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Presence of post-concussion syndrome symptoms in patients with chronic pain vs mild traumatic brain injury.

PRIMARY OBJECTIVE: Post-concussion syndrome (PCS) is a controversial diagnosis, in part because many symptoms may be present in other conditions, such as chronic pain (CP). However, direct comparisons between people with CP and mild traumatic brain injury (MTBI) are limited. The purpose of this study was to compare people with CP and MTBI on a measure of PCS symptoms. DESIGN: Group comparison between patients with CP and MTBI on the Rivermead Post-Concussion Questionnaire (RPCQ). METHODS: Sixty-three patients with CP and 32 with MTBI were evaluated at the authors' institutions. Patients completed the RPCQ as part of their initial evaluation. RESULTS: No group differences were found for total RPCQ scores. There were some differences in the proportion of patients endorsing specific symptoms. However, most people with CP endorsed symptoms consistent with PCS. CONCLUSIONS: PCS symptoms are not unique to MTBI, and may be seen in conditions such as CP.

Adult↗

A concussive-like brain injury model in mice (I): impairment in learning and memory.

The modeling of human concussive brain injury (CBI) in the laboratory has been challenging. In the present study, we developed an experimental CBI model in mice using a novel weight-drop device. Various injury levels were examined by adjusting the height of the falling weight (diameter 10 mm, length 20 cm, weight 21 g). At a height of 50 cm, the impact resulted in a mortality rate of 46.7% with a skull fracture rate of 28.6%. At a height of 25 cm, however, the impact produced a concussive-like brain injury (CLBI) to the mice without skull fracture. A series of pathophysiological and neurobehavioral responses was evaluated at this injury level. The CLBI mice lost muscle tone and righting reflex response immediately following the trauma and recovered from the latter within a short duration of 1.6 +/- 0.32 min (mean +/- SE). Brain edema formation started at 12 h, reached a maximum at 24 h and recovered 48 h. Typically edema was found in the neocortex, hippocampus, and cerebellum, but not in the brain stem. Deficits in the feeding behaviors lasted for 2 days, accompanied by lower body weight persisting for 5 days. The body weight growth rate for 24 h returned to the control levels by the third day postinjury. Learning and memory were evaluated at the end of 1-3 weeks after the trauma using a water-finding task. At 1 week, exploratory behaviors were slightly inhibited while learning and memory were profoundly impaired. Interestingly, the learning and memory deficits lasted for 2 weeks while recovering to the control levels by 3 weeks. No motor disability was found in the CLBI mice during the 3-week evaluations. These results indicate that the weight-drop impact produced graded injury to the brain, and at the injury level of 25 cm it produced a CLBI in the mice in which the characteristics of transient loss of neurobehavioral responses, short duration of brain edema, and long-lasting learning and memory deficits are similar to those of human CBI.

Animals↗

A concussive-like brain injury model in mice (II): selective neuronal loss in the cortex and hippocampus.

A novel concussive-like brain injury (CLBI) model characterized by transient neurobehavioral depression, short duration of brain edema, and long-lasting memory deficits has been reported in our companion paper. This was achieved by dropping a 21-g weight from a height of 25 cm onto the head of a mouse. In the present study, we examined the histopathological changes in this model. Male ddY mice were subjected to either the trauma or sham injury. Gross pathological examination of the brain 1 h posttrauma did not demonstrate subdural, subarachnoid, intraventricular, periventricular, and intraparenchymatous hemorrhage, focal lesions or contusions. Microscopic examination 24 h posttrauma with Nissl staining (cresyl violet), however, revealed a selective bilateral neuronal cell loss in the cerebral cortex and hippocampus but not in the regions of the thalamus, cerebellum, and brain stem. The characteristics of neuronal cell loss in the cortex suggested that this pathology was related in part, to the head impact dynamics, since the cell loss was noted in the central portion of the supraventricular cerebral cortex (p < 0.001), the site of the weight impact, gradually decreasing peripheral to this site, and disappearing in the areas remote from this locus. In contrast, neuronal cell loss seen in the hippocampus did not suggest that this pathology was directly associated with the impact site. Neuronal cell loss was concentrated in the pyramidal cell layer of CA2 (p < 0.01) and CA3 (p < 0.01), and a lesser degree was noted in the subfields of CA3c (p < 0.05) and the hilar region (p < 0.05) but not in the subfields of CA1 and the dentate gyrus layers. The present study characterized the histopathological change seen in the CLBI model, demonstrating the selective neuronal cell loss following weight-drop concussion in mice.

