The study of the effects of concussions on cognitive and physical performance is a fairly new area of concentration that is gaining rapid attention in fields of health care and clinical research (Ferguson, Mittenberg, Barone, & Schneider, 1999).  It is estimated that anywhere from two thirds to three fourths of head traumas are attributed to concussions, and up to 325,000 concussions are treated in hospitals each year (Ferguson et al., 1999).
    In such cases as previously noted, symptoms are so pronounced it is clear to the injured person he or she is in need of advanced medical assistance, and a concussion has in fact occurred.  In other cases where symptoms are not quite as pronounced one may not seek medical care. This latter situation leaves health care providers and researchers with the question of how many concussions go unreported each year. The benefit of knowing how many concussions occur each year is that health care providers and researchers would be able to track both short term and long term effects of concussions on performance.
    Barnes and colleagues (1998) defined a concussion as any hit or blow to the head resulting in a neuropsychological change in the brain.  While functioning can be altered for a few seconds, it can also be altered for the rest of one’s life.  The difference between these two situations (and anything in between) is that concussions have different levels of severity. It is because of these differences within each concussion that people are asking, what is a concussion and what exactly are its effects?

The problem of determining a concussion’s occurrence

    There is confusion as to when a concussion has occurred, because we rely heavily on self reported symptoms.  It is a combination of symptoms which allow us to decide the severity of neuropsychological change, and the estimated time needed for recovery before resuming any normal activities (Boden, Kirkendall, & Garrett, 1998).
    Contrary to the popular belief that all concussions must result in unconsciousness, only 10% of concussions have this symptom (Harmon, 1999).  This problem leaves sports trainers asking, what exactly is a concussion, and what are the guidelines for determining its occurrence?
    In 1986 the American College of Sports Medicine adopted guidelines that have become widely used (Harmon, 1999). Since 1986 revisions have been made to create new guidelines posted by the Colorado Medical Society, then by the National Collegiate Athletic Association (NCAA) and most recently by the American Academy of Neurology (AAN) (Harmon, 1999).
    Gram (2000) described symptoms as including (but not limited to) headache, disorientation, dizziness, nausea, vomiting, slurred or incoherent speech, lack of coordination, emotional outbursts, short term memory loss, loss of consciousness, light sensitivity and sound sensitivity.  When only a few of these symptoms are present after a blow to the head it may sometimes be difficult to determine whether a concussion actually occurred or if these symptoms are just the result of an “initial shock”.  To clarify the difference between shock and an actual occurrence of a concussion, levels have been set to explain differences within concussions.

Levels of concussions

    It is important to note that there are different levels of concussions: severe, mild, and acute (Harmon, 1999). Depending on several factors such as how hard you were hit, how many times you’ve been hit and if there was loss of consciousness (and for how long if so) will help determine how severe or how acute a concussion is (Boden et al., 1998).

