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).