The Incompletely Understood Phenomenon of Mirror-Writing

There’s no doubt about it. She’s the most precious little girl. She’s my Russian doll. She’s also the most obedient and she’s smart. She’s not like those kids who are so sharp that they’re almost cunning. She’s the most innocent human being I’ve ever interacted with.

She’s left handed. Because her right hand cannot hold bottles or pens like ours can. It cannot throw objects. It cannot help her swing on a horizontal bar. It cannot let her hi-five me. She’s too young to fully comprehend her limitations. Her left hand is naturally adept at what the right is lacking. She was born this way. Literally, a focal damage at birth to her left brain resulted in patchy weakness in her right hand and right foot. Yeah, she doesn’t walk ‘right’. She walks alright. Her right foot almost literally doesn’t touch the ground.

She’s intelligent. Her memory is very good for a four year old. She’s curious. During one of her gait-training sessions in my office, she glanced at the paintings on the walls and asked what they were. I told her they were Picassos. The next week, during the same gait training, she looked at another (Picasso) painting and remarked, “Picasso again?!” in the most innocent manner! Recognizing the art and recollecting a word like Picasso after one week for a four year old is impressive.

I make her practice colouring using her right hand to improve its grasp. It’s a difficult task. The only way she can hold a pen is by making a fist around the pen. There’s no precision. She lacks fine motor coordination. Her wrist and forearm don’t stay upright the way ours do when we hold a pen. I started by making her use her fingers for a grasp — all of them, initially, to get her used to using her fingers for grasping instead of a fist. I’d draw random shapes and figures for her to colour into. One particular day she wanted me to draw a triangle. So I did and she set forward to colour it with the yello highlighter. Thereafter I asked her to write her name down because she’d done such a good job at colouring. She didn’t complete writing it but what came out looked like this:

Notice the script in the top right corner.

Spiegelschrift. A classic mirror-script. And she saw nothing wrong with it. Essentially, there is nothing wrong with it. When I showed it to my colleague he remarked, “Dyslexic?”. Maybe. Yes, dyslexics demonstrate mirror-writing in various forms but then dyslexia is a much wider range of learning difficulties. Can it(mirror-writing) for sure indicate pathology? In any case, it triggered me to learn more about a phenomenon I’ve always taken so cavalierly.

I remember when I was little, I had somewhere read about da Vinci’s ambidexterity and mirror-writing, the latter arguably believed to be so to hide his writings from others. A sort of cipher. I had tried to mirror write myself just for fun. Never did it occur to me to understand why we should be able to write this way at all! Without any prior conscious training! That is, if you are taught to write with the right hand, how can you spontaneously just write with the left, and mirror-write at that?

When my favourite patient did this, it pushed me to read about it to see if there was, as I expected, a strong link between brain damage, and mirror writing in contralateral hand. Turns out, the answer is yes and no. Yes, those with focal lesions in the brain are more likely to demonstrate mirror writing but mirror writing is also demonstrated by perfectly healthy children and adults. Mirror writing therefore does not indicate pathology.

Mirror writing is a very heterogenous phenomenon:

  1. It can be voluntary or involuntary.
  2. If it’s involuntary, it maybe noticed and perceived as either normal or abnormal, or it may not be noticed at all.
  3. Sometimes a few letters are reversed/mirrored, and sometimes entire words and/or sentences.
  4. A strong correlation is seen to prevail between mirror writing and the left hand.

There’s a very interesting theory behind this. As we all know that some of our actions are instantaneous and reflexive. How can the brain execute certain actions so quickly? It so happens that the brain is continually learning. If it comes across a certain pattern of movements over and over again, it tends to remember all its components and save them into one file, known as the Motor Program. We will call it MP. Think of it as a circuit with resistances, inductances, etc, connected in parellel. Or like an ‘if-and-then’ loop. Highly automated. Various MPs are stored inside the brain, pulled out, and executed as needed. This way the brain doesn’t have to remember the entire sequence of the various neuromuscular connections required for performing simple day to day actions.

Naturally, there has to be an MP for writing. The theory that attempts to explain mirror writing rests on the basic idea that two identical MPs exist for a particular activity in both brain hemispheres but that only one of them is allowed to emerge. Mirror writing bases off the theory that MPs for writing too are activated in both hemispheres of the brain but the emergence of the unwanted one is suppressed. In brain-damage, the suppressing pathways are damaged or dysfunctional. Most commonly these suppressive pathways are said to be the ones in the corpus callosum, the crossing point between the two brain-hemispheres. With the suppressing pathways dysfunctional, it’s much likelier for mirror writing to present itself. This is more or less the crux of the motor center and visual hypotheses. Of course, how the brain decides which side is wanted or unwanted, is a broader question, and one which I haven’t read much about but I believe it has got to do with habit/teaching(parents and teachers training the children to use right hand for writing) and with genes.

Why mirror writing is more likelier with the left hand is also widely attributed to the theory that writing(like most of our movements) is an abductive(away from the body) movement and that abductive movements are more preferable. Interesting and fair enough. Yeah, I too found myself recalling all common movements to check if they’re abductive.

Mirror writing is not studied very extensively. Perhaps due to the ambiguous conclusions derived from the studies done so far. These studies have not established a strong, conclusive correlation. Forget about the cause. The only fact we do know for sure is the strong association between mirror writing and the left hand.

How did most of us come about writing with the right hand, is like I mentioned above, a broader question. Even languages that follow right to left orientation are written with predominately the right hand although it’s also known that those are also easier to mirror-write. Like Arabic and certain Chinese languages. There’s a tribe in Philippines called Mindoro who practice the script Hanunóo. This is one of those scripts which legitimately allows its users to mirror-write, with all axes mirrored and the script moving right to left. Who’d have thought?!

So while I may have gone about accumulating a lot of probably useless knowledge as I always do, the important thing to remember here is that mirror-writing is inconclusive albeit marvelous. My little patient inadvertently producing it is not problematic. Also, when I asked her to write her name again on other occasions, she wrote it ‘normally’ following the left to right convention and without any mirroring.

What mirror writing does hint at is the fascinating way our cognitive neural makeup works! If it were explored more and better, it could provide insights into the suppressed motor functions inside us, into the various activation and deactivation pathways, etc; because neuroscience is one field which is still (rapidly) growing despite loopholes, with tons of theories and computational models. How a bunch of neurons can be so diverse will forever continue to amaze me!

Meanwhile, this shall stay in my room as a gift from my little girl. Every time I look at it, I smile. Because she’s like that. If you knew her!

REFERENCES:

1). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2117809/pdf/5.pdf

2). http://archneur.jamanetwork.com/Mobile/article.aspx?articleid=787244

3). http://varenne.tc.columbia.edu/bib/texts/conklharl49bamblite.pdf


Originally published at tamannaashaikh.tumblr.com.