Objective: Concussive events are often associated with a disturbance in mood and affect. Previous research has suggested that the presence of depression can exacerbate and maintain post-concussive symptoms. Thus, the general level of psychological distress can be a significant factor in evaluating symptoms of post-concussion syndrome. The current study investigated pre- and post baseline assessment of affective symptoms among college varsity athletes to further explore the relationship between concussion, mood, and neuropsychological functioning.

Method: Of the 1,400 student-athletes participating in this multi-site study, 50 subjects acquired a concussion over the past season. Baseline pre-concussive symptoms were compared to baseline post-concussive presentation using the Immediate Post-Concussion Assessment Test (ImPACT©). Additionally, post-concussive symptoms were compared longitudinally across multiple post-concussive testing as well as to neuropsychological functioning.

Results: MANOVA revealed significant interaction effects for affect and neuropsychological presentation. Concussed athletes were more likely to endorse symptoms of emotional distress compared to those athletes who did not sustain a concussion. An additional MANOVA resulted in no significant difference between symptoms of emotional distress and the length of time associated with a recovery from a concussion. There were no differences among symptoms of mood and gender.

Conclusion: The current study suggests that post-concussive symptoms associated with a disturbance of mood are more prevalent in collegiate athletes who have sustained concussive injuries than those who have not. The interaction of mood, sports-related concussion, and neuropsychological performance will be discussed.

Statistics and Definitions
Approximately 3 to 5 million athletic injuries occur in the United States each year (Brewer, 1994) of which, an estimated 9% result in concussions (Klossner & Schluep, 2002; McKeever & Schatz, 2003). Athletic head injuries account for approximately 20% of all concussions reported annually in the United States (McKeever & Schatz, 2003).

Concussion, or mild traumatic brain injury, has been defined as head trauma caused by sudden deceleration and acceleration of the head resulting in a brief loss or alteration in consciousness and the immediate and transient impairment of neuropsychological functioning (Rubenstin, 1993). Although concussions may result in the loss of consciousness, the majority of concussions occur without any loss of consciousness (Kelly, 1999).

According to the National College Athletic Association (NCAA), of all reported injuries, women's lacrosse players (13.9%) reported the highest percentage of concussions during a game, followed by women's soccer (11.4%), men's ice hockey (10.3%), men's lacrosse (10.1%), football (8.8%), women's baseball (8.5%), field hockey (7.2%), men's soccer (7.0%), wrestling (6.6%), men's basketball (5.0%), men's baseball (4.2%), and women's volleyball (4.1%) (Klossner & Schluep, 2002). During athletic activity, concussions can result from direct trauma to the head or from indirect trauma to the head during collisions, falls, or other athletic activities if sufficient force is applied in a ÒwhiplashÓ mechanism (Kelly & Rosenberg, 1998).

Post-concussion Syndrome
Head injury generally results in a combination of physical, cognitive, and emotional symptoms making up the post-concussion syndrome (Bennett & Raymond, 1997). Specifically, physical symptoms of mild head injury include headache, vertigo (Bennett & Raymond, 1997), fatigue, tinnitus, blurred vision, nausea, vomiting (Wojtys, Hovda, Landry, Boland, Lovell, McCrea, & Minkoff, 1999; Mittenberg, DiGiulio, Perrin, & Bass, 1992), ringing in ears, and hypersensitivity to noise (Binder, 1997). Furthermore, individuals with head injury frequently complain of cognitive difficulties including disorientation, memory problems, reduced reaction time, difficulty sustaining attention, and impaired information processing (Bennett & Raymond, 1977; Mittenberg et al., 1992). Moreover, depression, anxiety, irritability, disinhibition, reduced self-esteem and self-concept (Bennett & Raymond, 1997), obsessional symptoms (McClelland, 1988), and temper problems (Binder, 1997) also occur as a result of concussion.

