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PubMed2002

Is head injury a risk factor for schizophrenia?

BACKGROUND: The few studies that have examined whether head injury is a risk factor for later schizophrenia have had important methodological problems. METHOD: We examined the rates of head injury among 8288 persons in the 15 years up to their first admission with schizophrenia and compared them with 82880 age- and gender-matched controls. We used hospitalization for concussion or severe head injury as a definition of head injury. We controlled for any generally altered accident proneness prior to schizophrenia by also comparing the groups with respect to exposition to fractures not involving the skull or spine. RESULTS: Males with schizophrenia had significantly reduced exposure to concussion (OR = 0.864, p = 0.024), whereas females had significantly increased exposure (OR = 1.322, p = 0.025). No differences were found as regards severe head injury. Males had significantly reduced risk of other fractures (OR = 0.616, p < 0.0001), whereas the risk in females did not differ from controls (OR = 1.154, p = 0.189). After adjusting head injury with the risk for other fractures, both concussion and severe head injury were significantly increased in males (OR = 1.501, p < 0.001 and OR = 1.516. p < 0.001, respectively) but not in females (OR = 1.15, p = 0.413 and OR = 0.819, p = 0.442, respectively). CONCLUSION: Our results do not exclude that for males, head injury may contribute to the risk for schizophrenia in a limited number of cases. This relation may also exist for females, but it is paralleled by an increased liability to traumas in general. Premorbid general accident proneness requires consideration when studying this association.

Accident Proneness↗
PubMed1993

Hypnosis and attention deficits after closed head injury.

In a controlled study of patients attending a concussion clinic because of ongoing postconcussion symptoms, attention deficits were recorded in the head-injured group for the aspects of alertness, assessed by the Continuous Performance Test (CPT), and processing capacity, assessed by a version of the Paced Auditory Serial Addition Test (PASAT). Selective attention was intact. Hypnotizability was assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A), with normal means and standard deviations found in both the concussed and control groups. There was a significant correlation, however, between HGSHS:A scores and PASAT scores in the concussed group only. The results of this preliminary study suggest that slower processing capacity after a closed head injury may predict higher hypnotizability and that hypnosis could be an appropriate rehabilitation technique for these patients who present with postconcussion symptoms.

Adolescent↗
PubMed1984

Neuropsychological sequelae of light head injuries in older children 6 months after trauma.

Fifty-six children, 9-13 years of age, underwent neuropsychological testing 4-8 months after concussion. They were individually matched with a control group on the variables of school grade, sex, and academic achievement. On 29 of the 32 test variables, the results of the control group were superior to those of the experimental group. Analysis of variance showed that the concussion factor explained most of the differences between the groups. The differences tended to decrease with increasing age, and to increase with increasing complexity of the tests. The results indicate that neuropsychological sequelae after concussion may be demonstrated, even when there are few subjective complaints and no perceptible lags in academic achievement.

Adolescent↗
PubMed1991

Cerebrovascular changes in a rat model of moderate closed-head injury.

We have developed and tested a rat (Wistar) model of moderate concussion. Concussion is produced by controlled and repeatable mechanical fixed, closed-head injury. Moderate concussion in this model is characterized by 4 to 10 minutes of unconsciousness, absence of skull fractures or brain contusions, and few, if any, acute neurologic symptoms. By 2 hours postinjury, the subsequent trauma is further characterized by regional and global increases in cerebrovascular permeability and decreases in cerebral blood flow. Such changes are accompanied by brain swelling and two phases of elevated intracranial pressure; one lasting about 5 hours with a peak of about 10 mmHg, the other lasting more than 3 days postinjury with a peak of about 30 mmHg. Regional neurohistologic damage detected between 3 and 4 days postinjury correlates for the most part with earlier changes in regional permeability and blood flow. Significant morphologic changes which are characterized by patchy neuronal degeneration can be found in numerous forebrain locations, particularly in the frontal (coup) and entorhinal (contre coup) cortices. These observations have important parallels in human head trauma and suggest that this reliable physiological model may be a useful, relatively simple and inexpensive tool for investigating the mechanisms and therapeutics of head trauma.

Animals↗
PubMed2005

Analysis of real-time head accelerations in collegiate football players.

