Implications of Traumatic Brain Injuries in Children and Adolescents

Introduction

 The CDC defines a traumatic brain injury (TBI) as a disruption in the normal function of the brain that can be caused by a bump, blow, or jolt to the head, or penetrating head injury. An injury to the brain may produce a diminished or altered state of consciousness, which results in an impairment of cognitive abilities or physical functioning. Severe disruptions of cognitive, emotional, and behavior functioning after TBI may provoke lifetime impairments that result in partial or total functional disability and psychosocial maladjustment.

Everyone is at risk to TBI, but children and elderly are at the greatest risk. Each year, an estimated 2.5 million Americans are diagnosed with a TBI during emergency department visits. Of these 2.5 million Americans, an estimated 564,000 of them are children who are seen for brain injuries, with an estimated 329,290 of those children being treated for sports related TBI. Children experience similar symptoms of a brain injury compared to adults, however, the functional life long impact is very different due to the child’s brain still developing. Often, the cognitive deficits are not immediately obvious after injury, but may become evident as the child gets older.

The implications of traumatic brain injury in children create a lifetime of challenges. These challenges may include problems with processing and understanding information, attention and concentration, language and communication, learning and remembering new information, as well as, inappropriate or impulsive behavior to name a few. Cognitive rehabilitation therapy is helpful for improving and maintaining cognitive skills. This paper discusses the extent that the above implications have on children who have suffered from a traumatic brain injury compared to adults.

Mechanism of Injury & Principle Consequences

 A traumatic brain injury may be caused by a fall, motor vehicle crashes, being struck by or against something, shaken baby syndrome, child abuse, domestic violence, gun shot wounds, sport injuries, workplace related injuries, as well as military actions. In children and adolescents ages 0 to 14, the common causes of TBI are falls (50.2%), being struck by/against events (24.8%), motor vehicle accidents (6.8%), assault (2.9%), and unknown/other (15.3%). The most common cause of TBI in infants and preschoolers are falls and assault. In older children, TBI is often from motor vehicle or bicycle accidents or sports-related (Faul et al., 2010).

 These causes of injury can further be broken down into the resulting physiological or structural damage. The four primary mechanisms of TBI are direct impact, sudden or rapid acceleration and deceleration, penetrating injury, and blast injury. Direct impact means to be struck in the head by something whether that be an object or by the ground from a fall. Sudden or rapid acceleration and deceleration occurs when nothing has come into direct contact with the head, but rather the brain still withstands a violent whiplash from the head moving rapidly back and forth. An example of this in children would be an assault such as shaken baby syndrome. A penetrating injury is cause by high-velocity projectiles being driven into the head and is usually seen in gun shot wounds to the head or in military personnel. The last mechanism, blast injury, is also commonly seen in military personnel as it is caused by the impact from a pressure wave due to an explosion or blast.

 From each of these external forces, there are three primary types of damage that can occur. Diffuse axonal injury, focal contusions, and hematomas or bleeding in or around the brain. Diffuse axonal injury (DAI) is one of the most common and devastating types of TBI as it is defined by widespread damage to the brain’s white matter. DAI happens when the brain rapidly shifts inside the skull as an injury is occurring, it may be is often caused from car accidents, a fall, sports accident, or as a result of child abuse. It is the major cause for loss of consciousness after a TBI. Axonal damage directly links to neurodegeneration which can cause pathology dissemination, and in turn, can lead to any of the neurodegenerative diseases such as ALS, Alzheimer’s, Parkinson’s, and CTE.

 The second type of primary damage is focal injury to the brain. Unlike diffuse injury that occurs throughout the brain, a focal brain injury is confined to one area. Focal injuries are bruises or swelling in specific areas of the brain and are often referred to as coup injuries. They are often the result of sever blows to the head or violent assault or falls.

 Hematomas or bleeding in or around the brain is another type of damage that can occur as a result of a traumatic brain injury. Hematoma can be broken down into different categories: epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and intracerebral hematoma. An epidural hematoma (EDH) occurs when there is bleeding of the brain between the dura mater and the skull. A subdural hematoma (SDH) is when there is a collection of blood outside the brain but below the inner layer of the dura mater. They often are caused by severe head injuries and can be life-threatening due to the increased pressure put onto the brain. A subarachnoid hemorrhage (SAH) is bleeding in the space between your brain and the subarachnoid space. SAH can be life threatening as the subarachnoid space is where the cerebrospinal fluid circulates which is responsible for protecting your brain. Bleeding in this area often leads to extended periods of unconsciousness, coma, paralysis, and even death. The final type of hematoma is the intracerebral hematoma which is a collection of blood within the skull that usually occurs as a result from a motor vehicle crash or fall.

 Each of these mechanisms of brain injuries pose severe challenges on the patient. A traumatic brain injury can affect how a person feels, thinks, acts and relates to others. It can also result in lifelong consequences, especially in children since their brains are still developing. These consequences include physical, cognitive, behavioral and emotional while also putting them at higher risk for other health problems later in life.

Subtypes of Challenges Faced After Traumatic Brain Injury & What We Know So Far

 Moderate to severe traumatic brain injury can cause permanent physical or mental disability. Physical effects of TBI may include sleep disorders, loss of stamina (fatigue), appetite changes, chronic pain, paralysis, seizures, and difficulty regulating body temperature. Sensorimotor impairments due to TBI are dependent on the location and severity of injury. These impairments may be localized or generalized while combinations of sensory deficits can have a major functional impact. An example of this would be impaired vision paired with balance problems.

This especially has an impact in children as TBI is the most common cause of childhood disability. The assumption used to be that children with a brain injury would recover better than adults due to brain “plasticity.” However, current research shows that is not the case and often times brain injuries in children have a more devasting impact than on an adult with the same severity level of injury.

