Types of head Injury & brain trauma
A head injury can be either open or closed. An open head injury generally involves a wound caused by a missile (ie. bullet) or some other type of open wound. Such injuries are rare. In contrast, closed head injuries are relatively common and occur when a child’s head strikes a hard surface, or they experience acceleration/ deceleration forces, either with or without impact to the skull.
Two types of injuries are generally seen with closed head injuries: focal and diffuse. Focal injury results from impact and is associated with a skull fracture or brain contusion (bruising). This type of injury occurs when the child’s head impacts with an object. Damage to the brain may occur at both the point of impact (coup) as well as the brain region where the brain rebounds from the impact (contrecoup). The contracoup impact is opposite the point of original impact, and may be bruised or have a hematoma (bleeding). Thus, hitting ones head at the front may also result in damage to the back of the brain.
Diffuse Injury is the result of the tearing of the neurons in the brain (both gray and white matter) due to the acceleration and deceleration of the brain. This diffuse injury is commonly seen in brain structures that are involved in the transfer of information around the brain (corpus callosum & internal capsule) as well as in structures involved in balance and motor movements (cerebellum). Damage is also seen in the front of the brain in the area of the eye sockets, which influences behaviour, emotion, memory and attention.
Your child may also have secondary effects of the head injury such as brain swelling, areas of ischemia (death of brain neurons), contusions of the brain, hemorrhage, and subdural hematomas
Severity of head injury
The Glasgow Coma Scale (GCS) is usually used to determine the severity of head injury. The higher the score the less impairment is present. The length of posttraumatic amnesia (PTA) is the time it takes for your child to understand time and spatial orientation and to recall prior events. The longer the PTA and lower the GCS, the more likely your child will suffer more severe and longer lasting cognitive problems.Mild head injury: PTA< 1 hour, GCS 13-15 Moderate head injury: PTA 1-24 hours, GCS 9-12 Severe head injury: PTA> 24 hours, GCS 3-8
BrainstemThe brainstem is comprised of 5 areas. The medulla oblongata is a continuation of the spinal cord and contains both sensory (ascending) and motor (descending) nuclei. It is at the medulla where sensory and motor tracts cross over into the opposite side of the brain so that sensory and motor information on the right side of the body is controlled by the left side of the brain (and vice versa). The recticular activating system (part of the medulla) is the arousal system and controls blood pressure, blood volume in organs, heart rate, and regulates sleep and wakefulness. This system maintains consciousness and attentional states for the brain and has been hypothesised to be involved in ADHD symptoms.
Cerebellum:The cerebellum is involved in the unconscious adjustment of muscles in the body for coordinated, smooth and complex motor activity. Injury can result in movement disorders ( dystaxia), slurred speech (dysarthria), blurred vision and dizziness (nystagmus), and loss of muscle tone (hypotonia). This region is one of the most common regions for tumours in children.
Limbic system:The limbic system is comprised of the hippocampus, septum, and cingulate gyrus. It is involved in responses to threatening situations, sexual responses, memory, emotion.
Basal Ganglia:The basal ganglia is comprised of the caudate nucleus, putamen, globus pallidus and the amygdala.
Cortex: Frontal Lobes:The frontal lobes are involved in many different cognitive skills, including motor function, problem solving, spontaneity, memory, language, initiation, judgement, impulse control, and social behavior. One of the most common symptoms of frontal lobe injury is difficulty in interpreting feedback from the environment. Perseverating on a response, risk taking, and non-compliance with rules, and impaired associated learning along with other executive skills are common.
Cortex: Parietal Lobes:As a part of the cortex, the parietal lobes are associated with processing sensory information. The parietal lobe is where information such as taste, temperature and touch are processed.
Cortex: Occipital Lobes:The occipital lobes are the main area for our visual perception. This region is involved in visuospatial processing, discrimination of movement and color discrimination. Disorders of the occipital lobe can cause visual hallucinations and illusions, along with word blindness with writing impairments.
Cortex: Temporal Lobes:The temporal lobe is associated with a number of different abilities, including auditory perception, long-term memory and emotional responses. The hippocampus is located in the temporal lobe and is involved in consolidating information from short-term memory into long-term memory. Damage to the temporal lobes can create problems with auditory sensation and perception, auditory attention, language comprehension, long-term memory problems, and changes in behavior and personality.
Neuropsychological problems following brain injury
The neuropsychological sequelae following a brain injury will vary according to the age at which the TBI occurred, the time which has elapsed since the injury, and the location, focal specificity, and extent of the lesion. Generalised impairments in intellectual functioning are typically as a result of an injury that is severe, diffuse, or multifocal in nature. There is a negative correlation between the severity of the brain trauma and global IQ scores. Often nonverbal IQ scores are lower than Verbal IQ scores. This may be due to the nonverbal subtests loading highly upon psychomotor functioning and speed of information processing, which are oftenimpaired after brain trauma.
Memory, new learning, and attentional problems are the most common cognitive sequelae of TBI in children. The more severe the injury the more significant and persisting the memory deficits will be. Although both verbal and nonverbal memory deficits are common, verbal memory is especially sensitive to closed head injuries affecting the left hemisphere. Other memory problems include deficits in encoding, and immediate and delayed recall. Attention and concentration difficulties may also be observed, including problems with sustained, selective, and divided attention. In general, the greatest risk for attention and concentration problems occurs in the initial posttraumatic period for all degrees of severity, but then the risk shifts disproportionally toward the severely injured at short-term and long-term follow-up.
After TBI children may also exhibit difficulties with executive abilities. They may show deficits in problem solving, planning, organization, mental flexibility, fluency, inhibition and behavioural regulation. Other deficits include slowed speed of information processing, which is inversely proportional to the severity of TBI. Language deficits may also be observed, although classic aphasia syndromes are infrequent in children. They may have problems with fluency, repetition, and written language. Head injured children often perform more poorly on motor tasks, such as finger tapping and motor dexterity, even in the absence of more gross motor impairments. Motor slowing is only likely to persist in severely injured children. Many of the deficits associated with TBI in children can undermine academic performance in areas such as reading writing, and mathematics. Children may also exhibit headaches, fatigue, irritability, lethargy, sleep disruptions, and possiblybehavioural and personality changes after sustaining a TBI.
Although many of the deficits seen in children who sustain a TBI are similar to those seen in adults there are some important differences. Neuropsychological sequelae may differ between children and adults as the causes of TBI in children are more variable than in adults and their pathophysiological responses to injury differ. Evidence suggests that children have an increased probability of survival and better motor-sensory recovery. It has been postulated that recovery may be greater in children than in adults due to the plasticity of children’s brains and possible reorganization of function. However, some studies have found that children who sustained a head injury prior to seven years of age performed more poorly than those who were injured after 7.
The neuropsychological sequelae of TBI in children is much more complex and variable than in adults as children have to both regain the abilities they have lost as well as continue to acquire new skills. Therefore deficits may accumulate with time or possibly only appear after a certain period following the injury. Maturational, psychosocial, and cognitive factors interact more in children than in adults, and children are more emotionally vulnerable to the impact of their injuries on the family and on their social relationships.
Treatment of cognitive problems following brain injury At the Sydney Cognitive development Centre we assess and treat the cognitive, behavioural, social, academic and emotional problems that arise following a TBI. We also offer parent and family support and counselling through the difficult recover phase.