Ann Otol Rhinal Laryngo199:1990
ELECTROMYOGRAPHY OF THE INFERIOR CONSTRICTOR AND CRICOPHARYNGEAL MUSCLES DURING SWALLOWING MARA SHOCHINA, MD
JOSEPH ELIDAN, MD BENJAMIN GONEN, MSc
ISAAC GAY, MD JERUSALEM, ISRAEL
Electromyography (EMG) of the inferior pharyngeal constrictor (Ie) and the cricopharyngeal (CP) muscle was recorded in 18 patients with swallowing and/or aspiration problems who were candidates for cricopharyngeal myotomy. The EMG recordings were compared to those of 13 "normal" subjects who did not suffer from such problems. Differences in EMG activity between the control group and the patient group were considered with respect to the clinical symptoms in the patient group. Recording of EMG in the CP and IC muscles is relatively safe, useful, and easily mastered. The technique may provide important information regarding the function of some of the muscles involved in deglutition. KEY WORDS -
dysphagia, electromyography, pharyngeal muscles.
52 years) who were hospitalized in various departments of our hospital and had been referred to our service for evaluation of swallowing and/or aspiration problems and for consideration of CP myotomy. These patients suffered from various neurologic and other conditions, which are summarized in Table 2. This Table shows also the various clinical symptoms within this patient group. An informed consent was obtained from all patients in whom EMG recordings were made.
Interest in the role of the cricopharyngeal (CP) muscle in disorders of swallowing has increased greatly in recent years.':" Extensive research has been conducted regarding the anatomy, innervation, and physiology of the upper esophageal sphincter. 4,S Several studies have been published on the recording of electromyographic (EMG) activity of the CP muscle and other pharyngeal muscles in experimental animals,":" but some of the data are contradictory. Few studies involving humans have been published, and even fewer in the English literature.v" In none of these studies were EMG recordings performed routinely in patients with swallowing problems.
For the EMG recordings, concentric needle electrodes (EINS2) were used. Lidocaine (1 %) was injected superficially under the skin at the puncture site, with care taken not to inject the muscles themselves.
The aim of the present study was to explore the EMG activity of the CP and inferior pharyngeal constrictor (IC) muscles in patients suffering from deglutition difficulties (with or without aspiration). These patients were candidates for surgical treatment by CP myotomy. This presumably would help in the localization of the site of lesion in the swallowing mechanism.
For the CP muscle the needle electrode was passed through the skin in a posterior and medial direction, at the level of and just lateral to the cricoid cartilage. The needle was advanced until it penetrated the CP muscle. When the needle entered the muscle there was a burst of activity - the insertional activity - that diminished gradually, reaching a resting "tonic" level. Functional verification of the location of the electrode was done by asking the patient to swallow and taking note of the change in the EMG activity. Typically, the CP muscle responded by a marked change in its activity only during the act of swallowing and very slightly or not at all during breathing or phonation. In cases in which the lateral cricoarytenoid muscle was penetrated accidentally, the EMG activity increased mainly during phonation. To sample the IC muscle a shorter concentric electrode was used and inserted through the skin after lidocaine infiltration. The puncture was made at the level of the upper border of the thyroid cartilage in a posteromedial direction until the EMG activity (insertional burst) was noticed. Again, activity was increased
MATERIAL AND METHODS
The normal patterns of EMG activity of the pharyngeal muscles at rest and during deglutition were determined in subjects who were hospitalized in the Department of Otolaryngology of Hadassah University Hospital for reasons other than swallowing or aspiration problems. This "control" group included eight men and five women who were between 30 and 70 years of age (mean, 42 years). The various causes for hospitalization are listed in Table 1. All subjects were screened by clinical history and by a physical examination. None of them suffered from pharyngeal symptoms. The other group of patients included ten men and eight women between 35 and 75 years of age (mean,
From the Departments of Otolaryngology (Elidan, Gay) and Rehabilitation Medicine (Shochina, Gonen), Hadassah University Hospital, Jerusalem, Israel.
