Instruct: Given a question, retrieve passages that answer the question.
Query: How many people have PCS after a concussion?
Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that may continue for weeks, months, or a year or more after a concussion– a mild form of traumatic brain injury (TBI).[1][2][3] The rates of PCS vary, but most studies report that about 15% of individuals with a history of a single concussion develop persistent symptoms associated with the injury. A diagnosis may be made when symptoms resulting from concussion last for more than three months after the injury.[4][5] Loss of consciousness is not required for a diagnosis of concussion or post-concussion syndrome.[6]
Not all people with PCS have abnormalities on imaging, however, and abnormalities found in studies such as fMRI, PET, and SPECT could result from other comorbid conditions such as depression, chronic pain, or post-traumatic stress disorder (PTSD).[25] Proponents of the view that PCS has a physiological basis point to findings that children demonstrate deficits on standardized tests of cognitive function following a mild TBI.[35] A few studies have shown that people with PCS score lower than controls on neuropsychological tests that measure attention, verbal learning, reasoning, and information processing, but issues related to effort and secondary gain can not be ruled out as contributing to these differences.[7] Recovery as measured by scores on cognitive tests frequently do not correlate with resolution of symptoms; individuals diagnosed with PCS may still report subjective symptoms after their performance on tests of cognitive functioning have returned to normal.[24] Another study found that although children with PCS had poorer scores on tests of cognitive functioning after the injury, they also had poorer behavioral adjustment before the injury than children with no persistent symptoms; these findings support the idea that PCS may result from a combination of factors such as brain dysfunction resulting from head injury and preexisting psychological or social problems.[35] Different symptoms may be predicted by different factors; for example, one study found that cognitive and physical symptoms were not predicted by the manner in which parents and family members coped with the injury and adjusted to its effects, but psychological and behavioral symptoms were.[35]
In the profession of athletic training there are many controversies, but none greater than the treatment and management of concussions. For many years people viewed concussions and big tackles in football games as athletes just "getting their bell rung" and coaches implored them to "shake it off and get back in the game". However, substantial research has shown that a concussion is a traumatic brain injury that may temporarily interfere with the way the brain works and can affect memory, judgment, reflexes, speech, balance, coordination and sleep patterns. A study from the National Center for Injury Prevention found that 47% of high school football players say they suffer a concussion each season, with 37% of those reporting multiple concussions in a season. Such serious injuries deserve appropriate attention to treatment and to prevention. With a concussion, function may be interrupted but there is no structural damage to the brain, so the physical examination often appears normal. The American College of Sports Medicine estimates that 85% of sports-related concussions go undiagnosed because athletes deny or fail to report symptoms and because subtle changes in brain function may not be obvious on a single examination. This May new standards for concussion management that were realized, and stated that if an athlete was involved in a play where a concussion was possible (a direct blow to the head), the athlete is supposed to be evaluated by a certified athletic trainer or a qualified physician if available. The new standards go on to say that if the athlete has any signs of a concussion, they are not able to return to play for the rest of the game or practice. According to the "New York Times", this seems like a good policy in theory, but with football season being over for a large majority of high schools (football having the highest risk of concussion), experts are finding that athletes have found ways to get around the standards, such as denying any concussion symptoms they are having, learning how to answer questions to hide any signs of concussion, or not saying anything about the possible concussion to the athletic trainer or physician working at the game. With these strategies, athletes put themselves at risk for the "second concussion", which can leave permanent brain damage and can even lead to death. Although in theory these new standards for concussions are great for significantly reducing the risk of missing symptoms that appear after 24 hours and preventing any further brain damage, but with athletes now hiding possible concussions from athletic trainers and physicians, these standards may actually have a negative effect on concussion management.