Animals↗

The dynamics of concussive head impacts in rugby and Australian rules football.

A study was commenced in 1998 at the University of New South Wales (UNSW) to investigate the dynamics of head impacts in football which resulted in concussion. Sixty-eight cases of medically verified concussion from Australian Rules Football and 32 from Rugby Union and Rugby League were analyzed. Video of each injury event was analyzed to obtain descriptive data regarding the head impact site and striking object. The video was analyzed quantitatively to obtain estimates of the closing speeds. A secondary analysis was undertaken using the conservation of momentum and energy relationships to estimate the change in velocity of the head during the impact, the change in momentum of the head, and the energy imparted to the head. Ninety-seven cases involved direct head contact, whereas three cases involved impulsive loading via the trunk. The majority of impacts were to the tempero-parietal region, and the striking body segment was commonly the arm or shoulder/thorax. The mean change in velocity of the head and head impact energy for all 97 cases of direct head impact were 4 m x s(-1) and 56 J, respectively. Head impact energy can be used as a performance criteria for testing and developing headgear for rugby and Australian rules football.

Athletic Injuries↗

The nature and duration of acute concussive symptoms in Australian football.

OBJECTIVE: The purpose of this pilot study was to document the nature and temporal profile of the clinical symptoms of acute sport-related concussion. DESIGN: Prospective cohort study PATIENT POPULATION: A total of 303 elite Australian football players participating in a national competition during a single season. OUTCOME MEASURES: Number and duration of symptoms, digit symbol substitution test (DSST) scores, time of return to play post injury. RESULTS: A total of 23 concussions were recorded over the course of the 20-week football season. No catastrophic head injuries occurred. Headache was the most common symptom and the most persistent, with 40% of players reporting headache symptoms lasting more than 15 minutes. Ten of the players (43%) returned to sport on the day of the injury with the remainder resuming play within 2 weeks. A low likelihood of return to play on the day of injury was found where 3 or more symptoms were present or where the symptoms lasted more than 15 minutes. These findings were significantly correlated with poor DSST performance. CONCLUSIONS: This pilot study suggests that both the number of postconcussive symptoms and their duration may be used as a measure of injury severity and a guide for return to play.

Analysis of Variance↗

Evidence-Based review of sport-related concussion: clinical science.

The clinical nature of sport-related concussion is discussed in this paper. Particularly highlighted are the difficulties with definition, injury severity grading, classification, and understanding of clinical symptoms. In addition, the well-recognized sequelae of concussion including the motor and convulsive manifestations are discussed in detail. Where possible, an evidence-based approach is adopted to assist the understanding of the literature in this complex area.

Athletic Injuries↗

Evidence-based review of sport-related concussion: basic science.

The evidence base for sport-related concussive brain injury is reviewed in this paper. In the past, pathophysiological understanding of this common condition has been extrapolated from studies of severe brain trauma. More recent scientific study demonstrates that this approach is unsatisfactory, and the clinical features of concussion represent a predominantly functional brain injury rather than manifest by structural or neuropathological damage. Such understanding of this condition remains incomplete at this stage.

Athletic Injuries↗

New frontiers in diagnostic imaging in concussive head injury.

Concussed athletes may have documented incapacitating postconcussive symptoms, neuropsychological deficits, and consequent important changes in their lives and sport, yet the majority of neuroimaging attempts reveal few findings to account for these signs and symptoms. In this paper, we explore new techniques in the neuroimaging of concussion including diffusion-weighted magnetic resonance imaging and functional brain imaging technology.

Athletic Injuries↗

Serial administration of clinical concussion assessments and learning effects in healthy young athletes.

OBJECTIVE: To determine if serial administration of the Standardized Assessment of Concussion (SAC) and Balance Error Scoring System (BESS) would elicit a learning effect in young athletes and to determine the intratester reliability of scoring the BESS. DESIGN: A prospective study of 50 healthy young athletes who were assigned to either the control or practice group. All subjects were administered the assessments on 2 occasions, 60 days apart. In addition, subjects in the practice group received serial administration of the assessments on 3 occasions in the week following the initial assessment. SETTING: University Sports Medicine/Athletic Training Research Laboratory. SUBJECTS: Fifty uninjured young athletes between 9 and 14 years of age. MAIN OUTCOME MEASURED: Scores on 2 clinical concussion assessments, the SAC and the BESS. RESULTS: We found a significant learning effect upon serial BESS testing in the practice group. BESS error scores were significantly lower than baseline (15.0 +/- 4.6) on days 5 (11.3 +/- 5.33), 7 (12.4 +/- 6.2), and 60 (12.6 +/- 6.2). We also found a significant learning effect upon the day 60 BESS administration across all subjects. We did not find a practice or learning effect with serial SAC test administration. The intratester reliability of the investigator's ability to score repeated observations of the same BESS test ranged from 0.87 to 0.98. CONCLUSIONS: Our results demonstrated that serial administration of the BESS elicited a learning effect, which was more prominent during the tandem conditions. Clinicians utilizing the BESS as a measure of postural stability should be aware of the potential for improvement with repeated testing. Clinicians should not expect improvement with the SAC, as scores remained relatively stable across all trials.

