Recover from Stroke
Lefties often recover speech more quickly than their right-handed counterparts following stroke. This is because the left side of the brain typically controls speech. Since lefties are less dependent on the left side, they are usually able to bounce back more quickly. In fact, 95 percent of right-handers have a left brain language dominance, whereas only 70 percent of lefties have this, meaning that the other 30 percent have language dominance in the right side of the brain or it's spread out between both halves [source: Jarrett].
This left-handed advantage could also extend to spatial neglect, which causes a person with brain injury or recovering from stroke to simply not acknowledge one-half of a situation, like not noticing food on the left side of a plate. Once again, lefties and their more evenly balanced brain power are thought to benefit, although further study is needed [sources: Madhusoodanan, Bareham, et. al.].