An EMG screening method (dysphagia limit) for evaluation of neurogenic dysphagia in childhood above 5 years old

Oropharyngeal dysphagia is not rare in older children before the adult age, especially the patients with cerebral palsy. Non-invasive simple tests are needed for the evaluation of children with neurogenic dysphagia including the patients with cerebral palsy. So we aimed to evaluate non-invasive ways to screen for dysphagia in children and the usefulness of this almost new electrophysiologic method for the detection of dysphagia in children with cerebral palsy. Twenty-eight healthy children and 12 patients with cerebral palsy were investigated for the applicability of this method. The movement of the larynx was monitored using a simple piezoelectric wafer sensor and submental surface EMG activity was recorded by bipolar silver-chloride electrodes taped under the chin over the submental muscle complex. The onset and duration of pharyngeal swallowing was recorded from submental-suprahyoid muscles such as the mylohyoid-genitohyoid-anterior digastric complex. By this method, the maximal water volume capacity was measured in single swallows with progressively increasing water volumes, this was called 'dysphagia limit'. The healthy control children revealed to swallow the bolus at once maximally 11.2+/-0.4 and 2.5 ml in average. Dysphagia limit varied from 7 to above 20 ml water volume from age 5-16 years old. Patients with cerebral palsy had the dysphagia limit of 7.7+/-1.8 and 6.4 ml in average. The dysphagia limit was significantly reduced in patients with cerebral palsy (p<0.05). Dysphagia limit seemed to be less sensitive in demonstrating the oropharyngeal swallowing disorders in childhood period (90% in the adult dysphagic patients). But the majority of patients with cerebral palsy (58%) showed abnormality. This electrophysiologic method is completely non-invasive, devoid from any hazard and applicable to children above 5 years. It may be candidate as a screening test before selection of dysphagic children.

Oropharyngeal swallowing in craniocervical dystonia

OBJECTIVE

To clarify the pathophysiology of dysphagia by electrophysiological methods.

METHOD

Electrophysiological methods related to oropharyngeal swallowing were used to investigate 25 patients with cervical dystonia and 25 age matched normal volunteers.

RESULTS

Dysphagia was suspected in 36% of patients with cervical dystonia on the basis of clinical assessment. The incidence of dysphagia increased to 72% on electrophysiological evaluation of pharyngeal swallowing. Submental muscle electromyographic (EMG) and laryngeal relocation times were significantly prolonged and the triggering time to swallowing reflex was significantly delayed. Some abnormalities seen in cricopharyngeal sphincter muscle EMG indicated that the striated sphincter muscle is hyperreflexive in some patients.

CONCLUSION

Neurogenic dysphagia was more prominent and longer lasting than mechanical dysphagia, which was transient and varied from patient to patient. Although these electrophysiological methods were not suitable for detecting anatomical changes during swallowing, as in videofluoroscopic studies, observations supported the neurogenic cause of dysphagia in patients with any kind of cervical dystonia.

Cerebral venous thrombosis in Down's syndrome

We report the first case of cerebral venous thrombosis (CVT) diagnosed in an adult with Down's syndrome (DS). A 25-year-old man with DS was admitted because of a generalized tonic-clonic seizure and prolonged postictal period. Cerebral magnetic resonance imaging (MRI) and MR venography revealed CVT. No particular cause of the thrombosis was identified. CVT may be an unusual cause of stroke in DS.

Dysphagia in lateral medullary infarction (Wallenberg's syndrome): an acute disconnection syndrome in premotor neurons related to swallowing activity?

BACKGROUND AND PURPOSE

We have investigated the pathophysiological mechanisms of dysphagia in Wallenberg's syndrome (WS) that are due to lateral medullary infarction (LMI).

METHODS

Twenty patients with WS were evaluated by means of clinical and electrophysiological methods that measured the oropharyngeal phase of voluntarily initiated swallowing. For comparison, 22 patients with unilateral hemispheric infarction were investigated during the acute stage of stroke, and 4 patients with unilateral peripheral 9th and 10th cranial nerve palsies were studied. Age-matched 30 healthy control subjects were also included in the study.

RESULTS

It was found that dysphagia was clinically more severe in WS patients than in the patients in the other groups. The pharyngeal phase of swallowing was predominantly impaired, whereas in patients with hemispheric stroke, dysphagia was related only to the delay of triggering of the voluntarily induced swallowing. In WS patients, the swallowing reflex was extremely slow in spite of the unilateral involvement due to LMI, whereas the pharyngeal phase of reflex swallowing remained within normal limits in patients with unilateral hemispheric stroke and patients with unilateral peripheral 9th and 10th cranial nerve palsies.

