seniors aging gracefully

Approximately 12%of the world is left handed

this figure has remained constant across time despite the historic negative association with being left handed

being left handed in Italian means sinister and some of us can recall how we were forced to use our right hand while growing up

yea left handers get a bad rap

but back to what it means – essentially it relates to where language centers are located in the brain

In a study published in Neurology in 2002 entitled “language lateralization in left handers and ambidextrous people ” it was found that language centers are located in the LEFT hemisphere, like most right handed folks. But 14% of the subjects had BILATERAL language representation while the remaining 8% had RIGHT language centers in the right hemisphere.

Thanks to advances in technics such as MRIs, we also know that not all right handers have language centers solely in the left hemisphere, but the percentage of these folks is small.

So what does this all mean – here is where it gets technical and I will try to explain it in a way you can understand.

For one thing, the fact that the percentage of left handers has remained fairly stable across time suggest that there is a genetic component to handedness and antidotally most people who are left handed are aware that there is a family history of this. Approximately 40 genes contribute to handedness. In studies of IDENTICAL twins, it has been found that 10 to 25% are discordant for handedness. This is a large range and probably relates to how handedness is measured. In any case, much more than genes plays a role in what hand you use.

Personally, I have a large number of left handers in my family and I am somewht ambidextrous. I have an autoimmune disease and tons of allergies, which occurs more frequently in left handers.

Left handers are more like to become President of the US – Obama, Bush, Clinton. Being left handed is associated with exception cognitive abilities, esp in areas such as music and art. Left handed baseball players clearly have an advantage. But left handers’ life expectancy is shorter and are disproportionately represented in folks with a range of learning problems.

Sorry for being so technical but I was a neuropsychologist for the bulk of my career, have published in the area, and have a life long fascination with understanding the brain.

I will provide more information on brain functioning in forthcoming blogs