Sleep Disorders: serious disorders in the normal sleep pattern that interfere with daytime functioning and cause subjective distress. (Hockenbury, 139) Sleep is the absolute confluence of factors biological, social, environmental, and psychological. Many of the sleep disorders, like other neurological disorders, represent “lesions” of the nervous system—largely microscopic, transient, or genetically determined. (Leschziner, 11) There are a number of sleep disorders that range from trouble falling asleep, to nightmares, sleepwalking, and sleep apnea. Poor sleep may also be caused by diseases such as heart disease, lung disease, or nerve disorders. (NCIt)

As we get older, the amount of wakefulness at night (very brief awakenings) increases. A complex system of brain “nuclei,” brain circuits, and “neurotransmitters” regulate this biological process, controlling the initiation and termination of sleep, as well as the switch between non-REM and “REM sleep.” (Leschziner, 13) We know the brain is active during sleep because scientists have spent a lot of time measuring this activity. The most common way to do this by sticking little pieces of highly conductive metal onto the scalp. These “microelectrodes” can detect tiny electrical signals created by nearby brain cells. (LewisP, 7) (According to) the “opponent process theory,” there are two forces that are locked in a—I’ll call it a 'death match'—in your life. One we call the “homeostatic sleep drive.” This is the drive to put you to sleep, and the sum total of tissues and molecular forces in your body that want to put you to sleep. And it’s at war all day and all night with your other drive, which we call the “circadian arousal system.” The circadian arousal system is the one that wants to keep you awake all the time. If you deregulate those you can begin to accumulate a sleep debt, because they’re supposed to be held in a fine balance. (Medina, BSP37) Sleep-deprived, the human brain exhibits changes in activity suggesting very focal areas of sleep continuously occurring in the cortex. When we are tired, we really are ‘half-asleep,’ or perhaps ‘one-tenth asleep.’ These changes are linked to performance errors when performing certain tasks, and… explain why we feel less capable when sleep-deprived. (Leschziner, 52) Sleep deprivation is correlated with poorer performance at school as well as behavioral issues and anxiety. (Leschziner, 24)

Chronotype: a person’s preference to go to sleep and wake up at a particular time. There is a broad spectrum of chronotypes. Studies in twins or in families suggest that up to 50 percent of our chronotype is under genetic control. Shifts in our chronotype also occur as the brain matures. Teenage circadian rhythms will typically shift later in the day, before then shifting back in adulthood. This shift in the body clock seen in teenagers is compounded by the use of electronic gadgetry late in the evening. Being glued to a tablet, laptop, or smartphone while in bed, as many teenagers are, provides a potent source of light to act as a ‘Zeitgeber’ and makes this delay worse. (Leschziner, 22-23) The gene that governs sleep/wake predisposition is called ‘Period’ or ‘PER’ for short. Like the gene for eye color, it comes in two different types. Let’s call them ‘PER1,’ which causes people to have “lark” tendencies and ‘PERo,’ which causes them to have “owl” tendencies. If you have two copies of PER1, you’ll be a lark. If you have two copies of PERo, you’ll be an owl. But if you have one copy of each (which is what 50% of the population has), you’ll be somewhere in between. (LewisP, 151)

Larks: in general, larks report being most alert around noon and feel most productive at work a few hours before they eat lunch. Larks report their favorite mealtime as breakfast and generally consume much less coffee than non-larks. Getting increasingly drowsy in the early evening, most larks go to bed around 9 p.m. (Medina, 157) Larks typically bounce out of bed well before the average person would want to open their eyes. They also get tired much earlier in the day and they can’t handle sleep deprivation— it disrupts their concentration. (Larks) make up quite a small percentage of the population— just 10 percent. (LewisP, 150-151) Also referred to as ‘morning larks’ and ‘early chronotypes.’

Owls: someone who wants to stay up long after the sun has set and ‘normal’ people have gone to bed. They often simply feel more alert at night. They may be able to concentrate better, feel they can do their best work then, or simply enjoy being awake more at night than during most parts of the day. They hate to get up early, and often can’t really function in the morning. They handle sleep deprivation very well. (LewisP, 150-151) In general, owls report being most alert around 6 p.m., experiencing their most productive work times in the late evening. They rarely want to go to bed before 3 a.m and invariably need an alarm clock to get them up in the morning. They report their favorite mealtime as dinner. Owls usually accumulate a massive ‘sleep debt’ as they go through life. (Medina, 157) Also referred to as ‘evening owls’ and ‘late chronotypes.’

