I'm a little lean on the electronics knowledge but I make my living with my recording studio by day. Speaking broadly, a mic is just a transducer that turns vibrations into AC voltage.
I'm not sure where to find mics of your exacting specs. I'm a little skeptical of a throat mic's ability to go up into the 20Khz ballpark...or ever 5Khz. This is not to say the mic itself won't pick it up, but I'm curious what kind of "information" (high frequency energy) can be found in the throat. It's my assumption this is almost entirely low frequency fundamental frequency stuff. How important that potentially missing high frequency energy is to your EasyVR is a total guess to me but the fact that they mention needing 100Hz-20Khz suggest high frequencies are important.
It is possible for a throat mic to compensate for the lack of high end, but I suspect it comes at the expense of isolation.
Then again, this could be a case of my background totally misleading me.
I found an audio clip of one (FINALLY!...Don't try Youtube.) http://www.iasus-concepts.com/nt/nt-3.htm I'm not hearing anything over 5k to speak of and could only guess what that means for speech recognition software, but the fact that a human has to squint a little bit to make out the words is a red flag.
How loud of environment are we talking? There may be other options other than the throat mic method.
Good luck!
Brandon