Posttraumatic epilepsy: neuroradiologic and neuropsychological assessment of long-term outcome

Post-Traumatic Epilepsy: Observations from an Urban Level 1 Trauma Center

There are approximately 2.5 million cases of traumatic brain injury (TBI) in the U.S. each year. Post-traumatic epilepsy (PTE), a sequela of TBI, has been shown to occur in approximately 15% of TBI patients. Pre-disposing risk factors for the development of PTE include severe TBI and penetrating head injury. PTE is associated with poor functional outcomes, increased negative social factors, and mental illness. We conducted a retrospective chart review with a 5-year timeframe at an urban Level 1 Trauma Center. Patients with ICD-10-CM codes associated with TBI were identified. Patients were coded as TBI with or without PTE by the presence of codes associated with PTE. Datapoints collected included risk factors for PTE and encounters with neurologists. A total of 1886 TBI patients were identified, with 178 (9.44%) classified as TBI with PTE. The most significant risk factor associated with PTE was severe brain injury, with an odds ratio (OR) of 2.955 (95% CI [2.062,4.236]; p < 0.0001). Only 19 of 178 patients (10.7%) visited a neurologist beyond 6 months after TBI. Our results suggest the presence of a significant population of patients with PTE and the need for better follow-up.

Hospital-acquired infections as a risk factor for post-traumatic epilepsy: A registry-based cohort study

OBJECTIVE

Hospital-acquired infections are a common complication for patients with moderate or severe traumatic brain injury (TBI), contributing to morbidity and mortality. As infection-mediated immune responses can predispose towards epilepsy, we hypothesized that post-injury hospital-acquired infections increase the risk of post-traumatic epilepsy (PTE).

METHODS

A retrospective cohort study of adults with moderate to severe TBI was conducted using data from the Victorian State Trauma Registry in Australia. Infections were identified from the International Statistical Classification of Diseases and Related Health Problems 10th Revision-Australian Modification (ICD-10-AM) codes, and diagnosis of PTE was determined by the Glasgow Outcome Scale - Extended questionnaire regarding epileptic fits at 24 months follow-up.

RESULTS

Of all TBI patients (n = 15 152), 24% had evidence of having had any type of infection, with the most common being pneumonia, urinary tract, and respiratory infections. Of those who responded to the PTE question at 24 months (n = 1361), 11% had developed PTE. Univariable analysis found that the incidence of PTE was higher in patients who had any type of infection compared to patients without an infection (p < 0.001). After adjustment for covariates associated with both development of PTE and risk of infection, multivariable analysis found a solid association between infection and PTE (adjusted RR = 1.59; 95% CI: 1.11-2.28; p = 0.011). Having any type of complicating infection acquired during admission was also associated with poor GOSE outcomes at subsequent follow-ups (adjusted OR = 0.20; 95% CI: 0.11-0.35, p < 0.001).

SIGNIFICANCE

These findings suggest that hospital-acquired infections contribute to PTE development after TBI. Future investigation into infections as a modifiable target to reduce poor outcomes after TBI is warranted.

PLAIN LANGUAGE SUMMARY

Hospital-acquired infections are common in patients with traumatic brain injuries. A database study of adults with moderate or severe brain injuries in Australia examined whether these infections are associated with the development of epilepsy after a brain injury. 24% of patients had infections, with pneumonia and urinary tract infections being the most common. Of those surveyed 2 years after the injury, 11% developed post-traumatic epilepsy. Patients with infections had a significantly higher risk of epilepsy, even when accounting for other known risk factors, and infections were also linked to poor outcomes more broadly. The study suggests that preventing hospital-acquired infections could be a crucial target for improving outcomes after traumatic brain injuries.

Investigation of the Effect of Antiseizure Medications on Cognition in Patients With Epilepsy

Background. The effect of antiseizure medications (ASMs) on cognition varies depending on the type of ASM. We aimed to investigate the effects of ASMs on patients with epilepsy based on the conflicting findings in the literature. Methods. Patients diagnosed with epilepsy who were taking ASMs were included. All patients underwent a neuropsychiatric assessment, Beck Depression and Anxiety Inventories, Positive and Negative Syndrome Scale, and general psychopathological tests. The patients were divided into polytherapy and monotherapy groups. Subgroups were categorized according to the type of ASMs, dosage, and duration of monotherapy. Results. Ninety-seven patients were included in this study. The polytherapy group showed a significant decrease in attention, total learning, and interpretation of proverbs compared to the monotherapy group. In the monotherapy group, carbamazepine use had a moderate positive correlation with working memory (r = .669; P = .034), and a strong negative correlation with maintaining attention (r = -.740; P = .014). The duration of levetiracetam monotherapy was negatively correlated with verbal memory (immediate recall r = -.436, P = .038; free recall r = .426, P = .043) and negatively weakly correlated with naming performance (r = -.488, P = .025). Conclusion. The study showed polytherapy may affect verbal and working memory. Carbamazepine may affect working memory and the maintenance of attention in a dose-dependent manner. Levetiracetam may cause impairments in verbal memory and naming, depending on the duration of usage.

Insights into epileptogenesis from post-traumatic epilepsy

Post-traumatic epilepsy (PTE) accounts for 5% of all epilepsies. The incidence of PTE after traumatic brain injury (TBI) depends on the severity of injury, approaching one in three in groups with the most severe injuries. The repeated seizures that characterize PTE impair neurological recovery and increase the risk of poor outcomes after TBI. Given this high risk of recurrent seizures and the relatively short latency period for their development after injury, PTE serves as a model disease to understand human epileptogenesis and trial novel anti-epileptogenic therapies. Epileptogenesis is the process whereby previously normal brain tissue becomes prone to recurrent abnormal electrical activity, ultimately resulting in seizures. In this Review, we describe the clinical course of PTE and highlight promising research into epileptogenesis and treatment using animal models of PTE. Clinical, imaging, EEG and fluid biomarkers are being developed to aid the identification of patients at high risk of PTE who might benefit from anti-epileptogenic therapies. Studies in preclinical models of PTE have identified tractable pathways and novel therapeutic strategies that can potentially prevent epilepsy, which remain to be validated in humans. In addition to improving outcomes after TBI, advances in PTE research are likely to provide therapeutic insights that are relevant to all epilepsies.