466
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Elidan et al, Electromyography of Pharyngeal Muscles TABLE 1. CAUSES FOR HOSPITALIZATION OF "CONTROL" CROUP OF PATIENTS Diagnosis Unilateral vocal cord polyp Unilateral vocal cord paralysis TI glottic carcinoma Acute laryngitis
No. of Patients 6 4 2 1
markedly during the act of swallowing, but was changed minimally or not at all by breathing or phonation. The EMG activity was amplified and displayed on a 15lOA Hewlett-Packard electromyograph, which has a frequency band of 15 to 5,000 Hz. A storage oscilloscope was connected to the electromyograph and triggered manually, either randomly to record resting activity or simultaneously with the start of a swallow. The stored EMG traces were photographed with a Polaroid camera. RESULTS
467
1. Patients in whom during swallowing there was only a slight or no increase at all in the EMG activity of the IC muscle (see Figure, D). 2. Patients in whom the "resting" activity in the CP muscle was increased markedly (see Figure, E). 3. Patients in whom no inhibition of activity in the CP muscle could be observed during swallowing, or in whom the drop in activity was smaller than that observed in the normal group. 4. Patients in whom there was abnormal timing between the burst of activity in the IC muscle and the inhibition of the CP muscle (see Figure, F). 5. Patients in whom various combinations of the above disturbances were observed.
Table 3 summarizes the type and the number of pathologic EMG traces among the various patients. It is evident that in patients who suffered from conditions such as motor neuron disease or progressive bulbar palsy, the most common finding was a lack of increased activity in the IC muscle, sometimes combined with abnormal synchronization with the CP muscle. These reflected mainly the weakness of hypopharyngeal contracture. On the other hand, in patients with idiopathic swallowing problems, increased resting (tonic) activity in the CP muscle was the main feature.
The normal EMG patterns of the CP and the IC muscles were determined in the "control" group. Whereas the IC muscle exhibited only minimal activity at rest, the CP muscle usually displayed marked resting activity (see Figure, A). When a swallow occurred, the IC muscle revealed a large burst of activity (about 0.5 mV maximal amplitude) lasting about 0.5 to 1 second. Simultaneously with or shortly before the initiation of the burst in the IC muscle, the resting activity of the CP muscle dropped markedly and almost disappeared (see Figure; A,B). It remained low until near the end of the IC burst. Quite often this inhibition of activity in the CP muscle was preceded by a short (20- to lOO-millisecond) burst (see Figure, C). Following the period of inhibition the CP muscle exhibited a second, larger and more intense burst ("rebound") lasting about 1 second, with gradual return to the preswallowing level of activity (see Figure; A,C). The EMG spikes of either the IC or the CP muscles reached up to 0.5 mV in amplitude and approximated 2 milliseconds in duration.
There is still a controversy in the literature regarding the role of the CP muscle and the IC muscle in the creation of the upper intraluminal high pressure zone and whether or not these muscles are "at rest" in tonic contraction. It was shown that at least in experimental animals the upper high pressure zone (sphincter) should be attributed in part to the elastic forces of the surrounding tissues and to the forward displacement of the larynx. 7 Moreover, CP myotomy in humans reduces but does not abolish the high pressure zone. I O• lI Doty'? was even more extreme in concluding that the upper high pressure zone is generated only by passive elasticity of the surrounding tissues.
Various deviations from the normal patterns were noticed among the patients with swallowing problems. The patients could be divided into five main categories:
A tonically contracted striated muscle should be associated with continuous EMG activity. This indeed was found in several studies in experimental animals'-" and in a few studies in humans. 5.8.9 In the
DISCUSSION
TABLE 2. CLINICAL DIAGNOSES AND SYMPTOMS IN DYSPHAGIA GROUP (N = 18)
Diagnosis Stroke Progressive bulbar palsy Pseudobulbar palsy Parkinson's disease Myasthenia gravis Motor neuron disease Multiple sclerosis Idiopathic swallowing problems (cricopharyngeal "spasm")
Dysphagia
Dysphagia and Aspiration
2 1 2 1 1
1
1 1
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Aspiration Alone
Dysphagia and Nasal Regurgitation
468
Elidan et al, Electromyography oj Pharyngeal Muscles
CP
CP
IC
IC
A
0.2 sec
B
10msec
CP
CP IC
;).
I~ C
0.2 sec
;).
I~ C)
D
0.2 sec
CP
CP ;).
