The corpus callosum, the white matter tracts that connect one side of the brain to the other, changes size and shape during childhood development and well into early adulthood. The thinning of the corpus callosum, particularly the posterior area, has been thought be a normal part of development.
However, a recent study has shown that childhood brain injury has a strong association with the thinning of the posterior area of the corpus callosum. The study looked at brain scans of people who suffered a childhood brain injury (ten years past) and compared them to scans of people who never had a brain injury. They found that 63% of people who had a childhood brain injury had significant thinning to the corpus callosum, versus only 30% of non-brain injured people.
The research that supported the developmental theory of the thinning corpus callosum did not take clinical history into account. This most recent study provides evidence that a thinning corpus callosum might not be a normal occurrence, but a marker of past brain injury.
Beauchamp MH, Ditchfield M, Catroppa C, et al. Focal thinning of the posterior corpus callosum: Normal variant or post-traumatic? Brain Injury. (September 2011).