hey. there is a research group in holland who write about EP and ANP. they talk about the neurophysiology... but basically they regard the following to be on a continuum:

PTSD - split between EP and ANP
Complex PTSD - split between different EP's and ANP
DID - split between different EP's (with some elaboration) and different ANP's (with some elaboration)

An EP is an 'emotional personality'. Inner children count as EP's. EP's have defensive functions. An ANP is an 'apparently normal personality'. The host / personality who bears the actual name is typically the ANP. ANP's have day to day functions like work, looking after children etc.

Different handwriting and so on are meant to be elaborations as the person spends a lot of time in the EP state.

So... Continuum.

Here is an article if you are interested:

http://www.trauma-pages.com/a/nijenhuis-2004.php