Sleep headphones

I've always been intrigued by sleep learning, and although the scientific evidence seems to be against it, I have a hunch that with research and optimisation that it could be a productive tool.

One barrier to sleep learning, particularly for restless sleepers that share their beds, is a set of headphones that are sufficiently comfortable to sleep in. Some thoughts on specification:

• They need to be wireless (for people who toss and turn and would therefore get caught by the wires)
• They need to be in-ear and small (for those who sleep with their heads on their sides)
• Perhaps each ear of the earphone could have its own battery and receiver eliminating the need for a connecting wire inbetween. Alternatively, the connecting wire could be embedded in a wide comfortable strip of fabric
• Perhaps hooked up with sleep sensors to ensure content is delivered in the optimum sleep phase, and to ensure that if the content is beginning to disturb the sleeper the delivery is stopped or the volume reduced

Such headphones would also work well to gently wake people from sleep, and would do so without disturbing their bed partner (a personal gradual alarm clock).