The symptoms that occur after a concussion have been described in various reports and writings for hundreds of years.[19] The idea that this set of symptoms forms a distinct entity began to attain greater recognition in the latter part of the 19th century.[64] John Erichsen, a surgeon from London, played an important role in developing the study of PCS.[64] The controversy surrounding the cause of PCS began in 1866 when Erichsen published a paper about persisting symptoms after sustaining mild head trauma.[12] He suggested that the condition was due to "molecular disarrangement" to the spine. The condition was originally called "railroad spine" because most of the injuries studied had happened to railroad workers.[12] While some of his contemporaries agreed that the syndrome had an organic basis, others attributed the symptoms to psychological factors or to outright feigning.[64] In 1879, the idea that a physical problem was responsible for the symptoms was challenged by Rigler, who suggested that the cause of the persisting symptoms was actually "compensation neurosis": the railroad's practice of compensating workers who had been injured was bringing about the complaints.[12] Later, the idea that hysteria was responsible for the symptoms after a mild head injury was suggested by Charcot.[12][65] Controversy about the syndrome continued through the 20thcentury.[65] During World War I many soldiers suffered from puzzling symptoms after being close to a detonation but without any evidence of a head wound. The illness was called shell shock, and a psychological explanation was eventually favoured.[66] By 1934 the current concept of PCS had replaced ideas of hysteria as the cause of post-concussion symptoms.[12] British authorities banned the term shell shock during World War II to avoid an epidemic of cases, and the term posttrauma concussion state was coined in 1939 to describe "disturbance of consciousness with no immediate or obvious pathologic change in the brain".[66] The term postconcussion syndrome was in use by 1941.[66]
The existence of PCS in children is controversial. It is possible that children's brains have enough plasticity that they are not affected by long-term consequences of concussion (though such consequences are known to result from moderate and severe head trauma).[61] On the other hand, children's brains may be more vulnerable to the injury, since they are still developing and have fewer skills that can compensate for deficits.[62] Clinical research has found higher rates of post-concussion symptoms in children with TBI than in those with injuries to other parts of the body, and that the symptoms are more common in anxious children.[38] Symptoms in children are similar to those in adults, but children exhibit fewer of them.[38] Evidence from clinical studies found that high school-aged athletes had slower recoveries from concussion as measured by neuropsychological tests than college-aged ones and adults.[62] PCS is rare in young children.[52]
Post-Concussive Symptoms (PCS) is an area of recovery that is often not discussed. New evidence suggest that new recovery protocols have been recommended and designed to more adequately and efficiently recover from concussions. PCS is a concussion symptom lasting longer than 14 days. Current protocols suggest that the athlete refrain from any physical activity until symptoms free. However, according to the Journal of Athletic Training "A physiological approach to prolonged recovery from sport-related concussion" suggests some aerobic activity may be beneficial to more appropriate healing from concussion, and may lessen the reoccurrence of repeated concussions.[125]
It is not known exactly how common PCS is. Estimates of the prevalence at 3months post-injury are between 24 and 84%, a variation possibly caused by different populations or study methodologies.[7] The estimated incidence of PPCS (persistent postconcussive syndrome) is around 10% of mTBI cases.[23] Since PCS by definition only exists in people who have suffered a head injury, demographics and risk factors are similar to those for head injury; for example, young adults are at higher risk than others for receiving head injury, and, consequently, of developing PCS.[43]
Dizziness is another common symptom reported in about half of people diagnosed with PCS and is still present in up to a quarter of them a year after the injury.[12] Older people are at especially high risk for dizziness, which can contribute to subsequent injuries and higher rates of mortality due to falls.[13]
The IBM PC was immediately successful. The PC was small, light weight, and easy to use. Because it was advertised as a personal computer for anyone and not just large corporations, and because it was small and could fit easily into people's home, it became a device of popular choice for many people. It couldn't have hurt that IBM also advertised it with the lovable Charlie Chaplin's tramp character, who after seeing the computer, falls in love with it and purchases the PC. Chaplin's character became the face of the company's PC.
"BYTE" reported a rumor that more than 40,000 were ordered on the day of the announcement; John Dvorak recalled that one dealer that day praised the computer as an "incredible winner, and IBM knows how to treat us — none of the Apple arrogance". One dealer received 22 $1,000 deposits from customers although he could not promise a delivery date. The company could have sold its entire projected first-year production to employees, and IBM customers that were reluctant to purchase Apples were glad to buy microcomputers from their traditional supplier. The computer began shipping in October, ahead of schedule; by then some referred to it simply as the "PC".
Depression, post-traumatic stress disorder, and chronic pain share symptoms resembling those of PCS.[25] One study found that while people with chronic pain without TBI do report many symptoms similar to those of post-concussion syndrome, they report fewer symptoms related to memory, slowed thinking, and sensitivity to noise and light than people with mTBI do.[7] Additionally, it has been found that neuroendocrinology may account for depressive symptoms and stress management due to irregularities in cortisol regulation, and thyroid hormone regulation.[73] Lastly, there is evidence that major depression following TBI is quite common, but may be better accounted for with a diagnosis of dysexecutive syndrome.[74]
The condition is associated with a wide range of symptoms: physical, such as headache; cognitive, such as difficulty concentrating; and emotional and behavioral, such as irritability. Many of the symptoms associated with PCS are common or may be exacerbated by other disorders, so there is considerable risk of misdiagnosis. Headaches that occur after a concussion may feel like migraine headaches or tension-type headaches. Most headaches are tension-type headaches, which may be associated with a neck injury that occurred at the same time of the head injury.[11]
In recent years the AFL have taken many steps forward to try reduce the effects of concussion and how many players are receiving concussion, which will also reduce the physical head injuries to with less head contact. The AFL have modified rules of the game to protect the head of the player and reduce head contact during contests, and have also given out a concussion management plan. Prevention is also up to the player as well, for a player to comply with the concussion management plan they must miss the next game, but with players not registering as being concussed and playing the next week they can develop worse injuries.
