People with insomnia may sometimes feel that they're awake — even if they're really sleeping.
I've spent the majority of my life surrounded by insomniacs.
I found myself caring for these people who were dear to me, and while I empathized deeply with their condition, at times, I would get slightly frustrated with them.
For instance, I can remember times when my partner's eyes were shut, his breathing was deep and regular, and he'd occasionally let out a snoring sound.
I'd think to myself, "Thank God he's finally sleeping" — only to be told the next morning that he "did not get a wink of sleep."
"So what was that about?" I'd ask myself. Was this a classic case of an "imaginary invalid," or was I misunderstanding insomnia?
Apparently, the experience of sleeping without even knowing it is not uncommon among those with the condition. Scientists have identified the phenomenon and, although they did not fully understand it, labeled it "sleep misperception."
New research, however, delves deeper into the mystery of sleep misperception and may have found an explanation for it.
According to study leader Daniel Kay — a psychology professor at Brigham Young University in Provo, UT — the reason behind why scientists have been missing out on the explanation for this phenomenon is that, traditionally, sleep is understood as a categorical experience: you're either asleep or you're not, and when you're asleep, you cannot be conscious.
But Prof. Kay doesn't believe that this is "necessarily true." He says, "I think you can be consciously aware and your brain [can] be in a sleep pattern. The question is: what role does conscious awareness have in our definition of sleep?"
Consciousness brain areas are key
To answer this intriguing question, Prof. Kay and team analyzed the sleep patterns and experiences of 32 people with insomnia and those of 30 participants who did not have the condition.
Using polysomnography — a traditional sleep studying method — the scientists examined the brain wave patterns of the participants. Once the researchers were able to detect, based on these brain waves, when the participants were asleep, they injected a radioactive tracer in their arms.
The version of the tracer that the researchers used enabled them to examine the brain neurons that were active in certain parts of the brain during sleep.
They also took brain scans of the participants to uncover where in the brain the activity occurred. Also, the participants were asked about their sleeping experience the following morning.
The study found that people with insomnia who reported that they had been awake, even when the polysomnography showed otherwise, had increased activity in brain areas associated with conscious awareness during the dreamless phase of sleep — that is, non-rapid eye movement sleep.
"Good sleepers," on the other hand — who reported falling asleep long before polysomnography recorded them as such — also had increased brain activity in the same areas.
Sleep misperception explained
According to Prof. Kay, both those with insomnia and those who sleep normally may go through an inhibition process when they fall asleep.
As the team explains, it is normal during the process of falling asleep for the brain to send inhibitory neurons that make people less and less consciously aware until they've reached a state of deep sleep.
However, what the findings of the new study suggest is that people with insomnia may not feel as though they're asleep until their brain experiences a greater inhibitory activity in areas that are linked to conscious awareness.
Increased inhibitory activity in brain areas related to consciousness might also be the reason why normal sleepers feel as though they've fallen asleep before a scientific measure shows that they have.
In other words, an impairment in this inhibition process, as revealed by the new study, is what may drive sleep misperception. The findings, hope the researchers, will help to devise new strategies for treating insomnia.
"In patients with insomnia," says Prof. Kay, "processes involved in reducing conscious awareness during sleep may be impaired [...] One of the strategies for targeting these processes may be mindfulness meditation."
"It may help the patients inhibit cognitive processes that are preventing them from experiencing sleep."
Prof. Daniel Kay