EFO_0009099 (arousal domain measurement) is a measurement of some aspect of psychological arousal/regulatory systems e.g. those responsible for generating activation of neural systems as appropriate for various contexts, and providing appropriate homeostatic regulation of such systems as energy balance and sleep.  Based on the NIH NIMH's research domain criteria (RDoC).  https://www.nimh.nih.gov/research-priorities/rdoc/definitions-of-the-rdoc-domains-and-constructs.shtml.