Sleep state misperception (SSM) is a difference between the subjective and objective measurements of sleep onset and/or being asleep. I.e. you don’t feel you were asleep, but us sleep scientists have data that proves your were asleep. Surprisingly this is more common than most people realise. In fact most mornings here in the sleep lab we will hear a patient tell us they took hours to fall asleep, when really they fell asleep quite quickly or quite normally. This can be quite serious at times, with some patients reporting insomnia who may not even have insomnia, this is known as paradoxical insomnia.
Hsiao et al. recently had a study accepted by the journal of sleep. What they did was have simultaneous fMRI and PSG (sleep study) recordings, allow patients to fall asleep and then wake them up. When the patients were awoken, they were asked about their sleep or lack thereof. What they found was that in patients who had a larger discrepancy between the reported and recorded sleep had certain traits being noted. They found these patients’ EEG activity was associated with lower theta power, as well as higher alpha, beta, and gamma power. And had a higher amplitude of low-frequency fluctuation (ALFF) levels in the prefrontal cortex. They concluded that these results lend support to the conjecture that the subjective-objective discrepancy is associated with central nervous system (CNS) hyperarousal.
Original abstract can be found here:
https://academic.oup.com/sleep/advance-article/doi/10.1093/sleep/zsy056/4953260
