Polysomnography (PSG) has some disadvantages, such as time-consuming, effort-consuming, long appointment time and high cost. During PSG examination, multiple sensors need to be placed in the patient's head, face, neck, chest and limbs, and sensors are needed to monitor data throughout the night. It is difficult for young children to cooperate, and it is easy to fail due to inaccurate sensor signal acquisition. PSG examination may miss diagnosis or underestimate the disease due to the first night effect. Based on the above reasons, the application of PSG in clinic, especially in pediatric patients is limited. The reflective optical path detection can be used to measure the peripheral blood oxygen saturation in the flat part of human skin. The investigators intend to use a reflectance pulse oximeterto evaluate its reliability and validity in the diagnosis of OSA in children at the same time as PSG.

During PSG examination, the participants wear reflectance pulse oximeter for continuous monitoring. Use PSG to record EEG, oculogram, chin electromyography, body movement, chest and abdomen movement, nose and mouth airflow, snoring, electrocardiogram, blood oxygen saturation and finger pulse monitoring. The effective monitoring time should be at least 6 hours. Oxygen desaturation index (ODI), average blood oxygen saturation, minimum blood oxygen saturation, percentage of blood oxygen saturation less than 90% in the whole recording time (TS90%), fastest heart rate, slowest heart rate and average heart rate are recorded by reflectance pulse oximeter. To compare the effective time (TST), the total number of hypoxemia events, the coincidence rate of comparing each hypoxemia event, identifying OSA, and identifying moderate and severe OSA by PSG and reflectance pulse oximeter.

Inclusion Criteria:

1. Snoring more than 3 nights per week in the last month
2. Pediatric sleep questionnaires score ≥ 0.33

Exclusion Criteria:

1. Acute exacerbation of asthma
2. Pulmonary infection
3. Heart disease

1. With the consent of the guardian, children who are scheduled to undergo PSG examination because of suspected OSA.
2. There is no serious dysfunction of heart, lung, liver and kidney.
3. Willing to participate in this project and sign the informed consent form.