Automated assessment of hyoid movement during normal swallow using ultrasound.

BACKGROUND: The potential for using ultrasound by speech and language therapists (SLTs) as an adjunct clinical tool to assess swallowing function has received increased attention during the COVID-19 pandemic, with a recent review highlighting the need for further research on normative data, objective measurement, elicitation protocol and training. The dynamic movement of the hyoid, visible in ultrasound, is crucial in facilitating bolus transition and protection of the airway during a swallow and has shown promise as a biomarker of swallowing function. AIMS: To examine the kinematics of the hyoid during a swallow using ultrasound imaging and to relate the patterns to the different stages of a normal swallow. To evaluate the accuracy and robustness of two different automatic hyoid tracking methods relative to manual hyoid position estimation. METHODS & PROCEDURES: Ultrasound data recorded from 15 healthy participants swallowing a 10 ml water bolus delivered by cup or spoon were analysed. The movement of the hyoid was tracked using manually marked frame-to-frame positions, automated hyoid shadow tracking and deep neural net (DNN) tracking. Hyoid displacement along the horizontal image axis (HxD) was charted throughout a swallow, and the maximum horizontal displacement (HxD max) and maximum hyoid velocity (HxV max) along the same axis were automatically calculated. OUTCOMES & RESULTS: The HxD and HxV of 10 ml swallows are similar to values reported in the literature. The trajectory of the hyoid movement and its location at significant swallow event time points showed increased hyoid displacement towards the peak of the swallow. Using an interclass correlation coefficient, HxD max and HxV max values derived from the DNN tracker and shadow tracker are shown to be in high agreement and moderate agreement, respectively, when compared with values derived from manual tracking. CONCLUSIONS & IMPLICATIONS: The similarity of the hyoid tracking results using ultrasound to previous reports based on different instrumental tools supports the possibility of using hyoid movement as a measure of swallowing function in ultrasound. The use of machine learning to automatically track the hyoid movement potentially provides a reliable and efficient way to quantify swallowing function. These findings contribute towards improving the clinical utility of ultrasound as a swallowing assessment tool. Further research on both normative and clinical populations is needed to validate hyoid movement metrics as a means of differentiating normal and abnormal swallows and to verify the reliability of automatic tracking. WHAT THIS PAPER ADDS: What is already known on this subject There is growing interest in the use of ultrasound as an adjunct tool for assessing swallowing function. However, there is currently insufficient knowledge about the patterning and timing of lingual and hyoid movement in a typical swallow. We know that movement of the hyoid plays an essential role in bolus transition and airway protection. However, manual tracking of hyoid movement is time-consuming and restricts the extent of large-scale normative studies. What this study adds We show that hyoid movement can be tracked automatically, providing measurable continuous positional data. Measurements derived from this objective data are comparable with similar measures previously reported using videofluoroscopy and of the two automatic trackers assessed, the DNN approach demonstrates better robustness and higher agreement with manually derived measures. Using this kinematic data, hyoid movement can be related to different stages of swallowing. Clinical implications of this study This study contributes towards our understanding of the kinematics of a typical swallow by evaluating an automated hyoid tracking method, paving the way for future studies of typical and disordered swallow. The challenges of image acquisition highlight issues to be considered when establishing clinical protocols. The application of machine learning enhances the utility of ultrasound swallowing assessment by reducing the labour required and permitting a wider range of hyoid measurements. Further research in normative and clinical populations is facilitated by automatic data extraction allowing the validity of prospective hyoid measures in differentiating different types of swallows to be rigorously assessed.

Translating Ultrasound into Clinical Practice for the Assessment of Swallowing and Laryngeal Function: A Speech and Language Pathology-Led Consensus Study.

Ultrasound (US) has an emerging evidence base for the assessment of swallowing and laryngeal function. Accessibility and technological advances support the use of US as a clinical assessment tool; however, there is insufficient evidence to support its translation into clinical practice. This study aimed to establish consensus on the priorities for translation of US into clinical practice for the assessment of swallowing and laryngeal function. Nominal Group Technique (NGT) was used as a formal method of consensus development. Clinicians and academics, all members of an international US working group, were invited to participate in the study. Two NGT meetings were held, where participants silently generated and then shared ideas. Participants anonymously ranked items. Rankings were aggregated before participants re-ranked items in order of priority. Discussions regarding rankings were recorded and transcribed to inform analysis. Member-checking with participants informed the final analysis. Participants (n = 15) were speech and language pathologists, physiotherapists and sonographers representing six countries. Fifteen items were identified and prioritised 1-13 (including two equally ranked items). Reliability, validity and normative data emerged as key areas for research while development of training protocols and engagement with stakeholders were considered vital to progressing US into practice. Analysis revealed common themes that might be addressed together in research, in addition to the ranked priority. A measured approach to the translation of US into clinical practice will enable effective implementation of this tool. Priorities may evolve as clinical and professional contexts shift, but this study provides a framework to advance research and clinical practice in this field.

The perception of intonation questions and statements in Cantonese.

