In the early 1970's Caffey defined "whiplash shaken infant syndrome." The Whiplash Shaken Infant Syndrome was described by Caffey as the result of manual shaking of an infant by the child 's extremities with whiplash-induced intracranial (brain) and intraocular (eye) bleeding.

Caffey linked the manual shaking of an infant to permanent brain damage and mental retardation. Caffey also stated that there are six elements necessary to make a positive diagnosis of Shaken Infant Syndrome. These elements are: Intracranial bleeding (bleeding in the brain), Intraocular bleeding (bleeding in the eye, typically called retinal bleeding), fractures of the long bones in the arms (as a result of holding the child by the arms as it is shaken), fractures of the rib cage (as a result of holding the child by the rib cage as it is shaken), bruising of the torso and arms (from holding the baby too tightly as it is being shaken) and finally, injuries to the neck due to the head whipping back and forth.

Through the years that list of symptoms has been reduced significantly. Two of the original elements (intracranial and intraocular bleeding) in Caffey's Whiplash Shaken Infant Syndrome have become the standards for a diagnosis and allegation of Shaken Baby Syndrome.

Doctor after doctor refer to Caffey's research when performing "new" research on the association between intracranial and intraocular bleeding and possible abuse.