A study by Crichton et al. (2018) examined the effects of time post injury and injury severity on fatigue after childhood TBI. Fatigue is one of the most commonly reported symptoms that leads to a decreased quality of life, reduced participation, and decreased school functioning. Although fatigue is one of the most frequently reported symptoms in childhood TBI, it is rarely assessed after. The results of the study showed that cognitive fatigue in children worsened over time rather than recovering from 6 to 12 months postinjury. Moderate/severe TBI was associated with the worse fatigue one-year postinjury.

 The mechanisms for why this occur were unclear, but the authors suggested that it may reflect “TBI-related damage to the neuronal pathways responsible for mediating arousal, attention, and response speed.” Each of these mechanisms also underpin “stalled” development after childhood TBI. The results support the notion that children sustaining any severity of traumatic brain injury should be followed up for cognitive fatigue symptoms that may be affecting their quality of life, especially in school.

Aside from cognitive fatigue, the most prominent cognitive consequences of a brain injury are memory loss and are often considered the most disabling consequence. Memory problems can affect a person’s ability to learn, retain, and use new information. This becomes especially challenging in children since they are enrolled in school. Other cognitive consequences include executive functioning such as planning, initiating, directing and monitoring activities, initiation impairments, speech and language impairments, and lack of awareness deficits.

A Child Neuropsychology study by Phillips et al. (2017) analyzed and assess working memory outcomes following TBI in children. Working memory is a complex brain system that relies on a vast network of brain structures that are sensitive to pediatric brain injury. When injured, it can negatively impact learning and academic performance. Children who suffer from TBI are also at risk for central executive deficiencies. Future research should each component of working memory and the implications each component has on a child’s success. 

The last part of the brain to fully develop is the prefrontal cortex which was implications in a person’s will to live, executive function, and planning complex cognitive behavior, decision making and personality expression. In men, the brain does not fully mature until age 25 and in women, at age 21. Damage to the prefrontal cortex as a child can have devasting lifelong impacts since the area is not fully matured.

When a child returns to school postinjury, their educational and emotional needs will likely be much different than before. It can also be emotionally and socially devasting on the child, family and friends as they may recall what the child was like before the injury and have trouble adjusting their expectations. On top of symptoms of difficulty with memory and comprehension, lack of energy, susceptibility to distraction and confusion, many children may experience mood swings and aggression due to frustration from being unable to meet expectations.

A study by Jones et al. (2018) examined differences in child behavior and patterns of recovery over the first 12 months following a traumatic brain injury. The differences were assessed through parent and child self-reports. Ninety-nine children aged from 8-15 and one of their parents completed a Behavioral Assessment Scale for Children. It was used to assess the child’s behavior, hyperactivity, anxiety and depression post-injury. The child’s recovery over the time period was also examined.

Results show that ratings for child’s hyperactivity, anxiety, and depression differed greatly amongst parent’s and their children. This could be due to the fact that parents may have a hard time adjusting to their child’s behavior due to expectations they had of the child preinjury. Eventually, both parents and children reported fewer hyperactivity and anxiety problems, while depression was still rated higher.

Durish et al. (2018) completed a scoping review to summarize what is known so far about depression and depressive symptoms in pediatric traumatic brain injury. They concluded that depressive symptoms are more common in TBI population compared to healthy or orthopedically injured population. Research also suggests that depression is a secondary outcome of pediatric TBI. It also suggests children with depressive symptoms postinjury are at greater risk for poorer functional outcomes.

Other areas of deficit may be causes by behavioral and emotional consequences such as self-injury, aggression, depression, and mood swings. Each of these have a major impact on independent living and can impede goals of rehabilitation. Injury may cause damage to other the somatosensory system as well as the sensory systems for olfactory, vision, audition, gustatory, and vestibular.

Prospective (Future Directions)

 Age specific studies are necessary to fully understand the long-term implications injuries have to the brain. Several experimental TBI models are now being scaled down from adult rodents to juvenile animals to gain a better understanding of TBI in children and adolescents. A study by Semple et al. (2016) discusses the adapted models for pediatric TBI as well as the importance of age equivalence across species during the development and interpretation of the model.

 Despite their work and others, research in pediatric TBI is still in its infancy. Further investigation is needed to understand the underlying mechanisms of neuroendocrine dysfunction and the disruption of sleep-wake behavior in children as it remains unclear. A better profile for how a traumatic brain injury in a developing brain differs from an injury to an adult that has a fully mature brain is still needed.

 In addition, future research should also consider what role sex and gender has in the outcomes of TBI patients. Currently there is evidence that suggests that even prior to sexual maturation, an individual’s sex is an important determinant in long-term recovery (Guevara, Gianotti, Roca, 2011). Studying differences in the circulation of sex hormones after TBI at different stages of development could give researchers a better understanding of why an individual’s sex plays a role in recovery.

 Research should also be directed towards social-emotional and behavioral effects of TBI in children. Lack of motivation, irritability, aggression and depression are all common symptoms postinjury. Directing research to this area may help shed light to the underlying mechanisms of these behavioral effects and produce better functional outcomes for children who sustain a traumatic brain injury.

References

• Guevara R, Gianotti M, Oliver J, Roca P (2011) Age and sex-related changes in rat brain mitochondrial oxidative status. Exp Gerontol 46:923–928
• Crichton, Alison, et al. “Fatigue Following Traumatic Brain Injury in Children and Adolescents.” Journal of Head Trauma Rehabilitation, vol. 33, no. 3, 2018, pp. 200–209. Ovid, doi:10.1097/htr.0000000000000330.