Some children are overwhelmed very quickly: by people, the environment, the volume. There are twelve things parents can look out for in order to know if their child is highly sensitive.
A child with a highly sensitive brain perceives too much. High sensitivity could be an advantage for the future, if you deal with the next generation properly now.. Some children with high sensitivity refuse to eat certain foods because of the smell or texture. They easily startles at sudden noises, such as when someone sneaks up on them.