It may be of little comfort to sufferers of insomnia to learn that some kinds of sleeplessness are worse than others.
Some restless periods in bed, which scientists call "arousals", tend to cause sleepiness the next day, while others have little or no effect.
Until recently it was next to impossible for clinicians to monitor the short-term changes in the brain, known as "microarousals", which could help explain the various brands of sleeping disorder.
But now they have Questar, a computer-based system developed by researchers in Oxford University's department of engineering science, Oxford's Churchill Hospital and the medical system division of Oxford Instruments. The system uses neural networks to analyse sleep second by second - a clear advantage over other techniques which can only manage to take readings at 20 to 30 second intervals.
Questar, which in sleep-expert speak stands for Quantification of EEG and Sleep Technologies Analysis and Review, is a spin-off from work on neural networks carried out in the department of engineering science by Lionel Tarassenko, who has been nominated for an award as a result.
He explained: "Questar is an excellent example of technology transfer from academia to industry. It started with the concept that the neural network algorithms developed by my research group might also be applied to the analysis of sleep and now, five years later, we have a new product on the market."
The involvement of Oxford Instruments has led to the system's development for clinical use. It is already being used to monitor patients with sleep disorders.
Robert Davies, consultant physician at the Churchill Hospital, said: "Questar looks at very rapid changes which provides us with a much clearer picture of what is going on."
Questar was presented to the seventh British Sleep Society conference in London last month.