Cognitive effects of mild head injury in children and adolescents

Consciousness Recovery in Traumatic Brain Injury: A Systematic Review Comparing Modafinil and Amantadine

OBJECTIVES

Acute traumatic brain injury is one of the most common causes of death and disability. Reduction in the level of consciousness is a significant complication that can impact morbidity. Glasgow Coma Scale (GCS) is the most widely used method of assessing the level of consciousness. Neurostimulants such as amantadine and modafinil are common pharmacologic agents that increase GCS in patients with brain trauma. This study aimed to compare the effectiveness of these 2 drugs.

METHODS

This systematic review obtained articles from Google Scholar, PubMed, Scopus, Embase, and MEDLINE databases. Extensive searches were conducted separately by 4 individuals in 3 stages. Ultimately, 16 clinical trials, cohort studies, case reports, and case series articles were obtained after reading the title, abstract, and full text and considering the exclusion criteria. The data of the final article were entered into the analysis table. This study was registered with PROSPERO (registration number CRD42022334409) and conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Amantadine seems to be associated with a higher overall response rate. In contrast, modafinil is associated with the most remarkable change in GCS score during treatment. However, the number of clinical trials with high quality and sample size has not been satisfactory to compare the effectiveness of these 2 drugs and their potential side effects.

CONCLUSIONS

The authors recommend additional double-blind clinical trials are needed to be conducted with a larger sample size, comparing amantadine with modafinil to delineate the efficacy and adverse effects, both short and long term.

The Use of Therapeutic Music Training to Remediate Cognitive Impairment Following an Acquired Brain Injury: The Theoretical Basis and a Case Study

Cognitive impairment is the most common sequelae following an acquired brain injury (ABI) and can have profound impact on the life and rehabilitation potential for the individual. The literature demonstrates that music training results in a musician's increased cognitive control, attention, and executive functioning when compared to non-musicians. Therapeutic Music Training (TMT) is a music therapy model which uses the learning to play an instrument, specifically the piano, to engage and place demands on cognitive networks in order to remediate and improve these processes following an acquired brain injury. The underlying theory for the efficacy of TMT as a cognitive rehabilitation intervention is grounded in the literature of cognition, neuroplasticity, and of the increased attention and cognitive control of musicians. This single-subject case study is an investigation into the potential cognitive benefit of TMT and can be used to inform a future more rigorous study. The participant was an adult male diagnosed with cognitive impairment as a result of a severe brain injury following an automobile accident. Pre- and post-tests used standardized neuropsychological measures of attention: Trail Making A and B, Digit Symbol, and the Brown- Peterson Task. The treatment period was twelve months. The results of Trail Making Test reveal improved attention with a large decrease in test time on both Trail Making A (-26.88 s) and Trail Making B (-20.33 s) when compared to normative data on Trail Making A (-0.96 s) and Trail Making B (-3.86 s). Digit Symbol results did not reveal any gains and indicated a reduction (-2) in free recall of symbols. The results of the Brown-Peterson Task reveal improved attention with large increases in the correct number of responses in the 18-s delay (+6) and the 36-s delay (+7) when compared with normative data for the 18-s delay (+0.44) and the 36-s delay (-0.1). There is sparse literature regarding music based cognitive rehabilitation and a gap in the literature between experimental research and clinical work. The purpose of this paper is to present the theory for Therapeutic Music Training (TMT) and to provide a pilot case study investigating the potential efficacy of TMT to remediate cognitive impairment following an ABI.

Return to Learn: Academic Effects of Concussion in High School and College Student-Athletes

While awareness and understanding of concussion have improved drastically, post-concussion management in academic settings is still at its infancy. The aim of the study was to examine to what extent concussion influences academic performance and to whether there would be a difference in concussion effects on academic performance between high school and college students. This cross-sectional survey study included students, who were between 14 and 24 years old and sustained a sport-related concussion within the previous year. The study used a modified chain-referral sampling method, by distributing a questionnaire link to 3,000 randomly stratified athletic trainers, who worked in high school or college settings. These athletic trainers were then asked to forward the questionnaire link to students in their team, who have sustained a concussion within the previous year. The questionnaire recorded responses regarding demographics (age, sex, race/ethnicity, number of previous concussions); 22 concussion-related symptoms in a binary scale (presence/absence); perception of difficulties in math, reading, writing, computer use, and attention in a 5-point Likert scale; and asymptomatic duration of academic engagement in a 7-point Likert scale. There were 130 respondents with a history of concussion in the past year (n = 59 high school, n = 71 college). While recovering from concussion, significantly more college students (84.5%) reported "difficulty concentrating" than high school students (68.6%: p = 0.049). High -school students experienced more difficulty with math than college students (p = 0.002), whereas college students experienced more difficulty with reading (p = 0.013) and computer use (p = 0.026) than high school students. Asymptomatic duration of cognitive activity was influenced by age (p = 0.0004), where younger students were less tolerant in performing academic tasks after a concussion than older students. Our data indicate that concussions can induce negative symptoms in the academic setting regardless of age. The post-concussion difficulties in academic performance may be a grade-dependent manner, where concussions triggered difficulty in math among high school students and in reading and computer use among college students. It is clear that there is a need for guidelines and accommodations to support students with concussion in academic settings, and the guideline should reflect the age-dependent response to concussions.

