The majority of children and adults fully recover from a<unk> , however some may experience a prolonged recovery. There is no single physical test, blood test (or fluid biomarkers), or imaging test that can be used to determine when a person has fully recovered from<unk> . A person's recovery may be influenced by a variety of factors that include age at the time of injury, intellectual abilities, family environment, social support system, occupational status, coping strategies, and financial circumstances. Factors such as a previous head injury or a coexisting medical condition have been found to predict longer-lasting post-concussion symptoms. Other factors that may lengthen recovery time after mTBI include psychological problems such as substance abuse or clinical depression, poor health before the injury or additional injuries sustained during it, and life stress. Longer periods of amnesia or loss of consciousness immediately after the injury may indicate longer recovery times from residual symptoms. Other strong factors include participation in a contact sport and body mass size. Pediatric<unk>  Most children recovery completely from<unk>  in less than four weeks, however 15–30% of youth may experience symptoms that last longer than a month. People aged 65+ with<unk>  Mild traumatic brain injury recovery time in people over age 65 may have increased complications due to elevated health concerns, or comorbidities. This often results in longer hospitalization duration, poorer cognitive outcomes, and higher mortality rates. Repeat<unk>  For unknown reasons, having had one<unk>  significantly increases a person's risk of having another. Having previously sustained a sports<unk>  has been found to be a strong factor increasing the likelihood of a<unk>  in the future. People who have had a<unk>  seem more susceptible to another one, particularly if the new injury occurs before symptoms from the previous<unk>  have completely gone away. It is also a negative process if smaller impacts cause the same symptom severity. Repeated<unk> s may increase a person's risk in later life for dementia, Parkinson's disease, and depression. Post-concussion syndrome In post-concussion syndrome, symptoms do not resolve for weeks, months, or years after a<unk> , and may occasionally be permanent. About 10% to 20% of people have post-concussion syndrome for more than a month. Symptoms may include headaches, dizziness, fatigue, anxiety, memory and attention problems, sleep problems, and irritability. Rest, a previously recommended recovery technique, has limited effectiveness. A recommended treatment in both children and adults with symptoms beyond 4 weeks involves an active rehabilitation program with reintroduction of non-contact aerobic activity. Progressive physical exercise has been shown to reduce long-term post-concussive symptoms. Symptoms usually go away on their own within months but may last for years. The question of whether the syndrome is due to structural damage or other factors such as psychological ones, or a combination of these, has long been the subject of debate. Cumulative effects As of 1999, cumulative effects of<unk> s were poorly understood, especially the effects on children. The severity of<unk> s and their symptoms may worsen with successive injuries, even if a subsequent injury occurs months or years after an initial one. Symptoms may be more severe and changes in neurophysiology can occur with the third and subsequent<unk> s. As of 2006, studies had conflicting findings on whether athletes have longer recovery times after repeat<unk> s and whether cumulative effects such as impairment in cognition and memory occur. Cumulative effects may include chronic traumatic encephalopathy, psychiatric disorders and loss of long-term memory. For example, the risk of developing clinical depression has been found to be significantly greater for retired American football players with a history of three or more<unk> s than for those with no<unk>  history. An experience of three or more<unk> s is associated with a fivefold greater chance of developing Alzheimer's disease earlier and a threefold greater chance of developing memory deficits. Chronic traumatic encephalopathy, or "CTE", is an example of the cumulative damage that can occur as the result of multiple<unk> s or less severe blows to the head. The condition was previously referred to as "dementia pugilistica", or "punch drunk" syndrome, as it was first noted in boxers. The disease can lead to cognitive and physical handicaps such as parkinsonism, speech and memory problems, slowed mental processing, tremor, depression, and inappropriate behavior. It shares features with Alzheimer's disease. Second-impact syndrome Second-impact syndrome, in which the brain swells dangerously after a minor blow, may occur in very rare cases. The condition may develop in people who receive a second blow days or weeks after an initial<unk>  before its symptoms have gone away. No one is certain of the cause of this often fatal complication, but it is commonly thought that the swelling occurs because the brain's arterioles lose the ability to regulate their diameter, causing a loss of control over cerebral blood flow. As the brain swells, intracranial pressure rapidly rises. The brain can herniate, and the brain stem can fail within five minutes. Except in boxing, all cases have occurred in athletes under age 20. Due to the very small number of documented cases, the diagnosis is controversial, and doubt exists about its validity. A 2010 Pediatrics review article stated that there is debate whether the brain swelling is due to two separate hits or to just one hit, but in either case, catastrophic football head injuries are three times more likely in high school athletes than in college athletes.
Concussion
Cerebellar abiotrophy
Tongue thrust
Sinus lift
Banding 
Sidaction
Lateral release 
Exertion