Posttraumatic Epilepsy and Dementia Risk

Importance

Although both head injury and epilepsy are associated with long-term dementia risk, posttraumatic epilepsy (PTE) has only been evaluated in association with short-term cognitive outcomes.

Objective

To investigate associations of PTE with dementia risk.

Design, Setting, and Participants

The Atherosclerosis Risk in Communities (ARIC) study initially enrolled participants from 1987 to 1989 and this prospective cohort study uses data through December 31, 2019, with a median follow-up of 25 years. Data were analyzed between March 14, 2023, and January 2, 2024. The study took place in 4 US communities in Minnesota, Maryland, North Carolina, and Mississippi. Of 15 792 ARIC study participants initially enrolled, 2061 were ineligible and 1173 were excluded for missing data, resulting in 12 558 included participants.

Exposures

Head injury was defined by self-report and International Classification of Diseases (ICD) diagnostic codes. Seizure/epilepsy was defined using ICD codes. PTE was defined as a diagnosis of seizure/epilepsy occurring more than 7 days after head injury. Head injury, seizure/epilepsy, and PTE were analyzed as time-varying exposures.

Main Outcomes and Measures

Dementia was defined using cognitive assessments, informant interviews, and ICD and death certificate codes. Adjusted Cox and Fine and Gray proportional hazards models were used to estimate dementia risk.

Results

Participants had a mean (SD) age of 54.3 (5.8) years at baseline, 57.7% were female, 28.2% were of self-reported Black race, 14.4% were ultimately categorized as having head injury, 5.1% as having seizure/epilepsy, and 1.2% as having PTE. Over a median follow-up of 25 (25th to 75th percentile, 17-30) years, 19.9% developed dementia. In fully adjusted models, compared with no head injury and no seizure/epilepsy, PTE was associated with 4.56 (95% CI, 4.49-5.95) times the risk of dementia, while seizure/epilepsy was associated with 2.61 (95% CI, 2.21-3.07) times the risk and head injury with 1.63 (95% CI, 1.47-1.80) times the risk. The risk of dementia associated with PTE was significantly higher than the risk associated with head injury alone and with nontraumatic seizure/epilepsy alone. Results were slightly attenuated in models accounting for the competing risks of mortality and stroke, but patterns of association remained similar. In secondary analyses, the increased dementia risk associated with PTE occurring after first vs second head injury and after mild vs moderate/severe injury was similar.

Conclusions and Relevance

In this community-based cohort, there was an increased risk of dementia associated with PTE that was significantly higher than the risk associated with head injury or seizure/epilepsy alone. These findings provide evidence that PTE is associated with long-term outcomes and supports both the prevention of head injuries via public health measures and further research into the underlying mechanisms and the risk factors for the development of PTE, so that efforts can also be focused on the prevention of PTE after a head injury.

Neuropsychological Impairments in Patients With Post-traumatic Epilepsy: A Scoping Review

OBJECTIVES

To date, the research on the prognosis of the neuropsychological function of patients with post-traumatic seizure (PTE) is sparse. This study aimed to systematically map the literature's extent, range, and characteristics regarding PTE and neuropsychological impairments.

METHODS

A systematic literature search was conducted in CINAHL, Cochrane, Embase, Medline, PubMed, Scopus, Web of Science, and ScienceDirect databases. The search terms were related to PTE and neuropsychological impairments.

RESULTS

This scoping review included seven studies, two of which examined the impact of PTE on neuropsychological outcomes. Among the three studies that used neuropsychological assessments, attention/concentration, and memory were the most frequently assessed domains. Only one study reported a significant difference between PTE and non-PTE patients. The cognitive rating scale findings in the other four studies were similar, indicating that patients with PTE performed worse than those without PTE.

CONCLUSIONS

The results of this review suggest that patients with PTE may have neuropsychological function impairments. More attention needs to be paid to older patients and those with higher brain injury and seizure severity. Additional investigation is necessary to determine the clinical characteristics of TBI and PTE and elucidate the relations between PTE and specific neuropsychological domains.

Incidence and risk factors of posttraumatic epilepsy following pediatric traumatic brain injury: A systematic review and meta-analysis

Posttraumatic epilepsy (PTE) is a well-known chronic complication following traumatic brain injury (TBI). Despite some evidence that age at the time of injury may influence the likelihood of PTE, the incidence of PTE in pediatric populations remains unclear. We therefore conducted a systematic review to determine the overall reported incidence of PTE, and explore potential risk factors associated with PTE after pediatric TBI. A comprehensive literature search of the PubMed, Embase, and Web of Science databases was conducted, including randomized controlled trials and cohort studies assessing the incidence of PTE in TBI pediatric patients. We excluded studies with a sample size of <10 patients and those in which a pediatric cohort was not clearly discernable. The review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We found that the overall incidence of PTE following pediatric TBI was 10% (95% confidence interval [CI] = 5.9%-15%). Subgroup analysis of a small number of studies demonstrated that the occurrence of early seizures (cumulative incidence ratio [CIR] = 7.28, 95% CI = 1.09-48.4, p = .040), severe TBI (CIR = 1.81, 95% CI = 1.23-2.67, p < .001), and intracranial hemorrhage (CIR = 1.60, 95% CI = 1.06-2.40, p = .024) increased the risk of PTE in this population. Other factors, including male sex and neurosurgical intervention, were nonsignificantly associated with a higher incidence of PTE. In conclusion, PTE is a significant chronic complication following childhood TBI, similar to in the adult population. Further standardized investigation into clinical risk factors and management guidelines is warranted. PROSPERO ID# CRD42021245802.