Pharmacokinetics and efficacy of PT302, a sustained-release Exenatide formulation, in a murine model of mild traumatic brain injury

Traumatic brain injury (TBI) is a neurodegenerative disorder for which no effective pharmacological treatment is available. Glucagon-like peptide 1 (GLP-1) analogues such as Exenatide have previously demonstrated neurotrophic and neuroprotective effects in cellular and animal models of TBI. However, chronic or repeated administration was needed for efficacy. In this study, the pharmacokinetics and efficacy of PT302, a clinically available sustained-release Exenatide formulation (SR-Exenatide) were evaluated in a concussive mild (m)TBI mouse model. A single subcutaneous (s.c.) injection of PT302 (0.6, 0.12, and 0.024 mg/kg) was administered and plasma Exenatide concentrations were time-dependently measured over 3 weeks. An initial rapid regulated release of Exenatide in plasma was followed by a secondary phase of sustained-release in a dose-dependent manner. Short- and longer-term (7 and 30 day) cognitive impairments (visual and spatial deficits) induced by weight drop mTBI were mitigated by a single post-injury treatment with Exenatide delivered by s.c. injection of PT302 in clinically translatable doses. Immunohistochemical evaluation of neuronal cell death and inflammatory markers, likewise, cross-validated the neurotrophic and neuroprotective effects of SR-Exenatide in this mouse mTBI model. Exenatide central nervous system concentrations were 1.5% to 2.0% of concomitant plasma levels under steady-state conditions. These data demonstrate a positive beneficial action of PT302 in mTBI. This convenient single, sustained-release dosing regimen also has application for other neurological disorders, such as Alzheimer's disease, Parkinson's disease, multiple system atrophy and multiple sclerosis where prior preclinical studies, likewise, have demonstrated positive Exenatide actions.

Novel GLP-1R/GIPR co-agonist "twincretin" is neuroprotective in cell and rodent models of mild traumatic brain injury

Several single incretin receptor agonists that are approved for the treatment of type 2 diabetes mellitus (T2DM) have been shown to be neuroprotective in cell and animal models of neurodegeneration. Recently, a synthetic dual incretin receptor agonist, nicknamed "twincretin," was shown to improve upon the metabolic benefits of single receptor agonists in mouse and monkey models of T2DM. In the current study, the neuroprotective effects of twincretin are probed in cell and mouse models of mild traumatic brain injury (mTBI), a prevalent cause of neurodegeneration in toddlers, teenagers and the elderly. Twincretin is herein shown to have activity at two different receptors, dose-dependently increase levels of intermediates in the neurotrophic CREB pathway and enhance viability of human neuroblastoma cells exposed to toxic concentrations of glutamate and hydrogen peroxide, insults mimicking the inflammatory conditions in the brain post-mTBI. Additionally, twincretin is shown to improve upon the neurotrophic effects of single incretin receptor agonists in these same cells. Finally, a clinically translatable dose of twincretin, when administered post-mTBI, is shown to fully restore the visual and spatial memory deficits induced by mTBI, as evaluated in a mouse model of weight drop close head injury. These results establish twincretin as a novel neuroprotective agent and suggest that it may improve upon the effects of the single incretin receptor agonists via dual agonism.

Mild Head Injury in Children and Adolescents

Although mild head injury is the most prevalent type of head injury in children and adolescents, only a relatively small number of studies on this kind of head injury have been reported. This article summarizes a review of studies examining cognitive, academic, and psychosocial outcomes in children who sustained mild head injuries. Despite earlier claims of mild head injury being a “silent epidemic,” the studies, which were published from 1970 to 1998, provide no compelling evidence to support this view.

Traumatic brain injury alters long-term hippocampal neuron morphology in juvenile, but not immature, rats

PURPOSE

Pediatric traumatic brain injury (TBI) represents a prominent yet understudied medical condition that can profoundly impact brain development. As the juvenile injured brain matures in the wake of neuropathological cascades during potentially critical periods, circuit alterations may explain neurological consequences, including cognitive deficits. We hypothesize that experimental brain injury in juvenile rats, with behavioral deficits that resolve, will lead to quantifiable structural changes in hippocampal neurons at chronic time points post-injury.

METHODS

Controlled cortical impact (CCI), a model of focal TBI with contusion, was used to induce brain injury on post-natal day (PND) 17 juvenile rats. The histological consequence of TBI was quantified in regions of the hippocampus at post-injury day 28 (PID28) on sections stained using a variation of the Golgi-Cox staining method. Individual neuronal morphologies were digitized from the dentate gyrus (DG), CA3, and CA1 regions.

