published_or_final_version / Clinical Psychology / Doctoral / Doctor of Psychology

Two anthropometric measurements were evaluated as possible risk factors for concussions among university contact-sport athletes: head and neck circumference ratio (HNCR) and body mass index (BMI). Athletes (N=575) competing in intercollegiate football, hockey, and soccer were followed prospectively for concussions over a 4-year period. A total of 86 concussions occurred, with a higher incidence among the female athletes. For HNCR, there was no consistent association observed with the exception of female hockey players. For BMI, there was no consistent association observed with the exception of male soccer players. Linear regression analysis revealed a statistically significant inverse association between HNCR and BMI among concussed athletes for both genders (p<0.001). In conclusion, the novel HNCR was found to be a valid and reliable measurement ratio that may have potential clinical applications in predicting the risk of sustaining a concussion among contact-sport athletes.

Diss. (sammanfattning) Umeå : Umeå universitet, 2006. / Härtill 3 uppsatser.

M.A. (Psychology) / The Post Traumatic Amnesic Syndrome, which follows a mild closed head injury, seems to be a common occurrence in the field of neuropsychology. The syndrome is primarily characterised by a transient memory loss of daily events, normally commencing within days after the injury. The symptoms include absent-mindedness, an inability to remember names, dates, numbers and faces, commands and orders given at work. Due to the relatively uncomplicated nature of a mild closed head injury, the syndrome is often overlooked and underestimated in terms of its intensity and psychological damage. Patients are sent home after a brief observation period and medical staff are of the opinion that the patients will recover successfully, without experiencing much psychological or cognitive strain. It is usually thought that the syndrome does not last for more than three to four months. The aim of the research was to determine the nature of the experience of not being able to remember daily events, as part of the post traumatic amnesic syndrome. The influence of the syndrome on the patients' support persons was also investigated

No description available.

The prevalence of injuries from improvised explosive devices (IEDs) in recent U.S. military conflicts has highlighted the lack of knowledge of the acute and long-term consequences of blast exposure. Real-world blast exposure is complex and multi-phasic. It is unclear whether the shock wave component of blast exposure (primary blast) can cause traumatic brain injury (TBI); however, other blast components, such as tertiary blast (inertial loading mechanics), have known potential to injure the brain. Clinical and in vivo studies suggest that complex blast loading of the whole body and head can result in acute and delayed behavioral deficits and neurodegeneration, yet tertiary blast exposure or injury to the body can initiate a systemic response that complicates understanding of this pathology. To set safe thresholds for primary blast exposure and design headgear that can guard against primary blast, tolerance criteria for primary blast specific to brain must be defined. We developed and validated a model of primary blast injury for use with in vitro organotypic hippocampal slice cultures (OHSCs) and determined that primary blast without concomitant tertiary blast loading or systemic response can injure isolated brain samples. This work was the first to define a cell death tolerance criterion for OHSCs to primary blast and report that the threshold for deficits in neuron function was below the threshold for cell death. Mild TBI (mTBI) or concussion, by definition, results in an altered mental state that can include loss of consciousness (LOC) for less than 30 minutes, dizziness, confusion, and retrograde amnesia. These symptoms typically subside within a week after injury; however, for some patients who experience multiple concussions over a relatively short period, these symptoms can persist for a year or longer; persistence of mTBI symptoms is called post-concussion syndrome (PCS). Studies suggest an initial mechanical trauma to the brain can initiate a period of time during which the brain is more vulnerable to additional injury. Little is known about this phenomenon; therefore the current standard of care for patients suffering from concussion is rest and removal from activities with a risk of additional brain trauma. During combat deployment, over 89% of service members reported an incidence of altered mental state and over 86% reported LOC following 2 or more exposures to blast. We evaluated the response of OHSCs to repetitive primary blast (shock wave loading) and repetitive tertiary blast (stretch injury) separately, characterizing the period of vulnerability that follows an initial insult to define safe rest-periods after blast-exposure and better understand pathologies of more complex injuries, i.e. combined primary and tertiary blast. Long-term potentiation (LTP) was significantly reduced by 2 primary blast exposures delivered 24 hours apart. An initial shock wave exposure increased tissue vulnerability to subsequent exposure, which lasted as long as 72 hours but not longer than 144 hours. Repetitive primary blast exposure also increased microglial activation. Similarly, a single mild stretch injury initiated a period of heightened vulnerability to subsequent mild stretch that lasted at least 72 hours but not longer than 144 hours long. Repetitive stretch injury significantly increased cell death, nitrite concentration, and astrogliosis and significantly reduced LTP. We also tested delayed administration of memantine as a treatment for repetitive stretch injury. Memantine is approved by the Food & Drug Administration for the treatment of Alzheimer’s disease, and preclinical studies suggest memantine may be neuroprotective following TBI. Cell death was reduced and LTP was rescued by delayed memantine treatment. Along with further preclinical and clinical investigation of repetitive primary and tertiary blast exposure, these studies may aid in setting safe rest periods and identifying new therapies for service members exposed to blast. This research has shown that primary and tertiary blast exposure can injure OHSCs causing cell death, altering neuron function, and increase vulnerability to a subsequent exposure. These studies expand our understanding of the neuropathology of primary and tertiary blast loading and evaluate methods to improve outcome after repetitive injuries with complementary strategies including rest periods and drug-treatment.

