Neurotrauma or brain damage is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage, while neurotoxicity typically refers to selective, chemically induced neuron damage.
The foundation for understanding human behavior and brain injury can be attributed to the case of Phineas Gage and the famous case studies by Paul Broca. The first case study on Phineas Gage’s head injury is one of the most astonishing brain injuries in history.
In 1848, Phineas Gage was paving way for a new railroad line when he encountered an accidental explosion of a tamping iron straight through his frontal lobe. Gage observed to be intellectually unaffected but exemplified post injury behavioral deficits.
A common category with the greatest number of injuries is traumatic brain injury following physical trauma or head injury from an outside source, and the term acquired brain injury is used in appropriate circles to differentiate brain injuries occurring after birth from injury, from a genetic disorder, or from a congenital disorder. Primary and secondary brain injuries identify the processes involved, while focal and diffuse brain injury describe the severity and localization.
Symptoms of brain injuries vary based on the severity of the injury or how much of the brain is affected. The three categories used for classifying the severity of brain injuries are mild, moderate or severe.
Symptoms of brain injuries can be influenced by the location of the injury and as a result impairments are specific to the part of the brain affected. Lesion size is correlated with severity, recovery, and comprehension. Brain injuries often create impairment or disability that can vary greatly in severity.
In cases of severe brain injuries, the likelihood of areas with permanent disability is great, including neurocognitive deficits, delusions (often, to be specific, monothematic delusions), speech or movement problems, and intellectual disability.
There may also be personality changes. The most severe cases result in coma or even persistent vegetative state. Even a mild incident can have long-term effects or cause symptoms to appear years later.
There are multiple responses of the body to brain injury, occurring at different times after the initial occurrence of damage, as the functions of the neurons, nerve tracts, or sections of the brain can be affected by damage. The immediate response can take many forms. Initially, there may be symptoms such as swelling, pain, bruising, or loss of consciousness. Post-traumatic amnesia is also common with brain damage, as is temporary aphasia, or impairment of language.
As time progresses, and the severity of injury becomes clear, there are further responses that may become apparent. Due to loss of blood flow or damaged tissue, sustained during the injury, amnesia and aphasia may become permanent, and apraxia has been documented in patients.
Recent research has demonstrated that neuroplasticity, which allows the brain to reorganize itself by forming new neural connections throughout life, provides for rearrangement of its workings. This allows the brain to compensate for injury and disease.