I~ C)
IC
0.5 sec
E
F
0.2 sec
Recordings of EMG activity. A) Of cricopharyngeal (CP) and inferior pharyngeal constrictor (IC) muscles in "normal" subject, before and during act of swallowing. Note "resting" activity in CP muscle, which is almost absent in IC muscle (see text). B) Of CP and IC muscles during swallowing recorded in "normal" subject with short time base. Note intense activity in IC muscle, while CP muscle is completely silent. C) Of CP muscle in "normal" subject before and during swallowing. Note short burst that precedes inhibition phase. D) In patient who suffered from motor neuron disease (amyotrophic lateral sclerosis). Note pathologically increased activity in CP muscle prior to inhibition (arrow). On other hand, there is only slight increase of activity in IC muscle, which corresponds to its weakness. E) Of CP muscle in patient with idiopathic CP "spasm." Note pathologically increased activity before and after act of swallowing (which corresponds to period of inhibition). F) In patient with Parkinson's disease. There is disturbance in synchronization between activity in IC and CP muscles, manifested by prolonged activity in IC muscle overlapping "rebound" in CP muscle.
opossum," the IC muscle also demonstrated continuous spike activity at rest, thus contributing to the upper high pressure zone. In humans, however, only minimal EMG activity was found at rest in the IC muscle." In the present study, differences in EMG activity between CP and IC muscles were obvious in all the
"normal" subjects. For example, the resting activity was much more prominent in the CP muscle than in the IC muscle. Whereas the CP showed a phase of inhibition followed by a rebound burst during deglutition, such inhibition could not be detected in the IC muscle in any of the subjects. Considering also the temporal relationships between the activity in the two muscles (the burst in the IC muscle syn-
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Elidan et al, Electromyography of Pharyngeal Muscles TABLE 3. FREQUENCY AND NATURE OF DISTURBED EMG TRACES AMONG PATIENTS WITH SWALLOWING PROBLEMS EMG Disturbance Lack of normal increase of EMG activity in IC muscle Abnormal increased resting activity in CP muscle Lack of normal inhibition in CP muscle Abnormal synchronization between IC and CP muscles Combination of disturbances
Normal
No. of Patients 4
2 2
3 4
3
EMG - electromyographic, IC CP - cricopharyngeal.
Clinical Diagnosis (No. of Patients) Motor neuron disease (2); ~rogressive bulbar palsy (2) Idiopathic swallowing problems (2) Parkinson's disease (1); pseudobulbar palsy (1) Multiple sclerosis (1); Parkinson's disease (1); myasthenia gravis (1) Stroke (1); multiple sclerosis (1); motor neuron disease (1); progressive bulbar palsy (1) Myasthenia gravis (1); stroke (1); pseudobulbar palsy (1) inferior pharyngeal constrictor,
chronized with the inhibition in the CP muscle) we conclude that in humans, the IC muscle functions as part of the hypopharyngeal musculature that squeezes the bolus downward, in contrast to the opossum, in which the IC muscle was shown to be a part of the upper esophageal sphincter. 7 The recording of EMG activity in the IC and CP
469
muscles in patients suffering from swallowing problems was found to be a useful technique for the assessment of the function of these muscles and the deglutition mechanism in general in neurologic conditions. The test is relatively safe, is easy to perform after mastering the technique, and is associated with minimal inconvenience to the patient. The data obtained by this test are important in that they reflect in the most direct way the function of deglutition musculature. The test can reveal directly whether a disorder involves the hypopharyngeal contraction due to lack of increased activity in the IC muscle, CP muscle spasm due to increased resting activity, absence of the mechanical relaxation of the CP muscle due to lack of the normal inhibition of EMG activity during deglutition, or disturbed synchronization between the IC muscle's contraction and the CP muscle's relaxation. In many cases, various combinations of disturbed function were found. It is not intended that EMG recording should replace the traditional tests that are currently used for the evaluation of swallowing problems. However, we believe that EMG recording of the IC and CP muscles should be added to these tests, as it might improve the localization of the site of lesion and the selection of patients who are most likely to benefit from CP myotomy.
REFERENCES 1. Palmer ED. Disorders of the cricopharyngeus muscle: a review. Gastroenterology 1976;71:510-9.