RESULTS

Soma area in the ipsilateral injured DG and CA3 regions of the hippocampus increased significantly at PID28 in comparison to controls. In CA1, dendritic length and dendritic branching decreased significantly in comparison to controls and the contralateral hemisphere, without change in soma area. To extend the study, we examined neuronal morphology in rats with CCI at PND7. On PID28 after CCI on PND7 rats, CA1 neurons showed no injury-induced change in morphology, potentially indicating an age-dependent morphological response to injury.

CONCLUSIONS

Long-lasting structural alterations in hippocampal neurons of brain-injured PND17 juvenile animals, but not PND7 immature animals, suggest differential plasticity depending on age-at-injury, with potential consequences for later function.

The young brain and concussion: imaging as a biomarker for diagnosis and prognosis

Concussion (mild traumatic brain injury (mTBI)) is a significant pediatric public health concern. Despite increased awareness, a comprehensive understanding of the acute and chronic effects of concussion on central nervous system structure and function remains incomplete. Here we review the definition, epidemiology, and sequelae of concussion within the developing brain, during childhood and adolescence, with current data derived from studies of pathophysiology and neuroimaging. These findings may contribute to a better understanding of the neurological consequences of traumatic brain injuries, which in turn, may lead to the development of brain biomarkers to improve identification, management and prognosis of pediatric patients suffering from concussion.

Relationship between circulating IGF-1 levels and traumatic brain injury-induced hippocampal damage and cognitive dysfunction in immature rats

It is well known that traumatic brain injury (TBI) induces the cognitive dysfunction resulting from hippocampal damage. In the present study, we aimed to assess whether the circulating IGF-I levels are associated with cognition and hippocampal damage in 7-day-old rat pups subjected to contusion injury. Hippocampal damage was examined by cresyl violet staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Spatial memory performance was assessed in the Morris water maze. Serum IGF-1 levels decreased in both early and late period of TBI. Decreased levels of serum IGF-1 were correlated with hippocampal neuron loss and spatial memory deficits. Circulating IGF-1 levels may be predictive of cognitive dysfunction resulted from hippocampal damage following traumatic injury in developing brain. Therapy strategies that increase circulating IGF-1 may be highly promising for preventing the unfavorable outcomes of traumatic damage in young children.

Post-concussive symptoms in children with mild traumatic brain injury

To investigate postconcussive symptoms (PCS) following pediatric mild traumatic brain injury (mTBI), 8- to 15-year-old children with mTBI (n = 186) and a comparison group with uncomplicated orthopedic injuries (OI, n = 99) were recruited from two emergency departments. Parent and child ratings of PCS and symptom counts were obtained within 3 weeks after injury (baseline) and at 1, 3, and 12 months postinjury. The mTBI group also completed magnetic resonance imaging at baseline. Group differences were examined using growth modeling, controlling for age at injury, sex, socioeconomic status, and (for parent-based measures) preinjury symptom levels. Relative to the OI group, the mTBI group had higher ratings of somatic PCS and parent counts of PCS at the initial assessments, but higher parent ratings of cognitive PCS and child counts of PCS throughout follow-up. Higher levels of PCS in the mTBI group were associated with motor-vehicle-related trauma, loss of consciousness, neuroimaging abnormalities, and hospitalization. The findings validate both transient and persistent PCS in children with mTBI and document associations of symptoms with injury and noninjury factors.

Postconcussive symptoms and neurocognitive function after mild traumatic brain injury in children

OBJECTIVES

We describe children's postconcussive symptoms (PCSs), neurocognitive function, and recovery during 4 to 5 weeks after mild traumatic brain injury (MTBI) and compare performance and recovery with those of injured control group participants without MTBIs.

METHODS

A prospective, longitudinal, observational study was performed with a convenience sample from a tertiary care, pediatric emergency department. Participants were children 10 to 17 years of age who were treated in the emergency department and discharged. The MTBI group included patients with blunt head trauma, Glasgow Coma Scale scores of 13 to 15, loss of consciousness for < or = 30 minutes, posttraumatic amnesia of < or = 24 hours, altered mental status, or focal neurologic deficits, and no intracranial abnormalities. The control group included patients with injuries excluding the head. The Post-Concussion Symptom Questionnaire and domain-specific neurocognitive tests were completed at baseline and at 1 and 4 to 5 weeks after injury.

RESULTS

Twenty-eight MTBI group participants and 45 control group participants were compared. There were no significant differences in demographic features. Control group participants reported some PCSs; however, MTBI group participants reported significantly more PCSs at all times. Among MTBI group participants, PCSs persisted for 5 weeks after injury, decreasing significantly between 1 and 4 to 5 weeks. Patterns of recovery on the Trail-Making Test Part B differed significantly between groups; performance on other neurocognitive measures did not differ.

