Sleep apnea syndrome can be diagnosed clinically by polysomnography. It is generally divided into three types: Obstructive Sleep Apnea Syndrome (OSA): refers to the absence of airflow from the nose and mouth, but thoracic and abdominal breathing still exists, and the main etiology is the obstruction of respiration caused by local anatomical narrowing of the airway, chronic inflammatory hyperplasia of the soft tissues, or reduced muscle tone. It is most common clinically. Central sleep apnea syndrome (CSA): refers to the simultaneous suspension of nasal and oral airflow and thoracic and abdominal breathing, the main cause of which is a lesion of the respiratory center or peripheral nerve conduction disorder. Mixed sleep apnea syndrome (MSA): refers to alternating obstructive and central apnea in the same patient overnight.