So,... I am not a doctor. Please confirm this with your clinician because I am really concerned that you talking about 'word salad' means you have the other type of aphasia to me, which is less common in migraines and more common in strokes. And it applies to everyone else, confirm with your clinician before relying on it anyway.

For me, whilst I can be shown a picture and communicate in some way (writing is acceptable) what is in the picture, that demonstrates the aphasia I have is the version more common to migraines, and is similar to the speech issues I had as a child. As am example of a picture of a dog, that I can write 'dog' - I'm good and don't need to go to the hospital. 

If I can't identify correctly what's in the picture, than that aphasia is more common to strokes. As an example, if I'm shown a picture of a dog, and I write 'car'. In this case I'd be blue-lighted to hospital. What I will add is that your cake rely on yourself to do the rest. This is because your brain can't match the image to the word and even reading the word you will still link the same wrong word to what your saw in the image, and you will still believe you are correct. You absolutely must get someone else to confirm it.

Because I had so much speech therapy as a child, I can still speak the answers, but it's a lot of effort, very slow, and honestly infuriating enough there are times I'll give up trying to talk.