No abstract available.
Laryngeal Muscles*

No abstract available.
Laryngeal Muscles*

We have had a case of unilateral vocal cord paralysis following endotracheal anesthesia for abdominal surgery. Electromyographic examination of the intrinsic laryngeal muscle to study the nerve injury was not done but we have considered that the recurrent laryngeal nerve was injured following endotracheal anesthesia according to the post-operative laryngeal view and recovery progress. Som factors of nerve injury such as overrotation of the neck during the operation, pressure on the nerve by an overexpanded cuff, vulnerability and the anatomy of the nerve were all deemed to do possible causes, and we considered the interaction of this combination responsible for the nerve injury. The recovery were relatively good and healed within 80 dyas after operation.
Anesthesia* ; Laryngeal Muscles ; Neck ; Recurrent Laryngeal Nerve ; Vocal Cord Paralysis*

Dysphonia/therapy* ; Humans ; Laryngeal Muscles/surgery*

BACKGROUND AND OBJECTIVES: The CT muscle is composed of three distinct bellies, pars recta, pars oblique and pars horizontalis. The function of each subunit is not clearly understood although it is believed that they act differently since their fibers run in different directions. This study is to clarify the pitch control mechanism of two bellies during production of speech using thyroidectomized patients. MATERIALS AND METHODS: Subjects are eight patients undergoing thyroidectomy. During surgery, pairs of 38 gauge hooked wire electrodes were inserted into the bellies of the pars recta and pars oblique. Several days after the surgery, the electrical activities of these muscles were evaluated by running speaking tasks. The EMG signals were rectified, integrated and smoothened using a Viking II EMG system. The EMG activities were analysed according tt the patterns of intonation during the running speech. RESULTS: The maximum EMG activity range of the pars recta and pars oblique are nearly equal. During the running speech, the pars oblique was activated initially and more predominantly than pars recta in the initial task of sentence, and graduxlly activated to the maximum during the Fo increase. However, pars recta was more predominantly activated to the maximum during the Fo increase than pars oblique in the interrogative sentence. This results demonstrated that the patterns of electrical activities of two bellies during speech are different From each other. CONCLUSION: The pars recta and pars oblique may have an individual anatomical function. The combined activity of the pars recta and pars oblique is important in adjustment of the vocal fold length during speech.
Electrodes ; Humans ; Laryngeal Muscles* ; Muscles ; Running ; Thyroidectomy ; Vocal Cords

OBJECTIVE: To analyze the clinical characteristics between neurogenic and non-neurogenic cause of vocal cord immobility (VCI). METHODS: The researchers retrospectively reviewed clinical data of patients who underwent laryngeal electromyography (LEMG). LEMG was performed in the bilateral cricothyroid and thyroarytenoid muscles. A total of 137 patients were enrolled from 2011 to 2016, and they were assigned to either the neurogenic or non-neurogenic VCI group, according to the LEMG results. The clinical characteristics were compared between the two groups and a subgroup analysis was done in the neurogenic group. RESULTS: Among the 137 subjects, 94 patients had nerve injury. There were no differences between the neurogenic and non-neurogenic group in terms of demographic data, underlying disease except cancer, and premorbid events. In general characteristics, cancer was significantly higher in the neurogenic group than non-neurogenic group (p=0.001). In the clinical findings, the impaired high pitched ‘e’ sound and aspiration symptoms were significantly higher in neurogenic group (p=0.039 for impaired high pitched ‘e’ sound; p=0.021 for aspiration symptoms), and sore throat was more common in the non-neurogenic group (p=0.014). In the subgroup analysis of neurogenic group, hoarseness was more common in recurrent laryngeal neuropathy group than superior laryngeal neuropathy group (p=0.018). CONCLUSION: In patients with suspected vocal cord palsy, impaired high pitched ‘e’ sound and aspiration symptoms were more common in group with neurogenic cause of VCI. Hoarseness was more frequent in subjects with recurrent laryngeal neuropathy. Thorough clinical evaluation and LEMG are important to differentiate underlying cause of VCI.
Electromyography ; Hoarseness ; Humans ; Laryngeal Muscles ; Laryngeal Nerves ; Pharyngitis ; Recurrent Laryngeal Nerve ; Retrospective Studies ; Vocal Cord Paralysis ; Vocal Cords*

OBJECTIVES: The sensitivity and positive predictive value of widely used intraoperative neuromonitoring (IONM) using electromyography (EMG) of the vocalis muscle in thyroid surgery are controversial. Thus, we developed a novel IONM system with an accelerometer sensor that uses the piezoelectric effect instead of EMG to detect laryngeal twitching. The objective of this study was to evaluate the feasibility and safety of this novel IONM system during thyroid surgery in a porcine model. METHODS: We developed an accelerometer sensor that uses the piezoelectric effect to measure laryngeal twitching in three dimensions. This novel accelerometer sensor was placed in the anterior neck skin (transcutaneous) or postcricoid area. Stimulus thresholds, amplitude, and latency of laryngeal twitching measured using the accelerometer sensor were compared to those measured through EMG of the vocalis muscle. RESULTS: The amplitudes of the accelerometer sensor at the anterior neck and postcricoid area were significantly lower than those of EMG because of differences in the measurement method used to evaluate laryngeal movement. However, no significant differences in stimulus thresholds between the EMG endotracheal tube and transcutaneous or postcricoid accelerometer sensors were observed. CONCLUSION: Accelerometer sensors located at the anterior neck or postcricoid area were able to identify laryngeal twitching. The stimulus intensity measured with these sensors was equivalent to that from conventional vocalis EMG. Our novel IONM system with an accelerometer sensor that checks changes in surface acceleration can be an alternative to EMG of the vocalis muscle for IONM in the future.
Acceleration ; Electromyography ; Laryngeal Muscles ; Methods ; Neck ; Recurrent Laryngeal Nerve ; Skin ; Thyroid Gland ; Thyroidectomy