The Legacy of the TTASAAN Report-Premature Conclusions and Forgotten Promises: A Review of Policy and Practice Part I

Brain perfusion single photon emission computed tomography (SPECT) scans were initially developed in 1970's. A key radiopharmaceutical, hexamethylpropyleneamine oxime (HMPAO), was originally approved in 1988, but was unstable. As a result, the quality of SPECT images varied greatly based on technique until 1993, when a method of stabilizing HMPAO was developed. In addition, most SPECT perfusion studies pre-1996 were performed on single-head gamma cameras. In 1996, the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (TTASAAN) issued a report regarding the use of SPECT in the evaluation of neurological disorders. Although the TTASAAN report was published in January 1996, it was approved for publication in October 1994. Consequently, the reported brain SPECT studies relied upon to derive the conclusions of the TTASAAN report largely pre-date the introduction of stabilized HMPAO. While only 12% of the studies on traumatic brain injury (TBI) in the TTASAAN report utilized stable tracers and multi-head cameras, 69 subsequent studies with more than 23,000 subjects describe the utility of perfusion SPECT scans in the evaluation of TBI. Similarly, dementia SPECT imaging has improved. Modern SPECT utilizing multi-headed gamma cameras and quantitative analysis has a sensitivity of 86% and a specificity of 89% for the diagnosis of mild to moderate Alzheimer's disease-comparable to fluorodeoxyglucose positron emission tomography. Advances also have occurred in seizure neuroimaging. Lastly, developments in SPECT imaging of neurotoxicity and neuropsychiatric disorders have been striking. At the 25-year anniversary of the publication of the TTASAAN report, it is time to re-examine the utility of perfusion SPECT brain imaging. Herein, we review studies cited by the TTASAAN report vs. current brain SPECT imaging research literature for the major indications addressed in the report, as well as for emerging indications. In Part II, we elaborate technical aspects of SPECT neuroimaging and discuss scan interpretation for the clinician.

Post-Traumatic Epilepsy and Comorbidities: Advanced Models, Molecular Mechanisms, Biomarkers, and Novel Therapeutic Interventions

Post-traumatic epilepsy (PTE) is one of the most devastating long-term, network consequences of traumatic brain injury (TBI). There is currently no approved treatment that can prevent onset of spontaneous seizures associated with brain injury, and many cases of PTE are refractory to antiseizure medications. Post-traumatic epileptogenesis is an enduring process by which a normal brain exhibits hypersynchronous excitability after a head injury incident. Understanding the neural networks and molecular pathologies involved in epileptogenesis are key to preventing its development or modifying disease progression. In this article, we describe a critical appraisal of the current state of PTE research with an emphasis on experimental models, molecular mechanisms of post-traumatic epileptogenesis, potential biomarkers, and the burden of PTE-associated comorbidities. The goal of epilepsy research is to identify new therapeutic strategies that can prevent PTE development or interrupt the epileptogenic process and relieve associated neuropsychiatric comorbidities. Therefore, we also describe current preclinical and clinical data on the treatment of PTE sequelae. Differences in injury patterns, latency period, and biomarkers are outlined in the context of animal model validation, pathophysiology, seizure frequency, and behavior. Improving TBI recovery and preventing seizure onset are complex and challenging tasks; however, much progress has been made within this decade demonstrating disease modifying, anti-inflammatory, and neuroprotective strategies, suggesting this goal is pragmatic. Our understanding of PTE is continuously evolving, and improved preclinical models allow for accelerated testing of critically needed novel therapeutic interventions in military and civilian persons at high risk for PTE and its devastating comorbidities.

An Interplay Between Post-Traumatic Epilepsy and Associated Cognitive Decline: A Systematic Review

Background

Post-traumatic epilepsy (PTE) is a devastating neurological outcome of traumatic brain injury (TBI), which may negatively impact the quality of life of patients with TBI, and may impose a huge socioeconomic burden. This burden may be due to long-term functional outcomes associated with PTE, particularly cognitive dysfunction. To date, the relationship between TBI and PTE remains unclear, with little known about how the effect of their link on cognitive function as well.

Objective

Thus, this systematic review aimed at elucidating the relationship between PTE and cognitive impairment in adults after TBI based on available clinical studies, in hopes to aid in the development of therapeutic strategies for PTE.

Methods

A systematic literature search was performed using 6 databases; MEDLINE, Embase, CINAHL, Psych INFO, Web of Science, and Cochrane to retrieve relevant clinical studies investigating the link between PTE and cognition in the context of TBI. The Newcastle-Ottawa Scale (NOS) was used to assess the methodological quality of relevant studies.

Results

A total of six eligible studies were included for critical appraisal in this review after performing the inclusion and exclusion criteria, which involved 1,100 individuals, from 1996 to 2021. The selected studies were derived from the civilian and military population, with a follow-up period that ranged from 6 months to 35 years. The average quality of the involved studies was moderate (6.6, SD = 1.89). Five out of six studies found poorer cognitive performance in people with PTE, compared with those without PTE. Although the association between PTE and cognitive impairment was insignificant after controlling for specific covariates, there was a statistical trend toward significance.

Conclusion

This systematic review suggests that there may be a possible link between PTE and cognitive decline in TBI patients, with the latter being reported to occur up to 35 years post injury. Variations in sample sizes, follow-up periods, and neuropsychological assessment tools may be the limitations affecting the interpretation and significance of this relationship. Therefore, future studies with standard cognitive assessment tools may be warranted to solidify the link between TBI-PTE-cognitive dysfunction, prior to the development of therapeutic strategies.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020221702, prospero identifier: CRD42020221702.