CONCLUSIONS

In children 10 to 17 years of age, self-reported PCSs were not exclusive to patients with MTBIs. However, PCSs and recovery patterns for the Trail-Making Test Part B differed significantly between the groups.

Beneficial effect from a cognitive training programme on children with acquired brain injuries demonstrated in a controlled study

PRIMARY OBJECTIVE

To test the effectiveness of a cognitive training programme in children and adolescents with attention and memory deficits after acquired brain injury (ABI).

RESEARCH DESIGN

Randomized controlled study.

PARTICIPANTS

Thirty-eight children with ABI, 9-16 years of age.

METHODS AND PROCEDURES

The treatment group trained with the cognitive programme for 30 minutes per day interactively with a teacher or parent for a period of 17 weeks. Children in the control group had a freely chosen interactive activity 30 minutes daily for 17 weeks. Pre- and post-training assessments were made using a neuropsychological test battery.

MAIN OUTCOME AND RESULTS

Significant improvements in the majority of neuropsychological tests of sustained and selective attention as well as in memory performance were shown in the treatment group as compared to controls.

CONCLUSIONS

The immediate effect of the training programme improved complex attention and memory functions, indicating that this method may be a valuable treatment option for improving cognitive efficiency in children after ABI. On the basis of these results, the next step will be to evaluate long-term effects and further ecological validity.

Hypothermia following pediatric traumatic brain injury

Preclinical as well as clinical studies in traumatic brain injury (TBI) have established the likely association of secondary injury and outcome in adults in children following severe injury. Similarly, there is growing evidence in experimental laboratory studies that moderate hypothermia has a beneficial effect on outcome, though the exact mechanisms remain to be absolutely defined. The Pediatric TBI Guidelines provided the knowledge and background for standard management of children following severe TBI and highlighted that there are very few clinical studies to date. In particular with respect to temperature regulation and the use of hypothermia, initial findings of case series of small numbers were promising. Further preliminary randomized clinical trials, both single institution and multicenter, have provided the initial data on safety and efficacy, though larger, Phase III studies are necessary to ensure both the safety and efficacy of hypothermia in pediatric TBI prior to implementation as part of the standard of care. It is expected that hypothermia initiated early after severe TBI will have a protective effect on the pediatric brain and can be done safely, but this still remains to be definitively tested.

Mild traumatic brain injury and executive functions in school-aged children

OBJECTIVE

This study sought to examine the effects of mild traumatic brain injury (TBI) on executive functions in school-aged children.

PARTICIPANTS AND METHOD

The prospective, longitudinal study involved 8-15 year old children, 186 with mild TBI and 99 with mild orthopaedic injuries (OI). They were administered the Stockings of Cambridge and Spatial Working Memory sub-tests from the Cambridge Neuropsychological Testing Automated Battery (CANTAB) approximately 10 days, 3 months and 12 months post-injury. Parents completed the Behavior Rating Inventory of Executive Functions (BRIEF) on each occasion, with ratings at the initial assessment intended to assess pre-morbid functioning retrospectively.

RESULTS

On the CANTAB, the groups did not differ on the Stockings of Cambridge and the mild TBI group unexpectedly performed better than the OI group on Spatial Working Memory. On the BRIEF, children with mild TBI showed a marginally significant trend toward more problems than the OI group on the Metacognition Index composite. The only BRIEF sub-scale on which they demonstrated significantly more problems was Organization of Materials. The presence of intracranial abnormalities on MRI was associated with more problems on the BRIEF Organization of Materials sub-scale at 3 months, but other findings were not consistent with hypothesized effects of TBI severity. The CANTAB sub-tests were significant predictors of later ratings on the BRIEF, but accounted for modest variance.

DISCUSSION

Children with mild TBI show limited evidence of deficits in executive functions, either cognitively or behaviourally, irrespective of injury characteristics. Cognitive tests of executive functions are modest predictors of ratings of executive functions in everyday life, for children both with and without mild TBI.

Midline brain injury in the immature rat induces sustained cognitive deficits, bihemispheric axonal injury and neurodegeneration

Infants and children less than 4 years old suffer chronic cognitive deficits following mild, moderate or severe diffuse traumatic brain injury (TBI). It has been suggested that the underlying neuropathologic basis for behavioral deficits following severe TBI is acute brain swelling, subarachnoid hemorrhage and axonal injury. To better understand mechanisms of cognitive dysfunction in mild-moderate TBI, a closed head injury model of midline TBI in the immature rat was developed. Following an impact over the midline suture of the intact skull, 17-day-old rats exhibited short apnea times (3-15 s), did not require ventilatory support and suffered no mortality, suggestive of mild TBI. Compared to un-injured rats, brain-injured rats exhibited significant learning deficits over the first week post-injury (p<0.0005), and, significant learning (p<0.005) and memory deficits (p<0.05) in the third post-injury week. Between 6 and 72 h, blood-brain barrier breakdown, extensive traumatic axonal injury in the subcortical white matter and thalamus, and focal areas of neurodegeneration in the cortex and hippocampus were observed in both hemispheres of the injured brain. At 8 to 18 days post-injury, reactive astrocytosis in the cortex, axonal degeneration in the subcortical white matter tracts, and degeneration of neuronal cell bodies and processes in the thalamus of both hemispheres were observed; however, cortical volumes were not different between un-injured and injured rat brains. These data suggest that diffuse TBI in the immature rat can lead to ongoing degeneration of both cell soma and axonal compartments of neurons, which may contribute, in part, to the observed sustained cognitive deficits.

