A respiratory system and chest symptom that is characterized by a respiration that is not normal and may include, but is not limited to: apnea, eupnea, orthopnea, dyspnea hyperpnea, hyperventilation, hypoventilation, tachypnea, Kussmaul respiration, Cheyne-Stokes respiration, sighing respiration, Biot respiration, apneustic breathing, central neurogenic hyperventilation, and central neurogenic hypoventilation. [ url:https://www.ncbi.nlm.nih.gov/books/NBK470309/ ]