J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.70.3.363 on 1 March 2001. Downloaded from J Neurol Neurosurg Psychiatry 2001;70:363–371 363 Electrophysiological evaluation of oropharyngeal swallowing in myotonic dystrophy C Ertekin, N Yüceyar,~ I Aydog˘du, H Karasoy Abstract Myotonic dystrophy (MyD) is the most Objective—Oropharyngeal dysphagia is a common adult form of muscular dystrophy common feature of patients with myotonic and pneumonia was reported to be the most dystrophy and is not usually perceived due common cause of death in these patients.1 to their emotional deficits and lack of Pneumonia in MyD results from a multiplicity interest. The aim was to show the existence of problems. Oropharyngeal dysphagia and and frequency of subclinical electrophysi- oesophageal motility disorders were found to ological abnormalities in oropharyngeal be the most important reasons causing aspira- swallowing and to clarify the mechanisms tion pneumonia.2–6 Dysphagia may be even a of dysphagia in myotonic dystrophy. more prominent problem when the swallowing Methods—Eighteen patients with myot- disorder seems to be present early in the course onic dystrophy were examined for of disease but is not usually subjectively oropharyngeal phase of swallowing by perceived until the advanced stages of disease clinical and electrophysiological methods. are reached.6 Ten patients had dysphagia whereas 11 Patients with MyD often exhibit disorders of patients had signs and symptoms reflect- personality and impairment of intellectual and ing CNS involvement. Four patients with cognitive functions, especially lack of interest in myotonia congenita and 30 healthy volun- their disease.7 This might play a part in the teers served as controls. Laryngeal move- unawareness of the swallowing dysfunction in ments were detected by means of a these patients. Therefore, it is necessary to piezoelectric sensor. EMG activities of the evaluate the oropharyngeal deglutition and submental muscle (SM-EMG) and needle oesophageal motility in every patient with EMG of the cricopharyngeal muscle of the MyD. upper eosophageal sphincter (CP-EMG) Alterations in pharyngeal and oesophageal were also recorded during swallowing. functions have been reported in MyD on the Results—In about 70% of the patients with basis of both manometric and radiographic 2 3 6 8–11 myotonic dystrophy, the existence of studies. These methods are important; oropharyngeal dysphagia was indicated however they are time consuming, expensive, objectively by means of the technique of and sometimes diYcult to apply, especially “dysphagia limit” and by clinical evalua- when patients will not cooperate. Furthermore, tion. Duration of the swallowing reflex as the physiological basis of swallowing dysfunc- tion is not clearly understood, as some http://jnnp.bmj.com/ defined by the laryngeal relocation time 9–11 (0–2 time interval) and submental muscle conflicting results exist. The oropharyngeal excitation as a part of the swallowing swallowing function in MyD has not been reflex (A-C interval) were significantly studied by electrophysiological techniques. prolonged in patients with myotonic dys- Therefore we had two aims in this study; the trophy, especially in dysphagic patients. first was to show the existence and frequency of Triggering time of the swallowing reflex subclinical physiological abnormalities in Department of Clinical oropharyngeal swallowing, the second was to (A-0 interval) also showed significant pro- on September 27, 2021 by guest. Protected copyright. Neurophysiology, Ege longation, especially in the patients having consider the mechanisms leading to oropha- University Medical both dysphagia and CNS involvement. ryngeal dysphagia in MyD. School Hospital, Bornova,~ Izmir, During swallowing, CP muscle activity Turkey was abnormal in 40% of the patients with Patients and methods C Ertekin myotonic dystrophy. Eighteen patients with myotonic muscular dys- I Aydog˘du ~ Conclusion—Both myopathic weakness trophy were studied. Diagnosis of MyD was and myotonia encountered in oropharyn- based on clinical and electrophysiological find- Department of geal muscles play an important part in the Neurology ings and the history of the patients’ pedigrees. C Ertekin oral and the pharyngeal phases of swal- The severity of disease was classified from 1 to N Yüceyar lowing dysfunction in myotonic dystrophy. 