OBJECTIVE: To measure and analyze head accelerations during American collegiate football practices and games. METHODS: A newly developed in-helmet 6-accelerometer system that transmits data via radio frequency to a sideline receiver and laptop computer system was implemented. From the data transfer of these accelerometer traces, the sideline staff has real-time data including the head acceleration, the head injury criteria value, the severity index value, and the impact location. Data are presented for instrumented players for the entire 2003 football season, including practices and games. SETTING: American collegiate football. SUBJECTS: Thirty-eight players from Virginia Tech's varsity football team. MAIN OUTCOME MEASUREMENTS: Accelerations and pathomechanics of head impacts. RESULTS: : A total of 3312 impacts were recorded over 35 practices and 10 games for 38 players. The average peak head acceleration, Gadd Severity Index, and Head Injury Criteria were 32 g +/- 25 g, 36 g +/- 91 g, and 26 g +/- 64 g, respectively. One concussive event was observed with a peak acceleration of 81 g, a 267 Gadd Severity Index, and 200 Head Injury Criteria. Because the concussion was not reported until the day after of the event, a retrospective diagnosis based on his history and clinical evaluation suggested a mild concussion. CONCLUSIONS: The primary finding of this study is that the helmet-mounted accelerometer system proved effective at collecting thousands of head impact events and providing contemporaneous head impact parameters that can be integrated with existing clinical evaluation techniques.

Acceleration↗
PubMedDate not supplied

Epidemiologic analysis of injury in five years of Canadian professional rodeo.

Longitudinal studies of rodeo injuries are rare. We prospectively investigated injuries in professional rodeo in Canada over a 5-year period. Our specific interests included injury incidence density in specific rodeo events, risk factors such as past injury, and the incidence of head injury. Of 323 professional rodeos from 1995 through 1999, 63 rodeos provided a convenience sample. These rodeos were selected because the Canadian Professional Rodeo Sport Medicine Team was in attendance at these events, thus providing both competitor health care and data collection. Four hundred fifty-one injuries were reported during 30,564 competitor-exposures. The greatest injury frequency and injury incidence density were in the rough stock events (bull riding, bareback riding, and saddle bronc). Bull riding accounted for the greatest injury frequency (141) and incidence density (32.2 injuries per 1000 competitor-exposures). Bull riding had a relative injury risk of 1.32 when compared with bareback riding; bareback riding had a relative injury risk of 1.39 when compared with saddle bronc riding. Concussions accounted for 8.6% of all reported injuries. Concussions and other head injuries (65) were second only to knee injuries (76) in frequency of injury to specific body parts. This concussion frequency is higher than has previously been reported.

Athletic Injuries↗
PubMed2004

Second-impact syndrome.

Sports-related injuries are among the more common causes of injury in adolescents that can result in concussion and its sequelae, postconcussion syndrome and second-impact syndrome (SIS). Students who experience multiple brain injuries within a short period of time (hours, days, or weeks) may suffer catastrophic or fatal reactions related to SIS. Adolescents are particularly susceptible to the dangers of SIS, and current return-to-play guidelines may be too lenient to protect a student from SIS. Any student with signs of a concussion should receive medical evaluation and not be allowed to return to play in the current game or practice. The role of the school nurse includes being knowledgeable about management of head injuries and return-to-play guidelines, providing follow-up for athletes who have concussions, and providing education on prevention and management of head injuries.

Adolescent↗
PubMed2003

Return to play following sports-related mild traumatic brain injury: the role for neuropsychology.

Cerebral concussions frequently occur at all levels of athletic competition. The effects from these concussions can be transient or may lead to chronic, debilitating symptoms. A growing literature has established that neuropsychological tests are useful in detecting the subtle neurocognitive changes that occur following concussions. The identification of these deficits and subsequent recovery of function can be important components in making return-to-play (RTP) decisions. This article describes the emergence of neuropsychology in sports medicine, discusses the context in which RTP decisions are made, outlines factors that are important to RTP decisions, and presents a model that views the RTP decision as a dynamic risk-benefit analysis that involves complex interactions among variables. It is argued that neuropsychology has a unique, but not exclusive, role in the decision making process. Implications for future research are discussed.