Diffuse alterations in synaptic protein expression following focal traumatic brain injury in the immature rat

INTRODUCTION

The mechanisms responsible for cognitive decline after traumatic brain injury (TBI) in pediatric patients are poorly understood. The present study examined the potential role of synaptic alterations in this process by using an animal model of immature head injury to define the impact of TBI on expression of the synaptic protein, synaptophysin.

MATERIALS AND METHODS

After craniotomy, TBI was induced in postnatal day 17 (PND17) rats using controlled cortical impact delivered to the left hemisphere. NeuN, a neuronal marker, and synaptophysin expression were examined 1 day, 1 week, and 1 month after injury by immunohistochemistry and immunoblotting.

RESULTS

There were significant decreases in both NeuN and synaptophysin after 1 day and 1 week but not 1 month after injury within the hippocampus and neocortex adjacent to the impact site compared to sham-injured controls. The decrease in synaptophysin and NeuN was also noted in the contralateral hippocampus by 1 day after injury and in the contralateral neocortex by 1 week, indicating that changes in protein expression were not solely localized to the injury site but occurred in more distant regions as well.

DISCUSSION

In conclusion, the decrease and recovery in synaptophysin parallel the cognitive changes that occur after experimental TBI in the PND17 rat, which suggests that changes in this protein may contribute to cognitive declines after injury. The results also suggest that, in spite of the focal nature of the impact, diffuse alterations in protein expression can occur after immature TBI and may contribute to the subsequent cognitive dysfunction.

Delineating Communication Impairments Associated With Mild Traumatic Brain Injury

BACKGROUND

Mild traumatic brain injury (mTBI) without frank neurological disturbance has been linked to persistent physical, cognitive, and affective disturbances in some cases. The cognitive sequelae of this syndrome represent the most frequently studied symptoms, yet the legacy of such injuries on communicative functions remains largely undetermined.

METHODS

A detailed language profile of a 19-year-old woman, 1 year 10 months following mTBI is compared with a matched normative cohort of 10 participants with nonneurological impairment.

RESULTS

Deficits in attention, lexical access, complex lexical-semantic manipulation, response monitoring, and organization were revealed as a consequence of mTBI.

CONCLUSIONS

This profile provides support for hypotheses pertaining to neuronal fallout mechanisms within the frontal lobes as a consequence of mild neurological insult.

Skull Fracture During Infancy: A Five-Year Follow-Up

A group of 19 children, who had received a skull fracture during infancy, were assessed at least 5 years following injury. The majority of the group (89%) had received a mild traumatic brain injury (TBI), with the remaining two (11%) having a moderate injury. The neuropsychological, academic, and psychosocial functioning of the TBI group was compared to that of 20 orthopedic subjects. The two groups were matched on the variables of gender, age, and socio-economic status. The TBI group was impaired on tests of visual attention and memory for faces. The two groups did not differ significantly on measures of language, sensorimotor functions, or visuospatial functioning. There were no statistically significant differences between the two groups on academic performance, or parent and teacher reports of psychosocial functioning. It is concluded that while there is an absence of deficits in the vast majority of functions, skull fracture in infancy can result in enduring impairment in specific cognitive skills related to the processing of complex nonverbal stimuli.

Neuropsychological function in a group of patients 25 years after sustaining minor head injuries as children and adolescents

Previous studies suggest that neuropsychological impairment following mild to moderate pediatric head injury may become persistent and interrupt the normal course of intellectual development. In this study 45 subjects were assessed with a standardized neuropsychological test battery 25 years after sustaining mild to moderate head injury as children. Although the group scores in the normal range, significant relations between head injury severity and current neuropsychological function were found. The most important predictor of poor outcome was length of PTA at injury, EEG pathology, and loss of consciousness at injury. No significant influence of pre- and post-injury risk factors on current neuropsychological function was evident. The findings support the view that complicated mild and moderate paediatric head injury may heighten the risk of developing subtle neuropsychological problems later in life.

