This chapter is designed to help you understand enough about this disability to feel more comfortable working with students with suspected or documented brain injury. Hopefully, it will also help both you and the student meet learning objectives with greater satisfaction and less frustration.
The Brain as a Human Command Center
The brain is a remarkable, mysterious organ and is responsible for all of a person's thoughts and actions. It even controls breathing, sleeping,digestion, and other automatic body functions. It is the center of intuition, social and sensory perception, imagination, emotions, intentions, and response.
The brain is both sensitive and robust. It is protected by a very hard shell, the skull, and withstands many instances when the head is struck or shaken. Most of us have experienced at least one such instance with no ill effect. Brain wiring (networks of neurons) is also somewhat redundant, meaning there is often more than one pathway for a message to travel from one part of the brain to another. If one path becomes disabled, there may be another to carry on. And new pathways form with experience.
On the other hand, inside the skull are bony ridges that can tear at neurons when the brain is shaken. The hard, inflexible skull can inflict bruising on soft brain tissue. This is why it doesn't take an impact or penetrating wound to significantly injure the brain. Any sudden and severe jolting of the brain inside the skull can cause injury.
All brain activities are conducted via a complex electro-chemical cascade designed to nourish brain cell function and maintain balance. This process can be altered by a number of means -- including the introduction of foreign chemicals, loss of oxygen-carrying blood to brain cells, changes as a result of a disease, and the neuro-chemical response of brain cells and networks to brain injury.
Sources of Brain Injury
By definition, a brain injury is acquired when a healthy brain is subject to an injurious force. It is not an inherited disorder or a product of genetic mutation. Thus, most experts in this field refer to the disorder as Acquired Brain Injury, even though some professionals still differentiate a traumatically-induced brain injury (TBI) from other sources.
Traumatic Brain Injuries
TBI has received increased attention during the conflicts in Iraq and Afghanistan because of the number of veterans returning with traumatically induced brain injuries. This group has also raised awareness of the co-occurrence of TBI and Post-Traumatic Stress Disorder, which can make an accurate diagnosis of TBI, difficult due to overlapping symptoms.
Another source of TBI is also receiving increased attention as neuropsychologists, sports physicians, and coaches team up to follow injured athletes. They have drawn attention to effects of repeated concussions during contact sports on cognitive and emotional functioning. Their efforts are particularly important for raising awareness of the potential importance of concussion -- a "mild" brain injury previously minimized or ignored by many health professionals.
An under-reported source of TBI is domestic abuse. When domestic violence accounts for 25% of crimes against people in Minnesota and family violence occurs in nearly one in three U.S. families, the incidence of TBI among victims of domestic abuse is expected to be much more significant than acknowledged by either victims themselves or healthcare providers.
Combat-related brain injuries, concussion and domestic violence are discussed in greater depth in the next chapter, Identification and Diagnosis.
Still, the major source of documented TBI is motor vehicle accidents in teens and young adults and falls in young children and older adults.
When a student reports a history of multiple head injuries resulting in loss of consciousness or confusion, it is likely but not certain they have acquired permanent effects of brain injury. The likelihood increases if combined with a history of substance use/abuse.
Non-Traumatic Brain Injuries
In some patient samples, more individuals have suffered a brain injury due to non-traumatic causes than TBI. Those brain injuries that are not traumatically induced occur when the normal, electro-chemical action of brain cells is blocked or altered by other means -- such as over-exposure to toxic substances, tumors, disease progression, temporary loss of oxygen, and an imbalance of fluids or hormones in the brain. A common source in older adults is stroke. In children it is often oxygen loss at birth or exposure to lead paint and other toxins.
Often the first sign of a progressive disease such as multiple sclerosis, AIDS, and cardiovascular disorder is a decline in cognitive functioning. Unexpected learning difficulties or changes in personality or thinking in a younger person may also lead one to suspect environmental causes (e.g., toxins, carbon monoxide exposure) or substance abuse (alcohol, illicit drugs, side effects of prescription drugs). A series of generalized seizures can cause brain injury along with reduced oxygen absorption due to lung disease and poor blood circulation.
These causes are more difficult to spot, and if suspected, the first thing to do is refer the student to a physician for medical evaluation.