilabial plosive production of /CVCVCVCVCV/ syllable strings of /p/ and /ph/ was obtained from 10 ES, 10 TE, and 10 laryngeal speakers of Cantonese. PCP values were obtained by using a pressure transduction system (Iowa Oral Performance Instrument) during speech production. RESULTS: The results showed that ES speakers exhibited a significantly greater PCP value than TE and laryngeal speakers, as revealed by cheek muscle compression force. In addition, the unaspirated bilabial plosive /p/ was associated with a greater PCP than its aspirated counterpart /ph/. CONCLUSION: The current findings might support the hypothesis of over-exaggerated speech for better intelligibility among alaryngeal speakers. In addition, the increased oral muscular effort could be associated with a compensatory strategy for maintaining a high intraoral pressure or the unique air intake by ES speakers.

A Volumetric Analysis of the Vocal Tract Associated with Laryngectomees Using Acoustic Reflection Technology.

OBJECTIVE: Previous studies of the laryngectomized vocal tract using formant frequencies reported contradictory findings. Imagining studies of the vocal tract in alaryngeal speakers are limited due to the possible radiation effect as well as the cost and time associated with the studies. The present study examined the vocal tract configuration of laryngectomized individuals using acoustic reflection technology. SUBJECTS AND METHODS: Thirty alaryngeal and 30 laryngeal male speakers of Cantonese participated in the study. A pharyngometer was used to obtain volumetric information of the vocal tract. All speakers were instructed to imitate the production of /a/ when the length and volume information of the oral cavity, pharyngeal cavity, and the entire vocal tract were obtained. The data of alaryngeal and laryngeal speakers were compared. RESULTS: Pharyngometric measurements revealed no significant difference in the vocal tract dimensions between laryngeal and alaryngeal speakers. CONCLUSION: Despite the removal of the larynx and a possible alteration in the pharyngeal cavity during total laryngectomy, the vocal tract configuration (length and volume) in laryngectomized individuals was not significantly different from laryngeal speakers. It is suggested that other factors might have affected formant measures in previous studies.

Designing, implementing and evaluating an online problem-based learning (PBL) environment--a pilot study.

Problem-based learning (PBL) has been shown to be effective for promoting student competencies in self-directed and collaborative learning, critical thinking, self-reflection and tackling novel situations. However, the need for face-to-face interactions at the same place and time severely limits the potential of traditional PBL. The requirements of space and for meeting at a specific location at the same time create timetabling difficulties. Such limitations need to be tackled before all potentials of PBL learning can be realized. The present study aimed at designing and implementing an online PBL environment for undergraduate speech/language pathology students, and assessing the associated pedagogical effectiveness. A group of eight PBL students were randomly selected to participate in the study. They underwent 4 weeks of online PBL using Adobe Connect. Upon completion of the experiment, they were assessed via a self-reported questionnaire and quantitative comparison with traditional PBL students based on the same written assignment. The questionnaire revealed that all participating students enjoyed online PBL, without any perceived negative effects on learning. Online PBL unanimously saved the students travel time to and from school. Statistical analysis indicated no significant difference in assignment grades between the online and traditional PBL groups, indicating that online PBL learning appears to be similarly effective as traditional face-to-face PBL learning.

Effect of Face Masks on Voice Quality Associated with Young and Older Chinese Adult Speakers.

OBJECTIVES: Face masks have become important after the pandemic, but the change in voice when wearing a face mask is still unclear. The study investigated the effect of face masks on the acoustic and perceptual characteristics of voice quality associated with young and older Chinese adults. METHODS: Voice samples of the sustained vowel /a/ and continuous speech produced by 44 older and 61 young adults with and without an ASTM level-3 surgical face mask were recorded and analyzed. Perceptual and acoustic parameters including mean fundamental frequency (F0) and intensity, perturbation measures (jitter and shimmer), harmonic-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPs), and long-term average spectrum (LTAS) measures were obtained and compared. RESULTS: When comparing masked to unmasked voices, for both male and female speakers, F0 and intensity showed no significant changes, except for F0 of continuous speech, which increased significantly. Meanwhile, perturbation measures such as jitter and shimmer were reduced, while HNR and CPPs increased. In addition, LTAS measures included low-frequency mean spectral energy (MSE), high-frequency MSE, and spectral tilt (ST), which were different. For perceptual measures, the overall grade of dysphonia, and roughness were reduced, except for the breathiness among older male speakers, while the other vocal qualities were not changed. Between young and older speakers, significant differences in shimmer, CPPs, and perceived breathiness among male speakers, and low-frequency MSE among female speakers were found. CONCLUSION: Wearing a surgical mask appeared to change the perceived voice quality. This is supported by the change in perturbation and LTAS measures, and HNR and CPPs values. In addition, some differences between young and older adults were observed. Oral Communication effectiveness may be affected when wearing surgical masks due to changes in voice quality. Additionally, clinicians need to exercise hightened caution in evaluating the voice quality of clients when wearing face masks.

