Narcolepsy is an important clinical manifestation of many sleep disorders, and serious cases can fall asleep regardless of time and place, which can have a great impact on the work and life of patients and even lead to accidents that endanger the safety of others and themselves. In recent years, it has been found that the incidence of traffic accidents related to drowsiness is comparable to that caused by drunk driving, but has not yet attracted attention. Clinical experience in China has shown that excessive sleepiness is one of the main reasons for patients to visit sleep centers. Accurately and comprehensively evaluating the severity of narcolepsy, finding the causes of narcolepsy, selecting appropriate treatment plans, and systematically assessing the effects of treatment are important issues to be addressed in the clinical practice of sleep medicine. Epidemiology The population prevalence of narcolepsy ranges from 0.5% to 35.8%, with most reports ranging from 5% to 15%, and the reasons for the wide variation are related to the population surveyed and the questionnaires used. 9.4% of Chinese elementary school students were found to sleep sometimes or often in class. The prevalence of drowsiness was higher among frequent shift workers, the elderly, adolescents, and females. In addition, with the accelerated pace of life and changes in lifestyle, the incidence of narcolepsy has increased. Although there are many causes of narcolepsy, sleep breathing disorder is the most important cause of daytime sleepiness in sleep centers in Europe and the United States, accounting for 75%; episodic sleep disorder is the next most important cause, accounting for 20%, and the remaining 5% includes leg movement syndrome. Sleep breathing disorders, especially sleep apnea hypoventilation (OSAHS) and upper airway resistance syndrome, account for 80% of the patients with narcolepsy treated in our hospital, while episodic sleeping sickness accounts for about 12%, primary narcolepsy and periodic leg movement syndrome can also be seen. Evaluation of daytime sleepiness Factors associated with daytime sleepiness include: length of sleep, quality of sleep, influence of circadian rhythms, medications and underlying diseases. After subjective and objective evaluation, together with detailed history taking, the severity of narcolepsy can be clarified, the cause of narcolepsy can be searched for and the effect of treatment can be initially evaluated. History-taking History-taking mainly consists of medical history-taking and a thorough physical examination. When taking medical history, the following aspects should be noted. One, is the patient excessively sleepy during the day? Setting a specific setting, such as a meeting, car ride, or lecture, helps to understand how the patient sleeps during the day. Many salivary patients often do not seek medical attention for excessive sleep, but complain of easy fatigue, lack of energy, memory loss, and depression, etc., which should be distinguished. Second, is the excessive sleep complained by the patient an abnormal phenomenon? Individuals vary greatly in the amount of sleep they need, so you should ask the patient how long they sleep to keep their energy and mental clarity during the day. Some people have short sleep time but it does not affect their daytime work and life, so it may not be a pathological phenomenon. Third, the length of the illness, episodic or persistent. Fourth, how are the sleep habits? The main considerations are sleep duration, sleep-wake rhythm, work schedule, short daytime sleep, sleep environment, eating habits and medication history. V. What are the accompanying symptoms? Understanding the concomitant symptoms of narcolepsy is helpful to clarify the cause of the disease. Since many of the pathological phenomena in sleep are not conscious, their family members or spouses can often provide a more objective history, and their cooperation should be obtained. For example, for patients with suspected sleep apnea hypoventilation syndrome, family members can be asked: 1. Is the snoring audible in the next room? Is the snoring unevenly high and low? If necessary, the patient’s snoring can be simulated. 2, Does the patient have frequent breathing intervals while sleeping? 3, Is the patient sleepy during the day, such as when watching TV, in meetings, or riding in the car. Systematic history taking is best accomplished with the aid of a more reasonably designed questionnaire. Physical examination often has no characteristic positive findings, and those with severe narcolepsy are unresponsive and have poor memory at the time of consultation, and can even doze off during the consultation. In addition to the routine examination, the upper airway and neurological system should be examined in patients with narcolepsy.