Circadian Clock: a timekeeper, an internal clock that coordinates our neurological and bodily functions with the external world. As we approach the dead of night, this clock exerts its strongest influence, compelling us to sleep. In the daytime, (it) makes us feel more alert. For the most part, the circadian (clock) and the homeostatic (mechanism), work in sync to ensure we sleep an appropriate amount at night and feel wide awake during the day. At least, they do when they are both working properly… (Leschziner, 14) The system that wants to keep you awake all the time. If you 'deregulate' (it) you can begin to accumulate a sleep debt. (Medina, BSP37) Also referred to as the ‘circadian arousal system’ and ‘circadian regulation.’

Circadian Rhythms: a cycle or rhythm that is roughly 24 hours long; the cyclical daily fluctuations in biological and psychological processes. (Hockenbury, 130) The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding. (MeSH) The basic framework of the molecular pathways in the cell that produce and maintain these daily rhythms has been elucidated. The central feature of the circadian pathways are two transcription factors, ‘BMAL-1’ and ‘Clock,’ that are expressed in a 24 hour cycle and that act together … to regulate the expression of other genes involved in maintaining the circadian rhythm. (NCIt) Our 24-hour rhythm influences our brain, our gut, our kidneys, our liver and our hormones— every cell in our bodies. 40 percent of our “genes” that encode “proteins” are under the “regulation” of the circadian rhythm. It is not simply a matter of exposure to light. The sun is the metronome that keeps this rhythm going. In the absence of the external cue of the sun’s light, body temperature, sleep and other physiological parameters retain this 24-hour rhythm, implying that somewhere within us is a clock that keeps time. (Leschziner, 18) If you descend into a cave for several days— where there are no clues to the light and dark cycles of the surface— your circadian rhythm would drift in a range between twenty-one and twenty-seven hours. This exposes the brain’s simple solution: build a non-exact clock and then calibrate it to the sun’s cycle. There is no need to genetically code a perfectly wound clock. The world does the winding. (Eagleman, 21) We are now aware of the influence of environmental cues that gently nudge our circadian rhythms forward or back. They are termed ‘Zeitgebers’— givers of time in German. The human circadian rhythm is set to 24.2 hours, and without Zeitgebers we would eventually find our internal clock drifting relative to the world around us. (These include) temperature, physical activity and eating, but the most potent Zeitgeber is light—particularly light at the blue end of the spectrum, like sunlight. (Leschziner, 20)

Delayed Sleep Phase Syndrome: associated with disruption of the normal 24 hour sleep wake cycle secondary to travel, shift work, or other causes. (MeSH) Affected individuals promptly fall asleep at 7:30 each night and awaken suddenly at 4:30 A.M., thanks to a "mutation" in a gene on chromosome 2 called 'period.' (Lewis, 153) Most people want to go to sleep between 10 p.m. and midnight and wake between 6 and 8 a.m. People with delayed sleep phase syndrome may want to sleep at 3 a.m., sometimes as late as 7 a.m., and wake up seven or eight hours later. If they get this amount of sleep, then they feel fine. Unfortunately, life often gets in the way of sleep—holding down a job or getting an education is difficult, if not impossible, on this sleep schedule. (Leschziner, 22) Also referred to as ‘familial advanced sleep phase syndrome.’

Suprachiasmatic Nucleus: a tear-shaped dense area of cells in the hypothalamus, which is responsible for regulating circadian rhythms. (NCIt) A cluster of neurons … that governs the timing of circadian rhythms. (Hockenbury, 131) A tiny area of the brain, comprising a paltry few thousand neurons. Sits in the “hypothalamus,” immediately above the optic chiasm, where the optic nerves carrying information from the eyes merge. (Leschziner, 20) Daily rhythms such as the sleep-wake cycle are set by (these) cells that form a 'circadian pacemaker.' In these cells, certain 'clock' genes are expressed in response to light or dark in the environment. (Lewis, 153) In the “retina,” at the back of the eye, in addition to the “rod” and “cone” cells responsible for converting light into vision, are cells known as “retinal ganglion cells.” A few of these cells have no contribution at all to vision. Their purpose is instead to conduct signals to the suprachiasmatic nucleus, through … the retinohypothalamic tract (pathway). It is through this pathway that light influences the rhythm in the suprachiasmatic nucleus, affecting... the relationship of the 24-hour rhythm to the outside world. For people without any vision, the control of the circadian rhythm can be problematic. (Leschziner, 22)

