Pittsburgh-based Ebb market a prescription device for treating insomnia.
Ebb appears to use an worn headband that cools the temperature of the forehead.
It is unclear what, if any, sensing modality (e.g. EEG) is involved.
Although the device is not available yet, it has been approved by the FDA "as a class II medical device indicated to reduce sleep latency to Stage 1 and Stage 2 sleep in patients with primary insomnia based on a de novo (new product) clearance request. Ebb is a prescription device."