Symptoms include chest tightness, rapidly progressive dyspnea (shortness of breath), dry cough, use of accessory respiratory muscles, labored breathing, and extreme wheezing.

Patients present with increasing weakness of facial, neck flexor and respiratory muscles.

Daytime hypopnea events are mostly limited to those with severely compromised respiratory muscles, as occurs in certain neuromuscular diseases.

The spinal neurons connect directly to the respiratory muscles.

The respiratory muscles move the vocal cords apart and serve breathing.