5 using the muscular disability rating scale ~I Aydog˘du It was also suggested that CNS involve- described by Mathieu .12 The mean age of H Karasoy et al ment might contribute to the delay of the the patients was 38.8 (range 19–66 years). triggering of the swallowing reflex and Correspondence to: Eight were women. The mean duration of the Professor C Ertekin, Nilhan some abnormal EMG findings in the CP disease was 14.3 years (range 1–35 years). Apt 1357, sok No1, D-10, sphincter, resulting in oropharyngeal dys- Clinical features of all patients are summarised Alsancak,~ Izmir, Turkey phagia in myotonic dystrophy. [email protected] in table 1. Clinical diagnosis of dysphagia was (J Neurol Neurosurg Psychiatry 2001;70:363–371) defined when there were persistent symptoms Received 2 July 2000 and in (nasal regurgitation, frequent necessity to clear revised form Keywords: myotonic dystrophy; oropharyngeal dys- 2 November 2000 phagia; central nervous system; electrophysiological the throat, feeling of food in the nasopharynx) Accepted 6 November 2000 evaluation obtained from their questionnaire and abnor- www.jnnp.com J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.70.3.363 on 1 March 2001. Downloaded from 364 Ertekin, Yüceyar, Aydog˘duetal Table 1 Summary of the clinical features of patients with myotonic dystrophy Duration of MDR Dysphagic Other GI Patient Age/sex MyD (y) scale symptoms symptoms CNS Symptoms 1 23, F 7 3 + + AP, MRI 2 40, F 3 3 + + AP, EDS, MRI 3 23, M 16 2 − + AP, BIQ, EDS 4 20, F 5 2 − − AP, BIQ 5 42, M 27 3 + + AP, EDS, MRI 6 33, M 23 4 − − AP, BIQ, EDS 7 19, M 12 2 + − AP, BIQ, EDS 8 50, M 35 4 + + AP, BIQ, EDS, MRI 9 54, F 2 3 − − AP, BIQ, EDS 10 46, M 26 3 + + AP, BIQ, EDS, MRI 11 39, M 14 3 + − AP, BIQ, EDS 12 49, M 5 3 + − − 13 66, F 23 4 − − − 14 42, F 1 1 − − − 15 41, M 14 2 − − − 16 31, F 9 3 + + − 17 45, M 30 3 + − − 18 35, F 5 4 − + − MDR=Muscular disability rating scale12; +=present;−=absent; AP=apathy; EDS=excessive daytime sleepness; BIQ=borderline IQ or mental retardation; MRI=abnormal findings by cranial MRI42–44; GI=gastrointestinal. mal signs closely related to swallowing disorder untarily with the bolus (tap water) positioned (cough during swallowing, accumulation of on the tongue and the tip of the tongue touch- saliva in the mouth, “wet” voice after swallow- ing the upper incisors. Swallow signals were ing water, nasal voice, palatal paresis, abnormal recorded after the delivery of 3 ml water head posture during swallowing). The patients through a graduated syringe. Mechanical having uncertain symptoms but lacking any upward and downward laryngeal movements objective signs that could be related to during swallowing were detected by means of a swallowing were not considered to be dys- piezoelectric sensor designed in our laboratory. phagic. Therefore 10 patients with dysphagia This was a simple piezoelectric wafer with a and eight patients without dysphagia were 4x2.5 mm rubber bulge fixed into its centre. classified according to the clinical evaluation The rubber bulge was placed on the coniotomy for dysphagia. Clinical and laboratory findings region between the cricoid and thyroid carti- in patients were documented in detail in our lages at midline. The sensor was taped onto the neuromuscular unit and gastrointestinal symp- neck and its output signal was filtered (band toms and signs were especially evaluated by the pass 0.01–20 Hz) and fed into one of the chan- clinic of gastroenterology. nels of the EMG apparatus (Medelec Mystro, Patients with MyD were also reclassified for MS-20, Surrey, UK). The submental muscle their symptoms reflecting CNS involvement EMG (SM-EMG) was recorded by bipolar sil- such as excessive daytime sleepiness, apathy, ver chloride EEG electrodes taped under the and mental retardation.13 14 Their MRI findings chin over the submental muscle complex are shown in table 1. Eleven patients had (mylohyoid, geniohyoid, and anterior digastric symptoms and signs suggesting CNS involve- muscles). Signals were filtered (band pass http://jnnp.bmj.com/ ment (patient 1 to patient 11 in table 1). 100 Hz to 10 kHz), amplified, rectified, and Four patients with myotonia congenita were integrated. studied to clarify the pure eVect of myotonia on Cricopharyngeal muscle activity of the upper the electrophysiological findings. Patients with eosophageal sphincter was recorded with a congenital myotonia had generalised myotonia sterile needle electrode (Medelec disposable without any weakness determined by both needle electrode DMC-37) inserted through clinical and EMG methods. They had clinically the skin at the level of the cricoid cartilage no dysphagia. Their mean age was 33 (range about 1.5 cm lateral to its palpable lateral bor- on September 27, 2021 by guest. Protected copyright. 17–40 years, all men). der in the posterior median direction. The CP The mean values and individual results of sphincter EMG (CP-EMG) was recorded swallowing variables obtained from patients together with the laryngeal movement signals were compared with the mean values and under the same recording conditions as for the ranges of 30 normal control subjects. (mean SM-EMG. age 38.5; range 20–65 years, 15 women). The The laryngeal sensor gave two deflections cricopharengeal (CP) muscle of the upper with generally opposing polarity during each oesophageal sphincter was investigated in 13 swallow. The first deflection of the laryngeal patients with MyD and the results were sensor represented the upward movement of compared with 20 normal control subjects with the larynx and the second deflection its down- a mean age of 39.3 (range 22–61 years, 13 ward movement.