Neuropsychological deficits associated with mild head injury appear to emerge within the first few days following the injury (Levin, Mattis, Ruff, Eisenberg, Marshall, Tabaddor, High, & Frankowski, 1987) with an estimated 50% to 80% of head injured individuals reporting more than one symptom (Wright & Telford, 1996; McAllister, 1994). Although the majority of symptoms generally resolve immediately following the injury, a few symptoms persist for weeks to months (Wojtys, et al., 1999). Additionally, although some individuals may continue to suffer from neuropsychological and/or psychosocial difficulties up to one-year post injury, these deficits represent a decline from symptoms reported up to one-month following the injury (Dikmen, et al., 1986; Kelly, 1999). Numerous factors including advanced age, premorbid psychological status, education level, previous head injuries (Binder, 1997), neurological impairment, neuropsychological deficits, physical difficulties, and compensation may explain why some symptoms persist in some individuals and not in others (Dimken, McLeans, & Temkin, 1986).

Affective disorders, of which the most common is depression, are very common following mild traumatic brain injuries (Saul, 1993; Gualtieri & Cox, 1991). Research suggests that emotional changes following head injury are due to both the direct and indirect effects of brain trauma (Prigatano, 1997; Alves, Macciocchi, & Barth, 1993). Neuroimaging has demonstrated that concussion results in identifiable macroscopic central nervous system lesions (Alves, et al., 1993) to the frontal and temporal lobes, regions generally associated with personality and psychological functioning (Bennett, 1989; Rubenstin, 1993). Research shows that damage to the frontal lobes is associated with behavioral changes including social inappropriateness, impulsivity, depression, flat affect, indifference, apathy, and difficulty initiating and completing activities (Bennett, 1989; Rubenstin, 1993). Furthermore, lesions to the temporal lobes result in heightened emotionality including irritability, angry outbursts, and "feeling more deeply" (Bennett, 1989).

Although mild head injury may directly influence psychological impairment, the possibility that emotional distress is a secondary response to the difficulty resuming premorbid activity cannot be ruled out (Diamond, Barth, & Zillmer, 1988). Concussion results in a myriad of cognitive and physical symptoms, which may compromise an individual's ability to function at his or her premorbid level resulting in frustration, which may in turn result in depression, irritability, anxiety, the loss of one's self-esteem (Bennett & Raymond, 1997; Prigatano, 1997; Wright & Telford, 1996) and the loss of the former self (Saul, 1993). Additionally, factors such as bereavement, job loss, financial difficulties, marital problems, divorce, and personal or family illness may increase one's risk of psychiatric illness following head injury (Binder, 1997).

Emotional disturbances may result from reactions to the trauma itself. Feelings of anxiety, fear, and shock result from being involved in a sudden, unexpected traumatic event (Rubenstein, 1993). Furthermore, research suggests that athletes experience feelings of depression, anger, fear, tension, disgust, panic, and anxiety when injured (Lynch, 1988).

Objective:
The purpose of the present study was to investigate the relationship between concussion, psychological functioning, and neuropsychological functioning. The present study investigated (a) the immediate influence of concussion on psychological and neuropsychological functioning and (b) the recovery patterns of psychological and neuropsychological functioning following a concussion.

Methods:
Approximately 1,400 student-athletes from five universities in the Delaware Valley (Drexel University, Rutgers University, St.Joeseph's University, Temple University and the University of Delaware) participated in baseline and post-concussion testing on the Immediate Post-Concussion Assessment Test (ImPACT©). Of the 1,400 student-athletes participating in this multi-site study, 32 athletes acquired a concussion over the 2002-2003 season.

In order to investigate the relationship between concussion, psychological functioning, and neuropsychological functioning, several analyses were conducted. (a) Baseline pre-concussive psychological symptoms were compared to post-concussive presentation using ImPACT©. These symptoms included irritability, sadness, nervousness, and emotionality. Student athletes indicated on a Likert scale (0-6) how much they were currently experiencing each symptom. (b) Furthermore, baseline pre-concussive neuropsychological functioning (verbal memory, visual memory, processing speed, reaction time, and impulse control) was compared to post-concussion neuropsychological functioning using ImPACT©. (c) Moreover, post-concussive symptoms were compared longitudinally across multiple post-concussive testing (0-48 hours, 2 days-5 days, and 5days-10 days). (d) Finally, post-concussion presentation was compared to baseline presentation to determine whether any impairment in psychological and neuropsychological functioning resolved.

