In truth, Sleep Learning DOES work. Sleep Learning is not actually done during sleep itself. Sleep Learning was designed to work during the hypnagogic stage, the barrier between sleep and wakefulness. Mind Awake, Body Asleep. In most people, it is a fast journey through that stage. In those who learn to maintain that state, it is exhilerating beyond belief.
Anywho, I read once about a researcher who used an EEG to turn on a tape player when the dominant brain state was at 7Hz (approximate zone of hypnagogia). As the brain states start to lower below 7Hz, the volume of the playback is automatically increased proportionately. This causes the user to become more alert, and ideally maintains the 7Hz brain state.
I think rather than sleep learning, it should have been called "relaxation learning".
BP