Sounds very very interesting. I am a lefthander myself, and suspect I have mixed dominance. I wish I could find out if I have mixed or actual reversed hemispheric dominance, just because I am curious.
I have had to force my hemispheres to work closely together in the last 15 years. My daughter, who was abandoned to an orphanage at birth and didn't get to come home with us til age 14 months, came to us not "seeing" gestures, body postures, facial expressions, other nonverbal cues; not hearing tone of voice, inflections, etc. She has tremendous problems using language. She chattered away precociously but much of it was repetitive nonsense; her UNDERSTANDING of language was far beneath her USE of language. It is my understanding that the left hemisphere is responsible for the words and syntax; the right is responsible for construction of meaning and understanding of the intent of language.
Along those same lines, it is thought that the right hemisphere is responsible for "avoidance" social behaviors and the left is responsible for "approach" behaviors --- and it is thought that the social promiscuity you see in kids from institutions, that usually have attachment disorders, is because the right frontal lobe is underdeveloped due to lack of stimulation. My daughter would go to any old lady in Walmart and would approach icky looking total strangers, not to mention all of the nice people at church or at the park. She still has weird issues with giggling and looking amused totally inappropriately, like when she hears about something awful happening or even when someone is speaking about a serious subject. this alienates other people, and I understand what is happening and it still annoys the heck out of me.
When she was 11, her horse fell with her and she cracked her skull and had a concussion --- on the right side. After the first freak-out was over and it was apparent that she was not going to die or be in a coma or be paralyzed --- I thought, great, just what she needs, a big old injury to the right hemisphere.
Back to my first point: I have had to work HARD at putting stuff that you can't verbalize into words. Explaining to her what tone of voice, gestures, facial expressions, nuances, all that nonverbal stuff, all mean. I couldn't believe how hard it was to explain in words why I got so mad when she would give me a little amused smile while I was speaking seriously to her, or why that same irritating thing would cause her younger brother to yell at her. When she was little, I had to explain "this (hand up, palm toward her) means stop. This (hand out, palm up) means take my hand."
I have learned to explain a lot but there is so much that she has no clue about because nobody can explain it to her. She does not pick up on it. She goes about unaware of so many subtle social rules and as a result tramples on other people's feelings and alienates others. Yet she does not appear to be on the autism spectrum, at least to have a casual conversation with her. It's a weird place for a child/teen to be --- not handicapped enough to be obvious, not even enough to get any kind of diagnosis, but handicapped enough that she is functionally disabled in complex situations.
She comes across as narcissistic. She blows you off when you try to explain that she is making you feel invalidated (and no, I don't try to use that particular term with her). She has limited ability to use logic in social situations. If once she comes to a conclusion, there is no changing her no matter what the evidence. She constantly uses the wrong word or even a really jumbled combination of words, and then blames the listener when we don't understand her. If we do finally figure out what she's trying to say, and say, "Oh, you mean X but you actually said Y," she deflects your correction by saying, "What I said meant the same thing." So you never get the sense that she is learning from her mistakes, because she never seems to register it when she's made a mistake.
She has limited ability to name feelings and for sure has not attained (at the age of 15) the ability to be aware of mixed feelings or conflicting feelings happening at the same time (which usually comes online around the age of 9 or 10). When something is odd, or strange, or creepy, or elicits some other uncommon feeling ... she calls it all "funny."
The logic thing is really disturbing ... she comes to really weird conclusions about a lot of things, but especially social situations. She still holds a grudge against my husband and I because we quit letting her hang out with a girl down the street after the head injury mentioned above ... we found out that this particular girl had been the reason my daughter had gotten on the horse in the first place (she had not been given permission to ride him except under supervision, and we just assumed she had been disobeying us on her own, immediately following the accident, but more evidence was uncovered afterwards). She doesn't apparently care that the reason we cut off the relationship was her personal, physical safety around an older girl that was manipulating her to do dangerous things.
Anyway, I'm sorry if I'm "hijacking" this thread ... if needed I can move this post ... but although I KNOW that my daughter has neuro issues, I do feel like I've raised a narcissist. She's not mean --- she has a lot of empathy for animals and babies and little children, but her ability to see others' viewpoints is sooo limited, and once a person gets old enough for her to feel challenged by their maturity, her empathy for them evaporates. Her younger brother (3 years younger) was "her baby" when he was born, but years ago she began to feel threatened that he was surpassing her in school and other intellectual ways. Which is true really, but it is sad and frustrating because she takes every possible opportunity to put him down and try to diminish him. I call both of them on it when they say inappropriate things to one another, and they both can be jerks to one another, but really a lot of it stems from her insecurity and inability to empathize totally.
I'm not sure why I'm rambling about this except it's really distressing to feel like she is a narcissist, whether this is because of neurological issues or not.