Results:
A paired-samples t-test was conducted to evaluate the immediate effects (0-48 hours) of concussion on student-athletes' psychological and neuropsychological functioning. There were no statistically significant differences in symptoms of irritability (p = 0.103), sadness (p = 0.361), nervousness (p = 0.094), and emotionality (p = 0.677) from baseline to 48 hours following a concussion. Neuropsychological presentation revealed statistically significant differences in reaction time (p = .012), verbal memory (p = 0.001), and visual memory (p = 0.001) from baseline to 48 hours following concussion, and no significant differences in processing speed (p = 0.071) and impulse control (p = 0.110) from baseline to 48 hours.

A one-way repeated measures ANOVA was conducted to investigate the psychological and neuropsychological recovery patterns post-concussion. Results indicate a significant effect for symptoms of irritability (p = 0.020), but not sadness (p = 0.161), nervousness (p = 0.138), and emotionality (p = 0.059) across time (0-48 hours, 2-5 days, 5-10 days). Furthermore, results indicate significant effects for reaction time (p = 0.004), visual memory (p = 0.037), and processing speed (p = 0.009), but not impulse control (p = 0.129) and verbal memory (p = 0.434) across time.

A paired-samples t-test was conducted to investigate whether there was a significant difference in psychological and neuropsychological presentation at baseline compared to 2-5 days and compared to 5-10 days post concussion. Results indicate no statistically significant differences in psychological presentation (p > .05) between baseline and 2-5 days and between baseline and 5-10 days post concussion. Furthermore, results indicate no statistically significant differences (p > 0.05) between baseline and 2-5 days post concussion and between baseline and 5-10 days post concussion (p > 0.05) for reaction time, processing speed, and impulse control. However, results revealed statistically significant differences (p < 0.05) for both visual memory and verbal memory between baseline and 2-5 days and between baseline and 5-10 days post concussion.

Conclusion:
The current study suggests that neuropsychological effects of concussion appear to be more pronounced than the impact on psychological functioning. The present study revealed immediate (within 48 hours of concussion) impairments in verbal memory, visual memory, and reaction time due to concussion. Furthermore, while the present study revealed that impairments in reaction time returned to pre-morbid levels within 2-5 days post concussion, impairments in verbal memory and visual memory did not return to baseline levels within 5-10 days indicating that these deficits may take longer to resolve. These results are consistent with previous literature which indicates that cognitive deficits are among the immediate symptoms of concussion (Wojtys et al., 1999). Furthermore, research suggests that mild head injury sequelae are relatively short lived, however, recovery rates have been reported to range from as long as 10 days to more than 1-year (Gunstad & Suhr, 2002).

Psychological functioning was not significantly impaired up to 10 days in the present study. Several explanations may account for these results. First, studies suggest that symptoms such as fatigue, irritability, anxiety, depression, and sleep disturbances tend to emerge several days or weeks following the trauma (Kelly & Rosenberg, 1998). Thus, samples of psychological functioning taken across a longer period of time may reveal more symptoms of psychological distress. Secondly, research suggests that athletes may be hesitant to report symptoms concussion as this would be seen as a sign of weakness and may result in the loss of playing time, position, or scholarship, in addition to letting down the team, coaches, school, and scouts, and being seen as a failure by oneself, friends, family, and fans (Levin book, 1989; Wojtys et al., 1999). Accordingly, the student athletes may have denied psychological distress to avoid possible negative consequences. Finally, the symptom check list indicated by ImPACT may not be sensitive enough to detect symptoms of psychological distress.

Today, more than ever, individuals are participating in competitive sports. Furthermore, there are approximately 300,000 sport related concussions annually and as participation in competitive sports continues to increase, this figure will rise making sports-related concussions a significant potential health concerns to all those participating in contact sports (Zillmer, 2003). Thus, it is imperative that future research be conducted to promote a greater understanding of psychological and neuropsychological distress related to concussion.

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