Thyroid cartilage loci and hyoid bone analysis using a video fluoroscopic swallowing study (VFSS)

Prediction of dysphagia aspiration through machine learning-based analysis of patients' postprandial voices

BACKGROUND

Conventional diagnostic methods for dysphagia have limitations such as long wait times, radiation risks, and restricted evaluation. Therefore, voice-based diagnostic and monitoring technologies are required to overcome these limitations. Based on our hypothesis regarding the impact of weakened muscle strength and the presence of aspiration on vocal characteristics, this single-center, prospective study aimed to develop a machine-learning algorithm for predicting dysphagia status (normal, and aspiration) by analyzing postprandial voice limiting intake to 3 cc.

METHODS

Conducted from September 2021 to February 2023 at Seoul National University Bundang Hospital, this single center, prospective cohort study included 198 participants aged 40 or older, with 128 without suspected dysphagia and 70 with dysphagia-aspiration. Voice data from participants were collected and used to develop dysphagia prediction models using the Multi-Layer Perceptron (MLP) with MobileNet V3. Male-only, female-only, and combined models were constructed using 10-fold cross-validation. Through the inference process, we established a model capable of probabilistically categorizing a new patient's voice as either normal or indicating the possibility of aspiration.

RESULTS

The pre-trained models (mn40_as and mn30_as) exhibited superior performance compared to the non-pre-trained models (mn4.0 and mn3.0). Overall, the best-performing model, mn30_as, which is a pre-trained model, demonstrated an average AUC across 10 folds as follows: combined model 0.8361 (95% CI 0.7667-0.9056; max 0.9541), male model 0.8010 (95% CI 0.6589-0.9432; max 1.000), and female model 0.7572 (95% CI 0.6578-0.8567; max 0.9779). However, for the female model, a slightly higher result was observed with the mn4.0, which scored 0.7679 (95% CI 0.6426-0.8931; max 0.9722). Additionally, the other models (pre-trained; mn40_as, non-pre-trained; mn4.0 and mn3.0) also achieved performance above 0.7 in most cases, and the highest fold-level performance for most models was approximately around 0.9. The 'mn' in model names refers to MobileNet and the following number indicates the 'width_mult' parameter.

CONCLUSIONS

In this study, we used mel-spectrogram analysis and a MobileNetV3 model for predicting dysphagia aspiration. Our research highlights voice analysis potential in dysphagia screening, diagnosis, and monitoring, aiming for non-invasive safer, and more effective interventions.

TRIAL REGISTRATION

This study was approved by the IRB (No. B-2109-707-303) and registered on clinicaltrials.gov (ID: NCT05149976).

Position of the Hyoid Bone and Dimension of Nasopharynx and Oropharynx after Occlusal Splint Therapy and Physiotherapy in Patients Diagnosed with Temporomandibular Disorders

Background: The aim of the study was to assess the position of the hyoid bone, as well as the width of the nasopharynx and oropharynx after occlusal splint therapy combined with physiotherapy in patients diagnosed with temporomandibular disorders (TMD). Methods: This was a clinical trial study. The study group consisted of 40 patients diagnosed with TMD, who were qualified for the treatment combining physiotherapy and occlusal splint therapy. Hyoid bone position as well as the width of the nasopharynx and oropharynx were assessed in lateral cephalograms taken before and after the end of the treatment. There were 15 generally healthy participants included into the control group, who had taken lateral cephalograms twice within the period of 1 to 2 years and did not receive any occlusal treatment in the meantime. Results: The position of the hyoid bone was significantly lowered and the dimension of the lower part of the oropharynx was significantly decreased after the end of the long-term occlusal splint therapy combined with physiotherapy in patients diagnosed with TMD. Conclusions: Long-term occlusal splint therapy combined with physiotherapy affected the position of the hyoid bone and the dimension of the lower part of the oropharynx.

Detection of poststroke oropharyngeal dysphagia with swallowing screening by ultrasonography

There are currently no standard evaluation tools for poststroke neurogenic oropharyngeal dysphagia. We previously suggested calculating the relative movements of the hyoid bone and larynx by ultrasonography to evaluate swallowing movement. Swallowing movement is altered in neurogenic oropharyngeal dysphagia. Therefore, the present study aimed to verify whether an ultrasonographic evaluation of swallowing movement facilitates the detection of neurogenic oropharyngeal dysphagia. Eighteen healthy male elderly participants (the healthy group) and 18 male stroke patients diagnosed with neurogenic oropharyngeal dysphagia (the dysphagia group) were enrolled. Participants swallowed 5 mL of liquid and water with an adjusted viscosity and the movements of the hyoid bone and larynx were visualized by ultrasonography. The results obtained revealed significant differences in laryngeal duration (static phase), laryngeal displacement (elevation phase), and the hyoid bone–laryngeal motion ratio (HL motion ratio) between the two groups. A multiple regression analysis was performed to adjust for confounding factors, and laryngeal duration (static phase) and the HL motion ratios were identified as factors affecting dysphagia. In the receiver operation characteristic curve of the two variations, the area under the curve for laryngeal duration (static phase) was 0.744 and the cut-off was 0.26 sec with 72.2% sensitivity and 88.9% specificity; the area under the curve for the HL motion ratio was 0.951 and the cut-off was 0.56 with 88.9% sensitivity and 88.9% specificity. Therefore, the objective evaluation of hyoid bone and larynx movements during swallowing by ultrasonography facilitated the detection of neurogenic oropharyngeal dysphagia.

