Oropharyngeal Dysphagia in Amyotrophic Lateral Sclerosis

Background and Aim : Amyotrophic Lateral Sclerosis(ALS) is the most common type of degenerative motor neuron disease in adults which progressively affect lower motor neurons (LMN) and upper motor neurons (UMN) in cortex,brainstem,and spinal cord,without showing cognitive impairment.Symptoms of LMN include muscle weakness,hypertonia,and hyperreflexia,while UMN symptoms are hypotonia,muscle weakness and atrophy,and absent stretch reflex.Based on the area that ALS begins,it can be divided into two categories:Spinal and bulbar.Although the etiology of ALS has not been determined yet,5-10percent of cases have a family history of this disease.The incidence of ALS is about 5/2 per 100,000 people.In general,the symptoms of ALS are fasciculation,atrophy,progressive skeletal muscle weakness,muscle spasms,dysarthria,dysphagia, and dyspnea.Dysphagia alone or related to dysarthria is one of the most debilitating clinical problems of ALS.Dysphagia is a suitable indicator of ALS stage and severity.The swallowing disorder has been reported in 85% of all ALS cases.Dysphagia interferes in three steps of swallowing and it progresses over time until oral feeding becomes impossible for the patient.The postnasal drip,especially during drinking liquid or intermittent choking on saliva,can be the early symptom of dysphagia.Initial levels of dysphagia in ALS are due to oral dysfunction.Dysphagia in ALS is due to weakness or spasms of swallowing muscles,including chewing,tongue,lip,pharynx,and larynx.The weakness of the chewing muscle (pterygoid,masseter,and temporalis) leads to fatigue during chewing.The weakness of the facial muscles also causes problems with the formation of lips and the control of saliva in the oral cavity.As the tongue muscle weakens,manipulation and transfer of the bolus will be in trouble.Palatal and pharynx weakness also lead to nasopharyngeal seal damage and the regurgitation of food through the nose.The weakness of the pharyngeal and hyoid muscles may cause choking and aspiration.These symptoms can increase the risk of aspiration,dehydration,malnutrition,pneumonia,decreased quality of life,choking,social isolation and embarrassment and eventually death.The purpose of this study was to review the pathophysiology,evaluation methods and therapeutic strategies of dysphagia in patients with ALS.Methods : In this study,we reviewed articles from 1996 to 2019 regarding the swallowing dysfunction in ALS.These papers were obtained through the following databases:Cochrane,PubMed,SAGE,CINHAL,ScienceDirect,ASHA,Wiley Online Library,and Google Scholar.We used swallowing disorder , amyotrophic lateral sclerosis , Swallowing rehabilitation(therapy) , oropharyngeal Dysphagia , Deglutition disorders as keywords for search.Results : In this work,44 papers have been reviewed.Among these,11 studies have described the physiological changes in swallowing function after ALS.17 articles have investigated the swallowing function through different methods of instrumental and non-instrumental assessment.The effectiveness of treatment on improving the swallowing function has been discussed in eight other papers.Four studies examined the changes in the quality of life while the remaining two were case reports.Conclusion : Due to the high prevalence of swallowing disorder in ALS patients and serious complications,it can be concluded that timely and rapid evaluation of dysphagia in these patients is essential.Providing appropriate therapeutic and rehabilitation strategies can help to improve this disorder and the quality of life for these patients and their families.Therefore,more elaborate research and appropriate therapeutic strategies for the treatment of dysphagia by a speech therapist with accompaniment to other members of the management team will be critical for the treatment of ALS patients.

کلیدواژه ها:

amyotrophic lateral sclerosis ، Oropharyngeal Dysphagia ، swallowing rehabilitation ، Therapy