Is visual gaze in children with autism spectrum disorder related to sequence of emotion intensity presentation? An eye-tracking study of natural emotion perception processes.

Emotion cognitive remediation is a critical component of social skills training for children with autism spectrum disorder (ASD). Visual perception of emotions is highly correlated with the intensity and sequence of presented emotions. However, few studies examined the effect of presentation sequence and intensity on emotion perception. The present study examined the gaze patterns of children with ASD in receiving different sequences of emotion presentation using eye-tracking technologies. Gaze patterns of ecologically-valid video clips of silent emotion stimuli by 51 ASD children and 34 typically developing (TD) children were recorded. Results indicated that ASD and TD children showed opposite visual fixation during different intensity presentation modes: children with ASD showed better emotion perception with a weak-to-strong emotion sequence when presented. The visual reductions in emotion perception in children with ASD may due to different perceptual threshold to emotional intensity. The extent of the reductions could be related to an individual's Personal-Social ability. The present study supports the importance of intensity of emotions and the order at which the emotional stimuli were presented in yielding better emotion perceptions in children with ASD, suggesting that the order of emotion presentation may potentially influence emotion processing during ASD rehabilitation. It is anticipated that the present findings could bring more insights to clinicians for intervention planning in the future.

Pitch control in esophageal and tracheoesophageal speech of Cantonese.

OBJECTIVE: Previous studies of English-speaking esophageal (SE) and tracheoesophageal (TE) speakers revealed a significantly lower voice fundamental frequency (F0) than normal laryngeal (NL) speakers. Studies of SE and TE speakers of a tone language, however, indicated discrepant findings. Tonal SE and TE speakers could produce comparable or even higher F0 than NL speakers. The present study examined the F0 characteristics associated with speech and nonspeech tasks produced by Cantonese SE and TE speakers. SUBJECTS AND METHODS: Speech produced by 15 superior SE, 15 superior TE and 15 NL speakers was recorded while each was reading a short passage and performing a pitch scaling task. F0 values were calculated from the speech samples. RESULTS: SE speakers had higher average F0 in reading tasks than TE and NL speakers, while the NL speakers exhibited the highest average F0 values followed by SE and TE speakers during pitch scaling. In addition, pitch scaling (nonspeech) tasks were associated with higher average F0 than passage reading tasks regardless of speaker type. CONCLUSION: The findings point to the fact that, despite the use of the new sound source, SE and TE speakers were still able to change F0 for specific speech tasks.

Analyzing neoglottal vibration of Cantonese tracheoesophageal speech: preliminary aerodynamic study using inverse filtering.

OBJECTIVE: Despite the many studies on tracheoesophageal (TE) speech, the actual vibratory characteristics of the neoglottis in TE speech are not known. The present study examined the neoglottal vibratory pattern of Cantonese TE speakers by comparison with the glottal waveform produced by laryngeal speakers. SUBJECTS AND METHODS: Eight superior TE and 8 laryngeal speakers of Cantonese participated in the study. All speakers were instructed to produce the vowels /i, œ, a, [see text], u/ 3 times, and both acoustic and aerodynamic signals were recorded. While the airflow signals were later inverse-filtered to obtain the neoglottal and glottal waveforms, the acoustic signals were analyzed to obtain vowel formants, which were used as inputs to inverse filtering. Aerodynamic parameters including open quotient (OQ), speed quotient (SQ), and area under the curve (AUC) were compared between TE and laryngeal speakers. - RESULTS: RESULTS revealed that TE speakers exhibited comparable OQ and AUC, but significantly reduced SQ when compared with laryngeal speakers. CONCLUSIONS: Both inverse-filtered airflow signals associated with TE and laryngeal speech of Cantonese appear to be triangular in shape, indicating the opening, closing and closed phases of the (neo)glottis. However, neoglottal waveforms are highly variable. Such variability and inconsistency in neoglottal waveforms might be related to the lack of complete control over the neoglottis in TE speakers.

