Best Practice Recommendations for Stroke Patients with Dysphagia: A Delphi-Based Consensus Study of Experts in Turkey-Part I: Management, Diagnosis, and Follow-up.

Dysphagia is one of the most common and important complications of stroke. It is an independent marker of poor outcome after acute stroke and may become chronic after the acute period and continues to affect all aspects of the patient's life. Patients with stroke may encounter any of the medical branches in the emergency room or outpatient clinic, and as in our country, there may not be specialists specific for dysphagia, such as speech-language pathologists (SLP), in every hospital. This study aimed to raise awareness and create a common opinion of medical specialists for stroke patients with dysphagia. This recommendation paper has been written by a multidisciplinary team and offers 45 recommendations for stroke patients with dysphagia. It was created using the eight-step Delphi round via e-mail. This study is mostly specific to Turkey. However, since it contains detailed recommendations from the perspective of various disciplines associated with stroke, this consensus-based recommendation paper is not only a useful guide to address clinical questions in practice for the clinical management of dysphagia in terms of management, diagnosis, and follow-up, but also includes detailed comments for these topics.

Best Practice Recommendations for Stroke Patients with Dysphagia: A Delphi-Based Consensus Study of Experts in Turkey-Part II: Rehabilitation.

Dysphagia is one of the most common and important complications of stroke. It is an independent marker of poor outcome following acute stroke and it continues to be effective for many years. This consensus-based guideline is not only a good address to clinical questions in practice for the clinical management of dysphagia including management, diagnosis, follow-up, and rehabilitation methods, but also includes detailed algorithms for these topics. The recommendation paper has been written by a multidisciplinary team and offers 117 recommendations for stroke patients with dysphagia. While focusing on management principles, diagnosis, and follow-up in the 1st part (45 items), rehabilitation details were evaluated in the 2nd part (72 items).

Human cremaster muscle and cremasteric reflex: A comprehensive review.

OBJECTIVE: Human research on the cremaster muscle (CM), cremasteric reflex (CMR) and genitofemoral nerve (GFN) and reports on their clinical applications using electrophysiological and histological techniques are rare. We aimed to present a detailed review of the human CM and CMR based on our earlier publications and relevant literature. METHODS: Electromyography (EMG) of the CM was recorded using disposable needle electrodes. CMR was obtained with tactile and/or electrical stimulation of the inner thigh. Transcranial magnetic stimulation (TMS) and magnetic stimulation of the upper lumbar roots were applied; GFN was stimulated using a surface electrode at the anterior superior iliac spine. RESULTS: CM striated fibers comprised multiple motor end plates. CM needle EMG results were similar to those of the limb muscles in chronic neurogenic disorders. TMS produced clear-cut evoked motor responses from CM. GFN motor conduction time to CM was absent or delayed in patients with inguinal hernia. EMG of CM was abnormal in 40% of patients with premature ejaculation. CONCLUSION: CM is different from other skeletal muscles both morphologically and physiologically. Intersegmental sacrolumbar reflexes are useful for evaluating ejaculatory dysfunction. SIGNIFICANCE: CM is an important muscle for testis thermoregulation and sexual reflexes. Neurophysiological techniques are available for physiological and clinical studies.

Swallow-induced syncope in 5 patients: Electrophysiologic evaluation during swallowing.

BACKGROUND: We sought to characterize a cohort of participants with swallow-induced syncope (SIS) with clinical and electrophysiologic evaluations. METHODS: Using electrocardiographic monitoring and neurophysiologic methods of swallowing, we evaluated a cohort of 5 patients with SIS, 4 of whom had longitudinal follow-up. RESULTS: We determined electrophysiologically that the duration between the onset of swallow and a bradyarrhythmia or asystole is extremely short (2-3 seconds) in SIS. Most participants with SIS do not have a neurologic or esophageal disorder. SIS can occur with different food types, in sitting or standing position, and has varying frequency in different participants. Permanent pacemaker placement is a curative measure in SIS. CONCLUSIONS: Our findings suggest that SIS is elicited by reflex afferent pathways originating in the oropharynx, rather than an esophageal origin, as previously proposed. Our longitudinally followed cohort with detailed clinical and electrophysiologic characterization should aid the clinician in the diagnosis and treatment of this potentially life-threatening condition.

Spontaneous yawning in patients with multiple sclerosis: A polygraphic study.