About 10% of people with PCS develop sensitivity to light or noise, about 5% experience a decreased sense of taste or smell, and about 14% report blurred vision.[12] People may also have double vision or ringing in the ears, also called tinnitus.[14] PCS may cause insomnia, fatigue,[15] or other problems with sleep.[8]
While the causes of symptoms occurring immediately after a concussion are likely to be physiological, it is less evident that persistent post-concussive symptoms have an entirely organic basis,[23][24] and nonorganic factors are likely to be involved in symptoms that last longer than three months.[21] PCS may also be exacerbated by psychosocial factors, chronic pain, or an interaction of some or all of these.[25] The majority of experts believe that PCS results from a mix of factors, including preexisting psychological factors and those directly relating to the physical injury.[7]
A wide range of factors have been identified as being predictive of PCS, including low socioeconomic status, previous mTBI, a serious associated injury, headaches, an ongoing court case, and female gender.[54] Being older than 40 and being female have also been identified as being predictive of a diagnosis of PCS,[7] and women tend to report more severe symptoms.[12] In addition, the development of PCS can be predicted by having a history of alcohol abuse, low cognitive abilities before the injury, a personality disorder, or a medical illness not related to the injury.[12] PCS is also more prevalent in people with a history of psychiatric conditions such as clinical depression or anxiety before the injury.[63]
Barksdale was called before Congress several times during hearings about Microsoft and its alleged abuse of its operating system monopoly to dominate the web browser market (see also: Browser wars). At one point he addressed the entire room: "How many of you use Intel-based PCs in this audience, not Macintoshes?" Most people in the room raised their hands. "Of that group who use PCs? How many of you use a PC without Microsoft's operating system?" All of the hands went down. He said to the Senate panel, "Gentlemen, that is a monopoly."
Post-concussion syndrome is believed to be able to arise for reasons aside from sustaining a (mild) traumatic brain injury. In one study, health professionals cited organic causes in general as being most responsible for the development of PCS; however, emotional and compensatory causes have also been implicated as factors. For example, depression may contribute to the development or severity of PCS, whether triggered by a physical injury or not. PCS symptoms also overlap with symptoms associated with other conditions, such as chronic pain. Because of this, the Rivermead Post-Concussion Symptoms Questionnaire is useful in the assessment of other conditions besides MTBI-induced PCS. The questionnaire has been used in studies with a slightly altered wording in order to remove references to head injuries, so that test-takers don't assume their symptoms are (or are not) derived solely from a head injury and so the questionnaire can be more broadly utilized.
Education about symptoms and their usual time course is a part of psychological therapy, and is most effective when provided soon after the injury.[51] Since stress exacerbates post-concussion symptoms, and vice versa, an important part of treatment is reassurance that PCS symptoms are normal, and education about how to deal with impairments.[16] One study found that PCS patients who were coached to return to activities gradually, told what symptoms to expect, and trained how to manage them had a reduction in symptoms compared to a control group of uninjured people.[9] Early education has been found to reduce symptoms in children as well.[50]
PCS, which shares symptoms with a variety of other conditions, is highly likely to be misdiagnosed in people with these conditions.[46] Cognitive and affective symptoms that occur following a traumatic injury may be attributed to mTBI, but in fact be due to another factor such as post-traumatic stress disorder,[37] which is easily misdiagnosed as PCS and vice versa.[46] Affective disorders such as depression have some symptoms that can mimic those of PCS and lead to a wrongful diagnosis of the latter; these include problems with concentration, emotional lability, anxiety, and sleep problems.[12] Depression, which is highly common in persistent PCS, can worsen other PCS symptoms, such as headaches and problems with concentration, memory, and sleep.[47] PCS also shares symptoms with chronic fatigue syndrome, fibromyalgia, and exposure to certain toxins.[15] Traumatic brain injury may cause damage to the hypothalamus or the pituitary gland, and deficiencies of pituitary hormones (hypopituitarism) can cause similar symptoms to post-concussion syndrome; in these cases, symptoms can be treated by replacing any hormones that are deficient.