Homeostatic Mechanism: one of two mechanisms that control the drive to sleep. With prolonged wakefulness, levels of certain “neurotransmitters” that promote sleep build up, increasing sleepiness and… promoting sleep onset. (Leschziner, 14) The sum total of tissues and molecular forces in your body that wants to put you to sleep. It’s at war all day with the circadian arousal system. (MedinaBFP, 8) Also referred to as ‘homeostatic sleep drive.’

Insomnia: the perception that you’re not getting enough sleep, even if you technically are. While some ‘insomniacs’ truly don’t sleep, or at least have serious problems falling asleep and staying asleep, others feel tired despite sleeping. These ‘non-restorative’ insomniacs typically show less slow-wave-like brain activity and more wake-like brain activity during sleep. You could almost say they aren’t fully asleep. (LewisP, 156-157) (A condition where) people repeatedly complain about the quality or duration of their sleep, have difficulty going to sleep or staying asleep, or wake before it is time to get up. (Hockenbury, 140) Impairment of the ability to initiate or maintain sleep. This may occur as a primary disorder or in association with another medical or psychiatric condition. (MeSH) Trouble falling asleep or staying asleep through the night. Episodes may come and go, last up to 3 weeks (short-term), or be long-lasting. Sleep habits we learned as children may affect our sleep behaviors as adults. When we repeat these behaviors over many years, they become habits. (PubMedHealth2) Insomnia is one of the most commonly experienced disorders of sleep. Can be caused by either excessive activity in the ‘arousal system’ or concurrent activation of both wake-promoting and sleep-promoting pathways. (LewisP, 44) 'Clock' genes and at least three other genes are associated with insomnia. (Lewis, 153)

Narcolepsy: a nervous system problem that causes extreme sleepiness and attacks of daytime sleep. (PubMedHealth2) A person with narcolepsy falls asleep suddenly several times a day. (Lewis, 152) Many people with narcolepsy have low levels of ‘orexin’ (also known as ‘hypocretin’). This is a chemical made in the brain that helps you stay awake. In some people with narcolepsy, there are fewer of the cells that make this chemical. (PubMedHealth2) People with narcolepsy literally melt into a pile, as all their bodily muscles relax when they enter REM. Caused by abnormalities in a neurotransmitter called ‘orexin.’ Orexin is produced by the lateral hypothalamus and acts to stabilize the sleep-wake flip-flop. This neurotransmitter helps to keep us awake, and thus biases the whole system toward wake rather than sleep. When orexin is absent or abnormal, the extra stability it normally provides is lost, and the system is able to switch more easily Into sleep as we see in people with narcolepsy. (LewisP, 42) Rarely inherited as a single-gene trait. More often "polygenic" requiring an environmental trigger. Related to the damage of only a tiny number of neurons deep in the center of the brain… in the area of the lateral hypothalamus. (These neurons) project widely throughout the brain. In particular, they link directly to areas of the “brainstem” involved in the regulation of sleep and wakefulness as well as dreaming. In humans with narcolepsy, neurons producing (orexin) are damaged. (Leschziner, 115-117) Narcolepsy can run in families. Researchers have found certain genes linked to narcolepsy. (PubMedHealth2) The orexin receptor gene is on chromosome 6. The brains of humans with narcolepsy and "cataplexy" are remarkably deficient in orexin, but it isn't the orexin gene that causes the condition in humans - it is likely another gene that controls it. (Lewis, 152-153)

Cataplexy: a condition characterized by transient weakness or paralysis of (muscles) triggered by an emotional stimulus or physical exertion. (MeSH) The sudden loss of postural tone. The patient crumples to the ground. Consciousness is preserved. Emotion, laughter or crying, can precipitate an attack. (Leschziner, 114) During these attacks, you can't control your muscles and can't move. Strong emotions, such as laughter or anger, can trigger cataplexy. Attacks often last from 30 seconds to 2 minutes. You remain aware during the attack. In severe cases, you may fall and stay paralyzed for as long as several minutes. (PubMedHealth2) Short and sudden episodes of "muscle" weakness. The jaw sags, the head drops, knees buckle and the person falls to the ground. Often occurs during a bout of laughter or excitement. (Lewis, 152) On average, people with cataplexy have lost 90 percent of their hypocretin-producing neurons. Something causes them to disappear, to simply vanish. (Leschziner, 118)