Advances in Postacute Rehabilitation After Childhood-Acquired Brain Injury

Despite traditional views, children do not necessarily recover well from brain injury. Residual functional impairments are commonly documented in physical, cognitive, educational, behavioral, and social domains and result in a significant, ongoing social and economic burden for the child's family and for the broader community. More recent acknowledgment of the serious, and often permanent, consequences of acquired brain injury in childhood has been paralleled by rapid advances in evidence-based, acute medical care and diagnostic technology. In contrast, child-based postacute rehabilitation and long-term interventions are less well developed. To date, child services have borrowed substantially from adult models, combining both direct therapies and interdisciplinary approaches. Despite their proliferation, and strong clinical support, such services are rarely the subject of rigorous evaluation and have given little acknowledgment to the important developmental factors that need to be considered when working with children. Using a developmental framework, this review aims to consider the nature of functional impairments that result from childhood traumatic brain injury, the recovery process postinjury, and the scope and role of child-based rehabilitation. In addition, the relatively scarce body of literature describing the evaluation of child rehabilitation models are reviewed with an emphasis on identifying approaches that provide evidence of enhanced function in the child's everyday life and, in particular, in the home and school contexts.

The Use of Serum Biomarkers to Predict Outcome After Traumatic Brain Injury in Adults and Children

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in adults and children. Predicting outcome after TBI is difficult, but it is important for acute management, counseling of family members, and provision of rehabilitation services. Serum biomarkers may be useful alone or in combination with clinical variables to predict outcome after TBI. This article reviews the potential uses of serum biomarkers for the clinician, current literature related to the use of serum biomarkers for outcome prediction after adult and pediatric TBI, limitations of the literature, and future direction for this field.

Executive memory dysfunctions following mild traumatic brain injury

OBJECTIVES

To explore the contribution of executive dysfunctions to mnemonic problems in adults with mild traumatic brain injury (MTBI).

DESIGN

Prospective quasiexperimental between-groups design.

PARTICIPANTS

Ninety-nine persons with MTBI were compared to 90 control group participants matched for gender, age, and education.

SETTING

Two Canadian brain injury rehabilitation programs.

MAIN OUTCOME MEASURE

California Verbal Learning Test.

RESULTS

Participants with MTBI showed a significant deficit in free recall on the California Verbal Learning Test but performed similarly to the comparison group on the recognition task. Furthermore, the participants with MTBI were less likely to use semantic clustering as a memorizing strategy and made more intrusion errors and false-positive errors on the recognition task.

CONCLUSIONS

While the scores for the participants with MTBI are only slightly lower than the norm, they demonstrate that MTBI has a negative effect on mnemonic performance. The results are explained in terms of a deficit in registration/retrieval processes rather than a malfunction of the storage processes. This supports the initial hypothesis that executive dysfunctions are detrimental to the quality of mnemonic functions in patients with MTBI.

Neurobehavioral Effects of Amantadine After Pediatric Traumatic Brain Injury

OBJECTIVE

To investigate the safety and efficacy of a dopamine agonist, amantadine hydrochloride (AMH), in the treatment of neurobehavioral sequelae of pediatric TBI.

PROCEDURES

Age- and severity-matched traumatic brain injury groups, randomized to AMH (n = 17) or usual care (n = 10), completed behavior scales and neuropsychological tests. Effect sizes measured the treatment effect within subjects and between groups. Side effects were tracked over the 12-week study course.

RESULTS

Behavior improved in the AMH group, but only those 2 years or fewer postinjury showed a treatment effect on cognitive tests.

CONCLUSIONS

After traumatic brain injury, a 12-week course of AMH was safe and, according to parent report, improved behavior. AMH may have the potential to improve cognition in more recently injured children.

Protective effect of melatonin against head trauma-induced hippocampal damage and spatial memory deficits in immature rats

It is well known that head trauma induces the cognitive dysfunction resulted from hippocampal damage. In the present study, we aimed to demonstrate the effect of melatonin on hippocampal damage and spatial memory deficits in 7-day-old rat pups subjected to contusion injury. Melatonin was injected intraperitoneally at the doses of 5 or 20 mg/kg of body weight immediately after induction of traumatic injury. Hippocampal damage was examined by cresyl violet staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Spatial memory performance was assessed in the Morris water maze. Melatonin significantly attenuated trauma-induced neuronal death in hippocampal CA1, CA3 regions and dentate gyrus, and improved spatial memory deficits, which was equally effective at doses of 5-20 mg/kg. The present results suggest that melatonin is a highly promising agent for preventing the unfavorable outcomes of traumatic brain injury in young children.

The long-term effects of mild head injury on short-term memory for visual form, spatial location, and their conjunction in well-functioning university students

Research has suggested the presence of subtle long-term cognitive changes in otherwise well-functioning individuals who have previously sustained a mild head injury (MHI). This paper investigated the long-term effects of MHI on visual, spatial, and visual-spatial short-term memory in well-functioning university students. Sixteen students who reported having sustained a MHI were compared to 16 controls on tests of short-term memory (STM) for abstract polygons in haphazardly arranged locations. The three tests differed only in the requirements for recall (shapes for the visual task, locations for the spatial task, and the shapes in their respective locations for the visual-spatial task). MHI participants were selectively impaired on spatial memory, suggesting that tasks of spatial STM may be more sensitive, compared to tasks of visual STM, to the subtle long-term cognitive changes that may be present after a MHI.

