Language lateralization and handedness in women prenatally exposed to diethylstilbestrol (DES)
The human brain is structurally and functionally asymmetrical and lateralized. It is divided into two halves called hemispheres. The two hemispheres have they own distinct functions that work in a different and complementary way, fascinating property of human brain.
Studies have reported that brain asymmetries would optimize information processing.
The left side of the brain controls the right side of the body and performs tasks that have to do with logic. On the other hand, the right hemisphere coordinates the left side of the body, and is specialized for the tasks that have do with creativity. Language functions such as discourse grammar, lesion studies, vocabulary and literal meaning are typically lateralized to the left hemisphere, whatever dominant hand.
In Neurotypical or NT individuals, dealing with language in the right hemisphere, the link between language and manual preference is proven.
Brain dominance is a multifactorial quality, responding to various mechanisms, innate for some, environmental for others, such as: brain anatomy, genetics, sex and sex hormones…
The lateralization of brain functions is the result of a lengthy evolution undoubtedly intended to optimize brain-cognition relationships.
The two most widely studied functions are lateralization of language and manual preference.
A study1 from July 2000 compared a group of women prenatally exposed to diethylstilbestrol with a control group. This research reveals unintended effects of DES exposure in utero on the manual preference and the lateralization of language.
Researchers observed an increased left-hand preference, especially for writing, within the DES-exposed group, particularly those exposed in early gestation.
This study highlighted a disturbance in the typical relationship between manual preference and lateralization of language in the group exposed to DES.
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1 Smith LL, Hines M. Language lateralization and handedness in women prenatally exposed to diethylstilbestrol (DES). 2000.