Identification and analysis of Nonlinear behaviors of vocal fold biomechanics during phonation to assess efficacy of surgery for benign laryngeal Diseases.

BACKGROUND: Current voice assessments focus on perceptive evaluation and acoustic analysis. The interaction of vocal tract pressure (PVT) and vocal fold (VF) vibrations are important for volume and pitch control. However, there are currently little non-invasive ways to measure PVT. Limited information has been provided by previous human trials, and interactions between PVT and VF vibrations and the potential clinical application remain unclear. Here, we propose a non-invasive method for monitoring the nonlinear characteristics of PVT and VF vibrations, analyze voices from pathological and healthy individuals, and evaluate treatment efficacy. METHOD: Healthy volunteers and patients with benign laryngeal lesions were recruited for this study. PVT was estimated using an airflow interruption method, VF vibrational frequency was calculated from accelerometer signals, and nonlinear relationships between PVT and VF vibrations were analyzed. Results from healthy volunteers and patients, as well as pre- and post-operation for the patients, were compared. RESULTS: For healthy volunteers, nonlinearity was exhibited as an initial increase and then prompt decrease in vibrational frequency at the end of phonation, coinciding with PVT equilibrating with the subglottal pressure upon airflow interruption. For patients, nonlinearity was present throughout the phonation period pre-operatively, but showed a similar trend to healthy volunteers post-operatively. CONCLUSION: This novel method simultaneously monitors PVT and VF vibration and helps clarify the role of PVT. The results demonstrate differences in nonlinear characteristics between healthy volunteers and patients, and pre-/post-operation in patients. The method may serve as an analysis tool for clinicians to assess pathological phonation and treatment efficacy.

Improvement in swallowing safety after injection laryngoplasty in patients with unilateral vocal paralysis complicated with aspiration.

BACKGROUND: The benefit of injection laryngoplasty (IL) on voice for unilateral vocal fold paralysis (UVFP) is supported increasingly in literatures, yet less is known for swallowing. Also, prevalence of patient-reported dysphagia is substantially higher than instrumental studies. This prospective study focused on swallowing outcomes, with predetermined flexible endoscopic evaluation of swallowing (FEES) protocol that simulates daily life situation. METHODS: Adult patients with UVFP and aspiration receiving IL were recruited. Voice outcome measurements, as well as swallowing outcomes including Eating Assessment Tool (EAT-10) and FEES, which challenged patients with different fluid volumes: 10 mL, 20 mL, and 90 mL cup sipping were evaluated. RESULTS: Significant improvements were demonstrated in all voice outcomes. Significant changes were also presented inEAT-10 (P < 0.01). Pre-operatively, penetration-aspiration scale (PAS) was 1.5 ± 1.3, 1.9 ± 1.7 and 2.3 ± 1.8 for 10 mL, 20 mL and 90 mL serial sipping, and improved to 1.1 ± 0.3, 1.1 ± 0.4 and 1.4 ± 0.7 post-operatively (P < 0.01). Safe swallowing (PAS ≤ 2) was achieved in all, except for one patient, who presented with a post-injection PAS of 4 (material enters the airway, contacts the vocal folds, and is ejected from the airway) on 90 mL cup sipping, whose pre-injection PAS was 7 (residue in trachea). CONCLUSION: Maintaining swallowing function suitable for social environment is important. Our results demonstrated the feasibility of the predetermined FEES protocol, and positive effects of IL on both voice and swallowing outcomes.

Proactive Swallowing Rehabilitation in Patients with Recurrent Oral Cancer Receiving Salvage Treatment: Long-Term Swallowing-Related Outcomes.