Ferrostatin-1 obviates seizures and associated cognitive deficits in ferric chloride-induced posttraumatic epilepsy via suppressing ferroptosis

Posttraumatic epilepsy (PTE) is a prevalent complication of brain trauma. Current anti-epileptic drugs available do not have satisfactory response to PTE. It is of desperate need to explore novel therapeutic approaches for curing PTE. Our prior work revealed that ferroptosis, a recently discovered mode of cell death, occurs in rodent model of PTE. In the present study, we aimed to further investigate the effect of ferrostatin-1 (Fer-1), a specific ferroptosis inhibitor, on seizure behavior and cognitive deficit in a mouse model of PTE. The preparation of PTE was performed by stereotaxical injection in the somatosensory cortex region of 50 mM FeCl₃. Seizure activity was assessed via Racine scoring and electroencephalogram analysis. PTE-related cognitive function was evaluated by novel object recognition and Morris water maze tests. Ferroptosis-related indices including glutathione peroxidase (GPx) activity and protein expressions of 4-hydroxynonenal (4-HNE) were detected using a commercial kit and immunofluorescence, respectively. It was found that treatment with Fer-1 significantly exerted protective effects against acute seizure and memory decline, although no evident effect on epileptic progression. Fer-1 also exhibited good tolerability and safety as we observed that it hardly influenced the body weight. Furthermore, it was noted that administration of Fer-1 suppressed ferroptosis-related indices including GPx activity and protein expressions of 4-HNE in hippocampus. These data altogether indicate that Fer-1 has potent therapeutic effects against seizures and cognitive impairment following PTE-induced brain insult. Fer-1 may act as a promising drug for curing PTE patients.

Post-Traumatic Epilepsy in Zebrafish Is Drug-Resistant and Impairs Cognitive Function

Post-traumatic epilepsy (PTE) is acquired epilepsy after traumatic brain injury (TBI). Despite the availability of more than 20 antiseizure medications (ASMs), there is no way at present to prevent epileptogenesis in TBI survivors, and many cases of PTE become drug-resistant. Importantly, the adverse effects of ASMs can significantly affect patients' quality of life. Mammalian models are commonly used for studying refractory PTE, but are expensive and laborious. Zebrafish models have become popular for studying epilepsy, but most focus on larvae, and there have been no reports to date of pharmacological screening in an adult zebrafish model of acquired epilepsy. Valid animal models are critical for understanding PTE and for developing novel therapeutics. The aim of the present study was to characterize the cognitive impairments of a zebrafish model of TBI that leads to the development of PTE. Using combined behavioral and electrophysiological approaches, we also characterized the pharmacological effects of the most commonly used ASMs to manage PTE (valproate, carbamazepine, and phenytoin). Zebrafish with PTE exhibited impairments in learning and memory, difficulty in decision making, and reduced social preference. Valproate and carbamazepine had a limited protective effect against behavioral seizures, and all three drugs failed to significantly reduce electrographical seizures. The negative impacts of TBI and ASMs in zebrafish parallel those observed in other animals, making the zebrafish model of PTE a promising high-throughput model of refractory and drug-resistant epilepsy.

Incidence of post-traumatic epilepsy following paediatric traumatic brain injury: protocol for systematic review and meta-analysis

INTRODUCTION

Post-traumatic epilepsy (PTE) is a recognised complication of traumatic brain injury (TBI), and is associated with higher rates of mortality and morbidity when compared with patients with TBI who do not develop PTE. The majority of the literature on PTE has focused on adult populations, and consequently there is a paucity of information regarding paediatric cohorts. Additionally, there is considerable heterogeneity surrounding the reported incidence of PTE following childhood TBI in the current literature. The primary aim of our study is to summarise reported PTE incidences in paediatric populations to derive an accurate estimate of the global incidence of PTE following childhood TBI. Our secondary aim is to explore risk factors that increase the likelihood of developing PTE.

METHODS AND ANALYSIS

A systematic literature search of Embase (1947-2021), PubMed (1996-2021) and Web of Science (1900-2021) will be conducted. Publications in English that report the incidence of PTE in populations under 18 years of age will be included. Publications that evaluate fewer than 10 patients, report an alternative cause of epilepsy, or in which a paediatric cohort is not discernable, will be excluded. Independent investigators will identify the relevant publications, and discrepancies will be adjudicated by a third independent investigator. Data extracted will include incidence of PTE, time intervals between TBI and PTE, seizure characteristics, injury characteristics, patient demographics and clinical data. Data extraction will be performed by two independent investigators and cross-checked by a third investigator. A descriptive analysis of PTE incidence will be conducted and a weighted mean will be calculated. If sufficient data are available, stratified meta-analysis of subgroups will also be conducted.

ETHICS AND DISSEMINATION

Ethics approval was not required for this study. We intend to publish our findings in a high-quality peer-reviewed journal on completion.

PROSPERO REGISTRATION NUMBER

CRD42021245802.

Epilepsy in prolonged disorders of consciousness: a systematic review

To date, no guideline exists for the management of epilepsy in patients with prolonged Disorders of Consciousness (DoC). This review aimed to assess the occurrence of epilepsy and epileptic abnormalities (EA) in these patients, to determine their impact on recovery; and to review the effect of antiepileptic drugs (AED) and therapeutic interventions on seizure occurrence and consciousness recovery. A structured search for studies on prolonged DoC and epilepsy was undertaken following PRISMA guidelines. From an initial search resulting in 5,775 titles, twelve studies met inclusion criteria. The occurrence of epilepsy and EA in DoC was poorly and inconsistently reported across studies. The results estimated a seizure prevalence of 27% in DoC. No conclusive data were found for the effects of AED on recovery nor on the influence of any therapeutic interventions on seizure occurrence. Given the scarcity of data, it is premature to make evidence-based recommendations on epilepsy in prolonged DoC. Based on this review and current clinical practices the following are recommended: (1) repeated standard EEG for detecting seizures and EA; (2) treating epilepsy while avoiding AEDs with sedating or cognitive side-effects. Future research should use standardized classification systems for seizures and EA.