CONCLUSIONS

Although in WS the lesion due to LMI is unilateral, its effect on oropharyngeal swallowing is bilateral. In LMI, primarily the premotor neurons in the nucleus ambiguous and their connections seem to be affected. Consequently, a disruption and/or disconnection of their linkage to swallowing-related cranial motor neuron pools bilaterally and to the contralateral nucleus ambiguous could produce the swallowing disorders in WS. However, the remaining intact ipsilateral premotor neurons and the contralateral center in the medulla oblongata may eventually begin to operate and overcome the severity and long-term persistence of dysphagia.

The effect of head and neck positions on oropharyngeal swallowing: a clinical and electrophysiologic study

OBJECTIVES

To determine the clinical usefulness of an electrophysiologic method for evaluating dysphagia and to identify the effects of various head and neck positions on oropharyngeal swallowing.

DESIGN

Experimental, with control group.

SETTING

An electromyography laboratory.

PARTICIPANTS

Patients with neurogenic dysphagia (n = 51) and healthy controls (n = 24). Patients were divided into 2 groups: those patients with unilateral lower cranial lesions (n = 9) and those without laterality in the function of the oropharyngeal muscles (n = 42).

INTERVENTIONS

Subjects were instructed to swallow doses of water, gradually increasing in quantity from 1 to 25 mL under 5 conditions: neutral, chin up, chin tucked, head rotated right, and head rotated left.

MAIN OUTCOME MEASURES

Change in dysphagia limit through specified head and neck postures. Oropharyngeal swallowing was evaluated by laryngeal movements that were detected by a piezoelectric sensor and electromyography of the submental muscle complex. Laryngeal sensor signals occurring within 8 seconds of a swallow were accepted as a sign of the dysphagia limit.

RESULTS

In the control group, dysphagia limit did not change significantly with changes in head and neck postures, except for the chin-up posture (p <.05) in which piecemeal deglutition occurred when subjects swallowed volumes less than 20 mL. Dysphagia limit improved significantly (p <.05) in 67% of the patients with unilateral lower cranial lesions when the head was rotated toward the paretic side. In dysphagic patients with bilateral symptoms, a significant (p <.01) improvement in dysphagia limit occurred in 50% of patients in chin-tuck position, but in the chin-up position, 55% of the patients experienced a significant (p <.01) decrease in dysphagia limit.

CONCLUSION

The electrophysiologic method of measuring dysphagia limit confirms neurogenic dysphagia and its severity in the neutral head position. Changes in head and neck positions do not significantly alter dysphagia limit in unimpaired subjects except for the chin-up position. Although the results obtained were not compared with other techniques (eg, videofluoroscopy), this simple electrophysiologic method for describing dysphagia limit may have a place in the evaluation of dysphagia and its variability in various head and neck positions.

Effect of etiology and topography of lesion on body temperature at stroke onset

BACKGROUND AND PURPOSE

Hyperthermia is a well-known factor for neurologic deterioration, morbidity, and mortality in the early phase of stroke. However, the timing, localization of lesion, origin of stroke, which may influence body temperature, have not been clearly established.

METHODS

The purpose of this study was to determine the relationship between body temperature and origin, lesion topography, and prognosis at 3 months after onset of stroke. Axillary temperature was taken every hour for 72 hours in 473 patients with supra- or infratentorial cerebral vascular lesion. The time at which hyperthermia (>38 degrees C) appeared was evaluated by logistic regression analyses regarding to stroke origin and lesion localization. The correlation between body temperature and stroke outcome was quantified by Barthel index and American Heart Association Stroke Outcome Classification by recording in each 12- hour interval from stroke onset during 72 hours and after 3 months.

RESULTS

The body temperature was higher in patients with large-artery atherosclerosis (odds ratio [OR], 3.98; 95% confidence interval [CI] = 2.16-8.97; P = .001) and hemorrhagic stroke (OR = 2.05, 95% CI = 1.07-8.68, P = .001) than those with small-artery disease. In patients with posterior circulation infarct, the body temperature was higher than those with anterior circulation infarct (OR = 3.71, 95% CI = 2.07-6.67, P = .001), whereas there was no difference between patients with infratentorial hemorrhage and those with supratentorial hemorrhage (OR = 1.04, 95% CI = 0.75-1.43, P = .80). High body temperature at 24 hours of stroke onset (OR = 2.17, 95% CI = 2.09-7.57, P = .001) and 48 hours (OR = 1.27, 95% CI = 1.06-4.84, P = .02) was correlated with poor outcome and mortality.