BACKGROUND: Patients with multiple sclerosis (MS) suffer from the repetitive yawning and sleep problems. Yawning is observed in MS and other central nervous system disorders and yawning and swallowing may be controlled by the network of the brain stem. Therefore it is important to investigate the MS patients with various clinical and radiological locations in order to understand the role of brainstem on the yawning mechanisms. One hour polygraphic recording would be crucial method for this purpose, because it is easy to observe spontaneous yawning (SY) and spontaneous swallowing (SS) together with their electrophysiologic counterparts. Previous studies reported that contagious yawn and swallow are temporally related and frequency of swallows was increased within 10s of post yawn period in normal adult subjects. We have re-investigated this phenomenon by studying the SY and SS in polygraphic recording in normal subjects and patients with MS. Then we hypothesized that SY is expected to be increased in MS patients. METHODS: 49 patients with MS and 19 control subjects were recruited in this study. We used a twelve-channel electroencephalography (EEG) device. Five channels were for electromyography (EMG) recording. We also used one channel for laryngeal sensor for vertical movements of the larynx during swallowing. Cardiac rhythm, respiration and sympathetic skin responses were synchronously recorded during swallowing. We evaluated rate of total SY, swallows inside the yawning, before and after 10s of the yawning and yawning unrelated with swallowing. RESULTS: Patients with MS yawned more frequently than healthy controls (p = 0,044). It was obvious that the yawning unrelated with spontaneous swallow was also significantly increased compared to normal controls (p = 0,047), whereas swallowing inside the yawn or before and after 10s of yawning were not significantly different in both groups. Among 49 MS patients, 16 (32.6%) had brainstem involvement. Yawning was observed in only 6 (37.5%) of them. CONCLUSION: Yawning is significantly increased in MS patients compared to normal controls by using the polygraphic method. There is no direct relation of the brainstem and the origin of yawning in MS patients according to clinical picture and MRI findings. However safe swallows during yawning could suggest that there is still need to some brain stem mechanism and/or oropharyngeal reflexes. Difficulties must be emphasized to detect anatomic localization in MS because of relapsing pattern of disease.

Guillain-Barré Syndrome and Swallowing Dysfunction.

PURPOSE: Patients with Guillain-Barré syndrome (GBS), especially severe cases that require treatment in intensive care units, often experience swallowing difficulties. However, the oropharyngeal function of patients with GBS not treated in intensive care units is not typically evaluated using neurophysiological techniques. METHODS: Electrophysiological techniques were used to determine dysphagia limit and sequential water swallowing values in an electromyography laboratory. RESULTS: This study assessed 18 patients with GBS who were not treated in the intensive care unit between 4 and 45 days after their hospital admission; 18 healthy volunteers were used as a control group. Of the 18 patients with GBS, 7 exhibited the clinical involvement of either a single cranial nerve or a combination of cranial nerves while 11 did not show any lower cranial nerve involvement. Clinical dysphagia was observed in seven patients and six of these cases involved a lower cranial nerve while five patients without cranial nerve involvement had silent dysphagia according to the dysphagia limit test. In addition, the duration of sequential swallowing was significantly prolonged in all patients with GBS compared with the control subjects. CONCLUSIONS: The present findings demonstrated that neurophysiological techniques are useful and easily applicable for patients with GBS and that there were no complications. Furthermore, cranial nerve involvement in patients with GBS likely increased the incidence of oropharyngeal dysphagia, and subclinical dysphagia may be present in this population as well. Therefore, neurophysiological techniques can be initially used and then repeated during follow-up visits for all types of patients with GBS.

Peripheral component of laryngeal and pharyngeal motor evoked potentials.

In this study, the responses of thyroarytenoid (TA) and cricopharyngeus (CP) muscles were simultaneously recorded to peripheral magnetic stimulation of the vagus nerve. Recordings were performed in 13 subjects by means of concentric needle EMG electrodes inserted in the TA and CP. Magnetic shocks were delivered to the vagus nerve with a round coil placed occipitally, while EMG was silent in the TA. In all subjects, clear-cut responses were obtained simultaneously in both muscles. In TA compared to CP, the maximum amplitude of the responses were higher, whereas the onset latency was shorter. Our results revealed that simultaneous recordings of TA and CP motor responses to occipital magnetic stimulation enabled a reliable evaluation of their peripheral innervation by the vagus nerve.

