Abusive Head

Abusive head trauma/inflicted traumatic brain injury — also called shaken baby/shaken impact syndrome (or SBS) — is a form of inflicted head trauma.

Abusive head trauma (AHT) can be caused by direct blows to the head, dropping or throwing a child, or shaking a child. Head trauma is the leading cause of death in child abuse cases in the United States.

How These Injuries Happen

Unlike other forms of inflicted head trauma, abusive head trauma results from injuries caused by someone vigorously shaking a child. Because the anatomy of infants puts them at particular risk for injury from this kind of action, the majority of victims are infants younger than 1 year old. The average age of victims is between 3 and 8 months, although these injuries can be seen in children up to 5 years old.

The perpetrators in these cases are most often parents or caregivers. Common triggers are frustration or stress when the child is crying. Unfortunately, the shaking may have the desired effect: although at first the baby cries more, he or she may stop crying as the brain is damaged.

Approximately 60% of identified victims of shaking injury are male, and children of families who live at or below the poverty level are at an increased risk for these injuries as well as any type of child abuse. It is estimated that the perpetrators in 65% to 90% of cases are males — usually either the baby's father or the mother's boyfriend, often someone in his early twenties.

When someone forcefully shakes a baby, the child's head rotates about the neck uncontrollably because infants' neck muscles aren't well developed and provide little support for their heads. This violent movement pitches the infant's brain back and forth within the skull, sometimes rupturing blood vessels and nerves throughout the brain and tearing the brain tissue. The brain may strike the inside of the skull, causing bruising and bleeding to the brain.

The damage can be even greater when a shaking episode ends with an impact (hitting a wall or a crib mattress, for example), because the forces of acceleration and deceleration associated with an impact are so strong. After the shaking, swelling in the brain can cause enormous pressure within the skull, compressing blood vessels and increasing overall injury to its delicate structure.

Normal interaction with a child, like bouncing the baby on a knee, will not cause these injuries. It's important to never shake a baby under any circumstances.