CONCLUSION

An association between hyperthermia within 72 hours of ictus and stroke subtypes was observed among patients with ischemic and hemorrhagic stroke. Hyperthermic patients with total anterior circulation infarct, posterior circulation infarct, and supratentorial hemorrhage were associated with a marked increase of 3-months' mortality. Large-artery atherosclerosis, cardioembolism, and supra-infratentorial hemorrhage associated with hyperthermia may increase the severity of neurologic deficits.

Voluntary and reflex influences on the initiation of swallowing reflex in man

The electrophysiological features of voluntarily induced and reflexive/spontaneous swallows were investigated. In normal subjects, swallows were elicited by infusing water either into the mouth (1-3 ml) or directly into the oropharyngeal region through a nasopharyngeal cannula (0.3-1 ml). For water infused orally, subjects were either requested to swallow voluntarily or instructed to resist swallowing and maintain the horizontal head position until swallowing occurred reflexively. Spontaneous saliva swallowing was investigated in patients with severe dysphagia who had a prominent clinical picture of suprabulbar palsy. Comparisons between different swallowing types were made by measuring the time interval between the onset of submental electromyographic activity (SM-EMG) and the onset of the upward movement of the larynx recorded by a movement sensor. This interval was less than 100 ms, even frequently less than 50 ms, in reflexive/spontaneous swallows, while in voluntarily induced swallows it was substantially longer. The rising time of submental muscle's excitation was also shorter in reflexive/spontaneous swallows. It was suggested that the triggering of voluntarily induced swallows commences more than 100 ms before the onset of swallowing reflex and that this mechanism is under the control of corticobulbar-pyramidal pathways. If the swallowing reflex is triggered within such a short period of time following the onset of SM-EMG, the central control by the bulbar swallowing center should be effective until the end of oropharyngeal swallowing.

Cricopharyngeal sphincter muscle responses to transcranial magnetic stimulation in normal subjects and in patients with dysphagia

OBJECTIVE

Cricopharyngeal (CP) muscle of the upper oesophageal sphincter (UES) has a significant role in the pharyngo-esophageal phase of deglutition. The linkage between the CP muscle of UES and the motor cortex has not been previously studied electrophysiologically in healthy humans and in patients with neurogenic dysphagia.

METHODS

Needle recordings of EMG responses were carried out from the CP sphincter muscle following transcranial magnetic stimulation (TMS) over the vertex around the Cz electrode position (cortical MEP), and on the parieto-occipital skull and the occiput ipsilaterally (peripheral MEP) in 14 healthy control subjects and in 26 patients with and without neurogenic dysphagia. Needle recordings obtained from the cricothyroid muscle of the larynx were also evaluated in six healthy subjects.

RESULTS

The cortical motor latency of CP sphincter muscle was 10.7+/-0.5 ms with an amplitude of 0.8+/-0.2 mV in healthy subjects. Both the latency and amplitude of CP-MEP were facilitated during swallowing. The peripheral MEP of the CP muscle was very stable in all normal subjects (5.1+/-0.3 ms; 1.3+/-0.3 mV) and swallowing did not influence these parameters. The cortically elicited CP-MEP was significantly longer than the cortical MEPs obtained from the cricothyroid muscle of the larynx. In 10 dysphagic patients with corticobulbar tract involvement (6 ALS and 4 pseudobulbar palsy) and with pathologic and hyperreflexic EMG of the CP-sphincter muscle, the cortical MEP of CP muscle of the upper esophageal sphincter could not be elicited, although the peripheral CP-MEPs were obtained. TMS never produced a swallowing movement in neither healthy subjects nor patients.

CONCLUSION

The CP muscle of the upper esophageal sphincter can produce MEPs by cortical TMS and by stimulation at the root/nerve levels of vagus nerve. The MEP latency values and central motor delay suggest that there is an oligosynaptic corticobulbar pathway to the motoneurons of CP muscles. When the pathway is affected by a pathology (i.e. ALS or pseudobulbar palsy) the CP sphincter becomes hyperreflexic due to disinhibition and the cortical MEP of the CP muscle disappears due to degeneration of the corticobulbar pathway. These mechanisms appear to be responsible for the pathogenesis of dysphagia.

