The study of laryngeal muscle activity in normal human subjects and in patients with laryngeal dystonia using multiple fine-wire electromyography.

The normal human larynx performs numerous complex tasks with nearly complete reliability. These tasks require precise timing of movements that are effected by the laryngeal muscles. The most specific method to examine these muscles is by electromyography. Although many studies on laryngeal electromyography have been reported using multichannel recordings, none has provided a detailed analysis of each laryngeal muscle's role during a variety of common tasks and the spectrum of normative values. Simultaneous eight-channel, fine-wire electromyographic recordings were made in 11 human subjects. The timing patterns of the laryngeal muscles during the coordinated efforts for phonation and other common glottic functions were examined. In addition, normative values for latencies and amplitudes of response were determined. During simple phonation, a "set pattern" for the thyroarytenoid, lateral cricoarytenoid , and interarytenoid muscles was found. The thyroarytenoid and lateral cricoarytenoid muscles demonstrated a burst at onset preceding phonation and then decreased activity, whereas the interarytenoid sustained glottic position during phonation. The coordination of the laryngeal muscles was similarly determined for connected speech, respiration, Valsalva maneuver, cough, throat-clear task, and swallow. These patterns of response, the latencies for activities, and the amplitudes of response in normal subjects provided the basis to examine the abnormal laryngeal function in a group of 59 patients with four clinical varieties of laryngeal dystonia (adductor, tremor, abductor, and mixed). The findings include abnormal patterns of response, increased latencies, and increased amplitudes of recruitment in many tasks including nonphonatory tasks. Although specific distinctions were noted in each group, the responses were remarkably similar, indicating that all clinical varieties of laryngeal dystonia should be classified as mixed dystonia with a clinical preponderance for one or more types of behavior.

The association of laryngoceles with ventricular phonation.

Laryngoceles represent dilatations of the laryngeal saccule that may extend internally into the airway, or externally through the thyrohyoid membrane. Unilateral laryngoceles are uncommon clinical entities and bilateral laryngoceles are rare. Certain activities like glass blowing and playing a wind instrument are associated with laryngocele development, as is laryngeal carcinoma in the ventricular area. This case describes development of bilateral laryngoceles in a patient who chronically uses ventricular phonation during speech. The pathogenesis involves repetitive elevation of intralaryngeal pressure during false vocal cord approximation, exposing the ventricles to abnormally high air pressures. The pathogenesis in this case, as well as in laryngoceles associated with occupational or anatomic risk factors, is discussed.

Evaluation and management of bilateral vocal cord immobility.

Bilateral vocal cord immobility can be life threatening for some patients. Others, who have an open glottic chink, may have a breathy dysphonia, intermittent dyspnea, and stridor. These signs and symptoms may also be found in a number of other conditions that cause weakness or paradoxical motion of the vocal cords that mimics paralysis. These other conditions include central nervous system diseases, neuromuscular disorders, laryngospasm, and psychogenic disorders. In addition, patients with cricoarytenoid joint immobility or interarytenoid scar can also have similar symptoms at presentation. It is critical to consider the differential diagnosis of an assumed bilateral vocal cord paralysis and understand the management of paradoxical movement, weakness, joint fixation, interarytenoid scar, laryngospasm, and psychogenic disorders. The treatment for bilateral immobility should proceed only after a thorough evaluation, which might include electromyography and/or examination during general anesthesia under dense anesthetic paralysis. Reconstructive procedures are the treatments of choice, and destructive procedures should be chosen only as a last resort.

Laryngeal electromyographic findings in Charcot-Marie-Tooth disease type II.

Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy that exhibits progressive muscular atrophy in the limbs, beginning with the lower extremities. It is now understood to be a heterogeneous group of disorders that can be differentiated both clinically and genetically. In Charcot-Marie-Tooth disease type II C, axonal neuropathy, diaphragm weakness, and vocal cord paralysis are described within kindreds. We used laryngeal electromyography to study a patient with this disorder. This technique has potential in the diagnosis of Charcot-Marie-Tooth disease type II.

Idiopathic bilateral vocal fold weakness.