7. Asoh R, Goyal RK. Manometry and electromyography of the upper esophageal sphincter in the opossum. Gastroenterology
2. Ross ER, Green R, Auslander MO, Biller HF. Cricopharyngeal myotomy: management of cervical dysphagia. Otolaryngol Head Neck Surg 1982;90:434-41.
1978;74:514-20. 8. Hellemans J, Vantrappen G, Valembois P, Janssens J, Vandenbrouche J. The electrical activity of human esophagus. Gastroenterology 1970;58:959.
3. Bonarina L, Khan NA, De Meester TR. Pharyngoesophageal dysfunctions. The role of cricopharyngeal myotomy. Arch Surg 1985;120:541-8. 4. Murakami Y, Fukuda H, Kirchner JA. The cricopharyngeus muscle - an electrophysiological and neuropharmacological study. Acta Otolaryngol [Suppl] (Stockh) 1972(suppI311).
9. Shipp T, Deatch WW, Robertson K. Pharyngoesophageal muscle activity during swallowing in man. Laryngoscope 1970; 80: 1-16. 10. Hurwitz AL, Duranceau A. Upper esophageal sphincter dysfunction. Pathogenesis and treatment. Am J Dig Dis 1978; 23:275-81.
5. Goyal RK, Cobb BW. Motility of the pharynx, esophagus and esophageal sphincters. In: Johnson LR, ed. Physiology of the gastrointestinal tract. New York: Raven Press, 1981:359-91.
11. Hurwitz AL, Nelson JA, Haddad JK. Oropharyngeal dysphagia: manometric and cineesophagographic findings. Am J Dig Dis 1975;20:313-24.
6. Levitt MN, Dedo HH, Ogura JH. The cricopharyngeus muscle, an electromyographic study in the dog. Laryngoscope 1965;75:122-36.
12. Doty RW. Neural organization of deglutition. In: Code CF, ed. Alimentary canal. Washington, DC: American Physiological Society, 1968:1861-902. (Handbook of physiology; vol 4.)
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
ELECTROMYOGRAPHY OF THE INFERIOR CONSTRICTOR AND CRICOPHARYNGEAL MUSCLES DURING SWALLOWING MARA SHOCHINA, MD
JOSEPH ELIDAN, MD BENJAMIN GONEN, MSc
ISAAC GAY, MD JERUSALEM, ISRAEL
Electromyography (EMG) of the inferior pharyngeal constrictor (Ie) and the cricopharyngeal (CP) muscle was recorded in 18 patients with swallowing and/or aspiration problems who were candidates for cricopharyngeal myotomy. The EMG recordings were compared to those of 13 "normal" subjects who did not suffer from such problems. Differences in EMG activity between the control group and the patient group were considered with respect to the clinical symptoms in the patient group. Recording of EMG in the CP and IC muscles is relatively safe, useful, and easily mastered. The technique may provide important information regarding the function of some of the muscles involved in deglutition. KEY WORDS -
dysphagia, electromyography, pharyngeal muscles.
52 years) who were hospitalized in various departments of our hospital and had been referred to our service for evaluation of swallowing and/or aspiration problems and for consideration of CP myotomy. These patients suffered from various neurologic and other conditions, which are summarized in Table 2. This Table shows also the various clinical symptoms within this patient group. An informed consent was obtained from all patients in whom EMG recordings were made.
Interest in the role of the cricopharyngeal (CP) muscle in disorders of swallowing has increased greatly in recent years.':" Extensive research has been conducted regarding the anatomy, innervation, and physiology of the upper esophageal sphincter. 4,S Several studies have been published on the recording of electromyographic (EMG) activity of the CP muscle and other pharyngeal muscles in experimental animals,":" but some of the data are contradictory. Few studies involving humans have been published, and even fewer in the English literature.v" In none of these studies were EMG recordings performed routinely in patients with swallowing problems.
For the EMG recordings, concentric needle electrodes (EINS2) were used. Lidocaine (1 %) was injected superficially under the skin at the puncture site, with care taken not to inject the muscles themselves.