In-depth characterization of a mouse model of post-traumatic epilepsy for biomarker and drug discovery

Post-traumatic epilepsy (PTE) accounts for 5% of all epilepsies and 10–20% of the acquired forms. The latency between traumatic brain injury (TBI) and epilepsy onset in high-risk patients offers a therapeutic window for intervention to prevent or improve the disease course. However, progress towards effective treatments has been hampered by the lack of sensitive prognostic biomarkers of PTE, and of therapeutic targets. There is therefore a pressing clinical need for preclinical PTE models suitable for biomarker discovery and drug testing. We characterized in-depth a model of severe TBI induced by controlled cortical impact evolving into PTE in CD1 adult male mice. To identify sensitive measures predictive of PTE development and severity, TBI mice were longitudinally monitored by video-electrocorticography (ECoG), examined by MRI, and tested for sensorimotor and cognitive deficits and locomotor activity. At the end of the video-ECoG recording mice were killed for brain histological analysis. PTE occurred in 58% of mice with frequent motor seizures (one seizure every other day), as determined up to 5 months post-TBI. The weight loss of PTE mice in 1 week after TBI correlated with the number of spontaneous seizures at 5 months. Moreover, the recovery rate of the sensorimotor deficit detected by the SNAP test before the predicted time of epilepsy onset was significantly lower in PTE mice than in those without epilepsy. Neuroscore, beam walk and cognitive deficit were similar in all TBI mice. The increase in the contusion volume, the volume of forebrain regions contralateral to the lesioned hemisphere and white matter changes over time assessed by MRI were similar in PTE and no-PTE mice. However, brain histology showed a more pronounced neuronal cell loss in the cortex and hippocampus contralateral to the injured hemisphere in PTE than in no-PTE mice. The extensive functional and neuropathological characterization of this TBI model, provides a tool to identify sensitive measures of epilepsy development and severity clinically useful for increasing PTE prediction in high-risk TBI patients. The high PTE incidence and spontaneous seizures frequency in mice provide an ideal model for biomarker discovery and for testing new drugs.

Development and external validation of a predictive nomogram model of posttraumatic epilepsy: A retrospective analysis

OBJECTIVE

We aimed to develop and validate a predictive model of posttraumatic epilepsy (PTE).

METHODS

The training cohort was patients registered at West China Hospital and diagnosed as traumatic brain injury (TBI) between January 1, 2011, and December 31, 2017. On the basis of multivariable cox proportional hazards model using a forward stepwise method, the nomogram was generated. We externally validated this instrument in 834 participants from two independent cohorts to assess its performance.

RESULTS

The nomogram was built based on the results of multivariable cox proportional hazards regression analysis of 1301patients from West China Hospital. The prevalence of PTE was 12.8% (95% confidence interval [CI], 10.9-14.6%) in training cohort, 10.5% (95% CI, 7.5-13.4%) in the testing 1 cohort, and 6.1% (95% CI, 3.7-8.4%) in the testing 2 cohort. 7 independent predictors of PTE composed the nomogram (sex, time of loss of consciousness, subdural hemorrhage, contusion sites, early posttraumatic seizures, TBI severity, and treatment). The C-index was 0.846 (95% CI, 0.817-0.876), and the corresponding sensitivity and specificity were 0.867 and 0.738. External validations showed good discrimination in overall testing cohorts with a C-index of 0.895 (95% CI, 0.859-0.930), in the testing 1 cohort (C-index 0.897, 95% CI, 0.855-0.938) and testing 2 cohort (C-index, 0.883, 95% CI, 0.814-0.952). Calibration of this model was also good since the calibration plots were close to the ideal line.

CONCLUSIONS

This nomogram was developed and validated in a large cohort for individualized prediction of PTE, which can identify individuals at high risk of epilepsy and help us find preventive drugs based on these targeted population.

Epilepsy after severe traumatic brain injury: frequency and injury severity

Objective: To estimate national frequency of posttraumatic epilepsy (PTE) after severe traumatic brain injury (TBI) and assess injury severity (Glasgow Coma Scale (GCS) and posttraumatic amnesia (PTA)) as prognostic factors for PTE.

METHODS

Data on patients ≥18 years surviving severe TBI 2004-2016 were retrieved from the Danish Head Trauma Database (n = 1010). The cumulative incidence proportion (CIP) was estimated using death as competing event. The association between injury severity and PTE was assessed using multivariable competing risk regressions.

RESULTS

CIP of PTE 28 days and one year post-TBI was 6.8% (95% confidence interval (CI) 5.4-8.5) and 18.5% (95% CI 16.1-21.1%), respectively. Injury severity was not associated with PTE within 28 days post-TBI but indicated higher PTE-rates in less severely injured patients. PTA-duration >70 days was associated with PTE 29-365 days post-TBI (Adjusted sub-hazard ratio 4.23 (95% CI 1.79-9.99)). GCS was not associated with PTE 29-365 days post-TBI.

CONCLUSION

The PTE frequency was higher compared to previous estimates. Increasing injury severity was associated with PTE 29-365 days post-TBI when measured with PTA, but not with GCS. Though nonsignificant, the increased PTE-risk within 28 days in lower severity suggests an underdiagnosing of PTE.

Psychiatric aspects of posttraumatic epilepsy: A still unexplored area

Traumatic brain injury (TBI) represents one of the most common causes of death and disability in young people, and posttraumatic epilepsy (PTE) accounts for 10% to 20% of all symptomatic epilepsies. However, PTE is still a relatively underappreciated condition. This paper aimed at reviewing current knowledge about psychiatric comorbidities of PTE, looking in particular at the nature of the relationship between TBI, psychiatric problems, and epilepsy, at the phenomenology of psychiatric disorders in PTE, and how to manage them. Data on psychiatric comorbidities of PTE are almost nonexistent, and this is a paradox considering that TBI itself is burdened by a number of cognitive and psychiatric sequelae, which can profoundly affect the everyday life of these patients. Preliminary data seem to suggest that the bidirectional relationship between epilepsy and psychiatric disorders is maintained in TBI and people with a psychiatric condition at the time of the TBI, or as a consequence of it, are at increased risk of developing PTE and vice versa. However, a number of questions are still unanswered concerning the genetic and environmental contributors, the phenomenology of psychiatric disorders in PTE, and how to prevent and address them properly. Further research in this area is urgently needed in order to provide the best possible care to people with PTE. Special Issue: Epilepsy & Behavior's 20th Anniversary.