The Status of Empirical Support for Treatments of Attention Deficits

Deficits in attention and self-regulation are common complaints associated with a number of disorders across the lifespan. The need to address attentional deficits is based on the premise that attention is a precursor and prerequisite to information processing and related cognitive tasks as well as a key factor in the success of other rehabilitation efforts. Many treatment programs have been developed with the intention of restoring or rehabilitating the impaired components of attention; the number and variety of attention programs is increasing rapidly. The purpose of this article is to evaluate available empirical support regarding the efficacy of treatments for remediation of attention deficits across disorders and age levels. The search of the major databases yielded 83 studies that included treatment of attentional deficits. Empirical studies were reviewed and categorized by the type of trial, whether or not the study included a control group, and the nature of the control group. The methodology and results of each study were then rated. For each treatment identified, the aggregated studies were then considered by the disorder of the samples included in the studies. Results indicated that, regardless of the treatment program or population, the existing research does not provide sufficient evidence to reach any conclusions about the efficacy of programs designed to address attention deficits. Before any conclusions, positive or negative, can be drawn, there is a need for more rigorous study of available treatment programs across age levels and disorders, with sufficient baseline and outcome data as well as control or alternative treatment conditions.

Recovery from mild head injury in pediatric populations

This article provides an overview of the diagnosis, classification, and pathophysiology of mild head injury (MHI) in children. The difficulties associated with determination of MHI severity are outlined. Also, recently published research pertaining to pediatric MHI is reviewed. The recent research pertaining to MHI in children is generally consistent with the conclusions reached by the authors of the most recent comprehensive review, which reported that children who have suffered MHI often experience a symptomatic phase that could extend up to a few months, but these symptoms usually resolve. Numerous preinjury variables have been identified, including premorbid learning and behavior problems, disadvantaged socioeconomic status, premorbid neurodevelopmental abnormalities, and adverse family conditions, that appear to explain the persistence of some symptoms experienced by a subset of children with MHI. Directions for future research are provided.

Long term psychosocial outcomes after mild head injury in early childhood

OBJECTIVES

The question of whether any adverse cognitive or psychosocial outcomes occur after mild head injury in early childhood has evoked considerable controversy. This study examined mild head injury before age 10 and potential differences in late childhood/early adolescence as a function of severity of mild injury and age at injury.

METHODS

A fully prospective longitudinal design tracked a large birth cohort of children. Confirmed cases of mild head injury before age 10 were divided on the basis of outpatient medical attention (n=64-84) or inpatient observation (hospital overnight; n=26-28 ) and compared with the non-injured remainder of the cohort (reference group; n=613-807). A range of pre-injury and post-injury child and family characteristics were used to control for any potential confounds. Outcome after injury before and after age 5 was also assessed.

RESULTS

After accounting for several demographic, family, and pre-injury characteristics, the inpatient but not the outpatient group displayed increased hyperactivity/inattention and conduct disorder between ages 10 to 13, as rated by both mothers and teachers. Psychosocial deficits were more prevalent in the inpatient subgroup injured before age 5. No clear effects were evident for various cognitive/academic measures, irrespective of severity of mild injury or age at injury.

CONCLUSIONS

Most cases of mild head injury in young children do not produce any adverse effects, but long term problems in psychosocial function are possible in more severe cases, perhaps especially when this event occurs during the preschool years. The view that all mild head injuries in children are benign events requires revision and more objective measures are required to identify cases at risk.

Long-term dysfunction following diffuse traumatic brain injury in the immature rat

Children often suffer sustained cognitive dysfunction after severe diffuse traumatic brain injury (TBI). To study the effects of diffuse injury in the immature brain, we developed a model of severe diffuse impact (DI) acceleration TBI in immature rats and previously described the early motor and cognitive dysfunction posttrauma. In the present study, we investigated the long-term functional ability after DI (150 gm/2 m) compared to sham in the immature (PND 17) rat. Beam balance and inclined plane latencies were measured daily for 10 days after injury to assess gross vestibulomotor function. The Morris water maze (MWM) paradigm was evaluated monthly up to 3 months after DI and sham injuries. Reduced latencies on the balance beam and inclined plane were observed in DI rats (p < 0.05 vs. sham [n = 10 per group]) at 24 h and persisted for 10 days postinjury. DI produced sustained MWM performance deficits (p < 0.05 vs. sham) as indicated by the greater latencies to find the hidden platform remarkably through 90 days after injury. Lastly, the brain and body weights of the injured animals were less than sham (p < 0.05) after 3 months. We conclude that a diffuse TBI in the immature rat: (a) created a consistent, marked, but reversible motor deficit up to 10 days following injury; (b) produced a long-term, sustained performance deficit in the MWM up to 3 months posttrauma; and (c) affected body and brain weight gain in the developing rat through 3 months after injury. This TBI model should be useful for the testing of novel therapies and their effect on long-term outcome and development in the immature rat.