The aim of the present study was to explore the EMG activity of the CP and inferior pharyngeal constrictor (IC) muscles in patients suffering from deglutition difficulties (with or without aspiration). These patients were candidates for surgical treatment by CP myotomy. This presumably would help in the localization of the site of lesion in the swallowing mechanism.
For the CP muscle the needle electrode was passed through the skin in a posterior and medial direction, at the level of and just lateral to the cricoid cartilage. The needle was advanced until it penetrated the CP muscle. When the needle entered the muscle there was a burst of activity - the insertional activity - that diminished gradually, reaching a resting "tonic" level. Functional verification of the location of the electrode was done by asking the patient to swallow and taking note of the change in the EMG activity. Typically, the CP muscle responded by a marked change in its activity only during the act of swallowing and very slightly or not at all during breathing or phonation. In cases in which the lateral cricoarytenoid muscle was penetrated accidentally, the EMG activity increased mainly during phonation. To sample the IC muscle a shorter concentric electrode was used and inserted through the skin after lidocaine infiltration. The puncture was made at the level of the upper border of the thyroid cartilage in a posteromedial direction until the EMG activity (insertional burst) was noticed. Again, activity was increased
MATERIAL AND METHODS
The normal patterns of EMG activity of the pharyngeal muscles at rest and during deglutition were determined in subjects who were hospitalized in the Department of Otolaryngology of Hadassah University Hospital for reasons other than swallowing or aspiration problems. This "control" group included eight men and five women who were between 30 and 70 years of age (mean, 42 years). The various causes for hospitalization are listed in Table 1. All subjects were screened by clinical history and by a physical examination. None of them suffered from pharyngeal symptoms. The other group of patients included ten men and eight women between 35 and 75 years of age (mean,
From the Departments of Otolaryngology (Elidan, Gay) and Rehabilitation Medicine (Shochina, Gonen), Hadassah University Hospital, Jerusalem, Israel.
466
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Elidan et al, Electromyography of Pharyngeal Muscles TABLE 1. CAUSES FOR HOSPITALIZATION OF "CONTROL" CROUP OF PATIENTS Diagnosis Unilateral vocal cord polyp Unilateral vocal cord paralysis TI glottic carcinoma Acute laryngitis
No. of Patients 6 4 2 1
markedly during the act of swallowing, but was changed minimally or not at all by breathing or phonation. The EMG activity was amplified and displayed on a 15lOA Hewlett-Packard electromyograph, which has a frequency band of 15 to 5,000 Hz. A storage oscilloscope was connected to the electromyograph and triggered manually, either randomly to record resting activity or simultaneously with the start of a swallow. The stored EMG traces were photographed with a Polaroid camera. RESULTS
467
1. Patients in whom during swallowing there was only a slight or no increase at all in the EMG activity of the IC muscle (see Figure, D). 2. Patients in whom the "resting" activity in the CP muscle was increased markedly (see Figure, E). 3. Patients in whom no inhibition of activity in the CP muscle could be observed during swallowing, or in whom the drop in activity was smaller than that observed in the normal group. 4. Patients in whom there was abnormal timing between the burst of activity in the IC muscle and the inhibition of the CP muscle (see Figure, F). 5. Patients in whom various combinations of the above disturbances were observed.
Table 3 summarizes the type and the number of pathologic EMG traces among the various patients. It is evident that in patients who suffered from conditions such as motor neuron disease or progressive bulbar palsy, the most common finding was a lack of increased activity in the IC muscle, sometimes combined with abnormal synchronization with the CP muscle. These reflected mainly the weakness of hypopharyngeal contracture. On the other hand, in patients with idiopathic swallowing problems, increased resting (tonic) activity in the CP muscle was the main feature.
The normal EMG patterns of the CP and the IC muscles were determined in the "control" group. Whereas the IC muscle exhibited only minimal activity at rest, the CP muscle usually displayed marked resting activity (see Figure, A). When a swallow occurred, the IC muscle revealed a large burst of activity (about 0.5 mV maximal amplitude) lasting about 0.5 to 1 second. Simultaneously with or shortly before the initiation of the burst in the IC muscle, the resting activity of the CP muscle dropped markedly and almost disappeared (see Figure; A,B). It remained low until near the end of the IC burst. Quite often this inhibition of activity in the CP muscle was preceded by a short (20- to lOO-millisecond) burst (see Figure, C). Following the period of inhibition the CP muscle exhibited a second, larger and more intense burst ("rebound") lasting about 1 second, with gradual return to the preswallowing level of activity (see Figure; A,C). The EMG spikes of either the IC or the CP muscles reached up to 0.5 mV in amplitude and approximated 2 milliseconds in duration.