Severe concussions and long term effects

    A severe concussion is a combination of three or more of the above noted symptoms [see Gram (2000)] in addition to a loss of consciousness for greater than five minutes and post traumatic amnesia up to twenty-four hours after the initial injury (Boden et al., 1998). In situations such as this, advanced medical care is needed.
    Once a determination of a severe concussion’s occurrence has been made, one must consider the consequences of such a hit.  Effects of one severe concussion (or of repeated blows to the head) may lead to long term damage to one’s reasoning ability, memory, attention span, planing ability, sleep and concentration (Gram, 2000).  In several cases, death has occurred when severe force and pressure (due to a concussion) has been placed upon the brain (Ryan, 1997).
    In instances where concussions have led to death, most often it is by way of second impact syndrome. When brain fluid still swells in the skull, a second impact results in too much fluid pressure in the head and death occurs (Ryan, 1997). Ryan (1997) noted “In 1991, a Colorado high school halfback died on the field after sustaining two concussions in a week. Neither had knocked him unconscious.  The player died after the second concussion from extreme swelling of the brain.  Since then at least four high school players and one college player have died from second impact syndrome” (39).
    Second impact syndrome is most common in young athletes who have received a hit or blow to the head, while still in the recovery stage of a first concussion. The chances of death happening are found to be greater the younger one is when he or she receive a concussion, and the greater the number of concussions one has had (Capruso & Levin, 1992). Its been observed by Williams of the Kerlan-Jobe Sports clinic in Los Angeles that athletes are four to six times more likely to have a second concussion after having a first (Gram, 2000).
    Another area of concern that should be considered when looking at long term effects of a concussion are the symptoms associated with post concussion syndrome.  This clinical diagnosis is given when a cluster of symptoms remain prevalent in an individual well after injury has occurred.
    Symptoms of the working diagnostic criteria (according to Axelrod, Fox, Lees-Haley, Earnest, Dolezal-Wood, & Goldman, 1996) include having a history of concussions with at least three of the following self-reported symptoms: fatigue, disordered sleep, headache, dizziness, irritability, anxiety-depression, personality change, and anhedonia.  Where concussion symptoms usually last about a week, but usually no more than one to three months, this diagnosis is given after a prolonged period of time of experiencing concussion symptoms (Capruso & Levin, 1992).  Post concussion syndrome is classified by The Diagnostic and Statistical Manual of Mental Disorders IV (1994) as a set of working criteria, and suggests the category is in need of additional research (APA, 1994).

Mild concussions and short term effects

    Between an acute concussion and a severe concussion is a mild concussion.  In a mild concussion one has lost consciousness for some amount of time less than five minutes, and also has had amnesia (less than thirty minutes)(Boden et al., 1998).  As with severe concussions, mild concussions must too have at least three of the defining symptoms outlined by Gram (2000).
    This second category of concussions is where a person may say with certainty that he or she has received a concussion, but often fails to seek advanced medical attention.  It is because of the failure to properly report a concussion’s occurrences during mild and acute levels, health care providers cannot say with certainty exactly how many concussions occur per year.
    In instances where a concussion is mild, short-term effects are fairly obvious (headache, dizziness, vomiting, lack of coordination and possible amnesia) (Gram, 2000). Unfortunately information remains unclear as to what the long term effects of a mild concussion may be.  A study by Hugenholtz, Stuss, Stethem, and Richard (1988) suggests that perhaps there may be a correlation between mild concussions and performance in attention, information processing, and reaction time.

Acute concussions and unknown effects

    Like severe and mild concussions, acute concussions must meet three or more of the symptoms described by Gram (2000).  In acute concussions there is no loss of consciousness and if there is amnesia it is for less than thirty minutes (Boden et al., 1998).
    While acute concussions do not lead to death, there is still the possibility of deficits occurring in cognitive functioning post injury.  Acute concussions are the most common type of concussion (Boden et al., 1998). Frequent symptoms at this level are headache and disorientation (Boden et al., 1998).  Other symptoms include dizziness, dazed, blurred vision, brief amnesia, and nausea.
    The overall difference between severe, mild, and acute concussions (with regard to the same symptoms they share) is the number of prevalent symptoms at one time, and the duration and intensity of these symptoms (Hugenholtz et al., 1988).  Because some symptoms at this level last for a relatively short period of time, acute concussions often go unnoticed.
    Fletcher, Ewing-Cobbs, Miner, Levin, and Eisenberg (1990) defined acute concussions as having no evidence of mass lesion, no deterioration of consciousness, and no brain swelling or skull fracture after initial injury.  In a study by Ferguson and colleagues (1999), findings showed acute concussions do not appear to cause persistent memory impairments or problems compared to an uninjured population.  The only significant difference between those who did not have a concussion history and those who had experienced an acute concussion was an increase in self-reported headaches.
    In summary, it appears a severe concussion leads to long term effects in multiple areas of functioning (i.e. reasoning, memory, attention and personality). Mild concussions have short-term consequences and possibly some long term damage in areas of concentration, reaction time and information processing.  Acute concussions have little if any long term effects on cognitive or physical functioning, but occurrences self-report of disorientation and headaches seem to be significantly greater than the uninjured population.

