This started a couple of years ago. I get a small, what can only be described as a spinning prism in the upper left of my vision. It moves around and can last up to 20 minutes. It creates a blind spot and I have to pull over if driving as it impairs my vision. This is then, more often than not, followed by a mother of a migraine. More worryingly than this. Maybe during one in three of these 'episodes' I get what can be best described as 'verbal dyslexia'. When I talk, half of the sentence is gobbledygook. The right letters come out but in the wrong order. I am aware of this happening but cannot say some words correctly no matter how hard I try. I get the verbal problems about 5 minutes into the visual impairment and seems to 'pass' at the same time. Just before the migraine kicks in.
I have read many instances about the vision issue being a symptom of migraines but not read anything about the verbal problem I get.
Typical migraine aura (symptoms that usually precede migraine headache), consist of visual and/or sensory and/or speech symptoms.
What you have experienced when being unable to express your self is known as aphasia, a problem understanding language (receptive) or speaking it (expressive).
It is a aura symptom that is not so common.
Different visual symptoms can be noticed during migraine aura.