Parasomnias: a sleep disorder that causes abnormal behavior while sleeping. The behavior can occur during any stage of sleep, including the transition from wakefulness to sleeping and vice versa. If you have a parasomnia, you might move around, talk, or do unusual things during sleep. (Healthline)

Non-REM Parasomnias: (conditions that) arise from non-dreaming, very deep sleep. (May be generated by) trying to wake a child from deep sleep. (Leschziner, 38)

Restless Leg Syndrome (RLS): typical symptoms include a terrible urge to move, usually the legs, that is only relieved by moving. The urge to move is often accompanied by unpleasant sensations— tingling, buzzing, pain, an electric feeling or cramping. One of the hallmarks of RLS is involuntary leg movement— kicking the legs, or twitches of the ankle, that occur deep in sleep. The leg jerks recur every five to ninety seconds for brief bouts or persistently throughout the night. Not only do sufferers experience the RLS symptoms that stop the drifting off to sleep, but once they do drift off, the leg movements disrupt the quality of their sleep, and sometimes wake them up. (Leschziner, 148-149)

Sleep Talking: a variation of “sleepwalking,” a non-REM parasomnia, common in children but rarer in adults. People can have full-blown conversations with their eyes open, and look… awake, but the chatter will often be inappropriate to the circumstances and will relate to some situation the sleep-talker imagines themselves in. Most people will talk of mundane matters, occasionally an argument, or, in the case of “sleep terrors,” some impending disaster. (Leschziner, 102-103)

Sleep Terrors: (characterized when) children will scream and cry inconsolably in the middle of the night and then go back to sleep, subsequently waking without any recollection. Most traumatizing, for parents rather than their children. (Leschziner, 38) Much more intense than a run-of-the-mill nightmare. Sharply increased physiological arousal - restlessness, sweating and a racing heart. Tend to be brief, usually lasting only a matter of seconds. Not regarded as a true sleep disorder or psychological problem unless they occur frequently. (Hockenbury, 141) (Dreams) are often visual imagery, disjointed in nature— walls crashing down, natural disasters, insects like spiders. (They) often occur in the first few hours of sleep. (Leschziner, 66) Also referred to as ‘night terrors.’

Sleep Walking: people often get out of bed and their eyes will be open as they pick up objects and sometimes act out complex tasks—even driving (a car or motorbike). Speech is usually intelligible, with fully formed sentences. Sometimes people can have limited conversations, albeit ones that are often nonsensical. (Leschziner, 66) Occurs during the deepest phases of slow wave sleep. (LewisP, 157) “Consciousness” takes us beyond an unconscious awareness of our body, and thereby allows us to attend to the world and react to it in what is known as ‘context-dependent’ ways. For example, if you’re sleepwalking, you can walk around; but since you’re unconscious, you can’t respond to your surroundings—which would be the “context.” And, of course, sleepwalking can be dangerous. (Campbell, BSP71) People with sleep-related eating disorders regularly get out of bed in their sleep and help themselves to the contents of their fridge or cupboard. They usually don’t realize this is happening and can grow obese as a result. (LewisP, 157) One of the areas identified in neuroscientific studies of sleepwalkers as being particularly active, the “cingulate cortex,” part of the “limbic system,” is the neurological seat of this experience. (Leschziner, 47) Also referred to as ‘somnambulism.’

REM Sleep Behavior Disorder (‘RBD’): (characterized by) the mechanism of paralysis going awry. Thought to affect less than 1 percent of the population, and typically coming on in the fifties or later. During RBD, the eyes are closed, and movements often appear purposeless, simply flailing or lashing out. There is little interaction with the external world, and people do not get out of bed. Speech is often not fully formed, usually largely unintelligible, and may be in the form of shouting or sweating. In RBD, dreams are stories developing over time. RBD is much more likely to happen in the the few hours before waking. (Leschziner, 65-66)

