SAPI Adaptation

I'm using SAPI 5.1 and VB6.  I noticed recently that there are actually two
separate settings for Adaptation in the SAPI online docs, one for AdaptationOn
and one for PesistedBackgroundAdaptation.   What is the difference between
these two settings?  Which one corresponds to the "Adaption" checkbox
in the
Speech control panel dialog?    I have been setting AdaptationOn to 0 through
code, but it doesn't seem to completely stop the engine from adapting. 
Occasionally it a profile seems to degrade to the point that it's
non-functional - I think it's listening to background noise when no one is
speaking, and incorporating what the noise into the profile - but I can't
always consistently duplicate the problem.  Do I need to set both Adaption
settings to 0 to turn off Adaptation?

Thanks in advance,
Miguel