Dysphagia in Alzheimer's disease.

OBJECTIVE: To investigate electrophysiological parameters of swallowing in all stages of Alzheimer's disease. METHODS: Forty Alzheimer's disease patients, 20 age-matched normal controls and 20 young normal controls were included. Dysphagia limit (DL) and sequential water swallowing (SWS) tests were performed. Cardiac rhythm, respiration and sympathetic skin responses were concomitantly recorded. RESULTS: Dysphagia was found in 30/40 (75%) of Alzheimer's disease patients. Mean volume at the DL test was significantly reduced (16.5±1.0mL) in the Alzheimer's disease group. Swallowing and apnea times in the SWS test were significantly prolonged in elderly controls, but even longer in Alzheimer's disease patients. CONCLUSIONS: Alzheimer's disease patients had electrophysiological features of dysphagia, even in the early period of disease. The cortical involvement and severity of cognitive disorder can increase swallowing problems, but subclinical signs of dysphagia may be observed even in patients with mild or moderate Alzheimer's disease.

Spontaneous Swallowing during All-Night Sleep in Patients with Parkinson Disease in Comparison with Healthy Control Subjects.

STUDY OBJECTIVES: Spontaneous saliva swallows (SS) appear especially during sleep. The rate of SS was rarely investigated in all-night sleep in patients with Parkinson disease (PD). Dysphagia is a frequent symptom in PD, but the rate of SS was never studied with an all-night sleep electroencephalogram (EEG). METHODS: A total of 21 patients with PD and 18 age-matched healthy controls were included in the study. Frequencies of SS and coughing were studied in all-night sleep recordings of patients with PD and controls. During all-night sleep, video-EEG 12-channel recording was used including the electromyography (EMG) of the swallowing muscles, nasal airflow, and recording of vertical laryngeal movement using a pair of EEG electrodes over the thyroid cartilage. RESULTS: The total number of SS was increased while the mean duration of sleep was decreased in PD when compared to controls. Sialorrhea and clinical dysphagia, assessed by proper questionnaires, had no effect in any patient group. The new finding was the so-called salvo type of consecutive SS in one set of swallowing. The amount of coughing was significantly increased just after the salvo SS. CONCLUSIONS: In PD, the rate of SS was not sufficient to demonstrate the swallowing disorder, such as oropharyngeal dysphagia, but the salvo type of SS was quite frequent. This is a novel finding and may contribute to the understanding of swallowing problems in patients with dysphagic or nondysphagic PD.

Electrophysiological Techniques to Evaluate Swallowing in Central and Peripheral Nervous System Disorders.

Neurogenic dysphagia is a frequent condition that may result in serious complications. Despite high incidence of neurogenic dysphagia, the neurologist is not really interested in its clinical diagnosis and management. In this review, several neurophysiological methods are described to evaluate the neurogenic dysphagia. These kinds of assessment methods are important for early diagnosis and some management strategies against to progressive swallowing pathology. The longitudinal follow-up of the patients also provides data about the prognosis of dysphagia. In our opinion, the neurophysiological methods presented in this review are reliable, cheap, and easy applicable quantitative tests to detect and follow both clinical and subclinical dysphagia. All these electrophysiological techniques can be applied within the discipline of the EMG laboratory.

Electrophysiological association of spontaneous yawning and swallowing.

Yawning and swallowing are fundamental physiological processes that are present from fetal stages throughout life and that involve sequential motor activities in the oropharyngo-larynx making it likely that they may share neuroanatomical pathways. We postulate that yawning and swallowing are controlled by a distributed network of brainstem regions including the central pattern generator of swallowing, and therefore spontaneous swallowing is frequently associated with spontaneous yawning. In this study, we sought to test this hypothesis by evaluating the elementary features of yawning in the facial, masseter and submental muscles, together with laryngeal movement sensor and respiratory recordings for spontaneous swallowing. We investigated 15 healthy, normal control subjects, 10 patients with Parkinson's disease (PD) and 10 patients with brainstem stroke (BSS). Apart from four subjects with PD and two with BSS, who had dysphagia, none of the other study subjects were dysphagic by published criteria. Twenty-five subjects (10 control, 10 BSS, 5 PD) were evaluated by 1-h polygraphic recording, and 10 (5 control, 5 PD) underwent whole-night sleep recordings. One hundred thirty-two yawns were collected, 113 of which were associated with spontaneous swallows, a clear excess of what would be considered as coincidence. The yawns related with swallows could be classified into the following three categories. The characteristics or the duration of swallows and yawns were similar between controls and disease subjects, with the exception of increased duration of yawning in subjects with BSS. Our findings support the presence of common neuroanatomico-physiological pathways for spontaneous swallows and yawning.

