Assessment of in vivo spinal cord conduction velocity in rats in an experimental model of ischemic spinal cord injury.

STUDY DESIGN: Experimental laboratory investigation of spinal cord conductivity alterations in a rat model of ischemic spinal cord injury (SCI). OBJECTIVE: To observe the epidural spinal cord stimulation-induced electromyography responses, and to investigate the possible alterations of spinal cord conduction velocity (SCCV) and compound muscle action potentials (CMAPs) after ischemic SCI in rats. SETTINGS: Adnan Menderes University, Institute of Health Science, Aydin, Turkey. METHODS: SCI was induced by transient occlusion of the abdominal aorta in male Sprague-Dawley rats. Spinal cord histopathology was examined to determine neuronal damage and Tarlov scale was used to grade locomotor functions. Epidural electrical stimulation of spinal cord was performed by monopolar needle electrodes sequentially at L1-L2 and L5-L6 levels, and CMAPs were recorded from the left gastrocnemius muscle by surface electrodes. Amplitudes and durations of CMAPs were evaluated and SCCVs were calculated by analyzing the latency difference of CMAPs. RESULTS: Ischemia-induced SCI resulted in significant reduction of Tarlov scores and a significant decline in number of viable neurons. Similarly, a significant decrement was observed in SCCV following spinal cord ischemia. CONCLUSION: This study demonstrated that measurement of SCCV via epidural electrical stimulation is possible and displays a significant decline after spinal cord ischemia in rats. We suggest that this method can be beneficial to quantify neuronal damage after experimental ischemic SCI.

Cerebral vasculitis as a major manifestation of rheumatoid arthritis.

OBJECTIVE AND IMPORTANCE: Cerebral vasculitis (CV) is a rare described complication of rheumatoid arthritis (RA). Although the most frequent neurological manifestations of RA are peripheral neuropathy and cervical spinal cord compression due to subluxation of the cervical vertebrae, CV can be seen especially in patients with seropositive and long-standing RA. CLINICAL PRESENTATION: We report two cases of CV associated with RA. Both patients had no extraarticular manifestations and RA clinics were under control. Our first case is a 30-years-old woman with seropositive RA for 15 years who had suddenly onset left facial and upper extremity weakness. In magnetic resonance imaging (MRI) DWI, hyperintensity in frontotemporal region due to acute ischaemia was detected. The new lacuner acute ischaemic lesions in right precentral gyrus, bilateral frontoparietal and corpus callosal region were detected in the control MRI. The cerebral MR angiography and transcranial doppler findings were consistent with CV. The patient responded favourably to pulse methylprednisolone and oral azathiopurine treatments. The second patient is a 52-year-old man who had been RA for 29 years. He admitted to our neurology clinic with speech difficulty and right upper extremity minimal weakness. Magnetic resonance imaging DWI showed left parietooccipital acute ischaemia which was progressed within a week and a new right parietooccipital ischaemia was added. His cerebral MR angiography and cerebral angiography were concordant with CV. The cyclophosphamide therapy was started since the cerebral ischaemia was progressed during pulse methylprednisolone and he responded well to this therapy. CONCLUSION: CV due to RA is an uncommon serious complication which can be life-threatening. Therefore clinicians should be aware of the possibility of CV especially in progressive strokes in RA.

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.

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.

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.

Repeated hypoglycemia and cognitive decline. A case report.