Affective, neurocognitive and psychosocial disorders associated with traumatic brain injury and post-traumatic epilepsy

Survivors of traumatic brain injury (TBI) often develop chronic neurological, neurocognitive, psychological, and psychosocial deficits that can have a profound impact on an individual's wellbeing and quality of life. TBI is also a common cause of acquired epilepsy, which is itself associated with significant behavioral morbidity. This review considers the clinical and preclinical evidence that post-traumatic epilepsy (PTE) acts as a 'second-hit' insult to worsen chronic behavioral outcomes for brain-injured patients, across the domains of emotional, cognitive, and psychosocial functioning. Surprisingly, few well-designed studies have specifically examined the relationship between seizures and behavioral outcomes after TBI. The complex mechanisms underlying these comorbidities remain incompletely understood, although many of the biological processes that precipitate seizure occurrence and epileptogenesis may also contribute to the development of chronic behavioral deficits. Further, the relationship between PTE and behavioral dysfunction is increasingly recognized to be a bidirectional one, whereby premorbid conditions are a risk factor for PTE. Clinical studies in this arena are often challenged by the confounding effects of anti-seizure medications, while preclinical studies have rarely examined an adequately extended time course to fully capture the time course of epilepsy development after a TBI. To drive the field forward towards improved treatment strategies, it is imperative that both seizures and neurobehavioral outcomes are assessed in parallel after TBI, both in patient populations and preclinical models.

Memory Rehabilitation in Patients with Epilepsy: a Systematic Review

Memory failure is a common clinical concern of patients with epilepsy and is associated with significant functional impairments. Thus, memory rehabilitation is of critical clinical importance. In this article, we aimed to systematically evaluate the efficacy of memory rehabilitation in patients with epilepsy. The Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) was used to guide searches, extraction and reporting of data in this review. PsycINFO, Medline and PsychBITE searches yielded 95 studies. Twelve papers met inclusion criteria, reporting outcomes of cognitive or behavioural interventions that specifically targeted the rehabilitation of memory in patients with epilepsy. Methodological rigour was rated using the Single-Case Experimental Design (SCED) scale for single-case studies and a modified version of the Downs and Black checklist for group studies. Twelve prospective studies, nine group (six pre-post design, one waitlist crossover, two randomised controlled trials) and three single-case studies were identified. Eleven of the studies included adults, eight of which involved adults with temporal lobe epilepsy (TLE). One paediatric study was identified. The quality of group studies ranged from 36% (poor) to 72% (good), using the modified Downs and Black checklist. Single-case studies were assessed using the SCED scale and assessed to range in quality from four to seven out to 11. Overall, memory rehabilitation was associated with improved memory function in all studies. Verbal memory outcomes were most commonly examined and associated with improvements. This review found that the level of evidence available to support rehabilitation of memory in patients with epilepsy was generally weak and inconsistent. Nevertheless, studies conducted to date, albeit of limited methodological quality, offer preliminary evidence that memory rehabilitation is associated with improvements in verbal memory in patients with temporal lobe epilepsy. Little is known about the efficacy of memory rehabilitation in patients with non-TLE, children, and other aspects of memory difficulties. Guidelines for future research are proposed.

Traumatic Brain Injury Severity, Neuropathophysiology, and Clinical Outcome: Insights from Multimodal Neuroimaging

Background

The relationship between the acute clinical presentation of patients with traumatic brain injury (TBI), long-term changes in brain structure prompted by injury and chronic functional outcome is insufficiently understood. In this preliminary study, we investigate how acute Glasgow coma score (GCS) and epileptic seizure occurrence after TBIs are statistically related to functional outcome (as quantified using the Glasgow Outcome Score) and to the extent of cortical thinning observed 6 months after the traumatic event.

Methods

Using multivariate linear regression, the extent to which the acute GCS and epileptic seizure occurrence (predictor variables) correlate with structural brain changes (relative cortical atrophy) was examined in a group of 33 TBI patients. The statistical significance of the correlation between relative cortical atrophy and the Glasgow Outcome Score was also investigated.

Results

A statistically significant correlative relationship between cortical thinning and the predictor variables (acute GCS and seizure occurrence) was identified in the study sample. Regions where the statistical model was found to have highest statistical reliability in predicting both gray matter atrophy and neurological outcome include the frontopolar, middle frontal, postcentral, paracentral, middle temporal, angular, and lingual gyri. In addition, relative atrophy and GOS were also found to be significantly correlated over large portions of the cortex.

Conclusion

This study contributes to our understanding of the relationship between clinical descriptors of acute TBI, the extent of injury-related chronic brain changes and neurological outcome. This is partly because the brain areas where cortical thinning was found to be correlated with GCS and with seizure occurrence are implicated in executive control, sensory function, motor acuity, memory, and language, all of which may be affected by TBI. Thus, our quantification suggests the existence of a statistical relationship between acute clinical presentation, on the one hand, and structural/functional brain features which are particularly susceptible to post-injury degradation, on the other hand.

Risk factors for posttraumatic epilepsy: A systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis was performed to identify risk factors for posttraumatic epilepsy (PTE).

METHODS

Two electronic databases (Medline and Embase) were searched to identify studies with a cohort, case-control, or cross-sectional design reporting on epidemiologic evidence regarding risk factors for PTE.

RESULTS

Men had a higher risk of developing PTE than women [relative ratio (RR), 1.32; 95% confidence interval (CI), 1.10-1.59]. A history of alcohol abuse (RR, 2.18; 95% CI, 1.26-3.79), posttraumatic amnesia (RR, 1.31; 95% CI, 1.12-1.53), focal neurologic signs (RR, 1.42; 95% CI, 1.16-1.74), and loss of consciousness at initial traumatic brain injury (TBI) (RR, 1.62; 95% CI, 1.13-2.32) were associated with a greater risk of PTE. TBI-related abnormal neuroimaging findings, including skull fracture (RR, 2.27; 95% CI, 1.49-3.44), midline shift (RR, 1.46; 95% CI, 1.14-1.87), brain contusion (RR, 2.35; 95% CI, 1.69-3.28), subdural hemorrhage (RR, 2.00; 95% CI, 1.33-3.01), and intracranial hemorrhage (RR, 2.65; 95% CI, 1.83-3.82) were strong risk factors for PTE. The risk of developing PTE after skull fracture, mild brain injury, and severe brain injury peaked within the first year after TBI, and then gradually decreased. However, a high risk of PTE was sustained for >10years.