Reassessment of Lhermitte's sign in multiple sclerosis.

The reliability and diagnostic value of Lhermitte's sign in multiple sclerosis (MS) has not been fully established. The purpose of this study was to determine the clinical, neurophysiological and neuroradiological correlations of Lhermitte's sign in a cohort of MS patients and reassess the relevance of this phenomenon in the clinical history of the disease. A prospective study of 694 patients with MS and 110 age-matched healthy adults was evaluated by a structured questionnaire that included basic demographic data, age of onset, clinical characteristics of the disease, and the inquiry of Lhermitte's sign. Cranial and spinal magnetic resonance imagings (MRI) and median and tibial somatosensory evoked potentials (SSEP) were performed at the same time. One hundred and twelve (16 %) patients were reported to have Lhermitte's sign; 582 (84 %) patients did not experience Lhermitte's sign during their disease duration (P < 0.026). No correlation was found between Lhermitte's sign and age, gender, EDSS, and disease duration; 88 % of patients with Lhermitte's sign had a demyelinating lesion on the cervical MRI. In negative Lhermitte's sign group, 64 % patients had a positive MRI. SSEP conductions were delayed in 92 % of patients with positive Lhermitte's sign and in 70 % of patients with negative Lhermitte's sign. Regarding the data, a significant correlation was found between MRI lesion and Lhermitte's sign (P < 0.001), and between SSEP abnormality and Lhermitte's sign as well (P < 0.001). This study underlines the relevance of this phenomenon with neuroradiological and neurophysiological abnormalities.

Electrophysiological Evaluation of Dysphagia in the Mild or Moderate Patients with Multiple Sclerosis: A Concept of Subclinical Dysphagia.

Swallowing mechanism and neurogenic dysphagia in MS have been rarely studied by electromyographical (EMG) methods. This study aims to evaluate the presence of subclinical dysphagia in patients with mild multiple sclerosis (MS) using electrophysiological methods. A prospective study of 51 patients with relapsing remitting multiple sclerosis and 18 age-matched healthy adults was investigated. We used electromyography to measure the activity of the submental muscles during swallowing. Electrophysiological recordings of patients were obtained during relapse, after relapse, and at any time in remission period. Clinical dysphagia was found in 12% of MS patients, while electrophysiological swallowing abnormalities were encountered in 33% of patients. Subclinical dysphagia was determined in 35% of patients during an MS relapse, in 20% of patients after a relapse, and in 25% of all 51 patients in the remission period based on EMG findings. Duration of swallowing signal of submental muscles in all MS patients was found to be longer than in normal subjects (p = 0.001). During swallowing of 50 ml of sequential water, the compensatory respiratory cycles occurred more often in MS patients than normal subjects, especially during a relapse (p = 0.005). This is the first study investigating swallowing abnormalities and subclinical dysphagia from the electrophysiological aspect in MS patients with mild disability. The electrophysiological tests described in this study are useful to uncover subclinical dysphagia since they have the advantage of being rapid, easy to apply, non-invasive, and without risk for the patients.

Diagnostic value of "dysphagia limit" for neurogenic dysphagia: 17 years of experience in 1278 adults.

