Tappigraphy

We compared two standard methods used to estimate sleep with that of a new tappigraphy-based algorithm based on the gaps in smartphone usage. Pooling all of the measurements together (by concatenating the sleep-related estimates obtained from each participant), we found strong correlations between the putative sleep times determined by actigraphy versus tappigraphy

Source: wiktionary

Tappigraphy has also uncovered associations between sleep patterns and mental health.

Source: wiktionary

This year Ghosh published a small clinical study of people with epilepsy that shows how subtle changes in smartphone tappigraphy alone could be used to infer abnormalities in their brainwaves.

Source: wiktionary