"Dyslexia" in reasoning? I was trying to use logical argument with a friend of mine recently, and found that she was missing my point and completely misunderstanding my position. So I wonder if there is something like dyslexia of reasoning/logic, a brain condition that makes people unable to understand and follow logical arguments.
Cognitive dissonance is often a problem when trying to convince someone of your position.  Depending on the subject matter and how closely the position is held for the opposing party it can be very difficult to follow even logical well reasoned arguments.  The opposing party often has a framework of reality in which they make sense of various situations or concepts.  If a new concept doesn't fit within that framework there is often underlying reasons as to why the argument is unable to land. So until the deeper views are addressed you are arguing in vein. 

For example in order for something you postulate to be true, it may require the opposite party to reconcile other beliefs that are deeply held in a way that they are potentially unwilling to address, or see no reason to address due to unwanted stress or emotional distress in addressing the beliefs. 

Alternatively there are neurological deficits or disabilities that could make getting your point across more difficult, but at least from my experience it is often a case of Cognitive Dissonance.