Athletic Injuries↗
PubMed2005

Balance performance with a cognitive task: a dual-task testing paradigm.

PURPOSE: Athletic performance demands simultaneous use of cognitive and postural control capabilities. Decrements to both systems have been observed following concussion. This study evaluated a dual-task methodology to establish the tenability of using this testing model in concussed athletes. METHODS: Nonconcussed subjects were assessed over 2 d. Subjects were introduced to the task-switching cognitive assessment test and a NeuroCom Smart Balance Master postural control assessment protocol on day 1. In the following session, subjects were evaluated on postural control and cognitive function tests independently (single task), and then concurrently (dual task). RESULTS: Significant improvements were seen in three of the four balance conditions and in three of the four reaction times when the cognitive and balance task were performed simultaneously (P<0.05). No significant balance by cognitive task interaction was revealed (P>0.05); however, significant differences existed in reaction time based on stimulus position and increasing balance demands (P<0.05). CONCLUSION: Combining the cognitive and balance assessments resulted in healthy subjects showing improved performance when compared with individual task performance. The dual-task methodology brought about systematic changes to reaction time in relation to increasing balance demands. The ability of this protocol to detect changes in postural control or cognitive function following concussive injury requires further study.

Adult↗
PubMed1998

Mild brain trauma in sports. Diagnosis and treatment guidelines.

Much has been written about the evaluation and management of mild brain trauma in sports. No less than 10 different 'guidelines' have been proposed and published to aid the clinician in the diagnosis of the condition. Too often, these guidelines have creating confusion instead of promoting an understanding of the spectrum of brain injury. As the understanding of the basic science of mild brain injury evolves, so must the approach to the concussed athlete. This article presents an up-to-date and clinically useful approach to the management of the athlete with a mild brain injury. The definition of 'concussion' is discussed and clarified and pertinent epidemiological data which highlight the importance of management skills as applied to athletes in a wide variety of sports are also reviewed. There is really no such thing as a 'mild concussion' if one considers the rare but catastrophic outcome of the second impact syndrome. For this reason, we review and expand upon the mechanisms of injury and pathophysiology. The accurate diagnosis of mild brain injury requires considerable experience, a high index of suspicion, a careful history and a series of examinations of the athlete, and a working knowledge of the athlete's personality and the likelihood of minimising their symptoms. The value of orientation questions pertinent to the athlete is now well established. Any focal neurological deficit or the deterioration of an athlete's condition warrants immediate hospitalisation, brain imaging and neurosurgical consultation. More commonly, athletes present with a brief alteration of consciousness, headache and amnesia and require careful examination and observation before returning to competition. The astute clinician will always err on the side of conservative management. The complete resolution of all symptoms before a return to play is imperative. Computerised tomography is very sensitive in the imaging of mild brain injuries. Neuropsychological testing is also very sensitive in the evaluation of brain injuries in athletes, and may become more clinically useful in the future.

Adolescent↗
PubMed1981

Changes in extracellular potassium concentration in cortex and brain stem during the acute phase of experimental closed head injury.

A high potassium concentration ([K+]o) in brain tissue impedes neuronal activity, as observed in spreading cortical depression. Experimental studies were performed on mice and rats to determine the role of changes of [K+]o in cerebral concussion. In the first experiment, a 600 gm-cm impact was delivered to the vertex of the mouse skull. This impact induced arrest of spontaneous movement for 465 +/- 55.9 seconds (mean +/- SD), accompanied by apnea, bradycardia, and low-voltage electroencephalographic recordings (EEG). The injury was also frequently followed immediately by epilepsy. This impact induced an increase of cortical [K+]o from the control level of 4.1 +/- 1.8 mM to 20-30 mM, with gradual recovery within 30 minutes to the control level. In the second experiment, an impact of 9000 gm-cm was delivered to the midline parieto-occipital area of the rat and produced concussion-like phenomena similar to those elicited in mice. This level of trauma induced a significant increase of cortical [K+]o from the control level of 4.2 +/- 0.8 mM to 20-50 mM in all of the rats, and also a significant increase of brain-stem [K+]o from 3.9 +/- 0.6 to 20-30 mM in 73% of the rats. In these latter rats, the impact also induced apnea and a transient elevation of blood pressure, and resulted in low-voltage EEG recordings. In 23% of the rats in which [K+]o changes in the brain stem were not significant, the impact caused a transient reduction of blood pressure. The present study disclosed that an increase of [K+]o in the cerebral cortex and also in the brain stem is an important element in the phenomenon of concussion.