Adolescent↗

Experimental brain damage from fluid pressures due to impact acceleration. 4. comparative studies with acceleration-concussion.

In order to elucidate the cause of brain damage in head injuries experiments are often designed to cause impacts to the intact skull of animals. To study the injurious significance of the contre-coup part of the impact acceleration pressure pattern we have previously applied direct loading through a parietal opening to the rabbit skull cavity. In order to evaluate the effects of the acceleration, similar impacts were delivered with greater magnitudes of such movements of the intact reinforced rabbit skull with the same equipment attached but without trephine opening. Varied and predictable acceleration, velocity and displacement of the head, and minimized skull deformation were possible with this model. Threshold levels of such impact acceleration were studied with regard to changes in respiratory and vasomotor activities ("concussive response"). Vascular permeability changes in the brain and spinal cord were studied with Ean's blue-albumin injection before the impact. Morphological observations were also made at the end of the experiments. No significant pathophysiological or morphological effects were elicited below peak acceleration of 2000 gn (duration 0.7 ms), peak velocity of 5 m/s or total dislocation of the head of 30 mm. At higher levels of impact a "concussive response" was elicited without fractures of the skull bone or significant brain lesions. Thus, in impact tests resulting in acceleration magnitudes far below those levels the signs of brain damage induced might mainly be related to the mechanical effects added--i.e. the fluid pressure loading.

Acceleration↗

Controlled trial of treatment for cerebral concussion.

In a study designed to compare two types of treatment of cerebral concussion, 178 patients were allocated to a routine treatment or to an active treatment group; in the latter a good prognosis was emphasized, the patient was mobilized early and given physiotherapy. In the routine treatment group the average time off work was 32 days compared with 18 days in the active treatment group. Physiotherapy seemed to be particularly valuable in old patients and in those with exaggerated fears about their condition. It is suggested that throughout their illness and follow-up, patients with cerebral concussion should be under the care of one doctor, one who is particularly interested in the subject and that more propaganda is needed

Absenteeism↗

Findings of mild traumatic brain injury in combat veterans with PTSD and a history of blast concussion.

Veterans with chronic posttraumatic stress disorder were evaluated for a history of blast concussion, controlling for confounding conditions. Electroencephalograms were analyzed by discriminant function for traumatic brain injury. A difference was found in discriminant scores between veterans with and without blast concussion. More members of the blast group had attentional symptoms and attentional dysfunction. Combat veterans with a remote history of blast injury have persistent electroencephalographic features of traumatic brain injury as well as attentional problems. The authors hypothesize that these constitute a type of chronic postconcussive syndrome that has cognitive and mood symptoms overlapping those of posttraumatic stress disorder.

Adult↗

Computer tomography of the brain and spectrophotometry of the CSF in cerebral concussion and contusion.

Computer tomography (CT) and spectrophotometry of CSF were performed in 30 patients with the clinical diagnosis of cerebral concussion or contusion. The patients with concussion all had normal CT-findings. Spectrophotometry of CSF was sometimes positive for cerebral contusion with normal CT-findings, but the two methods were complementary so that the extent of the lesion was determined by CT and spectrophotometry of CSF indicated the cause.

Brain Concussion↗

Incidence of reported cerebral concussion in adult taekwondo athletes.

The purpose of the present study was to assess the exact conditions under which cerebral concussions occur in full-contact taekwondo competition. Injury data were collected by project staff and tournament medical personnel with simple check-off forms that describe the athlete and nature, site, circumstances and severity of the injury. The Mann-Whitney U test was used to determine the difference in injury rate between men and women. The men (7.04/1,000 athlete-exposures) sustained more cerebral concussions than the women (2.42/1,000 athlete-exposures) (p < 0.001). The dominant injury mechanism in both the males and females was receiving a blow (6.46/1,000 athlete-exposures and 2.42/1,000 athlete-exposures for the men and women, respectively).