Why attention, memory, and intelligence?

    Regardless of a concussion’s severity, no research was found to report positive effects of a concussion.  Some perplexing questions being asked about concussions today are how concussions affect attention, intelligence, and memory (Finn, Eddy and Vossmer, 2000).  This area of research is of much concern to the college student because, to a great extent, attention, memory and intelligence are what determines one’s academic success.
    Ryan (1997) hypothesized that accuracy in these areas may deteriorate when one receives a concussion because nerve fibers are being damaged by rapid twisting of the upper cerebrum.  Finn (personal communication, November 14, 2001) noted several traumas associated with neural shearing are due to rapid acceleration/deceleration during a concussion.  Repeated occurrences of this (as in full contact sports like football and soccer) is what leads to more damage than if one was to only have a temporary disruption in electroactivity (Ryan, 1997).

Attention

    Attention has a profound effect on the completion of everyday tasks (i.e. getting out of bed, feeding oneself, getting to and from work) as well as on academically related cognitive functioning tasks (i.e. solving math problem, reading and writing). The ability to focus one’s attention on a particular activity, and sustain that attention, is a process humans learn at a young age and modify over a lifetime (Bernstein, Clarke-Stewart, Penner, Roy & Wickens, 2000).  By compromising one’s attention capacity through injury, challenges can be faced in completing both everyday tasks and academically related cognitive functioning.
    While attention deficits may result from injuries, this type of loss is not considered to be ADHD.  ADHD is a clinical diagnostic disorder with specific criteria that must be met (discussed in section headed Attention Deficit Disorder).  Injuries may consequently cause a loss of focused attention.  This focus of attention loss can be detected using ADHD scales and that is why one might choose to use attention deficit tests to observe the effects a concussion may have on the focus of attention post injury.
    Attention has a close relationship to memory in that memory often requires careful focus of attention for retention to occur.  Through the development of attentional skills humans are able to use strategies to enhance their information retention (these strategies will be addressed in the section headed Memory).  If one fails to acquire this ability of attention control, the effects are referred to as Attention Deficit Hyperactivity Disorder (ADHD)(Bernstein et al., 2000).
   In a study by Monteil, Marc, Brunot and Huguet (1996) results found students who have the ability to focus their attention on a particular task are more apt to accomplish that task in ample time and with more accuracy than those with ADHD. It is also with a loss of focused attention (due to injury) that one may experience similar performance effects as a person with ADHD.

    Attention Deficit Hyperactivity Disorder.  ADHD is diagnosed according to criteria presented by the Diagnostic and Statistical Manuel IV (APA, 1994).  Attention Deficit Hyperactivity Disorder can be inattentive type, impulsive type or a combination of both. Regardless of the type of attention deficit, all individuals diagnosed must have at least six [specified in the DSM-IV (1994)] symptoms or more, and the symptoms must persist for six months or more.  Diagnosis for impairment in attention must be present before the age of seven and must be present in two or more settings (e.g. school, home, work). Lastly, there must be clear evidence of impairment in social, academic or occupational functioning.

    Testing for Attention Deficit Disorder.  When testing for attention deficit, some tools specialists use are Symbol Digit Modalities Test, simple and choice reaction-time tasks, color naming and word reading on the Stroop and the Paced Auditory Serial Addition Test (Ponsford and Kinsella, 1992). With the use of these tools, researchers are able measure information processing, divided attention, focused attention and performance consistency (Stuss, Stethem, Hugenholtz, Picton, Pivik, & Richard, 1989).
    Speed of processing is one of the most successful tools in assessing attentional stability.  Among one of the most reliable and valid tests used for assessing ADHD (both in clinical and non-clinical settings) is the Connors’ Continuous Performance Test II (Conners, 1995).  While this is a widely used test, there are also other less time consuming tests which measure ADHD with a fair amount of accuracy.  One such test is the Jasper/Goldberg ADHD Scale (Jasper & Goldberg, 1992).
    Even without meeting the diagnostic criteria for ADHD, any slight deficit or decline in this area of concentration and focus can be picked up by the previously mentioned attention tests.  Whether clinically diagnosed ADHD, or accident induced loss of focused attention the average student’s academic performance can be altered a great degree by affecting our sustained attentional capacity.  It is therefore important to avoid injuries to the head in order to maintain maximum attentional focus at any educational level.