OBJECTIVE: To describe an unrecognized clinical entity, idiopathic bilateral vocal fold weakness, and propose recommendations regarding the diagnosis and management of these cases. STUDY DESIGN: Retrospective, nonrandomized case study. METHODS: All cases of bilateral vocal fold weakness evaluated at the University of Washington Voice Disorders Clinic between 1991 to 1998 were reviewed. RESULTS: Four patients with bilateral laryngeal weakness were determined to have idiopathic bilateral vocal fold paresis following exhaustive workups, including videostroboscopy, bilateral laryngeal electromyography (EMG), neurological consultation, and other pertinent studies. CONCLUSIONS: Performing bilateral laryngeal EMG is an essential aspect of the workup of any laryngeal weakness case, particularly if the etiology is unknown on presentation. Idiopathic bilateral vocal fold weakness is an underrecognized but real clinical diagnosis that will become more familiar with the increasing utilization of laryngeal EMG in clinical situations.

Direct measurement of subglottic pressure and laryngeal resistance in normal subjects and in spasmodic dysphonia.

This study tested the accuracy of indirect methods of measurement of laryngeal airway resistance in normal subjects and in spasmodic dysphonia (SD). The indirect method assumes that subglottic air pressure remains constant during the voiced segment of a syllable. In this study subglottic air pressure was directly measured via puncture of the cricothyroid membrane in seven normal subjects and seven subjects with SD. The true laryngeal airway resistance was calculated and compared with airway resistance measured using indirect techniques based on intraoral air pressure. In five of the seven normal subjects, subglottic air pressure did not remain constant during the voiced segment. As a result, the error produced using indirect method of calculating average laryngeal resistance for the normal subjects varied from -44% to +50%. For SD subjects the error ranged from -49% to +22%. In general, the indirect technique overestimated laryngeal airway resistance in normal subjects and underestimated the resistance in subjects with SD.

Dysphagia caused by neurologic deficits.

This article provides a brief review of the neurophysiology behind the normal swallow. The examination and work-up of a patient with dysphagia is then detailed. Finally, the major neurologic conditions associated with dysphagia are considered.

New laryngeal muscle weakness in post-polio syndrome.

The authors describe the clinical presentations of post-polio laryngeal muscle weakness in three patients with prior polio infection who presented with new complaints including slowly progressive dyspnea, dysphagia, and/or hoarseness. Evaluations by laryngeal videostroboscopy and electromyography revealed vocal cord abductor and/or adductor weakness, recurrent posterior glottic web in one case, and, in the two patients who agreed to electromyography, evidence of prior denervation and reinnervation in laryngeal muscles. Treatment was directed at attempting to maintain an airway and optimize vocal quality. One patient benefitted from tracheostomy, one benefitted from vocal cord medialization, and one benefitted from resection of interarytenoid scarring. The authors conclude that diagnosis of laryngeal post-polio syndrome is facilitated by laryngeal electromyography. Interventions directed at maintaining an appropriate airway and optimizing vocal quality may be helpful.

Analysis of voice changes after thyroplasty using linear predictive coding.

Objective measurement of vocal quality is difficult in patients with severe voice disorders. Improved success has been reported using a modeling technique known as linear predictive coding. This technique uses an inverse filter to estimate a glottic excitation signal. The pitch amplitude is defined as the height of the first peak of the autocorrelation of the glottic excitation signal. In this study linear predictive coding was used to analyze voice disorders in patients with vocal fold immobility. Voice recordings were made in 16 patients undergoing vocal fold medialization and 10 patients who had no surgical procedure between measurements. The voice quality was rated by three speech pathologists. Five acoustic parameters were calculated from the samples. The best agreement with the listeners' perceptual analysis was achieved using the pitch amplitude. Both pitch amplitude and the perceptual ratings of voice quality improved in patients undergoing vocal fold medialization. Therefore the linear model of speech production and inverse filtering are useful in measuring vocal quality in patients with vocal fold immobility.

Laryngeal electromyography for the diagnosis and management of swallowing disorders.