Acute Disease↗
PubMed1988

Effects of the 21-aminosteroid U74006F on experimental head injury in mice.

The ability of a novel non-glucocorticoid 21-aminosteroid U74006F to inhibit lipid peroxidation of central nervous system tissue in vitro and to enhance the early neurological recovery and survival of mice after a severe concussive head injury is described. In the in vitro studies, U74006F was found to be an extremely potent inhibitor of lipid peroxidation in an assay system where the glucocorticoid steroid methylprednisolone and the non-glucocortoid steroids U72099E and U75718A were almost completely ineffective. In the head-injury studies, unanesthetized male CF-1 mice were subjected to a 900 gm-cm closed head injury produced by a 50-gm weight being dropped 18 cm. This concussive injury resulted in immediate unconsciousness (loss of righting reflex) in all animals and death in approximately 30%. Survivors received a tail vein injection of either vehicle or U74006F (0.001 to 30 mg/kg) within 5 minutes postinjury. Their neurological status was evaluated 1 hour later using a grip test. The grip-test score indicated that intravenous administration of a single dose of U74006F resulted in a significant improvement by as much as 168.6% in the neurological status 1 hour postinjury over a broad dose range (0.003 to 30 mg/kg). A 1-mg/kg dose given intravenously within 5 minutes and again at 1 1/2 hours after a severe injury, in addition to improving early recovery, also increased the 1-week survival rate to 78.6% compared to 27.3% in vehicle-treated mice (p less than 0.02). The compound was also effective in enhancing early recovery after a more moderate injury. This study demonstrates that early treatment after severe concussive head injury with a potent inhibitor of iron-dependent lipid peroxidation can significantly benefit the injured brain in mice and promote both early neurological recovery and long-term survival.

Animals↗
PubMed2001

[Changes in the activities of oxidoreductases, content of malondialdehyde and medium weight molecules in the blood of patients with craniocerebral injuries of different severity].

Biochemical changes are determined by the severity of craniocerebral injury. Twenty-four hours after the injury the activity of succinate dehydrogenase in lymphocytes increases significantly in patients with brain concussion and contusion of medium severity. Glutamate dehydrogenase activity increases in patients with repeated brain concussion. The content of malonic dialdehyde is increased in patients with repeated brain concussion and decreased in severe brain contusion. The level of medium-weight molecules is increased in all patients with craniocerebral injuries. The activities of these enzymes are virtually unchanged in the patients with lethal outcomes.

Adolescent↗
PubMed1996

Postconcussive symptoms in craniofacial trauma.

In a private/institutional setting the prevalence of Postconcussive Syndrome (PCS) symptoms and related etiologic factors was surveyed in 122 concussion and other craniofacial trauma patients (mean age 32 years; 68% male) and 122 uninjured controls (mean age 21 years; 45% males). A Neurobehavioral Symptom Checklist was used to measure 44 self-related symptoms, summed to yield Overall Frequency; number of symptoms rated as 3 or 4 were also summed separately to yield High Frequency scores. The Concussion group had significantly greater Overall Frequency and High Frequency scores than the other patients and the controls. The Brain Damage group had significantly greater High Frequency (but not Overall Frequency) scores than the controls. The presence of litigation, unemployment, or middle-age yielded significantly greater Overall Frequency scores in the patients; these variables in the control group were not measured. The presence of craniofacial fractures had no effect. Results suggest PCS symptoms are greatest in concussion patients with the presence of litigation, unemployment or middle age, and are less affected by injury severity.

Adolescent↗
PubMed1992

[MRI findings of closed head injury in children; with special reference to the effect of central shearing force].