Graduation date: 2006

Many athletes and spectators believe that experiencing and controlling psychological momentum is a critical component to achieving success in sport (Perreault, Vallerand, Montgomery, & Provencher, 1998; Stanimirovic & Hanrahan, 2004). Despite this, little is known regarding why some individuals perceive momentum differently than others. This study was designed to determine if optimistic thinking has a relationship with psychological momentum perceptions. Female Division I NCAA volleyball players (N = 68) completed the Life Orientation Test – Revised (Scheier, Carver, & Bridges, 1994), the Sport Attributional Style Scale - Short (Hanrahan & Grove, 1990b), and a psychological momentum survey. The results indicated that attributional style constructs intentionality and globality were significant predictors of psychological momentum perceptions. Also, participants had greater disagreement regarding the momentum value of early and late points in a set than those in between. Neither dispositional optimism nor sport-specific optimistic attributional style were correlated with psychological momentum perceptions. Future attempts to measure psychological momentum perceptions should consider a mixed methods approach along with more ecologically valid assessment protocols. / Department of Psychological Science

The effects of repeated mild concussive head injury on professional rugby players were examined. Data were collected for rugby players (n=26) and cricket player controls (n=21) using a comprehensive neuropsychological test battery comprising five modalities (Verbal Memory, Visual Memory, Verbal Fluency, Visuoperceptual Tracking and Hand Motor Dexterity) and a self-report Postconcussive Symptomology Questionnaire. Group statistical comparisons of the percentage of individuals with deficit were carried out for (i) rugby versus cricket; (ii) rugby forwards versus rugby backs; and (iii) rugby forwards versus cricket. Rugby players performed significantly poorer than controls on SA W AIS Digit Symbol Substitution subtest and on the Trail Making Test. On Digits Forward and Digit Symbol Incidental Recall, the results approached significance with the rugby players showing a tendency toward impairment on these tests. Rugby players exhibited impairment in areas of visuoperceptual tracking, speed of information processing and attention, and there are tendencies of impairment in verbal and/or visual memory. Results obtained on the self-report questionnaire strongly reinforced cognitive test results and a significant proportion of rugby players reported difficulties with sustained attention, memory and lowered frustration tolerance as well as symptoms of anxiety and depression. It was consistently noted that players in the more full contact positions (rugby forwards) were most susceptible to impairment, confirming that these players, who are exposed to repeated mild head injuries, are at greater risk of exhibiting postconcussive sequelae.

The effects of repeated mild concussive head injury on professional rugby players were examined. Data were collected for rugby players (n=26) and cricket player controls (n=21) using a comprehensive neuropsychological test battery comprising five modalities (Verbal Memory, Visual Memory, Verbal Fluency, Visuoperccptual Tracking and Hand Motor Dexterity) and a self-report Postconcussive Symptomology Questionnaire. Group statistical comparisons of the percentage of individuals with deficit were carried out for (i) rugby versus cricket; (ii) rugby forwards versus rugby backs; and (iii) rugby forwards versus cricket. Rugby players performed significantly poorer than controls on SA W AIS Digit Symbol Substitution subtest and on the Trail Making Test. On Digits Forward and Digit Symbol Incidental Recall, the results approached significance with the rugby players showing a tendency toward impairment on these tests. Rugby players exhibited impairment in areas of visuoperceptual tracking, speed of information processing and attention, and there are tendencies of impairment in verbal and/or visual memory. Results obtained on the self-report questionnaire strongly reinforced cognitive test results and a significant proportion of rugby players reported difficulties with sustained attention, memory and lowered frustration tolerance as well as symptoms of anxiety and depression. It was consistently noted that players in the more full contact positions (rugby forwards) were most susceptible to impairment, confirming that these players, who are exposed to repeated mild head injuries, are at greater risk of exhibiting postconcussive sequelae / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in