Many individuals completely recover from brain injuries; however, many people do not. Brains that are injured significantly shift into a slower power distribution pattern. Comas are extreme examples of maximum brain slowing. Most often however, theta becomes the dominant frequency in the areas of injury.
(coup and contra-coup pattern)
Hughes and John (1999) concluded the common indicators in the EEG of post-concussive syndrome are:
1. increased focal or diffuse theta;
2. decreased alpha;
3. decreased coherence; and
4. increased asymmetry.
What this produces in the affected individual is a myriad of psychopathology dependent upon location and severity of injury. The psychopathology often progresses from sleep disturbances to increased anxiety, eventually resulting in depression.
Due to slower processing speed, learning disabilities are common. Irritability and anger are likely to follow along with ever-increasing attention deficit hyperactivity disorder (ADHD) symptoms and more times than not, substance abuse issues. The most notable symptoms are impulsivity, distractibility, and difficulty with focus on boring tasks. This makes higher education very difficult and working most professions intolerable. However, with proper evaluation and treatment there are professions well suited for brains that have such traits.