Sleep Apnea: a condition in which the flow of air pauses or decreases during breathing while you are asleep because the airway has become narrowed, blocked, or floppy. A pause in breathing is called an ‘apnea episode.’ A decrease in airflow during breathing is called a ‘hypopnea episode.’ Almost everyone has brief apnea episodes while they sleep. In ‘central sleep apnea’ breathing stops over and over during sleep. (PubMedHealth2) A sleep disorder that is marked by pauses in breathing of 10 seconds or more during sleep, and causes unrestful sleep. Symptoms include loud or abnormal snoring, daytime sleepiness, irritability, and depression. (NCIt) Disorders characterized by multiple cessations of “respirations” during sleep that induce partial “arousals” and interfere with the maintenance of sleep. (MeSH) A different order of magnitude (than '“snoring”). As we drift off to sleep, the countless small muscles that contribute to the stiffness of the walls of the airway slacken a little. If your airway is narrow enough, it can partially or completely obstruct. The collapse of the airway results in oxygen levels falling and heart rate increasing, (causing) a disruption in sleep. As the depth of sleep is fragmented, muscle tone in the airway returns briefly to allow us to breathe again, and this cycle can continue throughout the night. These obstructive events can happen ten, twenty and, in rare cases, even 100 times per hour. If our sleep is disrupted at these sorts of levels, it is entirely understandable that we may wake up tired. As we get larger and heavier, sleep apnea becomes more and more common. The rates of sleep apnea have increased in parallel with our girths and neck circumferences. Graphs of obesity in the U.S. population show a relentless slope upward, particularly since the early 1980’s. We are living through a sleep apnea epidemic. Increased weight may precipitate or worsen sleep apnea. Local deposition of fat in the neck makes the airway narrower and more likely to collapse, but fat on the chest increases the effort of breathing, reduces lung volume due to weight on the neck, and increases the metabolic demands on the body. Weight loss often improves sleep apnea. There are multiple other factors. Sleep apnea may run in families, and is often related to the shape of the airway. A large tongue base or a recessed lower jaw will cause a narrowing, as sometimes do very large tonsils. (Leschziner, 80-82) Also referred to as ‘dyssomnia.’

Sleep Apnea Health Impacts: sleep apnea is strongly associated with high blood pressure and the serious problems that it can cause, such as heart disease and strokes. Sleep apnea lessons the body’s response to insulin, causing what is termed ‘insulin resistance,’ the first step in the development of diabetes. Sleep apnea also influences the levels of two hormones— leptin and ghrelin. (They) are important for the regulation of appetite and metabolism. So it may be that sleep apnea in itself increases calorie intake… predisposing to further weight gain. Sleep apnea is also of relevance to headaches such as migraines and morning headaches, can result in increases in pressure inside the skull, and can worsen the effects of “Parkinson’s disease.” Within my own clinical practice, it can trigger sleepwalking, sleep paralysis and nightmares, and can complicate narcolepsy and insomnia. In my epilepsy clinic, I see many patients in whom sleep apnea complicates their epilepsy control. For the general population, one of the most worrying, is that of “Alzheimer’s disease.” While sleep apnea appears to cause significant deterioration in various aspects of “cognition,” like “attention,” vigilance, long-term verbal and visual memory, reasoning and problem-solving, it may also have a direct role in the development of “dementia.” In the elderly, build-up of the protein “beta-amyloid” has been associated with sleep apnea. If you consider that sleep apnea disrupts sleep sometimes hundreds of times per night, it is easy to understand why this might impair the function of the “glymphatic system,” why beta-amyloid levels in the brain might go up, and why this might predispose to Alzheimer’s. Some researchers have proposed that sleep apnea is a major modifiable “risk factor” for Alzheimer’s. (Leschziner, 83-88)

Sleep Medicine: clinical work… to unravel the causes for sleep disorders and attempt to find a treatment or cure. (Leschziner, 1)

Sleep Paralysis: the inability to move for a few minutes after awakening. (Lewis, 152) This is when you can't move your body as you start falling asleep or when you first wake up. It may last up to 15 minutes. (PubMedHealth2)

Sleeping Sickness: an infection with germs carried by certain flies. It results in swelling of the brain. When an infected fly bites you, the infection spreads through your blood. The disease does not occur in the United States. But travelers who have visited or lived in Africa can have the infection. (PubMedHealth2) Transmitted to humans and livestock by ‘tsetse flies’ in equatorial Africa as well as in parts of South America and Asia. Nearly half a million people become infected with sleeping sickness each year, and the disease is fatal if untreated. (Brooker, 598)

