So I'd like to tell you a little bit about the clinical approach that we take when we see patients with sleep disorders. This occurs every day at thousands of centers now across the country. These are sleep disorder centers. They can also occur in the offices of other physicians. And, as I said, sleep disorders and sleep medicine is very multi-disciplinary field. So the patient with sleep complaints may end up seeing a sleep specialist, who has roots in many different types of fields, such as psychiatry or neurology or internal medicine or family medicine or a pulmonary medicine or otolaryngology as examples. So when a patient comes in for a sleep complaint, the first thing we do is take a thorough history. And that's very similar to what we, as physicians, do for any other types of complaints too. And then, furthermore, like in other fields, probably the most important diagnostic information that we get from a patient is through the history, and we'll say, first of all, "What brings you to the clinic?" And, usually, for a sleep disorder patient, it has something to do with difficulty sleeping at night or feeling too sleepy during the day. There are other common complaints too, but few patients come in without one of those two issues. Some other common complaints might be for example, "Oh, Doctor, I snore very loudly and keep my spouse up," or "Doctor, I'm kicking my legs at night, and it's bothering my spouse," or "I can't seem to go to sleep because my legs are feeling like I have to move them." And there's a variety of other complaints, but probably the three most common are difficulty sleeping at night, difficulty with alertness during the day, or loud snoring. One of the things that's different about a history that we take from a sleep patient is that we usually like to have family members in the room. That's not always the case with other types of physicians, but with sleep physicians, we know that we often hear something different from a family member or a spouse than we hear from the patient him or herself. So for one obvious reason, people are asleep when they're having their sleep disorders, and oftentimes, having observations from a bed partner can play a critical role in the diagnosis. The other reason is that the effects of sleep disorders tend to be chronic in long term and may not be noticed that much, even by the patient him or herself. So, in particular, some patients grow over many years very accustomed to being sleepy during the day. And when you ask them, "Is sleepiness a problem for you?" they may say, "Well, no, not really," while the spouse or another family member is saying, "Yeah right" in the background and can usually come up with examples that the patient may not remember or may not be attuned to after years of suffering with a sleep disorder. In doing a history, we will often ask specifically about quality of sleep. Is sleep refreshing? Other symptoms during the night, are you hot and sweaty to get up and go to the bathroom? If you can't sleep, what do you do? What are you thinking about? We ask a lot questions about a sleep disorder itself but also general health questions because health can impact so much with sleep disorders. And so we go through that, as well as a past medical history, talk about ways that sleep disorders may have impacted the patient and then about any medications they may be on can be relevant to sleep certainly. Take a family history, do a social history, pretty much like you would for patients in other areas of medicine. The physical exam also plays a role in the diagnosis and we do general physical exams but also focus in good part on the upper airway, as we'll talk about later in this lecture because of the relevance of the upper airway and throat to obstructive sleep apnea. Sometimes we're looking on the physical exam for evidence of sleepiness. If a patient is falling asleep while you're interviewing them or while you're examining them, that's certainly a telltale sign of severe sleepiness. But many patients who are truly sleepy won't be yawning or dozing off in front of you. So a physical exam may have a more limited role in that sense. We can use sleep tests. They're both subjective assessments, as well as objective assessments, and we will talk about those. And they can play an important role in not only defining whether a sleep disorder is there but in other cases showing how bad it is or what the effects are acutely as the person is sleeping. And then, finally, aside from planning and doing and interpreting test, we make diagnoses, and we implement and talk about treatments. And treatments and sleep medicine can be very broad, ranging from behavioral therapy for some types of disorders to medications for others to machines and equipment that we can use to treat some types of sleep disorders, all the way ranging to surgery for other situations. We have a very broad armamentarium for treatments in sleep medicine. To a little bit more about assessment, we do have some tools that we can use, both for subjective and objective assessments. And this is an example of one of the most commonly used subjective assessment tools. It's called the Epworth sleepiness scale, and it's a short questionnaire. It's all on one page, and the instructions say, "How likely are you to doze off or fall asleep in the following situations in contrast to just feeling tired? This refers to your usual way of life in recent times, and even if you have not done some of these things recently, try to work out how they would have affected you." And these are the possible responses for each situation. Zero would never doze. One, you would have a slight chance of dozing in that situation; two, moderate chance of dozing; or three, high chance of dozing. And here are the questions, and I'm going to ask you to go through each of the eight questions and rate yourself with a zero for who would never doze all the way through three, high chance of dosing for each of those situations. And then I'll ask you to add up your scores from the eight questions to get a total score on the Epworth sleepiness scale. Here is the Epworth sleepiness scale, and we'll just pause for a moment now while you rate yourself for each of these situations. Okay. I hope that you've now filled out your Epworth sleepiness scale, and you should have a total score which can range from the minimum of zero to a maximum of 24 if you rated yourself three for each of the eight items. And let's talk about how to interpret it. We usually start to think that someone may be excessively sleepy, at least by their own subjective ratings, if their Epworth sleepiness scale score is 10 out of 24 or above. There's no magical cut-off there, but that's about where we start to think that there may be some unusual level of subjective sleepiness. Patients with obstructive sleep apnea can often score in the lower teens. Patients with narcolepsy can score 15, 16, 17, but there's no strict correlation, and you can certainly find exceptions to that. It's interesting if you ever do a search on the Internet for the Epworth sleepiness scale. You'll find all kinds of different advice offered by various companies or sleep centers or other parties that are interested in sleep. And we actually did a study of this more than 10 years ago now and found all the following examples of advice given for how to interpret your score on the Epworth sleepiness scale. One site said nine and up, seek the advice of a sleep specialist without delay. Another one said in capitals, if your score is above 10, it is recommended that you consult your physician to be evaluated for a sleep disorder. The other one said the ESS is an established test used worldwide by sleep professionals to measure sleep deprivation and daytime sleepiness. Obviously, I don't agree 100 percent with how all of these are phrased. And in this case, for example, I would take issue with as a measure of sleep deprivation and daytime sleepiness, it's true in a broad sense, but I would call it an assessment rather than a precise measure. It gives you an idea. And don't forget it's looking at subjectives of sleepiness. Another one said this should only be used for entertainment because obstructive sleep apnea or OSA might not become apparent with a study. We assume no liability for outcomes of this test, and you, by using this test, assume all responsibility contained herein. One of the advantages of the Epworth sleepiness scale, and there are other instruments somewhat like it, is that they, at least, provide a reliable and repeatable way to assess someone. So you can assess someone the same way for their sleepiness in New York as you might in California, and this instrument has actually been used in many places around the world. It is subjective. It's important to remember that sleepiness that you assess in that manner may not correlate with objective measures that you can make in a sleep laboratory of either sleep pathology or the extent of sleepiness that you measure. So, next, we'll talk about methods used to actually record and characterize sleep objectively.