Postconcussive symptoms in children with mild closed head injuries

OBJECTIVE

To examine the incidence and neuropsychological, behavioral, and neuroimaging correlates of postconcussive symptoms (PCS) in children with mild closed head injuries (CHI).

DESIGN

26 Children with mild CHI and 8 of their uninjured siblings, from 8 to 15 years old, were recruited prospectively and assessed at baseline (ie, within 7 days of injury) and at 3 months postinjury. Parents rated PCS, motivation and affective lability, and behavioral adjustment. Baseline ratings assessed premorbid functioning retrospectively, and follow-up ratings assessed postinjury status. On both occasions, children completed neuropsychological testing, and those with mild CHI also underwent magnetic resonance imaging (MRI).

RESULTS

Children with mild CHI did not differ from siblings in baseline ratings of premorbid PCS but displayed higher ratings on several PCS at 3 months postinjury. Thirty-five percent of children with mild CHI showed increases in PCS, compared with baseline premorbid ratings, but none of the siblings did so. Children with mild CHI whose PCS increased from premorbid levels showed poorer neuropsychological functioning at baseline than did children whose PCS did not increase, although the differences had partially resolved by 3 months. They also displayed decreased motivation over time. Their behavioral adjustment was poorer and they had smaller white matter volumes on MRI, but the latter differences were present at baseline and did not change over time, suggesting that they existed prior to the injury.

CONCLUSION

Postinjury increases in PCS occur in a sizable minority of children with mild CHI and more often than among uninjured siblings. Increases in PCS following mild CHI are associated with premorbid neurological and psychosocial vulnerability, but also with postinjury decrements in neuropsychological and neurobehavioral functioning.

Motor and cognitive functional deficits following diffuse traumatic brain injury in the immature rat

To determine the motor and cognitive deficits following a diffuse severe traumatic brain injury (TBI) in immature Sprague Dawley rats (17 days), four groups of animals were injured at different severity levels using a new closed head weight drop model: (sham, severe injury [SI: 100 g/2 m], SH [SI + hypoxemia (30 min of an FiO2 of 8% posttrauma)], and ultra severe injury [US: 150 g/2 m]). Latency on beam balance, grip test performance, and maintenance of body position on an inclined board were measured daily after injury to assess vestibulomotor function. Cognitive function was assessed on days 11-22 using the Morris water maze (MWM). Balance beam latency and inclined plane body position were reduced in both SI and SH rats (n = 20) (p < 0.05 vs. sham) (maximally at 24 h), and lasted 3-4 day postinjury; however, SH did not differ from SI. In the US group (n = 10), motor deficits were profound at 24 h (p < 0.05 vs. all other groups) and persisted for 10 days. The groups did not differ on grip test. In cognitive performance, there were no differences between sham, SI, and SH. US, however, produced significant cognitive dysfunction (vs. sham, SI, and SH), specifically, greater latencies to find the hidden platform through 22 days. Swim speeds were not significantly different between any of the injury groups and shams. These data indicate that (1) beam balance, inclined plane and MWM techniques are useful for assessing motor and cognitive function after TBI in immature rats; (2) SI produces motor but not cognitive deficits, which was not augmented by transient hypoxia; and (3) US created a marked but reversible motor deficit up to 10 days, and a sustained cognitive dysfunction for up to 22 days after TBI.

Management of attention and memory disorders following traumatic brain injury

Disorders of attention, memory, and executive function are common sequelae in children who have sustained traumatic brain injuries. Given the persistent nature of these deficits, there is a need for efficacious remedial approaches. Typically, remediation is approached, through one of three general intervention strategies: externally focused interventions aimed at changing the environment so that the effect of the dysfunction is minimized, internally focused interventions aimed at improving the underlying cognitive ability, and compensatory interventions aimed at teaching children to use alternate strategies that lessen the impact of the dysfunction. This article describes current research involving these approaches for the treatment of attention and memory disorders in children.

Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET)

The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.

Neuropsychological differences between college students with learning disabilities and those with mild head injury

College students with learning disabilities (LD) and those with a history of mild head injury (MHI) are two groups whose learning problems are not adequately addressed. We administered a comprehensive battery of neuropsychological, psychological, and academic achievement tests to college students with learning problems (LD, n = 35; MHI, n = 25) and a control group (n = 22), and completed a series of discriminant function analyses. A combination of six neuropsychological and psychoeducational test variables produced statistically significant differences among the three groups. The instruments were sensitive to LD, MHI, and the differences between them. The students with LD performed poorly on linguistically oriented psychoeducational tests, whereas the students with MHI showed cognitive deficits in visual-spatial skills and in the areas of attention, memory, and novel problem solving. Differential interventions addressing these deficits appear to be indicated.