It is considered that shearing effect as introduced by Holbourn may produce central concussion, diffuse brain swelling and diffuse axonal injury according to its grade of force. MRI was performed in 38 children who had been admitted to our hospital during the previous 1 year for the treatment of closed head injury of varying severity. In 8 out of 38 cases, abnormal high signal intensity was observed in the medial and para-medial brain parenchyma on MRI. All of these 8 cases suffered from head trauma caused by motor vehicle accidents. They included 2 cases of cerebral concussion, 1 of diffuse brain swelling, and 5 cases of diffuse axonal injury. In 2 cases of cerebral concussion, MRI (T2 weighted) revealed only localized high intensity in the corpus callosum, while CT showed normal and subarachnoid hemorrhage only at the interposium. These two children had been unconscious for periods of 20 to 30 minutes. In one case of diffuse brain swelling, MRI (T2W) showed a slightly obscure border between gray and white matter due to generally increased intensity. In 5 cases of diffuse axonal injury, most of these cases manifested lesions at the corpus callosum, deep white matter, periventricular gray matter, pons, midbrain and the cerebellum as demonstrated by high signal intensity on MRI (T2W) while CT in the acute stage showed small hemorrhage at the corpus callosum, corticomedullary junction and mid-brain and in the ventricles. Among these, two cases also demonstrated subdural hematoma and cortical contusional hemorrhage. At 3-4 weeks after injury, the area of high intensity previously demonstrated in the deep white matter and the corpus callosum on MRI (T2W) was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Axons↗
PubMed1992

[Magnetic resonance imaging in diffuse brain injury].

Forty cases diagnosed as diffuse brain injury (DBI) were studied by magnetic resonance imaging (MRI) performed within 3 days after injury. These cases were divided into two groups, which were the concussion group and diffuse axonal injury (DAI) group established by Gennarelli. There were no findings on computerized tomography (CT) in the concussion group except for two cases which had a brain edema or subarachnoid hemorrhage. But on MRI, high intensity areas on T2 weighted imaging were demonstrated in the cerebral white matter in this group. Many lesions in this group were thought to be edemas of the cerebral white matter, because of the fact that, on serial MRI, they were isointense. In mild types of DAI, the lesions on MRI were located only in the cerebral white matter, whereas, in the severe types of DAI, lesions were located in the basal ganglia, the corpus callosum, the dorsal part of the brain stem as well as in the cerebral white matter. As for CT findings, parenchymal lesions were not visualized especially in mild DAI. Our results suggested that the lesions in cerebral concussion were edemas in cerebral white matter. In mild DAI they were non-hemorrhagic contusion; and in severe DAI they were hemorrhagic contusions in the cerebral white matter, the basal ganglia, the corpus callosum or the dorsal part of the brain stem.

Adolescent↗
PubMedDate not supplied

[Prospective studies of multimodal evoked potentials in patients after cranio-cerebral injury].

In 42 patients aged 18-68 years somatosensory, visual and brainstem auditory evoked potentials were studied in the first month after trauma and after 6-8 months after craniocerebral trauma for evaluation of their diagnostic importance in less severe craniocerebral trauma. On the basis of the results of neurological examination, CT of the head, and duration of unconsciousness in 22 cases brain concussion and in 20 cases brain contusion was diagnosed. In patients after brain concussion the frequency of early and late abnormalities after head trauma was as follows: for SSEP 36.4% and 27.3% respectively, for visual evoked potentials 21.1% and 5.3%, for auditory potentials 9.5% and 4.8%. In cases of brain contusion abnormalities were found in the 1st month and 6-8 months after trauma in SSEP in 60% and 20% respectively, in visual EP in 11.1% and 22.2%, and in auditory EP in 30% and 40%. In the group of concussion the greatest and most persistent changes developed in the later components od SSEP. Among certain patients with brain contusion deterioration of the results of visual and auditory evoked potentials were noted late after trauma.

Adolescent↗
PubMed1991

[Plasma corticosterone level in experimental mild cranio-cerebral injury in rabbits].

The content of corticosterone in the rabbits blood plasma in dynamics of experimental brain concussion was studied. We found two peaks of elevating the content of corticosterone during two weeks (15 minutes-2 hours, 7 days). Level of corticosterone more than twice exceeded the control values after 3 months of concussion. We can conclude that the brain concussion distinct from the stress action was more deep and in some cases with irreversible changes in neuro-humoral status.

Animals↗