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Sleep Study Questions
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Click here if you have questions about sleep studies. 

General Sleep Questions
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Do we need 8 hours of sleep?
Many people believe that 8 hours of sleep is so important that obtaining less than 8 hours will cause medical problems. Many research publications have shown that people who report sleeping an average of less than 6 hours per night have more medical problems compared to those who report sleeping an average of 7-8 hours per night. What most people don't know is that those same medical problems were even more likely among those who reported sleeping an average of 9 hours or more per night! Simply put, asking people how much they sleep may be a "marker" for general health and wellness, and not a direct cause of health problems. It is an entirely different question as to whether altering one's sleep duration (either increasing or decreasing to target the 8-hour ideal) will improve health in any way. It is true that the average amount of sleep reported by adults per night is approximately 7.5-8 hours. For some people, sleep loss can cause symptoms like sleepiness, fatigue or foggy thinking. However, the performance consequences of self-reported insomnia remain difficult to ascertain (Shekleton 2010).

Should sleep happen in one solid block?
Many people believe that they should sleep "straight through" the night, without waking up. In reality, sleep is never continuous when measured objectively. A recent historical account of sleep presented strong evidence that until very recently, most people slept in two blocks at night, separated by about an hour or so of quiet waking time in the middle of the night (Ekirch: At Day's Close: Night in Times Past). In fact, some experiments show that splitting sleep into four quarters spread through the day is no different than an 8 hour block. When sleep is measured with electro-encephalography (EEG), we see that the brain awakens for at least 15 seconds between 10-20 times in a given night, but only a small fraction of these reach conscious awareness and are remembered the next day. If we consider EEG arousals, which are awakenings between 3-15 seconds, there may be 10-15 awakenings per hour of sleep, even among those who think they are sleeping through the night! Sliver of truth:It is true that multiple awakenings noticed by a patient can be a hint that something is disturbing sleep.

Is it really possible that I can be asleep, yet feel awake?
Yes. Many people with insomnia are actually sleeping more than they think they are. Some are shocked to learn just how much sleep they had, when they are tested in the overnight sleep lab. For decades we have known about this phenomenon of mismatch between subjective and objective sleep duration, sometimes called misperception or paradoxical insomnia. However, it may not occur to a patient experiencing insomnia that their very perception of conscious awareness, or elapsed time, might not be accurate. This is a major dilemma in the field, as the diagnosis, treatment decisions, and follow-up evaluations for patients with insomnia depend entirely on the self-report of the patient, such as the sleep diary, or simply their recollection.

Are sleeping pills a safe way to give back normal sleep?
Two issues here: whether sleeping pills are safe, and whether the sleep one gets after taking a pill is normal. There is a growing body of research raising serious safety concerns about even intermittent use of sleeping pills. Most sleeping pills alter sleep physiology in some way. For example, drugs like trazodone and mirtazepine other antidepressants can suppress REM sleep, and the benzodiazepines (e.g. lorazepam and diazepam) tend to suppress reduce both REM sleep and slow wave sleep among other changes in the EEG. Whether these changes are good, bad, or neither - is remains totally unknown.

General Sleep Disorder Questions
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My bed partner says I move my legs at night - does that mean i have restless legs syndrome?
RLS is diagnosed purely based on your symptoms while you are awake. You don’t even need a sleep lab test to diagnose RLS. The leg movements that occur within sleep are called Periodic Limb Movements. Some of the same blood tests and medications are useful in both cases.

I twitch when I'm about to fall asleep - does that mean I have restless legs syndrome?
The quick “jerky” movements of the arms or legs that happen just as a person falls asleep are called “hypnic jerks” and do not require treatment, although on some occasions the movements can be startling.

Sleep Apnea Questions
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I don't snore - could I still have sleep apnea?
Yes. Although snoring is a common feature of sleep apnea, they do not always go hand-in-hand. We do not think that snoring is a strong predictor, by itself, to know whether a person has sleep apnea. Some people snore but do not have sleep apnea. Other people have clear evidence of sleep apnea when tested in the sleep lab, without knowing (or being told) that they snore.