Effect of mucosal anaesthesia on oropharyngeal swallowing

The effect of the topical anaesthesia of the oropharyngeal mucosae was studied in order to evaluate the role of the mucosal sensory receptors on the oropharyngeal swallowing in 12 adult volunteers. Laryngeal vertical movements were detected by a piezoelectric sensor and electromyography of the submental muscle complex were simultaneously recorded. All subjects were instructed to swallow doses of water, gradually increasing in quantity from 3-20 mL and any recurrence of the signals related to swallowing within 8 s was accepted as a sign of dysphagia and its limit value measured. Before the topical anaesthesia of the oropharyngeal mucosae by xylocaine puffs; the dysphagia limit was never observed with less than 20 mL water. During topical mucosal anaesthesia lasting 4-6 min among the subjects, the dysphagia limit was less than 20 mL water and the recurrence of swallows two or more times was mainly recorded with 3-5 mL water. Five of the subjects demonstrated the clinical and electrophysiological signs of laryngeal aspiration at the earlier period of the topical anaesthesia. It is concluded that the sensory inputs from the mucosal receptors are important to trigger voluntary swallowing and their absence or dysfunction may contribute to oropharyngeal dysphagia and laryngeal aspiration.

Mechanisms of dysphagia in suprabulbar palsy with lacunar infarct

BACKGROUND AND PURPOSE

The objective of the present study was to investigate the neural mechanisms of dysphagia in suprabulbar palsy (SBP) with multiple lacunar infarct.

METHODS

We evaluated the swallowing disorders of patients with SBP (n=34) and age-matched healthy control subjects (n=35) by means of an electrophysiological method that recorded the oropharyngeal swallowing patterns. With this method, dysphagia limit, the triggering of voluntarily initiated swallows, duration of laryngeal relocation time, and total duration of oropharyngeal swallowing were recorded and measured. In addition, the EMG behavior of the cricopharyngeal (CP) muscle of the upper esophageal sphincter was also assessed.

RESULTS

In patients with SBP, the dysphagia limit in all except 1 patient was pathological with limits of <20-mL bolus volume, which is contrary to normal subjects, in whom the dysphagia limit exceeds the 20-mL bolus volume. Either triggering of swallowing reflex was delayed (P<0.04), or the swallow could hardly be triggered in 7 patients on the voluntary attempts for 3 mL water. Whenever the reflex swallowing could be triggered, it was slow and prolonged (P<0.01). The CP muscle of the upper esophageal sphincter appeared to have become hyperreflexic and incoordinated with laryngeal movements during swallowing.

CONCLUSIONS

It was proposed that the progressive involvement of the excitatory and inhibitory corticobulbar fiber systems linked with the bulbar swallowing center is mainly responsible for the triggering difficulties of the swallowing reflex and for the hyperreflexic/incoordinated nature of the CP sphincter. In addition, the dysfunction of the extrapyramidal system has a specific role in the slowing of oropharyngeal swallowing and the accumulation of saliva in the mouth.

The electromyographic behavior of the thyroarytenoid muscle during swallowing

The electromyographic (EMG) behavior of the laryngeal adductors (e.g., the thyroarytenoid [TA] muscle) during swallowing has been scarcely studied. However, the detailed analysis of TA muscle is important to understand the physiology of swallowing. We investigated 14 healthy adult subjects. Activation of the TA laryngeal adductor muscle was compared with the mechanically measured laryngeal up-down movement and with the onset of excitation of laryngeal elevators, such as submental (SM) muscles, during swallowing. The laryngeal adductor of TA and laryngeal elevators of SM muscles were electromyographically (integrated/rectified) recorded. The vertical laryngeal movements during swallowing were recorded using a piezoelectric sensor. The EMG behavior of the TA muscle revealed three different activities during swallowing. The basic activity was stable; it almost started with the upward movement of larynx and after the SM-EMG onset. A fore-burst was recorded just before the upward movement of the larynx and a late-burst appeared just after the downward movement. The fore-burst was proposed to be related with oral-laryngeal reflexes, and the late-burst could be a rebound activity after a short expiration of swallowing, while the basic activity is accepted to be a part of activity of central-pattern generator of swallowing program.

