The Sleep Onset Latency Test or Spoon Test
The idea behind this test is to see how quickly you fall asleep during the day, if you are given a chance. Day- time sleepiness is a good measure of “sleep debt” and therefore of whether you are getting enough good-quality sleep at night. If you fall asleep while watching TV or at the cinema, then you probably have “sleep debt”.
The great thing about this test is that it doesn’t require any fancy lab equipment; you just need a metal spoon and a metal tray. The version describe below was developed by a famous sleep researcher, Professor Nathaniel Kleitman, from the University of Chicago.
At the weekend, or whenever is most convenient, you skip your usual morning coffee or tea. Then, in the early afternoon, any time between 1pm and 3pm, you go to your bedroom with a metal spoon and a metal tray.
You close the curtains, place the metal tray on the floor by your bed, check the time, then hang your arm over the side of the bed, clutching the spoon. Finally, you close your eyes and try to drift to sleep. The idea is that if you fall asleep, the spoon will drop from your fingers and hit the tray with a loud clang, waking you up. As soon as that happens, you check your watch to see how much time has passed.
- If you fall asleep within five minutes of closing your eyes, it means you are severely sleep deprived.
- Falling asleep within five to ten minutes is deemed to be “troublesome”.
- Falling asleep after 10–15 minutes suggests you have a mild problem.
- If you stay awake for over 15 minutes, you’re probably fine.
An alternative version of this test which is more practical but less fun, is to go to bed in the afternoon, as described, but this time you just set an alarm on your phone to go to after 15 minutes. You then see if you drop off before the alarm goes off.
The Multiple Sleep Latency Test
This is a more sophisticated version of the above, normally carried out in a sleep lab.
When you arrive at the lab, you are attached to numerous machines (to record brainwaves, eye movements, muscle tone, etc.) and asked to lie down in a dark, quiet room during the day. The scientists measure how quickly you fall asleep and how deeply. After 20 minutes you are woken up. Then, two hours later, you do it again. And then again. In fact, you do this a total of five times. This test is used to diagnose whether you have a sleep problem, and if so what type. Do you have narcolepsy or idiopathic hypersomnolence? A breathing disorder or excessive daytime sleepiness? It is expensive, but it is the most reliable way of getting to the root of a persistent sleep problem.