One signal. Two rooms.
Fatigue on a night shift and neurological state at a bedside are the same measurement in different rooms.
The locus coeruleus governs arousal, and it drives the pupil and the eyelid.
Fatigue, sedation and impaired consciousness sit on one pathway. They differ in cause. They show up in the same measurements.
Source
Brainstem arousal system.
Output
Pupil size and reactivity, blink duration, lid reopening speed.
Read
Continuous, from outside the head, no electrodes.
Industrial shifts
Noddr scores eyelid and pupil metrics from head-worn eye tracking. Pupil diameter answers ambient light faster than it answers state, so the light response comes out first.
Clinical research
Doctoral research at UC San Diego will extend ambient-light-corrected pupillometry into clinical populations, where arousal has ground truth an industrial site cannot supply. It will run as research, with no product and no site.
Industrial deployment hardens the read. Clinical research validates it.
Each one makes the other credible.