Transcranial direct current stimulation over the primary motor cortex improves speech production in post-stroke dysarthric speakers: A randomized pilot study.

PURPOSE: The current study investigated the therapeutic potential of transcranial direct current stimulation (tDCS) on speech intelligibility, speech-related physiological and vocal functions among post-stroke dysarthric patients. METHOD: Nine chronic post-stroke dysarthric patients were randomly assigned to the stimulation or sham group. The stimulation group received 2mA of anodal tDCS over the left inferior primary motor cortex for 15 minutes, while the sham group received 30s of stimulation under the same settings. All the participants received 10 daily 15 minutes of individualized speech therapy targeting their dominant phonological process or phonemes with the greatest difficulty. The outcome measures included (1) perceptual analysis of single words, passage reading and diadochokinetic rate, (2) acoustic analysis of a sustained vowel, and (3) kinematic analysis of rapid syllable repetitions and syllable production in sentence, conducted before and after the treatment. RESULTS: The results revealed that both the stimulation and sham groups had improved perceptual speech intelligibility at the word level, reduced short rushes of speech during passage reading, improved rate during alternating motion rate, AMR-kha1, and improved articulatory kinematics in AMR-tha1 and syllables /tha1/ and /kha1/ production in sentence. Compared to the sham group, the stimulation group showed significant improvement in articulatory kinematics in AMR-kha1 and syllable /kha1/ production in sentence. The findings also showed that anodal stimulation led to reduced shimmer value in sustained vowel /a/ phonation, positive changes in articulatory kinematics in AMR-tha1 and syllables /pha1/ and /kha1/ production in sentence at the post treatment measure. In addition to positive effects on articulatory control, reduced perturbation of voice amplitude documented in the stimulation group post treatment suggests possible tDCS effects on the vocal function. CONCLUSIONS: The current study documented the beneficial effects of anodal tDCS over the primary motor cortex on speech production and suggested that combined tDCS and speech therapy may promote recovery from post-stroke dysarthria.

The use of the Lombard Effect in Improving Alaryngeal Speech.

OBJECTIVE: The present study examined and compared the Lombard effect among laryngeal and alaryngeal speakers including esophageal, tracheoesophageal, pneumatic artificial laryngeal, electrolaryngeal speakers of Cantonese. The subsequent change in intelligibility was also examined. METHODS: A total of 52 native Cantonese-speaking laryngeal and alaryngeal speakers (10 laryngeal , 8 laryngeal , 13 electrolaryngeal , 11 esophageal, and 10 tracheoesophageal) participated in a reading task involving three 10-syllable Cantonese sentences under 10 background conditions: quiet, 60 dB, 65 dB, 70 dB, 75 dB, 80 dB, 85 dB, 90 dB, 95 dB, and 100 dB white background noise. Speech intelligibility associated with speaking conditions were evaluated by five naïve Cantonese speakers. RESULTS: Output intensity was significantly increased in all speaker types under all nine noisy background conditions when compared with the quiet condition. However, the amount of increase was different for different modes of phonation. In addition, significant difference in speech intelligibility between laryngeal and alaryngeal speakers was found at all conditions, but not among any alaryngeal speech. DISCUSSION AND CONCLUSION: The Lombard reflex is still present after total laryngectomy. Yet, different alaryngeal speech was associated with different amount of loudness change, and subsequent improvement in intelligibility was not observed.

Effect of total laryngectomy on vowel production: An acoustic study of vowels produced by alaryngeal speakers of Cantonese.

