Functions of sleep? The easy answer is we don’t know. We do know, like with most physiologic functions, how do we know what it does? We take it away and see what happens. When you take sleep away experimentally you do have impaired performance and you do have sleep cravings. If you stop sleep, you will crave it more and more, just like hunger. And eventually you will sleep. You are more likely to fall asleep in an inappropriate setting, as we will discuss. Selective REM deprivation, the classic question and the old teaching was if you deprive somebody of REM sleep selectively you cause psychosis. That is not true. No, no, no. This is an artifact of a poorly-done study in the 1950’s. Not true. The same thing you get with non-REM sleep you get REM fresher, you get REM rebound, you get more and more craving of REM sleep and eventually, whether you like it or not, you go in REM sleep. That’s what people with narcolepsy do.
Sleep studies. Let me give you what you need to know about those. How do we sleep? How do we stage sleep? You need three things; EEG, EOG, EMG. The non-REM sleep stages is determined by EEG only. The reason we need those two is for REM sleep. Because REM sleep is defined by rapid eye movements and muscle atonia. So in order to make a comprehensive sleep staging you need all three. Technically you can do it with one EEG channel, in practice we like to have more. And especially central leads and occipital leads, which makes perfect sense. Central leads because the hallmark of non-REM sleep always, or often, predominates at the vertex. Vertex, sharp waves, spindles, K-complexes and occipital leads because the hallmark of wakefulness is in the occipital region. Then EMG, technically one channel is enough. I’ll show you pictures of all that. You might be shown a few pictures. With a polysomnogram, which is a comprehensive recording of a whole night. What we do in addition to sleep staging, we measure what we are likely to find abnormal and since sleep apnea is so important, we measure respiration, airflow, respiratory effort, oxygen saturation, EKG, this is obviously to look for periodic leg movements of sleep or nocturnal myoclonus. And this is to look for penile tumescence or erection when we evaluate erectile function, which is a totally different study. This isn’t done in a routine polysomnogram. It’s done when the indication is the assessment of impotence. They are usually referred by the urologist or the internist or the endocrinologist and we evaluate impotence. All they are asking me is, evaluate the erectile function at night. While we are on this topic, the only thing you need to know about this – which is common sense, I think – what we do is we do a polysomnogram and we look for penile tumescence, which is measured quantitatively, and if you have normal erection during REM sleep the erectile dysfunction or impotence is more likely to be psychogenic. If it’s organic, you lose the REM-associated erection. You do a full polysomnogram because you want to make sure that there is REM sleep, because if somebody has severe sleep apnea and no REM sleep, then you cannot say the erectile dysfunction is psychogenic because they did not go into REM sleep and you are not expected to have erections outside of REM sleep. Canadian pharmacy news