Basically this has been in use since the 1930's and to be honest, until these training courses, it never crossed my mind, even for a second that this might have in anyway anything to do with seisures.
So, what did I do? Well what I normally do and that is ask someone who might know. This is a direct quote from the Email I received from Epilepsy Action - www.epilepsy.org.uk:
"We are often asked about the word 'brainstorming' and whether its use is acceptable. Our view is that it depends upon the context: if the word is being used to describe a meeting where participants are suggesting ideas, then its use is not offensive to people with epilepsy. However, it should not be used to describe a seizure or the electrical activity within the brain during a seizure."And sanity prevails....