In tone languages there are potential conflicts in the perception of lexical tone and intonation, as both depend mainly on the differences in fundamental frequency (F0) patterns. The present study investigated the acoustic cues associated with the perception of sentences as questions or statements in Cantonese, as a function of the lexical tone in sentence final position. Cantonese listeners performed intonation identification tasks involving complete sentences, isolated final syllables, and sentences without the final syllable (carriers). Sensitivity (d' scores) were similar for complete sentences and final syllables but were significantly lower for carriers. Sensitivity was also affected by tone identity. These findings show that the perception of questions and statements relies primarily on the F0 characteristics of the final syllables (local F0 cues). A measure of response bias (c) provided evidence for a general bias toward the perception of statements. Logistic regression analyses showed that utterances were accurately classified as questions or statements by using average F0 and F0 interval. Average F0 of carriers (global F0 cue) was also found to be a reliable secondary cue. These findings suggest that the use of F0 cues for the perception of intonation question in tonal languages is likely to be language-specific.

Intonation contrast in Cantonese speakers with hypokinetic dysarthria associated with Parkinson's disease.

PURPOSE: Speech produced by individuals with hypokinetic dysarthria associated with Parkinson's disease (PD) is characterized by a number of features including impaired speech prosody. The purpose of this study was to investigate intonation contrasts produced by this group of speakers. METHOD: Speech materials with a question-statement contrast were collected from 14 Cantonese speakers with PD. Twenty listeners then classified the productions as either questions or statements. Acoustic analyses of F0, duration, and intensity were conducted to determine which acoustic cues distinguished the production of questions from statements, and which cues appeared to be exploited by listeners in identifying intonational contrasts. RESULTS: The results show that listeners identified statements with a high degree of accuracy, but the accuracy of question identification ranged from 0.56% to 96% across the 14 speakers. The speakers with PD used similar acoustic cues as nondysarthric Cantonese speakers to mark the question-statement contrast, although the contrasts were not observed in all speakers. Listeners mainly used F0 cues at the final syllable for intonation identification. CONCLUSION: These data contribute to the researchers' understanding of intonation marking in speakers with PD, with specific application to the production and perception of intonation in a lexical tone language.

Dysprosody and stimulus effects in Cantonese speakers with Parkinson's disease.

BACKGROUND: Dysprosody is a common feature in speakers with hypokinetic dysarthria. However, speech prosody varies across different types of speech materials. This raises the question of what is the most appropriate speech material for the evaluation of dysprosody. AIMS: To characterize the prosodic impairment in Cantonese speakers with hypokinetic dysarthria associated with Parkinson's disease, and to determine the effect of different types of speech stimuli on the perceptual rating of prosody. METHODS & PROCEDURES: Speech data in the form of sentence reading, passage reading, and monologue were collected from ten Cantonese speakers with Parkinson's disease. Perceptual analysis was conducted on ten prosodic parameters to evaluate five dimensions of prosody, based on a theoretical framework: pitch, loudness, duration, voice quality, and degree of reduction. OUTCOMES & RESULTS: The results showed that the most severely affected prosodic parameters were monopitch, harsh voice, and monoloudness, followed by breathy voice and prolonged interval. Differences were noted between speakers with mild and moderate dysprosody. No statistically significant differences were found between the three types of stimuli. However, qualitative analysis revealed noticeable differences between the three stimuli in two speakers. CONCLUSIONS & IMPLICATIONS: The prosodic profile of Cantonese speakers with hypokinetic dysarthria is similar to those of other languages (for example, English). The involvement of two new dimensions in the definition of prosody (voice quality and degree of reduction) provides additional insight in differentiating patients with mild and moderate dysarthria. Further investigation on the use of speech materials in the clinical evaluation of speech prosody in speakers with dysarthria is needed, as no single task was found to represent a patient's performance under all circumstances.

Effect of intonation on cantonese lexical tones.

In tonal languages, there are potential conflicts between the FO-based changes due to the coexistence of intonation and lexical tones. In the present study, the interaction of tone and intonation in Cantonese was examined using acoustic and perceptual analyses. The acoustic patterns of tones at the initial, medial, and final positions of questions and statements were measured. Results showed that intonation affects both the FO level and contour, while the duration of the six tones varied as a function of positions within intonation contexts. All six tones at the final position of questions showed rising FO contour, regardless of their canonical form. Listeners were overall more accurate in the identification of tones presented within the original carrier than of the same tones in isolation. However, a large proportion of tones 33, 21, 23, and 22 at the final position of questions were misperceived as tone 25 both within the original carrier and as isolated words. These results suggest that although the intonation context provided cues for correct tone identification, the intonation-induced changes in FO contour cannot always be perceptually compensated for, resulting in some erroneous perception of the identity of Cantonese tone.

Perceptual characteristics of Cantonese hypokinetic dysarthria.

The aims of this study were to provide a perceptual speech 'profile' for Cantonese speakers with hypokinetic dysarthria, to examine the reliability of non-expert listeners in perceptual judgements of dysarthric speech, and to investigate cross-language differences in profiles of hypokinetic dysarthria. Participants included 19 speakers with Parkinson's disease and 10 speech-language pathologists who served as listeners. Listeners rated 21 speech dimensions, using seven-point interval scales. Mean intralistener agreement was 94.52% and mean interlistener reliability was 0.88 (Cronbach's alpha). Mean scale values (MSV) for each dimension ranged from 3.37 to 1.36. The perceptual profile of Cantonese hypokinetic dysarthria was largely similar to profiles for English and Japanese speakers; notable differences are discussed. Possible reasons for the relatively high reliability obtained are presented.