Pathophysiological mechanisms of oropharyngeal dysphagia in amyotrophic lateral sclerosis

We investigated the pathophysiological mechanisms of dysphagia in amyotrophic lateral sclerosis. Forty-three patients with sporadic amyotrophic lateral sclerosis were examined by clinical and electrophysiological methods that objectively measured the oropharyngeal phase of voluntarily initiated swallowing, and these results were compared with those obtained from 50 age-matched control subjects. Laryngeal movements were detected by a piezoelectric sensor and EMG of submental muscles, and needle EMG of the cricopharyngeal muscle of the upper oesophageal sphincter of both the amyotrophic lateral sclerosis and control groups was recorded during swallowing. Amyotrophic lateral sclerosis patients with dysphagia displayed the following abnormal findings. (i) Submental muscle activity of the laryngeal elevators, which produce reflex upward deflection of the larynx during wet swallowing, was significantly prolonged whereas the laryngeal relocation time of the swallowing reflex remained within normal limits. (ii) The cricopharyngeal sphincter muscle EMG demonstrated severe abnormalities during voluntarily initiated swallows. The opening of the sphincter was delayed and/or the closure occurred prematurely, the total duration of opening was shortened and, at times, unexpected motor unit bursts appeared during this period. (iii) During voluntarily initiated swallows there was significant lack of co-ordination between the laryngeal elevator muscles and the cricopharyngeal sphincter muscle. These results point to two pathophysiological mechanisms that operate to cause dysphagia in amyotrophic lateral sclerosis patients. (i) The triggering of the swallowing reflex for the voluntarily initiated swallow is delayed and eventually abolished, whereas the spontaneous reflexive swallows are preserved until the preterminal stage of amyotrophic lateral sclerosis. (ii) The cricopharyngeal sphincter muscle of the upper oesophageal sphincter becomes hyper-reflexic and hypertonic. As a result, the laryngeal protective system and the bolus transport system of deglutition lose their co-ordination during voluntarily initiated swallowing. We conclude that these pathophysiological changes are related mainly to the progressive degeneration of the excitatory and inhibitory corticobulbar pyramidal fibres.

Generalized tonic-clonic status epilepticus: causes, treatment, complications and predictors of case fatality

We retrospectively reviewed the clinical course of 66 patients treated for generalized tonic-clonic status epilepticus at the Ege University neurological intensive care unit from 1988 to 1997. Seventy-two per cent of the study group had a pre-existing seizure disorder, and antiepileptic drug withdrawal was the most prominent cause of status epilepticus. The other causes included drug toxicity, central nervous system infection, cerebrovascular disease, tumour and trauma. Seventy-three per cent of all patients responded to the first-line therapy (diazepam and/or phenytoin), and the remainder were considered to have refractory status epilepticus and required pentobarbital anaesthesia. Overall case fatality was 21%, but death could be attributed directly to status epilepticus and/or treatment complication in 10% of the study group. Major determinants of fatal outcomes were: increasing age, longer duration of status epilepticus before initiation of therapy and central nervous system infection as a causal factor.

Electrodiagnostic methods for neurogenic dysphagia

OBJECTIVE

Swallowing mechanisms and neurogenic dysphagia have not been systematically studied by the EMG technique. It is desirable to evaluate neurogenic dysphagia for diagnostic and possibly for therapeutic purposes using electrophysiological methods.

METHODS

The following methods were described: mechanical upward/downward movements of the larynx were detected using a piezoelectric sensor, while submental integrated EMG activity was recorded during dry and wet swallowing. The EMG activity of cricopharyngeal muscle of the upper oesophageal sphincter was also recorded in some normal subjects and patients. Piecemeal deglutition and the dysphagia limit were determined in all patients to detect dysphagia objectively. In this study 75 normal subjects and 177 neurological patients with various degrees of dysphagia were investigated.

RESULTS

Voluntarily triggered oropharyngeal swallowing was commonly pathological in the majority of patients, with or without overt dysphagia. The dysphagia limit appeared to be an objective measure of the degree of dysphagia in more than 90% of patients. Pathophysiological mechanisms were different in at least three groups of patients with neurogenic dysphagia. In the group of patients with muscular disorders, laryngeal elevators were involved while the CP-sphincter was intact. The second group included patients with the clinical signs of corticobulbar fibre involvement such as amyotrophic lateral sclerosis and pseudobulbar palsy. In these patients, there was incoordination between paretic laryngeal elevators and hyperreflexic CP-sphincter. In the third group (patients with Parkinson's disease), the swallowing reflex was delayed and prolonged.

CONCLUSIONS

EMG methods described in the present study are very useful for the diagnosis of neurogenic dysphagia, objectively and quickly. They are important to understand the physiological mechanisms for deglutition and its disorders.