The article is a case report. They’re almost always N=1. They’re just meant to contribute to the sum total of general knowledge of practicing medicine.

By definition a case report describes a single patient (n = 1).

Why is it so surprising that continuous measurement is likely to catch a failing system? The more surprising belief is that sporadic random measurements at random times give you good enough predictive powers. Like all the blood work and vitals we do at the doctor’s office - I’m sure it captures some problems but more subtle deviations from baseline are much more difficult to suss out.

Yes, this is a „case study“.