What changes does having a fever have on a baby's or child's brain?

Usually none. Unless the fever is unusually high-around 106-107-for a prolonged period of time, the elevated temperature usually only causes brain injury to the worried parents. A frequent concern of parents is that of febrile seizures, which occur in about 5% of all infants and unless related to a serious underlying infection, such as meningitis, also do not cause permanent brain damage or developmental delays.