Cerebral palsy is a condition that encompasses a lot of symptoms. The broad range of functions affected can be movement, learning, hearing, seeing, and thinking. Logically, there are a lot of causes of cerebral palsy. It can happen during early infancy because of bleeding in the brain, brain infections, head infections, jaundice, or if the mother has infections during pregnancy.
I found a very interesting article that outlines a hypothesis about the causes of cerebral palsy that are of unknown etiology. The hypothesis is that the unnoticed death of one identical early in pregnancy could cause this condition. The mechanism that they suggest behind this is ‘hemodynamic instability with episodes of acute feto-fetal transfusion that produce ischemic organ impairment in either or both twins’. Okay, let’s break down that sentence into something that we can actually understand. “Hemodynamic instability” is a state where you can’t keep your blood pressure or cardiac output stable. “Feto-fetal transfusion” is the unbalanced transfer of blood between twins. Overall translation: cerebral palsy may be caused by the unbalanced transfer of blood between twins when one or both twins have a difficult time maintaining a stable blood pressure, which leads to insufficient blood supply to organs, thus causing impairments.
Kind of a mouthful, but it’s a very interesting topic. The severity of symptoms vary based on when the other twin dies, as well as which organ is affected. This being a neuroscience blog, I guess we should be most interested in the case when the blood supply is insufficient for the brain. The article suggests that the brain is affected more often because it is of larger volume than other organs, and therefore requiring more blood supply. Also, that the brain is much more complex and possibly more vulnerable than other organs to slight perturbations in hemodynamic balance. We know that the brain is very sensitive, but we also know that the brain is very plastic.
Do we buy this argument? Could this be the answer to the cases of cerebral palsy of unknown etiology?
Peter O. D. Pharoah. (2005) Causal Hypothesis for Some Congenital Anomalies. Twin Research and Human Genetics 8(6): 543–550.