Neuromuscular Diseases:
Neuromuscular diseases are associated with increased respiratory disturbances, including dysphagia, cough impairment, and frequent retching. In myasthenia gravis, there is cranial nerve impairment and bulbar weakness, which may be the initial symptoms that cause frequent aspiration, and consequently increase the frequency of coughing. However, if the patient develops respiratory insufficiency, the associated hypoxia causes peripheral and central impairment of cough reflex sensitivity (40).