The ICD-10 established a set of diagnostic criteria for PCS in 1992.[39] In order to meet these criteria, a patient has had a head injury "usually sufficiently severe to result in loss of consciousness"[35][40] and then develop at least three of the eight symptoms marked with a check mark in the table at right under "ICD-10" within four weeks.[39][41] About 38% of people who suffer a head injury with symptoms of concussion and no radiological evidence of brain lesions meet these criteria.[42] In addition to these symptoms, people that meet the ICD-10 criteria for PCS may fear that they will have permanent brain damage, which may worsen the original symptoms.[3] Preoccupation with the injury may be accompanied by the assumption of a "sick role" and hypochondriasis.[38] The criteria focus on subjective symptoms and mention that neuropsychological evidence of significant impairment is not present.[23] With their focus on psychological factors, the ICD-10 criteria support the idea that the cause of PCS is functional.[35] Like the ICD-10, the ICD-9-CM defines PCS in terms of subjective symptoms and discusses the greater frequency of PCS in people with histories of mental disorders or a financial incentive for a diagnosis.[23]
It has been argued that psychological factors play an important role in the presence of post-concussion symptoms.[37] The development of PCS may be due to a combination of factors such as adjustment to effects of the injury, preexisting vulnerabilities, and brain dysfunction.[38] Setbacks related to the injury, for example problems at work or with physical or social functioning, may act as stressors that interact with preexisting factors such as personality and mental conditions to cause and perpetuate PCS.[25] In one study, levels of daily stress were found to be correlated to PCS symptoms in both concussed subjects and controls, but in another, stress was not significantly related to symptoms.[7]
Conventional neuroimaging studies of the brain following a concussion are typically normal. However, studies have found some subtle physiological changes associated with PCS using more novel imaging modalities. Studies using positron emission tomography have linked PCS to a reduction in glucose use by the brain. Changes in cerebral blood flow have also been observed as long as three years after a concussion in studies using single photon emission computed tomography (SPECT).[12] At least one study with functional magnetic resonance imaging (fMRI) has shown differences in brain function during tasks involving memory after mild traumatic brain injury (mTBI) although they were not examining PCS specifically.[29] Additional studies have shown, using various MRI techniques (such as Diffuse Tensor Imaging (DTI) MRI), that individuals with PCS have various abnormalities in their brain structure.[30][31][32][33] Similar findings have recently been reported in soldiers with blast-induced mTBI/PCS.[34]
Post-concussion syndrome (PCS), is a set of symptoms that a person may experience for weeks, months, or occasionally years after a concussion with a prevalence rate of 38–80% in mild traumatic brain injuries, it may also occur in moderate and severe cases of traumatic brain injury. A diagnosis may be made when symptoms resulting from concussion, depending on criteria, last for more than three to six months after the injury, in which case it is termed persistent postconcussive syndrome (PPCS). In a study of the prevalence of post concussion syndrome symptoms in patients with depression utilizing the British Columbia Postconcussion Symptom Inventory: "Approximately 9 out of 10 patients with depression met liberal self-report criteria for a postconcussion syndrome and more than 5 out of 10 met conservative criteria for the diagnosis." These self reported rates were significantly higher than those obtained in a scheduled clinical interview. Normal controls have exhibited symptoms of PCS as well as those seeking psychological services. There is considerable debate over the diagnosis of PCS in part because of the medico-legal and thus monetary ramifications of receiving the diagnosis.
Common symptoms associated with a diagnosis of PCS are related to cognition,[19] attention,[20] and memory, especially short-term memory, which can also worsen other problems such as forgetting appointments or difficulties at work.[12] In one study, one in four people diagnosed with PCS continued to report memory problems a year after the injury,[12][21] but most experts agree that cognitive symptoms clear within six months to a year after injury in the vast majority of individuals.[12]
The prognosis for PCS is generally considered positive, with total resolution of symptoms in many, but not all, cases. For 50% of people, post-concussion symptoms go away within a few days to several weeks after the original injury occurs.[22] In others, symptoms may remain for three to six months,[19] but evidence indicates that many cases are completely resolved within 6 months.[12] The majority of symptoms are largely gone in about half of people with concussion one month after the injury, and about two thirds of people with minor head trauma are nearly symptom-free within three months. Persistent, often severe headaches are the longest lingering symptom in most cases and are the most likely symptom to never fully resolve.[51] It is frequently stated in the literature and considered to be common knowledge that 15–30% of people with PCS have not recovered by a year after the injury, but this estimate is imprecise because it is based on studies of people admitted to a hospital, the methodologies of which have been criticized.[25][46][56] In approximately 15% of people, symptoms may persist for years or be permanent. If symptoms are not resolved by one year, they are likely to be permanent, though improvements may occur after even two or three years,[43] or may suddenly occur after a long time without much improvement.[57] Older people and those who have previously suffered another head injury are likely to take longer to recover.[57]