Sleep Stages: sleep changes both in quantity and quality. A newborn will sleep for two-thirds of the day. Adults tend to sleep between roughly six and a half, and eight and a half hours a night. Sleep is not a static state. There are actually multiple stages involved. Over the course of the night we cycle through these various stages of sleep, usually four or five times. (Leschziner, 12-13) Importantly, the brain doesn’t just move through these four stages of sleep once in a night. It cycles through them repetitively, with each cycle lasting about 90 minutes. (LewisP, 9)

Non-REM Sleep: non-rapid eye movement sleep. Although your pulse and body temperature drop somewhat during the deeper stages of non-REM, there aren’t too many other changes as far as your body is concerned. (LewisP, 9-10) The dreaming of non-REM sleep often contains only simple visual imagery, like animals, people, or inanimate objects. When mixed in with strong emotional stimulation, these images are often scary or even terrifying—spikes crashing down from the ceiling, insects on the walls, or snakes in the bed. And it appears that this surge of “adrenaline” mediated by the “autonomic nervous system” means it is more likely for people in this sort of episode to wake up, sometimes partially but sometimes fully, and to remember their experiences. (Leschziner, 47)

Stage 1 Sleep: the brain exhibits a quietening of normal waking electrical activity and the eyes slowly roll from side to side. (Leschziner, 12) As you get drowsy and start t close your eyes, the electrical signals from your brain slow down and get slightly bigger. The stage when you initially fall asleep. (LewisP, 8-9) Also referred to as ‘drowsiness.’

Stage 2 Sleep: brain wave activity slows further. When we record the brainwaves during this stage… alternations in the background brainwave rhythm. not evident in wakefulness, become visible. For example, ‘sleep spindles’ and ‘K-complexes.’ (Leschziner, 12) We can tell when your sleep gets deeper because new types of electrical activity called sleep spindles soon start to appear on our electrodes. These are little bursts of frenetic activity, often stemming from specific areas of the brain. (LewisP, 8) Also referred to as ‘light sleep.’

Stage 3 Sleep: within about thirty minutes or so of drifting off, the brainwaves slow considerably but increase in size. The majority of this sleep (occurs) in the first half of the night. (Leschziner, 12) (Characterized by) high amplitude (brain waves) and deep sleep. (The brain waves) are a sign that, instead of doing lots of very separate tasks, many areas on the brain are acting together in a coordinated, but slow, fashion. Slow wave sleep may occur (but only briefly) during the last couple of (sleep) cycles when REM dominates. (LewisP, 9) Also referred to as ‘slow-wave sleep’ and ‘deep sleep.’

REM Sleep: rapid eye movement sleep. (Occurs after drifting off), sixty to seventy-five minutes or so. The eyes dart back and forth rapidly, the brainwaves look to be highly active— a little like being awake. It is in this state of sleep that we most obviously dream. The majority of REM sleep (occurs) in the second half (of the night). (Leschziner, 13) During REM sleep the electrical activity in your brain resembles the activity we see during drowsy wakefulness. The reason REM is named ‘rapid eye movement’ sleep is because your eyes make rapid darting movements, usually under closed lids, during this phase. The eyes are the only area of the body where movement is possible, since all other skeletal muscles are paralyzed. (LewisP, 10) The time spent in REM and (stage 3 sleep) is inversely proportional. You get a lot of slow wave sleep and little REM during the first part of the night, and show the reverse pattern later in the night. This means that if REM occurs at all in the first few 90-minute sleep cycles it is very brief. (LewisP, 9) Previous notions of REM sleep being the stage of sleep exclusively in which we dream are not correct. Dreaming in non-REM sleep is not unusual at all, although the content of the dreams is different. Individuals woken from REM sleep often describe dreams with a narrative structure, a tory evolving like the plot of a book or a film. (Leschziner, 47) During this stage of sleep, which occurs about four or five times per night, our brainwaves look like we are almost awake. But, our bodies are largely paralyzed. All muscles, with the exception of the muscles of the eyes, the diaphragm, and (some) sphincters, develop complete weakness. The muscles essentially are shut down. (Leschziner, 64)

Snoring: (characterized by) a narrow airway or partially blocked nasal passages (that) disturb the airflow at the back of our mouths, causing the soft tissues in our throat, the soft palate, tonsils, adenoids, and uvula, to reverberate. (Leschziner, 79)