The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy

All mammalian infants suckle, a fundamentally different process than drinking in adults. Infant mammal oropharyngeal anatomy is also anteroposteriorly compressed and becomes more elongate postnatally. While suckling and drinking require different patterns of muscle use and kinematics, little insight exists into how the neuromotor and anatomical systems change through the time that infants suckle. We measured the orientation, activity and contractile patterns of five muscles active during infant feeding from early infancy until weaning using a pig model. Muscles not aligned with the long axis of the body became less mediolaterally orientated with age. However, the timing of activation and the contractile patterns of those muscles exhibited little change, although variation was larger in younger infants than older infants. At both ages, there were differences in contractile patterns within muscles active during both sucking and swallowing, as well as variation among muscles during swallowing. The changes in anatomy, coupled with less variation closer to weaning and little change in muscle firing and shortening patterns suggest that the neuromotor system may be optimized to transition to solid foods. The lesser consequences of aspiration during feeding on an all-liquid diet may not necessitate the evolution of variation in neuromotor function through infancy.

Swallowing dysfunction following surgery for well-differentiated thyroid cancer with extrathyroid invasion

BACKGROUND

Differentiated thyroid carcinoma (DTC) can invade the surrounding aerodigestive tract. Radical surgery for locally advanced DTC will require resection of the trachea, recurrent laryngeal nerve (RLN), inferior pharyngeal constrictor muscles (IPCMs), or a part of the esophagus. The purpose of this study was to demonstrate the effect of resection of these surrounding tissues combined with total thyroidectomy and neck dissection on swallowing function following surgery.

METHODS

We performed total thyroidectomy combined with neck dissection and resection of the RLN in 24 patients with DTC with extrathyroidal invasion (19 unilateral, 1 bilateral), IPCMs (n = 5), or muscle layers of esophagus (n = 9). Nine patients received a tracheostomy placement due to a window resection of the trachea for tumor invasion (n = 6) and necessary upper airway management (n = 3). We used the duration of nasogastric tube feeding to evaluate swallowing function following surgery.

RESULTS

Patients who underwent tracheostomy or IPCM resection showed significantly longer periods of tube feeding (p = 0.0057 and 0.0017, respectively). In contrast, resection of the unilateral RLN or esophageal muscle layer showed no difference in tube feeding duration. Multiple regression analysis indicated that tracheostomy and IPCM resection were significant independent predictors of longer periods of tube feeding (p = 0.04583 and 0.00087, respectively).

CONCLUSION

These results indicate that tracheostomy placement and resection of the IPCMs, together with total thyroidectomy, extends the tube feeding duration in the postoperative period.

The effect of preterm birth, recurrent laryngeal nerve lesion, and postnatal maturation on hyoid and thyroid movements, and their coordination in infant feeding

Movements of the hyoid and thyroid are critical for feeding. These structures are often assumed to move in synchrony, despite evidence that neurologically compromised populations exhibit altered kinematics. Preterm infants are widely considered to be a neurologically compromised population and often experience feeding difficulties, yet measuring performance, and how performance matures in pediatric populations is challenging. Feeding problems are often compounded by complications arising from surgical procedures performed to ensure the survival of preterm infants, such as damage to the recurrent laryngeal nerve (RLN) during patent ductus arteriosus correction surgery. Here, we used a validated infant pig model for infant feeding to test how preterm birth, postnatal maturation, and RLN lesion interact to impact hyoid and thyroid excursion and their coordination. We filmed infant pigs when feeding using videofluorscopy at seven days old (1-2 months human equivalent) and 17 days old (6-9 months human equivalent) and tracked movements of the hyoid and thyroid on both days. We found that preterm birth impacted the coordination between hyoid and thyroid movements, but not their actual excursion. In contrast, excursion of the two structures increased with postnatal age in term and preterm pigs. RLN lesion decreased thyroid excursion, and primarily impacted hyoid movements by increasing variation in hyoid excursion. This work demonstrates that RLN lesion and preterm birth have distinct, but pervasive effects on feeding performance in infants, and suggest that interventions targeted towards reducing dysphagia should be prescribed based off the etiology driving dysphagia, rather than the prognosis of dysphagia.