Working memory and (athetoid) CP

Can anyone point me at any decent research into issues around working memory and CP, in particular athetoid?  This is re someone who does not have a traditional "learning disability" and in fact they are in higher education, but they are non-verbal and do have issues with some aspects of working memory, which can be classed as a cognitive impairment.  We think this is very tied in with the non-verbal thing too, cos no inner voice and everything they want to say has to be written down, via AAC, so very different mental processes to those that are used in speech.  Ta