OBJECTIVE: Diabetes mellitus has a high incidence in general population and goes by high morbidity by specific micro vascular pathology in the retina, renal glomerul and peripheral nerves. In type 1 DM, intensive therapy can prevent or delay the development of long-term complications associated with DM but hypoglycaemia especially severe hypoglycaemia defined, as a low blood glucose resulting in stupor, seizure, or unconsciousness that precludes self-treatment is a serious threat. Hypoglycaemia that may preferentially harm neurons in the medial temporal region, specifically the hippocampus, is a potential danger for the brain cognitive function which several studies failed to detect any significant effects, whereas others indicated an influence on it. A young diabetic case presented here with severe cognitive defect. Great number of severe hypoglycaemic or hyperglycaemic attacks and convulsion episodes were described in his medical history. RESULTS AND CONCLUSION: Neuroradiologic findings on CT and MRI, pointed that global cerebral atrophy that is incompatible with his age. Brain perfusion studies (SPECT, (99m)Tc-labeled HMPAO) also showed that there were severe perfusion defects at superior temporal region and less perfusion defects at gyrus cingulum in frontal region. These regions are related with memory processing. Severe cognitive defect in this patient seems to be closely related these changes and no another reason was found to explain except the repeated severe hypoglycaemic episodes.

Epidemiology and clinical characteristics of migraine among school children in the Menderes region.

The goal of this study was to collect and analyse information on the prevalence of childhood migraine and disability due to migraine in primary school children of 4th to 8th grades (ages ranging from 9 to 17 years) in the Aydin urban area. A cross-sectional school-based study was conducted between March and June 2004. There were 76 333 children of 4th to 8th grades in primary schools in Aydin. Nearly 10% of this population (7721 out of 76 333) was evaluated by a multistage clustered sampling procedure. Four questionnaire forms were applied to each child by a study neurologist during class time. Questionnaire A consisted of a single question, 'Have you ever had a headache?'. To those who responded 'yes', questionnaire B was applied as a second step, which consisted of eight questions. Diagnosis of migraine headache was made according to International Classification of Headache Disorders 2004. Migraine disability was measured with questionnaire C, which was originally the Pediatric Migraine Disability Assessment (PedMIDAS). Migraine history, previous migraine diagnosis and pain intensity were measured with questionnaire D. According to questionnaire A, 79.6% of boys and 87.1% of girls suffered from headaches. The prevalence of migraine was 9.7% (7.8% in boys, 11.7% in girls) according to questionnaire B. The male:female ratio was 1:1.5. Total PedMIDAS score was 9.94 +/- 8.41 days in boys and 11.50 +/- 12.28 days in girls. Only 1.9% of the children had previously been diagnosed with migraine. The average migraine headache history was 2.48 +/- 1.18 years in girls and 2.57 +/- 1.18 years in boys. Although migraine is a common health problem among school children in Aydin, it is mostly still under-recognized.

Proximal and distal motor nerve conduction in obturator and femoral nerves.

OBJECTIVE: To study the proximal and distal motor conduction properties of obturator and femoral nerves. DESIGN: For evaluation of distal motor conduction properties, obturator and femoral nerves were stimulated at the inguinal ligament, and M responses were recorded with needle electrodes from gracilis and rectus femoris muscles. Upper lumbar roots were stimulated with needle electrodes inserted between L1-L2 vertebral laminae. PARTICIPANTS: Sixteen healthy adults, eight of each gender, age 22 to 52 years (mean 37.5). MAIN OUTCOME MEASURES: Description of a method for assessing motor conduction along the obturator nerve and evaluating proximal motor conduction measurements obtained with stimulation of obturator and femoral nerves. RESULTS: Distal motor conduction latencies were 3.9 +/- 0.7 msec for gracilis and 4.6 +/- 0.5msec for rectus femoris after stimulation of obturator and femoral nerves, respectively. Proximal conduction times from lumbar vertebral level were 10.4 +/- 0.3msec for the obturator nerve and 10.8 +/- 0.4msec for the femoral nerve. Conduction velocities of proximal segments of both nerves were similar, 62m/sec for the obturator nerve and 65m/sec for the femoral nerve. Submaximal stimulation of both nerves evoked H-reflex responses from their associated muscles. CONCLUSIONS: Motor conduction properties of the obturator nerve can be assessed by the method described, particularly to differentiate between peripheral, plexus, or radicular lesions that involve the obturator nerve.

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.

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.

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.

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.

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.

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.