What is left is right

The ‘Mollydooker’
Notions of laterality and handedness have always intrigued. In primary school, I admit to being slightly suspicious of the left handed children or mollydookers as they were called in Australia, although they could be rather tricky on the sporting field which probably made me more suspicious.

Handedness has been subject to much contemplation and research. For example, why do 60-85% of people hold a baby in their left arm (except in Madagascar where it is the opposite?). Any why is this bias stronger for younger babies and weaker for left handers? And why are other valuable but non organic items held more in the right hand (Harris 2007).

Gliding through life cool with left and right
There are other dimensions to laterality which are more around our appreciation of left and right, rather than the preferential use of a side, although there may be links. As we encounter the world, our brains presumably weigh up all incoming information in terms of existing circuitry and real time decisions to construct the perceived ideal coping outputs such as movement, sweating, blood pressure, pain etc. The notions or concepts of left and right must be a part of this. We glide though life with our brain left/right decision makers looking after us – those who are good at sport may have better integrated laterality decision making circuitry. Not that we ever think “that person is looking towards me from the left, I should react accordingly” – much of this is subconscious especially the bit about the left. Complex neurosignatures (schemas) must exist in the in the brain to handle this essential part of premotor planning.

What if you can’t work out left and right?
In the last few years a body of literature has emerged which links chronic pain with alterations in brain neurosignatures. Disrupted body image such as orientation of body part has been reported in the groups studied (reviewed in Lotze and Moseley 2007). It seems feasible that if the laterality neurosignatures are disrupted and can’t be ‘called upon’ when needed, that perturbed coping strategies may result perhaps showing first in altered pain, motor and sympathetic outputs.

Laterality appreciation (i.e intact working laterality neurosignatures) has been tested by asking participants whether a pictured limb is left or right (e.g. Parsons and Fox 1998; Schwoebel, Friedman et al. 2001). Altered laterality appreciation has been shown in people with phantom pain (Flor, Elbert et al. 1995), Complex regional pain syndrome (Moseley 2004) and recently in people with chronic low back pain (Bray and Moseley 2009).

The good news is that you may be able to do something about it. Many readers are becoming familiar with Lorimer Moseley’s work with Graded Motor Imagery (Moseley 2006) and Lorimer suggests that as a therapy, the GMI work should be considered no longer embryonic, but perhaps foetal and well on the way to being born. Referring back to a previous NOI notes ….. It does appear that we finally have a rational therapy for once difficult to manage neuropathic pain states. But we need to know more.

Can you help? – May we test your laterality neurosignatures?
We would like to invite you, and your friends, family and colleagues to take part in an online laterality study involving the neck. We are seeking the normal responses to a neck laterality challenge and some of the variables (such as handedness, injury) which could influence it. We hope to sample 1,000 people worldwide as part of a series of NOI studies investigating the laterality issue.
The study takes about 20 minutes. There is a questionnaire about yourself, and then you will be taken through series of images with people turning their head. You will be asked to indicate whether the model in the image has their head turned to the left or to the right. And don’t be surprised if it’s not as easy as you may originally have thought!

To participate in our project you can either click here or go to the current research projects link on the www.noigroup.com homepage.

Please see all references at the bottom.

Your turn
Why do you think people hold babies on their left arm the most? The best or closest reason will receive their choice of a Graded Motor Imagery Pack or an Explain Pain combo.


One Response to “What is left is right”

  1. Stephany Says:

    For the simple reason that a majority of the population is right handed (I’m assuming) and when you hold the baby in your left arm, it leaves the right one free to do other things that require more dexterity…it allows multitasking with baby in arms!

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