They look very similar to some parts made by the company I work for (also a medical devices company). The plastic parts are often single-use and therefore cheap, but one is needed for each patient. The expensive bit is the ventilator to drive them.
I had one (an AgendA), and I don't remember typing with it in my pocket, but I could use it at night without turning on the lights. I would really like a Bluetooth version of that keyboard. Sadly, the only one that I know used LED output, so not useful these days.