OBJECTIVE: To investigate the electrophysiological characteristics and pathological changes in different recurrent laryngeal nerve injury models. METHOD: Twenty dogs were divided into different models of recurrent laryngeal nerve injury. Electrophysiological changes of animal models and histopathological changes in laryngeal muscles were investigated at different time. RESULT: Amplitude of MUP in TA decreased at first and then increased a little, while duration of MUP keeps decreased. The latent periods of the evoked potential in the incomplete injury group increased at first and then went down. In animal histopathological investigation, the lighter of the muscle injuries and the bigger of the diameter of muscle fibers and fascicles, and the smaller of the number of cellular nucleolus per square inch. In the early periods after injury, the correlation among the standard amplitude, threshold amplitude, maximum amplitude of EP and the diameter of fascicles were positive; while in the late period, the correlation among the amplitude, duration, area of MUP and nucleolus number was positive. CONCLUSION The physiological characteristics of laryngeal nerves and muscles could be known. LEMG was an important method in diagnosis of laryngeal nerve and muscle diseases.
Animals ; Disease Models, Animal ; Dogs ; Electromyography ; Evoked Potentials ; Laryngeal Muscles ; innervation ; physiopathology ; Recurrent Laryngeal Nerve Injuries

BACKGROUND AND OBJECTIVES: As a technique to assess vocal function, electroglottography (EGG) has become popular among clinicians and researchers. Because it is fairly simple and non-invasive, EGG is easily adopted for routine clinical use. The purpose of this study is to evaluate the effect of weight lifting on the tension of laryngeal adductory muscles and electroglottography. MATERIALS AND METHODS: The normal control group was composed of 10 healthy males and 10 healthy females who do have voice disorder. The disease group was composed of 10 male and 10 female patients who have vocal polyp or nodule. Electroglottography taken during comfortable phonation was compared with that taken during phonation produced when the subjects were lifting a weight of 15 kg. RESULTS: The closed quotient of electroglottography in the normal male and female groups were 0.46+/-0.04 and 0.46+/-0.05, respectively. The closed quotient in the male and female patients were 0.47+/-0.05 and 0.50+/-0.05, respectively. The closed quotient of electroglottography was not different between the comfortable voice and the voice during weight lifting. The exception was the normal male control group, but the actual effect of weight lifting in this group was not so significant, compared to the effect of increasing vocal intensity. CONCLUSION: Weight lifting does not produce significant short-term effects on laryngeal muscle tension and on the closed quotient of electroglottography.
Female ; Humans ; Laryngeal Muscles ; Lifting ; Male ; Muscles ; Ovum ; Phonation ; Polyps ; Voice ; Voice Disorders ; Weight Lifting*

OBJECTIVES: Voice and speech alternations that can occur after total thyroidectomy are usually due to recurrent or superior laryngeal nerve injury. These alterations may also be associated with other extralaryngeal factors, such as neck muscle dysfunction and scar contracture of the neck. We performed a prospective acoustic analysis on speech changes after surgery, in the absence of laryngeal nerve injury. METHODS: Patients aged 19 to 58 years undergoing total thyroidectomy, in the absence of laryngeal/pulmonary disease, previous neck surgery, or other malignant diseases, were recruited prospectively. For the running speech analysis, the speaking fundamental frequencies (SFo), range of SFo and speaking intensity were evaluated before surgery, 7 days, and 1 and 3 months after surgery. For consonant analysis, the acoustic distinctions of stop consonant, the voice onset time (VOT), vowel duration and closure duration were evaluated at the same periods. RESULTS: SFo and range of SFo were specifically diminished after surgery, while speaking intensities were not changed significantly after surgery. The thyroidectomized speakers displayed systematically varied VOT for the consonant production, which was phonetically representative. However, VOT after surgery could be longer in the strong aspirated and glottalized stops, but not in the lax stop than before surgery. The vowel and closure durations were not affected before and after surgery. CONCLUSION: Patients with thyroidectomy have some difficulty of pitch control and consonant articulation during speaking. VOT is also one of the meaningful acoustic parameters and provide a reference for comparing acoustic measures before and after thyroidectomy.
Acoustics ; Cicatrix ; Contracture ; Humans ; Laryngeal Nerve Injuries ; Laryngeal Nerves ; Neck ; Neck Muscles ; Prospective Studies ; Running ; Thyroidectomy* ; Voice