OBJECTIVE: Neurogenic dysphagia (ND) is a prevalent condition that accounts for significant mortality and morbidity worldwide. Screening and follow-up are critical for early diagnosis and management which can mitigate its complications and be cost-saving. The aims of this study are to provide a comprehensive investigation of the dysphagia limit (DL) in a large diverse cohort and to provide a longitudinal assessment of dysphagia in a subset of subjects. METHODS: We developed a quantitative and noninvasive method for objective assessment of dysphagia by using laryngeal sensor and submental electromyography. DL is the volume at which second or more swallows become necessary to swallow the whole amount of bolus. This study represents 17 years experience with the DL approach in assessing ND in a cohort of 1278 adult subjects consisting of 292 healthy controls, 784 patients with dysphagia, and 202 patients without dysphagia. A total of 192 of all patients were also reevaluated longitudinally over a period of 1-19 months. RESULTS: DL has 92% sensitivity, 91% specificity, 94% positive predictive value, and 88% negative predictive value with an accuracy of 0.92. Patients with ALS, stroke, and movement disorders have the highest sensitivity (85-97%) and positive predictive value (90-99%). The clinical severity of dysphagia has significant negative correlation with DL (r=-0.67, p<0.0001). CONCLUSIONS: We propose the DL as a reliable, quick, noninvasive, quantitative test to detect and follow both clinical and subclinical dysphagia and it can be performed in an EMG laboratory. SIGNIFICANCE: Our study provides specific quantitative features of DL test that can be readily utilized by the neurologic community and nominates DL as an objective and robust method to evaluate dysphagia in a wide range of neurologic conditions.

Electrophysiological evaluation of oropharyngeal Dysphagia in Parkinson's disease.

Parkinson's disease (PD) is a chronic, neurodegenerative movement disorder that typically affects elderly patients. Swallowing disorders are highly prevalent in PD and can have grave consequences, including pneumonia, malnutrition, dehydration and mortality. Neurogenic dysphagia in PD can manifest with both overt clinical symptoms or silent dysphagia. Regardless, early diagnosis and objective follow-up of dysphagia in PD is crucial for timely and appropriate care for these patients. In this review, we provide a comprehensive summary of the electrophysiological methods that can be used to objectively evaluate dysphagia in PD. We discuss the electrophysiological abnormalities that can be observed in PD, their clinical correlates and the pathophysiology underlying these findings.

Diagnostic value of lumbar root stimulation at the early stage of Guillain-Barré syndrome.

OBJECTIVE: The aim of this study is to investigate diagnostic value of electrical lumbar root stimulation (RS) at the laminar level in the early stage of Guillain-Barré syndrome (GBS). METHODS: Fifteen patients (30 sides) and nine controls (17 sides) were included in the study. Conventional nerve conduction studies, needle electromyography, F responses and electrical lumbar RS were obtained from both groups. The needle electrical stimulation was performed at the L2-3 intervertebral level. Vastus lateralis, tibialis anterior and soleus muscles were investigated bilaterally and simultaneously in the first and fourth weeks. RESULTS: In all patients, the amplitudes elicited by lumbar RS were significantly attenuated while the conventional electrophysiological findings were normal and/or not diagnostic in 6 of 15 patients (40%) within the first week. Motor latencies by the lumbar RS were prolonged in the patients, compared to the controls, but the results were not statistically significant. CONCLUSIONS: M-responses elicited by lumbar RS appear to be helpful in disclosing proximal conduction abnormalities of GBS early in the course. SIGNIFICANCE: Lumbar RS seems to be a useful method in making the diagnosis of GBS early and there is no considerable side effect of this particular method.

Orbicularis oculi muscle activation during swallowing in humans.

Intraoral trigeminal afferents elicit EMG activity from the lower facial muscle, orbicularis oris (OR) during swallowing. The upper facial muscles and especially orbicularis oculi (OC) were not previously known to be associated with deglutitional events. Nevertheless, given the large area of intraoral mucosa and teeth innervated by the trigeminal nerve afferents, a connection between OC motoneurons and deglutition may theoretically be expected, which we sought to evaluate in this study. Healthy controls were investigated for the possible synchronization of orbicularis OC and OR muscles during deglutition by the following methods: EMG activities were recorded during voluntary dry, 3-, 10-, 20-ml discrete wet swallowing, and sequential swallowing from a cup, concurrent with respiratory recording. A polygraphic recording was obtained from these muscles to determine whether they were synchronously activated during spontaneous swallowing. The polygraphic recording during spontaneous swallowing demonstrated that the OC and OR muscles were synchronously activated in all subjects. This synchronous activation was less prominent in voluntary discrete swallowing. It is proposed that this might be based on trigemino-solitarii-facial pathways with weaker connection to OC muscles. The synchronization of OC muscle activity with deglutition may be an evolutionary process that should be rudimentary in higher mammals including humans. The swallowing-induced cranial muscle activities could potentially explain some movement disorders, such as craniofacial dystonias.

The detection of sensitivity of proprioception by a new clinical test: the dual joint position test.