CONCLUSION

The current meta-analysis identified potential risk factors for PTE. The results may contribute to better prevention strategies and treatments for PTE.

Late Post-traumatic Epilepsy in Children and Young Adults: Impropriety of Long-Term Antiepileptic Prophylaxis and Risks in Tapering

BACKGROUND

After traumatic brain injury, epilepsy affects up to 20 % of children. It is a risk factor, for both clinical recovery and cognitive performance; therefore pharmacological therapy is advisable. Current guidelines recommend prophylaxis to be initiated as soon as possible and tapered 1 week after trauma. However, no guideline exists for paediatric patients and the clinical practice is heterogeneous.

OBJECTIVE

In our institute, prophylaxis was routinely tapered 6 months after trauma. Therefore we investigated whether this prophylaxis or its tapering influenced the development of post-traumatic epilepsy, together with several clinical-demographic factors.

METHODS

The study population comprised all patients with post-traumatic brain injury referred to this institute between 2002 and 2009 who consented to participate. Clinical, epileptological and pharmacological data were collected. The role of prophylaxis and several other predictors on occurrence of post-traumatic epilepsy was analysed through logistic regressions.

RESULTS

Two hundred and three patients (145 paediatric) were followed for 57 months on average. Risk factors for epilepsy were past neurosurgery [odds ratio (OR) = 2.61, 95 % confidence interval (CI) 1.15-5.96], presence of epileptiform anomalies (OR = 6.92, 95 % CI 3.02-15.86) and the presence of prophylaxis (OR = 2.49, 95 % CI 1.12-5.52), while higher intelligence quotient (IQ) was protective (OR = 0.96, 95 % CI 0.95-0.98). While evaluating possible different effects within and after 6 months (tapering, for those under prophylaxis), we found that epileptiform anomalies (OR = 7.61, 95 % CI 2.33-24.93, and OR = 8.21, 95 % CI 3.00-22.44) and IQ (OR = 0.96, 95 % CI 0.94-0.98, and OR = 0.97, 95 % CI 0.95-0.98) were always significant predictors of epilepsy, while neurosurgery (OR = 4.38, 95 % CI 1.10-17.45) was significant only within 6 months from trauma, and prophylaxis (OR = 3.98, 95 % CI 1.62-9.75) only afterwards.

CONCLUSIONS

These results suggest that prophylaxis was irrelevant when present; furthermore its tapering increased the risk of epilepsy. Since the presence of epileptiform anomalies was the main predictor of post-traumatic epilepsy, such anomalies may be useful to better direct the choice of prophylaxis.

Risk factors for post-stroke seizures: a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis to identify risk factors associated with early seizure (ES) or late seizure (LS) onset in adults following stroke.

DATA SOURCES

Electronic databases (MEDLINE and EMBASE), archives of stroke or epilepsy patients, and bibliographies of relevant articles, which were written in English.

STUDY SELECTION

We included studies published since 1990 that reported the stroke and seizure outcomes of adult patients during follow-up. We independently performed title, abstract and full-text screening and resolved disagreements through discussion.

DATA EXTRACTION

Two authors performed the data extraction. We recorded all possible risk factors predictive of seizure onset.

DATA SYNTHESIS

We used odds ratios (ORs) or the mean difference (MD) to compare the pooled rates of seizure onset between the exposed group and the non-exposed group. All meta-analyses were performed with Review Manager Software.

RESULTS

Intracerebral hemorrhage (OR=1.88, 95% CI=1.43-2.47), cerebral infarction with hemorrhagic transformation (OR=3.28, 95% CI=2.09-5.16), stroke severity (OR=3.10, 95% CI=2.00-4.81, p<0.01, I(2)=0%; MD=3.98, 95% CI=1.06-6.90, p<0.01), and alcoholism (OR=1.70, 95% CI=1.23-2.34, p<0.01) were associated with a significantly greater probability of ES occurrence. There were significant effects of cortical involvement (OR=2.50, 95% CI=1.93-3.23) and stroke severity (MD=5.72, 95% CI=4.23-7.22, p<0.01, I(2)=0) on LS onset. However, there was no significant difference in the probability of single LS episode between patients with intracerebral hemorrhage and infarction stroke (OR=1.20, 95% CI=0.92-1.55).

CONCLUSIONS

Evidence suggests that cortical involvement, stroke subtypes and stroke severity are significant predictors of seizure onset following stroke. However, we did not find a significant difference in the rate of onset of single LS episodes between patients with intracerebral hemorrhage and cerebral infarction.

Neuroimaging the epileptogenic process

Epilepsy is one of the most common chronic neurological conditions worldwide. Anti-epileptic drugs (AEDs) can suppress seizures, but do not affect the underlying epileptic state, and many epilepsy patients are unable to attain seizure control with AEDs. To cure or prevent epilepsy, disease-modifying interventions that inhibit or reverse the disease process of epileptogenesis must be developed. A major limitation in the development and implementation of such an intervention is the current poor understanding, and the lack of reliable biomarkers, of the epileptogenic process. Neuroimaging represents a non-invasive medical and research tool with the ability to identify early pathophysiological changes involved in epileptogenesis, monitor disease progression, and assess the effectiveness of possible therapies. Here we will provide an overview of studies conducted in animal models and in patients with epilepsy that have utilized various neuroimaging modalities to investigate epileptogenesis.

Clinical utility of SPECT neuroimaging in the diagnosis and treatment of traumatic brain injury: a systematic review

Purpose

This systematic review evaluated the clinical utility of single photon emission computed tomography (SPECT) in traumatic brain injury (TBI).

Methods

After defining a PICO Statement (Population, Intervention, Comparison and Outcome Statement), PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria were applied to identify 1600 articles. After screening, 374 articles were eligible for review. Inclusion for review was focus on SPECT in the setting of mild, moderate, or severe TBI with cerebral lobar specificity of SPECT findings. Other inclusion criteria were comparison modalities in the same subjects and articles in English. Foreign language articles, SPECT studies that did not include comparison modalities, and case reports were not included for review.

