Biomedical subjects
Publications and source records attributed to A D Hillel.
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.
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.
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.
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.
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.
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 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.
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.
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.
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.
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.
The eleventh cranial nerve shoulder syndrome, which results from denervation of the trapezius muscle, contributes significantly to the postoperative morbidity of radical neck dissections. Multiple techniques exist for the reinnervation of muscles that have injured motor nerves. Reinnervation of denervated trapezius muscles was examined in the New Zealand white rabbit by use of three techniques of reinnervation: (1) neuromuscular pedicle transfer of the accessory nerve from the trapezius muscle, (2) direct accessory nerve implantation, and (3) neuromuscular pedicle transfer of the accessory nerve from the sternocleidomastoid muscle. The reinnervated trapezius muscles were examined grossly by direct nerve stimulation, electrophysiologically by evoked electromyography, and histologically by enzymatic muscle staining and silver-reducing nerve staining. The gross, electrophysiologic, and histologic results confirmed successful reinnervation of the trapezius muscle within 6 weeks of operation. No significant difference was observed between the various techniques of reinnervation.
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The bulbar symptoms of ALS include difficulty with the management of swallowing, saliva, aspiration, and communication. These symptoms originate from the disability of the oropharyngeal muscles and actually represent varying degrees of severity of a single problem. The management of these symptoms requires the concerted effort of a rehabilitation team, which should include a surgeon, speech pathologist, neurologist, psychosocial worker, and dietitian. Early education of the patient and patient's family greatly facilitates successful management of bulbar symptoms. Early recognition of the signs of dysphagia, aspiration, and communicative disability are important in order to provide solutions before severe and possibly life-threatening debilitation occurs. The treatments and techniques presented in this chapter must be applied to each patient on an individual basis. The moral and social decisions regarding the providing or withholding of treatment to ALS patients are difficult ones. It is important, however, to realize that management decisions of ALS patients must deal not only with the quantity of life but also the quality of life. This distinction often falls into a 'gray zone' with management of bulbar symptoms since swallowing difficulties are life-threatening as well as uncomfortable. One of the difficulties that we present ourselves as health care providers in ALS is that, more often than not, our patient is in a noncommunicative position and cannot contribute to treatment decisions. If careful and aggressive care is taken to preserve the communicative abilities of our patients, the difficult situation of making decisions based on the family's inclinations and our own inclinations can be avoided. When we are confronted with a decision to maintain or cease support for a patient, the moral and emotional issues that present can be overwhelming. However, the patient's input, if it were direct and included the ability to express complex thoughts, could often provide the information necessary to make the decisions more clear.
One hundred eight patients underwent primary parotid gland resections at Stanford University Medical Center between 1977 and 1980. Sixty-nine percent of the patients received intraoperative frozen-section diagnosis. Of these, 81% were benign and 19% were malignant. Four patients who received frozen-section diagnosis benefited by further surgery during the initial procedure. Two of four patients who did not receive frozen-section diagnosis could have benefited by further surgery. False-negative results (a malignant tumor called benign on frozen-section diagnosis) occurred in 5%. False-positive results (a benign lesion called malignant on frozen-section diagnosis) did not occur and no unnecessary surgery was performed.
Fourteen patients who underwent composite resections for oropharynx and tongue base cancers had lateral laryngeal suspensions in order to improve postoperative swallowing ability, minimize the surgical defect, and decrease shifting of the mandible after composite resection. Eleven of these patients had significant base of tongue resections (30-90%) and 3 had oropharyngeal resections. Thirteen (93%) were able to eat by mouth, 14 patients (100%) had a normal airway, and 14 (100%) had intelligible speech.
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.
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.