Purpose: To investigate the effect of total laryngectomy on vowel production, the present study examined the change in vowel articulation associated with different types of alaryngeal speech in comparison with laryngeal speech using novel derived formant metrics.Method: Six metrics derived from the first two formants (F1 and F2) including the First and Second Formant Range Ratios (F1RR and F2RR), triangular and pentagonal Vowel Space Area (tVSA and pVSA), Formant Centralisation Ratio (FCR) and Average Vowel Spacing (AVS) were measured from vowels (/i, y, ɛ, a, ɔ, œ, u/) produced by oesophageal (ES), tracheoesophageal (TE), electrolaryngeal (EL), pneumatic artificial laryngeal (PA) speakers, as well as laryngeal speakers.Result: Data revealed a general reduction in articulatory range and a tendency of vowel centralisation in Cantonese alaryngeal speakers. Significant articulatory difference was found for PA and EL compared with ES, TE, and laryngeal speakers.Conclusion: The discrepant results among alaryngeal speakers may be related to the difference in new sound source (external vs internal). Sensitivity and correlation analyses confirmed the use of the matrix of derived formant metrics provided a more comprehensive profile of the articulatory pattern in the alaryngeal population.

Cultural Adaptation and Validation of Speech Handicap Index: A Scoping Review.

Objectives The Speech Handicap Index (SHI) is a self-reported speech-related quality of life assessment originally developed for measuring the psychosocial speech impact in patients with oral or pharyngeal cancer. This review article provides a scoping review of the literature on the validated SHI, with the purpose of identifying and documenting available studies and procedures for the cultural adaption and validation of SHI. Method Prime databases including PubMed, EMBASE, and Google Scholar were searched for journal publications reporting validation of the SHI. Reviews and reference cross-checking were performed using a priori selection criteria. A body of literature related to SHI was scoped and publication quality was categorized independently by two investigators. After applying all the screening criteria, articles that met the eligibility criteria were included in the review. Results The scoping review yielded 10 articles that met the inclusion criteria presenting the SHI in eight different languages, including Dutch, U.K. English, French, Korean, Simplified Chinese (Mandarin), Lithuanian, Italian, and European Portuguese. All of them reported validity, reliability, and translation method. Discussion and Conclusions High reliability and validity between various language versions of the SHI were identified. The current scoping review provides a useful summary and could be a helpful precursor to a systematic review on SHI in the future. Supplemental Material https://doi.org/10.23641/asha.14082704.

Rabeprazole is effective in treating laryngopharyngeal reflux in a randomized placebo-controlled trial.

BACKGROUND & AIMS: There is controversy about the efficacy of treating patients with laryngopharyngeal reflux (LPR) using proton pump inhibitors (PPIs). We assessed the effects of high doses of the PPI rabeprazole in patients with LPR. METHODS: Patients with LPR symptoms were assigned randomly to receive rabeprazole (20 mg, twice daily, n = 42) or placebo (n = 40) for 12 weeks. All patients completed symptom questionnaires; these provided demographic information and the reflux symptom index before, during, and 6 weeks after cessation of treatment. Videolaryngostroboscopy was used to document the laryngeal findings and determine the reflux finding score. RESULTS: Twenty-four patients (57.1%) in the rabeprazole group and 27 patients (67.5%) in the placebo group had pH-documented LPR. The total reflux symptom index score decreased significantly in the group given rabeprazole, compared with patients given placebo, at weeks 6 and 12, but not at week 18. However, there were no significant differences in reflux finding scores between the rabeprazole and placebo groups at any of the time points. CONCLUSIONS: Twelve weeks of treatment with rabeprazole (20 mg, twice daily) significantly improved reflux symptoms, compared with placebo, in patients with LPR. Relapse of symptoms was observed 6 weeks after stopping PPI therapy, indicating the requirement for longer treatment duration in patients with LPR.

Quality of life in patients with laryngopharyngeal reflux.

BACKGROUND: Laryngopharyngeal reflux (LPR) disease is an extraesophageal manifestation of gastroesophageal reflux disease (GERD). The impact of GERD-related LPR on the psychological well-being and quality of life (QOL) in Chinese is not known. AIM: To assess the QOL in patients with LPR disease. METHODS: 76 LPR and 73 healthy subjects were recruited. Psychological well-being was assessed by the Hospital Anxiety and Depression Score and QOL was assessed by SF-36. RESULTS: 51/76 (67.1%) patients had GERD-related LPR. More LPR subjects had taken sick leave (36.2 vs. 5.6%, p = 0.001) and reported adverse social life impact (60.5 vs. 38.9%, p = 0.013). LPR patients showed significantly worse results on the Voice Handicap Index (47.8 vs. 7.6, p = 0.001), were more anxious and had worse QOL in social functioning, pain and general health perception domains of SF-36. GERD-related LPR subjects had a higher depression score (4.8 vs. 3.8, p = 0.014) and a lower mental summary score (41.8 vs. 48.4, p = 0.01) in SF-36 compared with those without GERD. CONCLUSIONS: LPR had a negative impact on psychological status, social functioning and QOL. GERD symptoms appeared to be the main contributor to decrease QOL. GERD-related LPR patients had a significant impact on the mental component of their QOL.