Laryngeal electromyography has proved useful for the evaluation of neurologic disorders of the larynx. The techniques for this procedure are also well suited to investigate disorders of the pharyngeal phase of swallowing. The responses from the thyroarytenoid muscles, the cricothyroid muscles, and the cricopharyngeus muscle can offer information to aid in the diagnosis, prognosis, and in some cases, treatment of dysphagia. A general review of electromyographic responses with sample tracings from the larynx are included in this article.

Management of oral-pharyngeal dysphagia symptoms in amyotrophic lateral sclerosis.

Oral and pharyngeal dysphagia is a common symptom in patients with amyotrophic lateral sclerosis (ALS) and is the result of a progressive loss of function in bulbar and respiratory muscles. Clinicians involved in the management of ALS patients should be familiar with the common clinical findings and the usual patterns of temporal progression. The prevention of secondary complications, such as nutritional deficiency and dehydration that compound the deteriorating effects of the disease, requires careful monitoring of each patient's functional status and timely intervention with appropriate management techniques.

The 11th nerve syndrome. Accessory nerve palsy or adhesive capsulitis?

The 11th nerve syndrome classically involves the majority of patients undergoing neck dissections even when the accessory nerve is preserved. A preliminary analysis of our data of 31 of 44 patients who underwent neck dissections from a prospective study showed numerous findings of shoulder disability that are not attributable to accessory nerve palsy but are well described by the syndrome of adhesive capsulitis of the glenohumeral joint. At 1 month postoperatively, although accessory nerve palsy symptoms were common, adhesive capsulitis symptoms were significant. At 6 months, the frequency of accessory nerve palsy symptoms was less as the accessory nerve had begun to recover. At 12 and 18 months, when most of the accessory nerves had recovered, the accessory nerve palsy symptoms were comparatively uncommon while the adhesive capsulitis symptoms predominated as the remaining symptoms of the 11th nerve syndrome. We propose that adhesive capsulitis is a principal component of the 11th nerve syndrome that can significantly compound the morbidity of a neck dissection even when the accessory nerve recovers. We also propose that adhesive capsulitis accounts for the persistence and variability of shoulder symptoms after neck dissection that cannot be attributed to trapezius muscle dysfunction.

Using phonation time to estimate vital capacity in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neuromuscular disease in which progressive respiratory weakness is usually the proximate cause of death. Since continued assessment of respiratory function is important in predicting progression, phonation time was measured in a group of 41 ALS patients and correlated with measured vital capacity. The findings show that the variance in phonation time accounts for nearly 50% of the variability of vital capacity, and therefore, successive measurements of phonation time are a useful means of estimating the loss of vital capacity.

Palliative surgery in patients with bulbar amyotrophic lateral sclerosis.

Patients with amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disorder, commonly develop bulbar symptoms including dysphagia, dysarthria, and defective airway protection. Otolaryngologists/head and neck surgeons are frequently asked to assist in the management of these problems. We reviewed our experience of 13 surgical procedures in 7 patients with advanced bulbar ALS. In spite of technically good surgery, 3 patients died within 1 week of hospitalization. Four patients appeared to benefit from the surgery. Patients with bulbar ALS are a high risk group because of chronic malnutrition and dehydration, covert aspiration and pneumonitis, and diminished ventilation. A team approach to these problems is stressed. Perioperative morbidity can be reduced with careful preoperative preparation and patient selection.

Trumpet maneuver for visual and CT examination of the pyriform sinus and retrocricoid area.

The trumpet maneuver, a technique to inflate the hypopharynx with air, allows visualization of the pyriform sinuses and retrocricoid area during both fiberoptic examination and CT scanning. The technique is useful in delineating both normal and abnormal anatomy, and is especially useful in the evaluation of patients with hypopharyngeal symptoms in whom there is a low suspicion of anatomic disease. The methods, endoscopic photographs, and CT scan images are presented.

Aberrant carotid artery. Presentation in the near midline pharynx.

Three cases of an aberrant internal carotid artery presenting at or near the midline in the posterior part of the pharynx occurred. In all three cases, the anomalous finding was not correlated with the presenting symptoms of the patient. In two of the three cases intraoral pulsations were detected during initial examination. In the third case, pulsations were appreciated on reexamination after roentgenographic evaluation. Intraoral photographs, computed tomographic scan, magnetic resonance imaging, and arteriography of these findings are shown. A review of the literature and the embryology of the lateral pharyngeal carotid artery are presented along with the rare finding of the near midline carotid artery and the clinical implications of this anomaly.

