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Forces applied to vocal fold tissue as the vocal folds collide may cause tissue injury that manifests as benign organic lesions. A novel method for measuring this quantity in humans in vivo uses a low-profile force sensor that extends along the length and depth of the glottis. Sensor design facilitates its placement and stabilization so that phonation can be initiated and maintained while it is in place, with minimal interference in vocal fold vibration. In 2 individuals with 1 vibrating vocal fold and 1 nonvibrating vocal fold, peak collision force correlates more strongly with voice intensity than pitch. Vocal fold collision forces in 1 individual with 2 vibrating vocal folds are of the same order of magnitude as in previous studies. Correlations among peak collision force, voice intensity, and pitch were indeterminate in this participant because of the small number of data points. Sensor modifications are proposed so that it can be used to reliably estimate collision force in individuals with 2 vibrating vocal folds and with changing vocal tract conformations. KEY WORDS: vocal fold collision, vocal fold biomechanics, phonation, voice production, Collisions between the vocal folds during phonation have implications for voice quality and vocal fold injury. Voice quality is largely determined by the major influence that vocal fold closure has [...]

The electrolarynx (EL) voice prosthesis is widely used, but suffers from the inconvenience of requiring manual control. Therefore, a hands-free EL triggered by neck muscle electromyographic (EMG) activity was developed (EMG-EL). Signal processing circuitry in a belt-mounted control unit transforms EMG activity into control signals for initiation and termination of voicing. These control signals are then fed to an EL held against the neck by an inconspicuous brace. Performance of the EMG-EL was evaluated by comparison to normal voice, manual EL voice, and tracheo-esophageal (TE) voice in a series of reaction time experiments in seven normal subjects and one laryngectomy patient. The normal subjects produced voice initiation with the EMG-EL that was as fast as both normal voice and the manual EL. The laryngectomy subject produced voice initiation that was slower than with the manual EL, but faster than with TE voice. Voice termination with the EMG-EL was slower than normal voice for the normal subjects, but not significantly different than with the manual EL. The laryngectomy subject produced voice termination with the EMG-EL that was slower than with TE or manual EL. The EMG-EL threshold was set at 10% of the range of vocal-related EMG activity above baseline. Simulations of EMG-EL behavior showed that the 10% threshold was not significantly different from the optimum threshold produced through the process of error minimization. The EMG-EL voice reaction time appears to be adequate for use in a day-to-day conversation. Index Terms--Electromyography, prosthesis, voice.

Research has been conducted on the velo-cardio-facial/DiGeorge syndrome characterized by the phenotypic features such as cardiovascular defects. The cre-loxP strategy in generating the mice which are hemizygous for the deletion has been used to investigate the etiology of the cardiovascular disorder and the results are presented.

Objective: Tracking recovery after nerve injury may require many intermittent assessments over long periods, preferably with non- or minimally invasive methods. We developed subcutaneous electrical connection ports (ECPs) for repeated connection to nerve cuff or intramuscular electrodes via transdermal needles and evaluated them during studies of laryngeal reinnervation.Study Design: Animal experiment.Setting: Laboratory.Methods: ECPs were designed and 3-dimensionally printed for connection to bipolar electrodes with biocompatible polymers. Dual compartments filled with conductive silicone capped with nonconductive silicone were used to make the connections between electrode leads and transdermally inserted needles. Ten dogs (19-29 kg) were implanted with 22 ECPs. In 7 dogs, 11 electrodes were placed on recurrent laryngeal nerves proximal to transection and suture repair to track laryngeal reinnervation. In 6 dogs, 8 spinal accessory nerve cuff electrodes were used to stimulate neck muscle contraction. In 2 dogs, 3 electrodes were implanted in the thyroarytenoid muscle. Stimulation thresholds, electromyography, and videolaryngoscopic imaging were obtained in 156 tests over survival periods up to 32 months. Stimulation data provided information about ECP performance.Results: ECPs added negligible resistance to electrodes (mean ± SD, 2.14 ± 0.9 Ω). Despite some electrode leads breaking distally, ECPs were reliable and well tolerated at implant sites and enabled periodic assessment of nerve and muscle function over the time course of laryngeal reinnervation. Histology showed ECP encapsulation as thin layers of connective tissue and minimal acute inflammation.Conclusion: Custom ECPs are easily fabricated and cause little tissue reaction over months to years of subcutaneous implantation, facilitating long-term physiologic studies. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: We previously developed an instrument called the Aerodynamic Vocal Fold Driver (AVFD) for intraoperative magnified assessment of vocal fold (VF) vibration during microlaryngoscopy under general anesthesia. Excised larynx testing showed that the AVFD could provide useful information about the vibratory characteristics of each VF independently. The present investigation expands those findings by testing new iterations of the AVFD during microlaryngoscopy in the canine model.Study Design: Animal model.Methods: The AVFD is a handheld instrument that is positioned to contact the phonatory mucosa of either VF during microlaryngoscopy. Airflow delivered through the AVFD shaft to the subglottis drives the VF into phonation-like vibration, which enables magnified observation of mucosal-wave function with stroboscopy or high-speed video. AVFD-driven phonation was tested intraoperatively (n = 26 VFs) using either the original instrument design or smaller and larger versions three-dimensionally printed from a medical grade polymer. A high-fidelity pressure sensor embedded within the AVFD measured VF contact pressure. Characteristics of individual VF phonation were compared with typical two-fold phonation and compared for VFs scarred by electrocautery (n = 4) versus controls (n = 22).Results: Phonation was successful in all 26 VFs, even when scar prevented conventional bilateral phonation. The 15-mm-wide AVFD fits best within the anteroposterior dimension of the musculo-membranous VF, and VF contact pressure correlated with acoustic output, driving pressures, and visible modes of vibration.Conclusions: The AVFD can reveal magnified vibratory characteristics of individual VFs during microlaryngoscopy (e.g., without needing patient participation), potentially providing information that is not apparent or available during conventional awake phonation, which might facilitate phonosurgical decision making.Level Of Evidence: NA Laryngoscope, 130: 1980-1988, 2020. [ABSTRACT FROM AUTHOR]