Adult↗

Construct validity and reliability of the Rivermead Post-Concussion Symptoms Questionnaire.

OBJECTIVES: To provide further evidence of reliability and internal and external construct validity of the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), which measures severity of postconcussion symptoms following head injury. DESIGN AND SETTING: A cross-sectional study of consecutive patients presenting with a head injury in two urban teaching hospitals and a community trust. PATIENTS: Three hundred and sixty-nine patients returned a questionnaire from 1689 consecutive adult patients (18 years and above) referred to radiology for a skull X-ray following a head injury, and those who were currently under the care of a community-based multidisciplinary head injury team. METHOD: Internal construct validity tested by fit to the Rasch Measurement model; external construct validity tested by correlations with Rivermead Head Injury Follow-up Questionnaire (RHFUQ); test-retest reliability tested by correlations at two-week intervals. OUTCOME MEASURES: Rivermead Post-Concussion Symptoms Questionnaire and Rivermead Head Injury Follow-up Questionnaire. MAIN RESULTS: RPQ scores ranged from 0 to 64 (17.3% floor, 0.3% ceiling). Overall fit to the Rasch model was poor (item fit mean -0.416, SD = 1.989, chi-squared= 172.486, p<0.01) suggesting a lack of unidimensionality. The items headaches, dizziness and forgetful displayed misfitting residuals and the first two items also displayed significant item trait fit statistics (p < 0.0006). After removing the items headaches, dizziness and subsequently nausea the RPQ demonstrated good fit at overall and individual item levels, both for the remaining 13 items (RPQ-13) and the three items (RPQ-3) which now formed a subsidiary scale. All items functioned consistently across age and gender. The RPQ-13 and RPQ-3 scales showed test-retest reliability coefficients of 0.89 and 0.72 (both p-values < 0.01) and positive correlations with RHFUQ scores (0.83 for RPQ-13, 0.62 for RPQ-3, both p-values < 0.01). CONCLUSIONS: As currently used, the RPQ does not meet modern psychometric standards. Its 16 items do not tap into the same underlying construct and should not be summated in a single score. When the RPQ is split into two separate scales, the RPQ-13 and the RPQ-3, each set of items forms a unidimensional construct for people with head injury at three months post injury. These scales show good test-retest reliability and adequate external construct validity.

Adolescent↗

Persistent prolongation of simple reaction time in sports concussion.

A baseline computerized cognitive assessment was completed by 483 military cadets before their initial school year. Fourteen cadets concussed during physical education boxing were retested <1 hour after injury and again on return to full activity 4 days later. Compared with baseline testing, postinjury performance on simple reaction time and continuous performance tests was significantly slowed, even after cadets experienced resolution of physical symptoms and were cleared to resume full activity. These findings may be relevant to current concussion management guidelines.

Brain Concussion↗

Severity of sports-related concussion and neuropsychological test performance.

Concussion severity grades according to the Cantu, Colorado Medical Society, and American Academy of Neurology systems were not clearly related to the presence or duration of impaired neuropsychological test performance in 21 professional rugby league athletes. The use of concussion severity guidelines and neuropsychological testing to assist return to play decisions requires further investigation.

Brain Concussion↗

Concussion in professional football: recovery of NFL and high school athletes assessed by computerized neuropsychological testing--Part 12.

OBJECTIVE: Acute recovery from concussion (mild traumatic brain injury) is assessed in samples of NFL and high school athletes evaluated within days of injury. METHODS: All athletes were evaluated within days of injury using a computer-based neuropsychological test and symptom inventory protocol. Test performance was compared to preinjury baseline levels of a similar but not identical group of athletes who had undergone preseason testing. Statistical analyses were completed using Multivariate Analysis of Variance (MANOVA). RESULTS: NFL athletes demonstrated a rapid neuropsychological recovery. As a group, NFL athletes returned to baseline performance in a week with the majority of athletes having normal performance two days after injury. High school athletes demonstrated a slower recovery than NFL athletes. CONCLUSION: Computer-based neuropsychological testing was used within the overall medical evaluation and care of NFL athletes. As found in a prior study using more traditional neuropsychological testing, NFL players did not demonstrate decrements in neuropsychological performance beyond one week of injury. High school players demonstrated more prolonged neuropsychological effects of concussion.

Adult↗