The present study aimed to evaluate the impact of proactive swallowing rehabilitation on swallowing function and quality of life in patients with recurrent oral cancer in the first 2 years after salvage treatment. Consecutive adult patients with recurrent oral cancer who received salvage surgery and free flap reconstruction were recruited prospectively, to whom proactive swallowing rehabilitation was provided. Body weight (BW); fiberoptic endoscopic evaluation of swallowing (FEES), functional oral intake scale (FOIS), and diet level; 10-item eating assessment tool (EAT-10), and MD Anderson Dysphagia Inventory (MDADI); and adherence at baseline, 1, 3, 6, 12, 18 and 24 months were evaluated. A total of 50 patients were included during May 2018 to July 2020. Compared to the baseline, significant deterioration in BW, FOIS, and MDADI was noted at one month. However, a trend of recovery was observed in BW and FOIS from one month, and in MDADI from three months. All patients were free of tube feeding at 18-24 months and tolerated diet with special preparations or compensation. Safe swallowing could be achieved in approximately 80% participants after 12 months of diet modification or compensatory maneuvers. Proactive swallowing therapy was feasible in patients with recurrent oral cancer receiving salvage treatment. Although this patient population might have pre-existing dysphagia from previous treatments, rehabilitation could facilitate safe per oral intake and maintain adequate nutrition with adaptive maneuvers or compensatory strategies. Patients who underwent proactive swallowing rehabilitation had better recovery in the functional oral intake level.

Effects of surgery on the relationship between subglottic pressure and fundamental frequency in vocal fold dynamics in patients with benign laryngeal diseases.

PURPOSE: Subglottic pressure (Ps) and fundamental frequency (F0) play important roles in governing vocal fold (VF) dynamics. Theoretical description, model simulation, excised larynx and animal models have been used in previous studies, yet clinically applicable measurements are still lacking. This study aimed to evaluate the effects of surgery for benign laryngeal lesions by investigating the relationship between F0 and Ps. METHODS: Patients with benign laryngeal lesions who underwent phonosurgery were prospectively recruited. Participants were instructed to sustain voicing the vowel /o/ at three incremental frequencies four semitones apart in the modal register (F01, F02, F03). F0 was estimated by VF vibration on the accelerometer. Ps change was achieved and measured using the airflow interruption method. RESULTS: Thirteen patients with a mean age (SD) of 43.5 (12.4) years were included. The change in F0 per unit change of Ps, which is the slope (Hz/kPa) of the regression line of the frequency-pressure data pairs, decreased as the tension of the VF increased. The slopes significantly increased after the operation for F01 and F02 (36.43 ± 14.68 preoperatively, 53.91 ± 30.71 postoperatively, p = 0.011 and 26.02 ± 10.71; 34.85 ± 17.92, p = 0.046, respectively). In addition, there was a significant decrease in phonation threshold pressure and improvements in the grade, roughness, breathiness, asthenia, strain scale, and the voice handicap inventory-10. CONCLUSIONS: The relationship between F0 and Ps may serve as an objective assessment of the outcomes in the treatment of benign laryngeal diseases with clinical relevance.

Long-term swallowing-related outcomes in oral cancer patients receiving proactive swallowing therapy.

OBJECTIVES: The present study aimed to evaluate the impact of proactive swallowing rehabilitation on swallowing function and quality of life (QoL) in oral cancer patients in the first two years after definitive treatment. MATERIALS AND METHODS: Consecutive adult patients with locally advanced oral cancer who received radical surgery, free flap reconstruction, and adjuvant radiotherapy were recruited prospectively, to whom proactive swallowing rehabilitation was provided. Body weight (BW); fiberoptic endoscopic evaluation of swallowing (FEES), functional oral intake scale (FOIS), and diet level; 10-item eating assessment tool (EAT-10), and MD Anderson Dysphagia Inventory (MDADI); and adherence at baseline, 1, 3, 6, 12, and 24 months were evaluated. RESULTS: A total of 104 patients were included during May 2018 to July 2020. Compared to the baseline, significant deterioration in BW, FOIS, and MDADI was noted at one month. However, a trend of recovery was observed in FOIS from one month, and in BW and MDADI from three months. A total of 94% patients were free of tube feeding at 12 months but with a diet requiring special preparations or compensation. Safe swallowing could be achieved in approximately 90% of the participants after six months with diet modification or compensatory maneuvers. BW at 18 and 24 months did not differ significantly from baseline. CONCLUSION: Proactive swallowing therapy is feasible for patients with locally advanced oral cancer receiving definitive treatments. It facilitates safe oral intake and adequate nutrition. Patients who performed swallowing exercises had a faster and better recovery in swallowing function and swallowing-related QoL.