There is still a controversy in the literature regarding the role of the CP muscle and the IC muscle in the creation of the upper intraluminal high pressure zone and whether or not these muscles are "at rest" in tonic contraction. It was shown that at least in experimental animals the upper high pressure zone (sphincter) should be attributed in part to the elastic forces of the surrounding tissues and to the forward displacement of the larynx. 7 Moreover, CP myotomy in humans reduces but does not abolish the high pressure zone. I O• lI Doty'? was even more extreme in concluding that the upper high pressure zone is generated only by passive elasticity of the surrounding tissues.
Various deviations from the normal patterns were noticed among the patients with swallowing problems. The patients could be divided into five main categories:
A tonically contracted striated muscle should be associated with continuous EMG activity. This indeed was found in several studies in experimental animals'-" and in a few studies in humans. 5.8.9 In the
DISCUSSION
TABLE 2. CLINICAL DIAGNOSES AND SYMPTOMS IN DYSPHAGIA GROUP (N = 18)
Diagnosis Stroke Progressive bulbar palsy Pseudobulbar palsy Parkinson's disease Myasthenia gravis Motor neuron disease Multiple sclerosis Idiopathic swallowing problems (cricopharyngeal "spasm")
Dysphagia
Dysphagia and Aspiration
2 1 2 1 1
1
1 1
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Aspiration Alone
Dysphagia and Nasal Regurgitation
468
Elidan et al, Electromyography oj Pharyngeal Muscles
CP
CP
IC
IC
A
0.2 sec
B
10msec
CP
CP IC
;).
I~ C
0.2 sec
;).
I~ C)
D
0.2 sec
CP
CP ;).
I~ C)
IC
0.5 sec
E
F
0.2 sec
Recordings of EMG activity. A) Of cricopharyngeal (CP) and inferior pharyngeal constrictor (IC) muscles in "normal" subject, before and during act of swallowing. Note "resting" activity in CP muscle, which is almost absent in IC muscle (see text). B) Of CP and IC muscles during swallowing recorded in "normal" subject with short time base. Note intense activity in IC muscle, while CP muscle is completely silent. C) Of CP muscle in "normal" subject before and during swallowing. Note short burst that precedes inhibition phase. D) In patient who suffered from motor neuron disease (amyotrophic lateral sclerosis). Note pathologically increased activity in CP muscle prior to inhibition (arrow). On other hand, there is only slight increase of activity in IC muscle, which corresponds to its weakness. E) Of CP muscle in patient with idiopathic CP "spasm." Note pathologically increased activity before and after act of swallowing (which corresponds to period of inhibition). F) In patient with Parkinson's disease. There is disturbance in synchronization between activity in IC and CP muscles, manifested by prolonged activity in IC muscle overlapping "rebound" in CP muscle.
opossum," the IC muscle also demonstrated continuous spike activity at rest, thus contributing to the upper high pressure zone. In humans, however, only minimal EMG activity was found at rest in the IC muscle." In the present study, differences in EMG activity between CP and IC muscles were obvious in all the
"normal" subjects. For example, the resting activity was much more prominent in the CP muscle than in the IC muscle. Whereas the CP showed a phase of inhibition followed by a rebound burst during deglutition, such inhibition could not be detected in the IC muscle in any of the subjects. Considering also the temporal relationships between the activity in the two muscles (the burst in the IC muscle syn-
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
Elidan et al, Electromyography of Pharyngeal Muscles TABLE 3. FREQUENCY AND NATURE OF DISTURBED EMG TRACES AMONG PATIENTS WITH SWALLOWING PROBLEMS EMG Disturbance Lack of normal increase of EMG activity in IC muscle Abnormal increased resting activity in CP muscle Lack of normal inhibition in CP muscle Abnormal synchronization between IC and CP muscles Combination of disturbances
Normal
No. of Patients 4
2 2
3 4
3
EMG - electromyographic, IC CP - cricopharyngeal.
