Pseudo-insomniacs are rare cases that complicate the classical rules of sleep science. While they perceive themselves to be awake all night, traditional lab tests show nothing other than completely normal sleep. ‘Pseudo-insomniacs’ have made scientists take a closer look at the sleeping brain, but the science of sleep is still far from being completely understood.
Do you lie awake at night, tormented by an inability to sleep? About 1 in 8 of us suffer some form of chronic or severe insomnia, making it a widespread and serious health concern. If you are especially unlucky, you might have the sort of insomnia that can’t be detected in a sleep clinic. This is the problem faced by about 5% of people who claim to have insomnia.
More than hypochondria?
Pseudo-insomnia, also known as ‘sleep state misperception’ or ‘paradoxical insomnia’, has usually been regarded as a psychological problem, or a type of hypochondria. People can easily overestimate how long it takes for them to get to sleep, and underestimate how long they sleep for. While this may be part of the explanation, some scientists believe that the lab tests may not be giving the full story.
So is there something unique about the brains of pseudo-insomniacs that distinguishes them from both normal sleepers and verified insomniacs? In order to help answer this question, scientists have been taking a closer look at the electrical patterns in the brain during sleep. But the answers aren’t exactly clear cut. Pseudo-insomniacs, if not hypochondriacs, may simply be blurring the distinctions between waking and sleeping. After all, there is currently no completely reliable way of identifying a sleeping brain from readings in the lab. Discovering an objective signature of sleep is still a holy grail of sleep science.
Decoding the brain’s message
Brain activity can be detected because it is fundamentally electrical in nature. Billions of cells in the brain are constantly exchanging electrically charged chemicals in a vast and intricate network which we are only beginning to untangle. The electroencephalogram (EEG) is the instrument that can detect large-scale patterns of this sort of electrical activity.
Scientists in the 1960s developed a series of rules for diagnosing different sleep states based on patterns seen on the EEG. For example, relaxed wakefulness is often accompanied by oscillations called ‘alpha waves’, which are just voltage variations in the EEG reading with a certain frequency range. ‘Delta waves’ are slower and larger, and tend to be associated with deep sleep.
Pseudo-insomnia is the exception to the rules, with non-sleepers showing plenty of delta wave activity. While this discrepancy has been known about since the 1970s, more recently sleep scientists have attacked the problem with a technique called ‘spectral analysis’.
Reading the fine print
Where a signal seems noisy or random to the human eye, spectral analysis provides an efficient and objective way to identify any dominant cycles.
Applying spectral analysis to EEG readings reveals some fine details that can be overlooked by the human eye. Relative to normal sleepers, the spectra of pseudo-insomniacs contain not only more alpha wave activity (wakefulness), but also more beta and gamma waves. The difference is subtle, but it is there.
The same pattern is also detected with many regular insomniacs, which makes it unclear whether pseudo-insomnia is really something unique.
So what does the presence of beta and gamma waves mean? Waves of this type have traditionally been associated with consciousness. When your brain is giving off these signals, you are likely to be actively concentrating, or feeling stressed and anxious.
Insomniac brains just can’t quite seem to turn off, and ‘pseudo-insomniacs’ may be no exception. Bizarrely enough, insomniacs have been documented to be better than the well-rested at learning new physical tasks, and display more activity in corresponding areas of the brain. The interpretation seems to be that insomniacs are in a constant state of information processing.
Blurring the lines
Depending how closely you look, pseudo-insomniacs can display brain activity similar either to normal sleepers or regular insomniacs. The take-home message might just be that our understanding of sleep is incomplete. The brain is a bafflingly complex system that we might never fully understand.