OBJECTIVES: To date, very few studies have paid attention to the joint sense (proprioception) of toes other than the big toe. We evaluated the sensitivity of joint position sense at the joint of the great toe in comparison to other digits, and with that determined by the dual digit stimulation test, in a sample of healthy normal controls and patients with clinical diagnosis of the lemniscal system dysfunction. MATERIAL AND METHODS: Seventy-two patients with lemniscal system dysfunction (55 clinically definitive multiple sclerosis, 17 vasculitis) and 110 healthy volunteers participated in the study. All subjects underwent the joint position sense test of all digits of upper and lower extremities. The position sense resulting from the combined operation of the joints of the second and the fourth digits (simultaneous two digits position sense) was also measured and subsequently compared with the results of the great toe position sense. RESULTS: Upper extremities: no difference was found in recognition of the position sense in the single digits of the upper extremities between patients and healthy volunteers. There was a significant difference in the dual joint position test of the right upper extremity between patients and the case group (p<0.05) but not in the left upper extremity. Lower extremities: there was no significant difference in proprioception of the great toe neither in the right and nor in the left side between patients and normal subjects. However, the joint position sense of other single digits was deteriorated in the patients, a difference that was significant compared to normal controls (p<0.05). Additionally, patients and normal controls displayed a difference in dual digit position sense of the right and left lower extremities (p<0.05). CONCLUSIONS: We show in this paper that the proprioception of simultaneous dual digits is diminished in patients when compared to a single digit position sense. Moreover, the great toe proprioception is less sensitive than other digits. Taken together, these observations lend evidence for a new clinical method which we named as dual joint position test. We suggest this novel method offers clinical utility to demonstrate lemniscal system dysfunction.

The interaction between breathing and swallowing in healthy individuals.

In this article, we aimed at investigating the interaction between breathing and swallowing patterns in normal subjects. Ten healthy volunteers were included in the study. Diaphragm EMG activity was recorded by a needle electrode inserted into the 7th or 8th intercostal space. Swallowing was monitored by submental EMG activity, and laryngeal vertical movement was recorded by using a movement sensor. A single voluntary swallow was initiated during either the inspiration or expiration phases of respiration, and changes in EMG activity were evaluated. When a swallow coincided with either inspiration or expiration, the duration of the respiratory phase was prolonged. Normal subjects were able to voluntarily swallow during inspiration. During the inspiration phase with swallowing, diaphragmatic activity did not ceased and during the expiration phase with swallowing, there was a muscle activity in the diaphragm muscle.

Diagnostic value of cauda equina motor conduction time in lumbar spinal stenosis.

OBJECTIVE: Lumbar spinal stenosis (LSS) is a chronic degenerative disease with pain in the back, buttocks and legs aggrevated by walking and relieved after rest without associated vascular disease of lower extremities observed in patients between 50 and 60 years. Several studies, using different methods indicated an association between slowing or blocking of root-nerve conduction and LSS. None of the previous research had applied the more conceivable methods such as recording the cauda equina potentials from the lumbar level or stimulating the spinal roots within the canal using either leg nerves or muscles. In this study, electrical lumbar laminar stimulation was used to demonstrate prolongation of cauda equina motor conduction time in lumbar spinal stenosis. METHODS: Twenty-one LSS patients and age matched 15 normal control subjects were included in the study. Lumbar laminar electrical stimulation from L1 and L5 vertebra levels were applied by needle electrodes. Compound muscle action potential (CMAP) from gastrocnemius muscles were recorded bilaterally. Latency difference of CMAPs obtained from L1 and L5 spine levels were accepted as the cauda equina motor conduction time (CEMCT). RESULTS: CEMCT was significantly longer in patient group when compared to normal controls. Mean latency difference was 3.59 ± 1.07 msec on the right side, 3.49 ± 1.07 msec on the left side in LSS group, it was 1.45 ± 0.65 msec on the right side, 1.35 ± 0.68 msec on the left side on normal control group (p<0.0001). CONCLUSIONS: The prolongation of CEMCT was statistically and individually significant in patient group. This may indicate that lower lumbosacral motor roots were locally and chronically compressed due to lumbar spinal stenosis. Lumbar spinal stenosis may have induced local demyelination at the cauda equina level. SIGNIFICANCE: Since the prolongation of CEMCT was found only in patients with LSS, the method of laminar stimulation can be chosen for patients with uncertain diagnosis of LSS.