The majority of clinical insomnia is primary insomnia, caused by a weakened brain nerve function. There is also a small percentage of insomnia, caused by secondary to other problems, and the patient’s insomnia is examined. Patients should have respiratory sleep monitoring to analyze whether there are any respiratory disturbances during the patient’s sleep, and whether there are any disturbances caused by restless legs. Patients should have cerebrovascular disease and pulmonary function tests to see if the patient has obstructive sleep or apnea. Patients should have a rhinolaryngological examination to see if there is a narrowing or obstruction of the airway, which is done through a laryngoscope or rhinoscope. Many patients may be caused by emotional anxiety disorders, and these patients will not need to be examined; there is no test that can check the cause of the patient’s insomnia.