Hugh Pickens writes "Emily Singer reports in MIT Technology Review that a nightshirt embedded with fabric electronics can monitor user's breathing patterns while a small chip worn in a pocket of the shirt processes that data to determine the phase of sleep, such as REM sleep (when we dream), light sleep, or deep sleep. 'It has no adhesive and doesn't need any special setup to wear,' says Matt Bianchi, a sleep neurologist at Massachusetts General Hospital and co-inventor of the shirt. 'It's very easy—you just slip it on at night.' Until now people with sleep disorders were hooked up to a complex array of sensors that monitor brain activity, muscle activity, eye movement, and heart and breathing rate but the 'smart pajamas' simplify this by focusing only on respiration. 'It turns out that you can tell if someone is awake or asleep and which stage of sleep they are in purely based on breathing pattern,' says Bianchi. 'That's a much easier signal to analyze than electrical activity from the brain.' Sleep specialists hope the pj's can help patients with insomnia or other sleep disorders since the shirt allows repeated measurements over time in the home so users can log their habits, such as coffee or alcohol intake, exercise, or stress, and look for patterns in how those variables affect their quality of sleep."