Voice onset time characteristics of esophageal, tracheoesophageal, and laryngeal speech of Cantonese.

PURPOSE: To investigate the ability of standard esophageal (SE) and tracheoesophageal (TE) speakers of Cantonese to differentiate between aspirated and unaspirated stops produced at 3 places of articulation were investigated. METHOD: Six Cantonese stops, /p, t, k, p(h), t(h), k(h)/, followed by the vowel /a/ produced by 10 SE, TE, and normal laryngeal (NL) speakers were examined through perceptual tasks and voice onset time (VOT) analysis. RESULTS: Perceptual experiments showed lower accuracy of identification of stops produced by SE and TE than by NL speakers, with mostly misidentification of aspirated stops as their unaspirated counterparts. Acoustic analysis revealed that aspirated stops produced by NL, SE, and TE speakers were associated with significantly longer VOT values than their unaspirated counterparts. Unaspirated velar stops showed significantly longer VOT than bilabial and alveolar stops in NL and SE speech. SE and TE speakers were still able to use VOT to signal aspiration contrast, but TE was unable to differentiate among different places of articulation.

An acoustical and perceptual study of vowels produced by alaryngeal speakers of Cantonese.

OBJECTIVE: The present study determines the acoustical and perceptual differences between alaryngeal and laryngeal speakers of Cantonese in the production of Cantonese vowels. SUBJECTS AND METHODS: Formant frequencies (F1 and F2) associated with eight Cantonese vowels [see text] produced by 40 alaryngeal (10 esophageal, 10 tracheoesophageal, 10 with pneumatic artificial larynx, 10 electrolaryngeal) and 10 laryngeal speakers were obtained. To assess how formants affect vowel perception, the vowels were identified by 20 naïve listeners, based on which confusion matrices were established. RESULTS: Spectral analysis revealed that F1 and F2 values of Cantonese vowels produced by the alaryngeal speakers were significantly higher than those produced by laryngeal speakers, with the exception of F2 of [see text], /i/ and /y/ produced by alaryngeal speakers using pneumatic artificial larynx, and [see text] produced by electrolaryngeal speakers. CONCLUSION: The acoustic findings suggest a general shortening of the effective vocal tract length for resonance in alaryngeal speakers after laryngectomy. Percent correct identification of vowels from the perceptual experiment indicated similar error patterns in vowel identification between alaryngeal and laryngeal speaker groups. Among the different alaryngeal speaker groups, naïve listeners tended to perceive the vowels produced by electrolaryngeal speakers more accurately.

The Lombard effect associated with Chinese male alaryngeal speech.

Objective: Alaryngeal speech shows marked reduction in vocal intensity, resulting in reduced intelligibility. Lombard effect, speaking with background noise has been found to boost speakers' intensity. The study investigated oesophageal (ES), tracheoesophageal (TE) and electrolaryngeal (EL) speech production under quiet and noisy background conditions to determine if the Lombard effect is still present after laryngectomy.Method: Fifteen laryngeal and thirty-seven alaryngeal speakers who were native speakers of Cantonese were recruited and instructed to read aloud a Cantonese passage under two background conditions: quiet and 100 dB background noise conditions.Result: Significant increase in vocal intensity was found in all speaker types under the noise condition. In addition, perceived intelligibility ratings provided by naïve Cantonese listeners revealed that the overall intelligibility under noise was improved for TE and laryngeal speakers, but not for ES and EL speakers, when compared with quiet condition.Discussion and conclusion: Results confirmed that the Lombard effect is still present after total laryngectomy. However, intelligibility may not always be improved with increased vocal loudness. Improved intelligibility was only observed for TE and laryngeal speakers, but not ES and EL speakers. Clinical implications for the use of the Lombard effect in post-laryngectomy speech rehabilitation are discussed.