Why brain injuries affect children and adults differently

When we think about a brain injury, it is easy to assume that the same thing happens in everyone; a bump to the head, swelling, and hopefully a recovery. In reality, things aren’t quite that simple. A child’s brain is not a smaller version of an adult’s, it is still developing, which makes it both incredibly adaptable and, at the same time, especially vulnerable. 

Smaller bodies, bigger risks

Although the brain’s basic reaction to injury is similar in children and adults, injuries in younger people tend to cause more widespread and severe damage. This is due to the differences in anatomical development. 

Children’s heads are proportionally larger compared to the rest of their bodies, and their neck muscles are much weaker than those of adults. This means that when a child falls or is knocked, their head can move suddenly and forcefully, placing extra strain on the brain.

On top of that, children’s brains have a higher water content and are softer in texture, which makes them more vulnerable to rotational forces and acceleration-deceleration injuries. These types of movements can lead to diffuse axonal injury, where nerve fibres are torn across large areas, and cerebral swelling, both of which are less common in adults experiencing similar trauma. 

A clear example of this vulnerability is seen in abusive head trauma. When an infant is shaken, their softer skull and brain structure can lead to a combination of skull fractures, internal bleeding, and swelling. Sadly, these injuries are often linked to very poor outcomes.

The double-edged sword of brain plasticity

One of the most remarkable things about the young brain is its plasticity, which is its ability to reorganise itself and form new connections after injury. This flexibility often means that children recover some functions, such as movement or daily activities, more quickly than adults do in the early months after a brain injury.

However, this adaptability has limits. During childhood, the brain is constantly developing new skills and abilities. If an injury occurs during one of these critical periods, it can interrupt processes essential for normal development. 

This means that difficulties might not appear straight away. A child could seem to recover well at first but then struggle later when their brain is expected to handle more complex tasks, such as problem-solving or emotional regulation. Over time, recovery often plateaus, and children may continue to face long-term challenges with learning, behaviour, and social interaction. 

Research also shows that injury severity is a major factor in long-term outcomes. Children who suffer severe traumatic brain injuries are more likely to experience lower academic performance and, later in life, face higher rates of unemployment or lower paid work compared with their peers.

Behaviour, learning and life after injury

Brain injuries in childhood can also affect behaviour and mental health. Conditions such as ADHD are especially common following injury, affecting between 20-50% of children. These difficulties can make returning to school and social life far more challenging.

Children from lower socioeconomic backgrounds often experience extra barriers, including limited access to rehabilitation and educational support. This can increase the risk of social isolation and mental health difficulties.

Children are also more likely than adults to develop secondary brain conditions, such as epilepsy, after an injury which adds further complexity to their recovery.

Why recovery is not the same

The main difference between children and adults lies in what needs to be rebuilt. Adults are generally trying to re-learn skills they already had, while children are still learning those skills for the first time. That makes recovery a much more delicate and unpredictable process. 

Moreover, most rehabilitation is concentrated in the first few months after the injury, but children’s challenges often become clearer years later, when their brains, and the demands placed on them, have developed further. 

In summary

The developing brain is both fragile and flexible. While its biological features make it more prone to injury, its capacity for plasticity allows for impressive short-term recovery. Yet the same developmental processes that support growth also make it more vulnerable to long-term disruption.

Injuries sustained during childhood can alter the course of brain development, leading to lasting effects on thinking, learning, and behaviour. These consequences can shape a person’s future long after the initial recovery period has ended.

Understanding these differences is crucial, not just for doctors, but also for teachers, parents, and anyone supporting a young person recovering from a brain injury.

Written by Alice Greenan

Related articles: Synaptic plasticity / Traumatic Brain Injury (TBI) / Childhood intelligence

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