Concussion Basics

Mild traumatic brain injury (MTBI), commonly known as concussion, is defined as a head injury with a temporary loss of brain function causing a variety of physical, cognitive, and emotional symptoms. There is no overt physical evidence of trauma, and the victim may immediately appear to be confused, disoriented, dazed or even experience a brief loss of consciousness. These symptoms often resolve within a brief period of time or may last for days, weeks, months and even years after the incident. Clinical experience shows that fatigue becomes a notable factor over time with reports of decreased performance and needing more rest.

Current diagnosis of MTBI required expert observation and behavioral checklists. Long-term symptoms may be examined with a CT scan or MRI and neuropsychological testing. Presently, the quantitative EEG (qEEG) is one of few techniques to accurately examine MTBI as other methods do not pick up bruising or microscopic tears within the brain. Numerous research labs are also also experimenting with other ways to diagnose and monitor closed-head injuries. Concussion consequences can vary from mild to fatal. Historically, the brain was thought to be “hardwired,” and unchangeable. We now know the brain is flexible and able to heal and change, although it sometimes requires help. This concept is called neuroplasticity.

Concussions commonly occur when the brain hits the inside of the skull. This happens when a body (skull) stops suddenly, changes direction suddenly, or is repeatedly exposed to micro-traumas. As the skull stops moving, the brain continues to move subject to the laws of physics. Even though the brain is enclosed in a fluid called cerebral spinal fluid, which acts to cushion the brain, if the change in direction or force is too great, the brain will collide with the skull.

Inside the front of the skull is the sinus cavity, with sharp ridges and edges. If the brain hits these points, it can tear and causing micro-bleeding. The area’s most commonly affected are the called the prefrontal, frontal and temporal lobes. The back of the skull is quite smooth and curved, and collisions with it can cause extensive bruising. Injuries caused by hitting the sinus cavities are usually quite discrete (specific effects), whereas injuries caused by hitting the back of the skull are quite diffuse (impacting various regions).

1. Neurochemical Damage

Brain cells communicate through a cascade of electrical charges down a long stem, called an axon. Axons contain pumps and channels that allow ions, such as sodium and calcium, to go in and out of the cell when needed. The forceful impact of a concussion causes diffuse damage in these ionic channels, resulting in a reduction of general cognitive functioning, information processing and slowness of thought.

2. Bruising / Micro-tearing

There are certain patterns that occur with this, which include issues with short-term memory, self-awareness, social acuity, and depression. These types of injuries are rarely able to be picked up through typical brain imaging techniques due to their microscopic nature. Assessing brain function, rather than brain structure, is a way to mitigate this. Function is how to brain is operating; structure is the physical makeup.

3. White / Grey Matter Damage

There are two types of matter in the brain: grey and white matter. Grey matter makes up the outer cerebral cortex, which houses a large portion of the “content” in the brain. The white matter connects the various regions. Shear forces (sliding) of grey and white matter can stretch the brain cells’ axons. As they depend on this portion of the cell to relay information, injuries of this sort often lead to reduced clarity and slowness of thought.

Our behaviours are organized as “hubs” or “functional modules” in the brain. A hub consists of the areas of the brain that work together to produce a thought, behaviour or emotion. While there are countless hubs, seven have been extensively studied: addiction, anxiety, attention, default network, depression, pain, and schizophrenia.

The default network is what the brain does when it is at rest, and not engaged in a task or not ruminating about the past/present. This network involves the several areas including the cingulate gyrus, hippocampus, medial frontal lobes, temporal lobes, and parietal lobes. Injury to any one of these areas, or damage to the axons running between these areas, can disrupt the activity of the default network.

In medicine, the term “comorbid” refers to medical condition(s) existing simultaneously, but independently, with another condition. It can also be related addition to the primary condition. Effects are evident in both physical and mental health. Due to the nature of brain injuries, changes occur in the complex, internal functions of the body, such as the systems responsible for regulating body temperature, blood pressure, and bowel and bladder control.

Post-concussion syndrome contains many features seen in psychological conditions. For example, the reported symptoms of Attention Deficit Hyperactivity Disorder (ADHD) are very similar to that of MTBI. Other psychological factors such as depression, anxiety, and social issues may also worsen due to MTBI.

The reasons or mechanisms involved in this phenomena are not presently understood, and family relationships often become strained and dysfunctional. Research indicates that 45% of the homeless have suffered concussions. Before the MTBI occurred, 87% of those homeless individuals owned their own homes.