Rowan, don't apologise - you have to move like greased weasel droppings to keep up with changes in that terminology. The broader heading was "learning difficulties" last time I was involved. Following on from McGrath's last post, I suspect that our brains do indeed assimilate a musical grammar, but to judge by the multi ethnic groups I've done therapeutic work with it must be pretty damn broad, immensely subtle and just a few thousand years old. Specific isn't a word that comes readily to mind, and I suspect the author of falling into the trap of wanting human endeavour to be tidy. I must get sight of the article before further comment though.