Memory

    Memory is the ability to remember information taken in through our senses and is processed for the purpose of later recall (Bernstein et al., 2000). Sensory information is first placed into short-term memory and later moved to long term memory if cognitive processing allows.
    Immediate memory is that which we take in through our senses and hold for approximately thirty seconds. Consequently, any information remembered for longer than thirty seconds (and possibly up to the rest of one’s life) is considered to be long term memory (Bernstein et al., 2000).
    Bebko and Ricciuti (2000) have noted the use of strategies significantly improves memory recall. Strategies noted by Berk (1997) include taking notes, using calendars, using landmarks, rehearsal, systematic organization (or categorization), and elaboration techniques.
    Memory is important for academic success in many ways.  In a study done by Vaquero and Rojas (1996) researchers found the use of models for information processing predicted better overall academic performance in university level students.
    Unfortunately when a hit or blow to the head (either through sports or by way of accident) damages the brain’s functioning, information processing (working memory, structural mental capacity, functional mental capacity and formal operational reasoning) often deteriorates.
    Examples of standard tests used to evaluate memory damage and functioning include three word memory and “serial sevens” (Harmon, 1999). While these tests are used to look at immediate memory damage, there are also more detailed tests, such as the Wechsler Memory Scale-third edition, which measure memory on eleven subtests, six primary tests, and five optional tests. (Wechsler, 1997).

Intelligence

    Intelligence is frequently described in terms of IQ (other wise known as an intelligence quotient) (Bernstein et al., 2000).  This single quotient is best thought of as a stable characteristic remaining constant over the course of one’s lifetime.
    When testing intelligence, predictability is essential to each test’s validity.  While an IQ score does give a global idea of one’s intelligence, it is important to note actual intelligence capacity is never fully expressed in a single number. Intelligence tests should measure practical problem solving abilities, verbal abilities, and social competence (Beck, 1997).

    Some intelligence tests commonly used today include the Stanford-Binet, the Kaufman ABC and the Wechsler Intelligence Scale (WIS).  Because these tests can be time consuming to administer, measures such as the North American Adult Reading Test (NAART) offer a brief alternative to global, verbal IQ (Spreen & Stratus, 1998).
    It is with the use of these and many other unmentioned tests that health care providers are able to detect learning disabilities, locate specific areas of memory loss and measure the magnitude of accident induced deficits such as concussions.
 

Summary

    Given the literature on concussions, attention, memory and intelligence, it could be expected that if one receives a significant blow to the head (i.e. a concussion) he or she may acquire deficits in specific areas of functioning (i.e. attention and memory), possibly leading to an overall drop in intelligence.  Hence, academic performance would consequently drop as well.

Hypothesis

    The current study investigated individuals who have a history of self-reported concussions, and compared their test scores (in attention, memory and intelligence) to individuals who report no history of concussions. The hypothesis (given demonstrated literature) suggested those individuals with a history of concussions would do more poorly in these selected cognitive performance areas than those who have not had a concussion.

Further basis for hypothesis

    In a study done by Finn, Eddy and Vossmer (2000), it was found that twenty-eight out of twenty-nine randomly selected football players had had at least one or more self-reported concussions.  The question regarding concussion history was used as a covariate to rule out possible dysfunctions in the student athlete’s sleeping, eating and study patterns.  The researchers made reference to the need for further investigation in the area of concussions. Suggestions were made to focus particularly on how concussions may affect multiple regions of functioning (specifically factors relating to academic performance).  This study will use attention, memory and intelligence along with SAT scores and current grade point averages to test for differences in functions between those who have had concussions and those who have not.