Effects of general anesthesia on the human blink reflex.

The blink reflex was studied in 10 patients undergoing elective procedures under general anesthesia. Anesthetic agents were isoflurane, halothane, nitrous oxide, methohexital, and thiopental in various combinations. At induction, blink reflexes were diminished by low-dose thiopental (1-1.5 mg/kg) and abolished by high-dose thiopental (4-8 mg/kg) and methohexital (1.5 mg/kg). Blink reflexes were absent during halogenated volitile inhalational anesthesia and did not return until patients were in the recovery room, well after end-tidal anesthetic levels were zero by mass spectroscopy. Recovery of consciousness and the ability to blink on command often preceded return of any blink reflex activity, indicating that the blink reflex is not useful as a postoperative test of facial nerve function in the operating room after anesthesia. In six patients, blink reflexes were still diminished 2-3 hours after cessation of anesthesia, at a time when patients were fully oriented and corneal and eyelid reflexes were clinically normal. This finding suggests that the blink reflex might be a sensitive test of subtle CNS dysfunction after inhalational anesthesia and potentially could serve as a useful objective indicator of recovery from anesthesia for outpatient surgery.

Radical neck dissection: a subjective and objective evaluation of postoperative disability.

Nearly all patients who undergo radical neck dissection note significant morbidity if the XIth cranial nerve is sacrificed. Physicians can be misled to believe in a lower morbidity because the usual physical examination is unreliable in detecting weakness and because patients rarely persist in mentioning shoulder problems during follow-up visits. Eleven patients between the ages of 55 and 70, who had undergone unilateral neck dissection with sacrifice of the XIth cranial nerve, were given questionnaires and were objectively evaluated for strength and active range of motion on a Cybex II dynamometer. Eighty-two percent of patients experienced pain, 91% experienced weakness, and 91% experienced impairment on the affected side. Peak torque for the affected side ranged between 0 to 85% of the peak torque for the normal shoulder. Gravity-free active range of motions were 20 degrees to 162 degrees with 8 of 11 at 100 degrees or less. In all but two patients, the passive range of motion was limited by pain.

Amyotrophic lateral sclerosis severity scale.

The amyotrophic lateral sclerosis (ALS) severity scale has been developed to provide an ordinal staging system and a means of rapid functional assessment for patients with ALS. The scale allows an examiner to evaluate the symptoms of ALS numerically in four categories that describe speech, swallowing, lower extremity, and upper extremity abilities. These scores, combined with a vital capacity measured on a hand-held respirometer, provide a rapid, accurate assessment of a patient's disease status and can be used for treatment planning. The ALS severity scale has been shown to have an average estimated reliability coefficient of 0.95 between examiners. Speech ratings were correlated greater than 0.80 for objective speech measures. Rates of progression of the total score in a small group of patients ranged from -3.4 to -24.0 points/year with a mean of -11.3 points/year.

Bulbar amyotrophic lateral sclerosis: patterns of progression and clinical management.

Patients with bulbar amyotrophic lateral sclerosis (ALS) are often referred to the otolaryngologist/head and neck surgeon and speech pathologist for evaluation and management of dysphagia and dysarthria. These patients comprise an unusual group because of the progressive and multi-system nature of their illness. The neuromuscular disabilities associated with bulbar ALS cause a myriad of related symptoms associated with swallowing, speech, and respiration. Although the rate of progression cannot be predicted, a general pattern of progression is noted. Bulbar disease accounts for the majority of the worst symptoms of ALS. The loss of the ability to swallow changes eating from a pleasurable task to a burden of survival. Loss of communication effectively imprisons the patient in a state of isolation. The progressive weakness of respiration, predominantly a spinal rather than bulbar manifestation, is the cause of death for nearly all ALS patients and is also discussed. The general patterns of progression of bulbar ALS are outlined in this paper. The development of symptoms are correlated with specific treatment recommendations to aid the clinician in devising an orderly plan of management for this progressive disease.