I feel fine - could I still have sleep apnea?
Yes. We know from large studies that only about half of patients with sleep apnea – even in the severe range – have sleepiness during the day. In other words, we do not think that sleepiness or fatigue is a reliable enough symptom to predict whether a person has sleep apnea. Patients with certain risk factors should undergo testing, even if they feel fine.

I am not over-weight - could I still have sleep apnea?
Yes. Although being overweight is a major risk factor for sleep apnea, it is one of many factors. We know from large studies that there are many patients with significant sleep apnea who are not overweight.

Is home testing as good as spending the night in the sleep lab?
No. Home testing has become increasingly available, but it is important to know the pros and cons. The benefit is that it can be performed in the home, and the test-cost is lower than a night in the lab. However, the home apnea testing kits don’t actually measure sleep – they measure breathing problems. For some patients, this is sufficient, if the question is simply to confirm sleep apnea in a person felt to have a high chance of having significant apnea. Here are some things to think about when it comes to deciding whether home testing is appropriate:

Most home kits do not measure sleep. The only exception is the WatchPAT. This is important for patients who have insomnia, and may be awake for some of the night, which affects the readings.

Most home kits do not measure body position. This is important because about half of patients with sleep apnea have more trouble on their back and less on their side – which can impact the readings on a given night.

Home testing kits are only recommended by the American Academy of Sleep Medicine for specific patients. It is not recommended for general screening, for those with certain cardiac or neurological disorders, for patients with another sleep disorder such as insomnia, or for patients who have a low or moderate chance of having significant sleep apnea.

If the home test shows no sleep apnea, the American Academy recommends repeating the test in the sleep lab to confirm that there is truly no sleep apnea. This is called a “false negative” problem, and can occur with home testing kits, which is why the AASM makes this recommendation. Put another way, the home kits are only useful for “confirming” the diagnosis of sleep apnea when they show a positive result.

I have sleep apnea - do I really have to wear a mask?
The mask is considered the gold standard treatment for sleep apnea. However, there are other options to treat sleep apnea if a person cannot tolerate the mask.

I can only wear the mask sometimes - how much is "enough"?
It depends. One perspective is that many insurers require a minimum use to cover the equipment, which is 70% of nights with at least 4 hours of use. However, for the person who sleeps 8 hours per night, this “minimum” standard is only about one-third of your sleep! We suggest using the mask as much as possible. How much is enough could depend on how severe your apnea is – the more severe the case, the more we suggest the mask to be worn. For some patients, they notice a difference in energy with a certain amount of use. However, we caution patients that the connection between fatigue/sleepiness and mask use is different for each person, and just because a person feels improved with part-time use doesn’t necessarily mean their apnea is under good control.

I don't sleep on my back, why did they ask me to sleep on my back in the lab?
Most people change body positions during the night, even if they don’t realize it. Many patients have more breathing trouble on their back, especially during REM sleep that occurs while on the back. We cannot obtain a full picture of the potential sleep apnea severity without seeing the “worst-case” scenario in the lab. For example, some patients have sleep apnea only on their back – if we allowed them to sleep on their side the whole night in the lab, we run the risk of concluding the breathing is normal when it could be quite severe if the person rolls onto their back at home, even for only a part of the night.

I can't breathe with the mask on - what should I do?
There are several reasons for trouble breathing with the mask, ranging from claustrophobia, to improper mask fitting, to having a pressure that is too high. Figuring out which of these factors is most important can be a challenge – ask your doctor whether a mask fitting visit or a pressure evaluation is needed.

What is the difference between CPAP, BiPAP, and Auto-PAP?
CPAP means Continuous positive airway pressure – basically the fan blows air at a constant pressure. BiPAP means bi-level pressure – in these machines, two levels of pressure are used, a larger amount while you inhale, and a smaller amount while you exhale. Auto-PAP can be either CPAP or BiPAP, and these machines have a range of pressures to give you, based on how your breathing is going throughout the night. Ask your doctor which type of pressure system is right for you.

What is complex apnea?
Complex apnea is a term used for the subset of patients in whom breathing problems remain or even worsen when they use CPAP, BiPAP or Auto-PAP. Patients with complex apnea may benefit from a special kind of machine called Adaptive Servoventilation.

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