Clinical Diagnosis (No. of Patients) Motor neuron disease (2); ~rogressive bulbar palsy (2) Idiopathic swallowing problems (2) Parkinson's disease (1); pseudobulbar palsy (1) Multiple sclerosis (1); Parkinson's disease (1); myasthenia gravis (1) Stroke (1); multiple sclerosis (1); motor neuron disease (1); progressive bulbar palsy (1) Myasthenia gravis (1); stroke (1); pseudobulbar palsy (1) inferior pharyngeal constrictor,
chronized with the inhibition in the CP muscle) we conclude that in humans, the IC muscle functions as part of the hypopharyngeal musculature that squeezes the bolus downward, in contrast to the opossum, in which the IC muscle was shown to be a part of the upper esophageal sphincter. 7 The recording of EMG activity in the IC and CP
469
muscles in patients suffering from swallowing problems was found to be a useful technique for the assessment of the function of these muscles and the deglutition mechanism in general in neurologic conditions. The test is relatively safe, is easy to perform after mastering the technique, and is associated with minimal inconvenience to the patient. The data obtained by this test are important in that they reflect in the most direct way the function of deglutition musculature. The test can reveal directly whether a disorder involves the hypopharyngeal contraction due to lack of increased activity in the IC muscle, CP muscle spasm due to increased resting activity, absence of the mechanical relaxation of the CP muscle due to lack of the normal inhibition of EMG activity during deglutition, or disturbed synchronization between the IC muscle's contraction and the CP muscle's relaxation. In many cases, various combinations of disturbed function were found. It is not intended that EMG recording should replace the traditional tests that are currently used for the evaluation of swallowing problems. However, we believe that EMG recording of the IC and CP muscles should be added to these tests, as it might improve the localization of the site of lesion and the selection of patients who are most likely to benefit from CP myotomy.
REFERENCES 1. Palmer ED. Disorders of the cricopharyngeus muscle: a review. Gastroenterology 1976;71:510-9.
7. Asoh R, Goyal RK. Manometry and electromyography of the upper esophageal sphincter in the opossum. Gastroenterology
2. Ross ER, Green R, Auslander MO, Biller HF. Cricopharyngeal myotomy: management of cervical dysphagia. Otolaryngol Head Neck Surg 1982;90:434-41.
1978;74:514-20. 8. Hellemans J, Vantrappen G, Valembois P, Janssens J, Vandenbrouche J. The electrical activity of human esophagus. Gastroenterology 1970;58:959.
3. Bonarina L, Khan NA, De Meester TR. Pharyngoesophageal dysfunctions. The role of cricopharyngeal myotomy. Arch Surg 1985;120:541-8. 4. Murakami Y, Fukuda H, Kirchner JA. The cricopharyngeus muscle - an electrophysiological and neuropharmacological study. Acta Otolaryngol [Suppl] (Stockh) 1972(suppI311).
9. Shipp T, Deatch WW, Robertson K. Pharyngoesophageal muscle activity during swallowing in man. Laryngoscope 1970; 80: 1-16. 10. Hurwitz AL, Duranceau A. Upper esophageal sphincter dysfunction. Pathogenesis and treatment. Am J Dig Dis 1978; 23:275-81.
5. Goyal RK, Cobb BW. Motility of the pharynx, esophagus and esophageal sphincters. In: Johnson LR, ed. Physiology of the gastrointestinal tract. New York: Raven Press, 1981:359-91.
11. Hurwitz AL, Nelson JA, Haddad JK. Oropharyngeal dysphagia: manometric and cineesophagographic findings. Am J Dig Dis 1975;20:313-24.
6. Levitt MN, Dedo HH, Ogura JH. The cricopharyngeus muscle, an electromyographic study in the dog. Laryngoscope 1965;75:122-36.
12. Doty RW. Neural organization of deglutition. In: Code CF, ed. Alimentary canal. Washington, DC: American Physiological Society, 1968:1861-902. (Handbook of physiology; vol 4.)
Downloaded from aor.sagepub.com at Bobst Library, New York University on July 10, 2015
