THE ASSOCIATION BETWEEN LOCATION OF BRAIN LESION AND FINDINGS OF FLEXIBLE ENDOSCOPIC EVALUATION OF SWALLOWING (FEES) IN STROKE PATIENTS: WHICH EXERCISE IS BENEFICIAL?

Background: Dysphagia is a frequent occurrence following stroke. Various brain regions have been shown to control deglutition. However, it is still controversial as to which of the two hemispheres plays more important role in deglutition, and which injured hemisphere is more likely to cause the specific patterns of dysphagia seen in stroke patients. An accurate estimate of the incidence of dysphagia will be critical to assess benefits of dysphagia interventions. Objective: To investigate whether patterns of dysphagia are associated with the location of brain lesion in stroke patients and to examine whether pharyngeal strengthening exercise and hyolaryngeal exercise are proper for patients, based on the findings of FEES and location of brain lesion. Methods: The subjects were stroke outpatients who visited our clinic from January 2016 to April 2018. To localize brain lesion, Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) have been employed. The locations of brain lesions were classified into cortical, subcortical, and brain stem. FEES was conducted to assess the patterns of deglutition disorders. These data were collected via retrospective chart review. Results: Of the 11 subjects, mean age (SD) was 62.73 (8.67) years and seven (63.64%) subjects were male. All subjects got ischemic stroke, eight (72.73%) had right hemispheric lesion and three (27.27%) had left hemispheric lesion. By brain lesion, there were nine subcortical, five cortical, and four brain stem lesions. All FEES findings, especially standing secretion, penetration, residue, and reduced hypopharynx sensitivity were higher in subcortical lesion, followed by brain stem and cortical lesion successively. Conclusion: Right hemisphere was involved more than left hemisphere in dysphagia patients. Standing secretion, penetration, residue, and reduced hypopharynx sensitivity occurs more often in subcortical lesion. Further studies on big samples in a perspective structure are needed. Based on this result, there is a place for pharyngeal strengthening exercise and hyolaryngeal complex range of motion and strengthening exercise to be implemented to the patients with neurogenic dysphagia after stroke.

reduced hypopharynx sensitivity were higher in subcortical lesion, followed by brain stem and cortical lesion successively. Conclusion: Right hemisphere was involved more than left hemisphere in dysphagia patients. Standing secretion, penetration, residue, and reduced hypopharynx sensitivity There is deglutition area in the cerebral cortex, includes the prefrontal gyrus, somatosensory cortex, insula, cingulate gyrus and precuneus regions. When stroke occurs, the areas could be damaged, the network become disrupted and the command center is also debilitated. Deglutition disorder can also occur if a stroke lesion affects the brain stem. Therefore, deglutition becomes impaired.3 It is still controversial as to which hemisphere has much role to associate with the specific patterns of deglutition disorders in stroke patients.4,5 The dysphagia has result in higher risk of pulmonary complications and also mortality.6,7 The most common pulmonary complications is aspiration pneumonia resulting in deaths.8 Pneumonia and other respiratory illnesses are still being the most common factor causing hospital readmission post stroke.9 Besides, post stroke dysphagia is also associated with malnutrition.10 Aspiration pneumonia will increase the catabolic condition and needs more energy, so that the demand will be increased too. However, dysphagia patient who has inability to swallow normally, could not afford to fulfill the elevated demand, creating a vicious cycle.3 Effective and efficient management of dysphagia becomes the most important thing. Behavioral exercise treatments are often used in newly research, because these treatments are focus on the underlying deficits and therefore have a long-life effect.11 A precise estimation of the amount of dysphagia event in stroke patients and the risk of pulmonary complication it caused could be a guideline to make another research to have information about the benefits of dysphagia treatments.6 In this study, we would like to investigate firstly whether patterns of dysphagia are associated with the location of brain lesion in stroke patients and then examine whether pharyngeal strengthening exercise, hyolaryngeal complex range of motion and strengthening exercise are proper for patients with neurogenic dysphagia after stroke, based on the findings of FEES. The results of this study could guide us whether these exercises can be implemented and have benefits to this neurogenic dysphagia after stroke patients. 4 Methods Subjects of this study were: (1) ischemic stroke patients confirmed by brain imaging, (2) 40-70 years old, and (3) had neurogenic dysphagia confirmed by FEES. The exclusion criteria were as follow: (1) Patients who had other disease that might cause dysphagia, (2) patients with bilateral stroke. We reviewed the patients' medical records and examination results retrospectively. Their demographic and clinical characteristics were recorded. The interval between ischemic onset and FEES evaluation were all on subacute onset. The FEES was conducted by ENT-HNS specialist. About the interpretation of FEES, we evaluated the findings such as: (1) lip closure, (2) tongue movement, (3) buccal tone, (4) velopharyngeal movement, (5) standing secretion, (6) penetration, (7) aspiration, (8) residue, (9) laryngeal elevation, (10) hypopharyngeal sensitivity, (11) cough reflex, and (12) laterality.
About the classification of brain lesion location, the results of brain computed tomography (CT) or magnetic resonance imaging (MRI) were classified into 3 groups; the cerebral cortical lesion, subcortical lesions, and the brain stem lesions. The lesions were divided into right and left hemispheric lesions.
Participants' characteristics were summarized as means and standard deviations for continuous data, and frequency counts for categorical data. We use Statistical Package for the Social Sciences (SPSS) 23.0 to analyze the data.

Results
Eleven ischemic stroke patients participated in this study. Of the 11 subjects, mean age (SD) was 62.73 (8.67) years and seven (63.64%) subjects were male. All subjects got ischemic stroke, eight (72.73%) had right hemispheric lesion and three (27.27%) had left hemispheric lesion. By brain lesion, there were nine subcortical, five cortical, and four brain stem lesions. All FEES findings, especially standing secretion, penetration, residue, and reduced hypopharynx sensitivity were higher in subcortical lesion, followed by brain stem and cortical lesion successively.
There was no predominance of hypopharynx sensitivity in stroke in subcortical lesion as well as decreased of cough reflex.  Patients are asked to swallow strongly or swallow with great effort by giving force to the bolus and prolonging the closure of the airway. This technique will increase posterior tongue base movement and anterior pharyngeal wall movement, so that the bolus passages also increase.28,29 This exercise is performed as a compensation maneuver for patients who experience a decrease in tongue base retraction which can be seen from the presence of residues in the vallecula.28 Hyolaryngeal exercise prolongs laryngeal elevation and is thought to maintain increased velopharyngeal pressure. In addition, there is prolonged duration of the opening of the upper esophageal sphincter and increased contraction of the pharyngeal peak and conversely decreases the contraction pressure of the top of the esophageal sphincter. Elevation of the larynx will create a negative pressure effect on the upper esophageal sphincter so that this exercise will reduce this 9 negative pressure when deglutition. This will facilitate safe bolus displacement due to reduced resistance.29

Conclusion
In this study, we concluded that right hemisphere was involved more than left hemisphere in dysphagia patients. Standing secretion, penetration, residue, and reduced hypopharynx sensitivity

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Availability of data and materials
All data generated or analyzed during this study are included in this published article. The confidential patient data could not be shared.