These signs and symptoms include the following:
• Physical or somatic – fatigue, dizziness, spinning sensation, headaches, sleep disturbance, and lack of energy. Headache is the most commonly reported symptom in TBI/concussion, followed by dizziness, vertigo, and fatigue. A hallmark reported somatic symptom suggesting a disruption in the brain cycle is difficulty falling asleep and staying asleep.
• Cognitive – mental fog, memory and attentional impairment, and word-finding and visual perception problems. The hallmark feature of TBI/concussion is the inadequacy in executive functions, manifested by diminished insight, speed of processing, trouble with social graces, and in one’s ability to shift from one set of cognitive tasks to another.
• Neurobehavioral – anxiety, OCD, depression, low self-esteem, disinhibition (loss of filter), fear, short fuse, and personality changes that could include aggression, emotional lability (inappropriate laughter or crying), impulsivity (lack of impulse control), and irritability (Riggio 2009).
• According to Riggo (2009), neuropsychiatric or neurobehavioral symptoms actually are correlated with the severity, type, and duration of the somatic symptoms. This issue of which comes first the chicken or the egg, i.e. the physical somatic symptoms causing the cognitive and behavioral symptoms or vice versa is critical to understand TBI and concussions and how to treat such conditions.
Signs and symptoms in the immediate and chronic phases Immediate:
• Impaired attention – vacant stare, delayed responses, inability to focus
• Slurred or incoherent speech
• Gross incoordination
• Disorientation
• Emotional reactions out of proportion
• Memory deficits
• Any loss of or alteration of consciousness
Within one hour to days:
• Persistent headache
• Dizziness/vertigo
• Poor attention and concentration
• Memory dysfunction
• Nausea or vomiting
• Frequent fatigue
• Irritability
• Intolerance of bright lights
• Intolerance of loud noises
• Anxiety and/or depression
• Sleep disturbances
Concepts on Classification – It is now commonly believed that a proper classification system is necessary for the allocation of resources, treatment, and for determining the severity, prognosis, and outcomes. However, due to our recent understanding from new pathological studies, imaging, and new emerging clinical evaluation and treatment methods, we now can revisit how we define and classify TBI and concussion.
For years, experts in the field of TBI/concussion have applied many classification systems to better define the condition. However, these systems that worked previously may not be as relevant given the new understanding we have of injury and the science of the body. Many of the very strict classification systems used in the past that supported research initiative and clinical evidence required the patient to have suffered LOC and in some cases hospitalization. In fact, many of the older publications on concussion stipulated that one had to have a loss of consciousness as a criterion for establishing a concussion. No wonder many physicians (including neurologists), attorneys, and sports medicine programs still hold on to that belief.
Here is a classification system utilized for concussion, based on the acute severity at the time of the injury, which has been utilized by the VA and Department of Defense.
Table # 2 -- Classification of TBI Severity
| Criteria | Mild | Moderate | Severe |
| Structural imaging | Normal | Normal or abnormal | Normal or abnormal |
| Loss of consciousness (LOC) | 0–30 min | > 30 min and < 24 hrs | > 24 hrs |
| Alteration in consciousness/mental state (AOC) | a moment up to 24 hrs | > 24 hours; severity based on other criteria | |
| Post-traumatic amnesia (PTA) | 0-1 day | > 1 and < 7 days | > 7 days |
| Glasgow Coma Scale (GCS) (best available score in first 24 hours) | 13–15 | 9–12 | < 9 |
Source: O’Neal 2013
Note that PTA refers to a period of time following an injury when the patient is confused and unable to form new memories.
So, the question is: when does a concussion end or get resolved?
Utilizing the VA/DOD criteria, it was found that approximately 12–23% of service members returning from Iraq and Afghanistan suffered a TBI while deployed with most of the injuries being mild to moderate. Overall, only 10–20% of the individuals following a TBI experienced symptoms beyond 30 days. However, returning military has a larger percentage of individuals that remain symptomatic beyond 30 days. Moreover, one must consider the limited reporting of those conditions at the time (O’Neal 2013).
Consensus statements from the 4th International Conference on Concussion and the National Athletic Trainers Association estimated that most athletes recover within 7–10 days of a concussion (McCrory 2013, Broglio 2014).
Signs and symptoms have been viewed as the major evidence of when a concussion or TBI occurs and when it is resolved. But is it ever completely resolved?
The new markers of injury and the tools that are emerging may provide better answers to those questions. We now understand that the brain changes every day and every moment that we exist. I don’t know if there is a saying out there for this one, but I will go ahead and say, “We never have the same brain as yesterday.” These changes are accelerated by age and injury and result in the reorganization of the brain and its capacity to continue to reorganize. Current findings have suggested that these issues are more complex than we first realized. On the micro level, just thinking of the impact of injury in the disorganization of the brain is a challenge. The disruption of over a hundred million neurons with over a thousand trillion connections presents a problem of exponential magnitude. It is also highly challenging to look at the recovery process and the subsequent reorganization of the relationships between the many trillions of nerve terminal connections that exist together with all of the neurotransmitter (neurochemicals) substances that are responsible for creating and maintaining the complex messaging system that makes us human. We are far from understanding how much reorganization the brain experiences before a patient cease to experience the signs and symptoms. This certainly begs the question of when and how clinicians know from the signs and symptoms that the concussion or TBI is cured or treated, even if the symptoms have dissipated and the patient reports not experiencing the effects of TBI/concussion. This phenomenon of injury and the miracle of recovery will remain a mystery for a long time. However, we continue to make major strides in our understanding of these mysteries of the human brain.
Pathophysiology of a concussion
At its core, a concussion is highly related to an imbalance between energy utilization and availability throughout the brain or in certain parts of the brain. These delicate structures in the brain that are responsible for producing energy to ensure the appropriate functioning of the nerve cells working in a complex array become impaired. After an injury, the brain remains impaired until there is a recovery of the hierarchical organization of the array of neurons on a physiological and anatomic basis to manage energy efficiently to facilitate appropriate human functioning.
Energy-mismatched neuro-metabolic changes in concussion, as described by Hovda, represent a mismatch period where the demand for fuel (glucose) is high, while the blood flow to bring the glucose to the cell and the oxygen required to cause combustion is low. This results in a mismatch where sufficient energy is not created to keep the cells going.