Results

We identified 19 longitudinal and 52 cross-sectional studies meeting inclusion criteria. Three longitudinal studies examined diagnostic predictive value. The first showed positive predictive value increases from initial SPECT scan shortly after trauma to one year follow up scans, from 59% to 95%. Subsequent work replicated these results in a larger cohort. Longitudinal and cross sectional studies demonstrated SPECT lesion localization not detected by CT or MRI. The most commonly abnormal regions revealed by SPECT in cross-sectional studies were frontal (94%) and temporal (77%) lobes. SPECT was found to outperform both CT and MRI in both acute and chronic imaging of TBI, particularly mild TBI. It was also found to have a near 100% negative predictive value.

Conclusions

This review demonstrates Level IIA evidence (at least one non-randomized controlled trial) for the value of SPECT in TBI. Given its advantages over CT and MRI in the detection of mild TBI in numerous studies of adequate quality, and given its excellent negative predictive value, it may be an important second test in settings where CT or MRI are negative after a closed head injury with post-injury neurological or psychiatric symptoms.

Febrile and other occasional seizures

Seizures with fever that result from encephalitis or meningitis usually occur late in the course of febrile illness, and are focal and prolonged. Febrile seizures are by far the most common affecting 5% of the population, followed by posttraumatic seizures and those observed in the setting of a toxic, infectious, or metabolic encephalopathy. This chapter reviews the clinical presentation of the three most common forms, due to fever, trauma, and intoxication. Febrile seizures carry no cognitive or mortality risk. Recurrence risk is increased by young age, namely before 1 year of age. Febrile seizures that persist after the age of 6 years are usually part of the syndrome of Generalized epilepsy febrile seizures plus. These febrile seizures have a strong link with epilepsy since non-febrile seizures may occur later in the same patient and in other members of the same family with an autosomal dominant transmission. Complex febrile seizures, i.e., with focal or prolonged manifestations or followed by focal defect, are related to later mesial temporal epilepsy with hippocampal sclerosis; risk factors are seizure duration and brain malformation. Prophylactic treatment is usually not required in febrile seizures. Early onset of complex seizures is the main indication for AED prophylaxis. Early posttraumatic seizures, i.e., within the first week, are often focal and indicate brain trauma: contusion, hematoma, 24 hours amnesia, and depressed skull fracture are major factors of posttraumatic epilepsy. Prophylaxis with antiepileptic drugs is not effective. Various psychotropic drugs, including antiepileptics, may cause seizures.

A multimodal imaging approach to the evaluation of post-traumatic epilepsy

Object

Electroencephalography-functional magnetic resonance imaging (EEG-fMRI) coregistration and high-density EEG (hdEEG) can be combined to map noninvasively abnormal brain activation elicited by epileptic processes. By combining noninvasive imaging techniques in a multimodal approach, we sought to investigate pathophysiological mechanisms underlying epileptic activity in seven patients with severe traumatic brain injury.

Materials and methods

Standard EEG and fMRI data were acquired during a single scanning session. The EEG-fMRI data were analyzed using the general linear model and independent component analysis. Source localization of interictal epileptiform discharges (IEDs) was performed using 256-channel hdEEG. Blood oxygenation level dependent (BOLD) localizations were then compared to EEG source reconstruction.

Results

On hdEEG, focal source localization was detected in all seven patients; in six out of seven it was concordant with the expected epileptic activity as defined by EEG data and clinical evaluation; and in four out of seven in whom IEDs were recorded, BOLD signal changes were observed. These activities were partially concordant with the source localization.

Conclusion

Multimodal integration of EEG-fMRI and hdEEG combining two different methods to localize the same epileptic foci appears to be a promising tool to noninvasively map abnormal brain activation in patients with post-traumatic brain injury.

Seizures: emergency neuroimaging

The various findings observed on computed tomography (CT) and magnetic resonance (MR) imaging examinations in patients with seizures reflect the variety of different causes that give rise to this common neurologic symptom. In the emergency setting, CT is most valuable in its ability to accurately identify acute abnormalities that require emergent medical or surgical treatment. MR imaging, by contrast, is usually reserved for patients with recurrent or refractory seizures. The accurate interpretation of either modality requires familiarity with how seizures are classified clinically, the most common presenting features of different causes for seizures, the relevant neuroanatomy, and the imaging manifestations of both common and uncommon causes of seizures and epilepsy. Of particular practical importance to the radiologist is the ability to recognize (1) the most common findings in patients with recurrent seizures and (2) potentially reversible causes for seizures that require prompt intervention to avoid or minimize permanent brain injury. This article surveys a variety of different causes for seizures and epilepsy, focusing on specific clinical features that can help to refine differential diagnosis, and on imaging findings characteristic of different disorders.

Post-traumatic seizures exacerbate histopathological damage after fluid-percussion brain injury

The purpose of this study was to investigate the effects of an induced period of post-traumatic epilepsy (PTE) on the histopathological damage caused by traumatic brain injury (TBI). Male Sprague Dawley rats were given a moderate parasagittal fluid-percussion brain injury (1.9-2.1 atm) or sham surgery. At 2 weeks after surgery, seizures were induced by administration of a GABA(A) receptor antagonist, pentylenetetrazole (PTZ, 30 mg/kg). Seizures were then assessed over a 1-h period using the Racine clinical rating scale. To evaluate whether TBI-induced pathology was exacerbated by the seizures, contusion volume and cortical and hippocampal CA3 neuronal cell loss were measured 3 days after seizures. Nearly all TBI rats showed clinical signs of PTE following the decrease in inhibitory activity. In contrast, clinically evident seizures were not observed in TBI rats given saline or sham-operated rats given PTZ. Contusions in TBI-PTZ-treated rats were significantly increased compared to the TBI-saline-treated group (p < 0.001). In addition, the TBI-PTZ rats showed less NeuN-immunoreactive cells within the ipsilateral parietal cerebral cortex (p < 0.05) and there was a trend for decreased hippocampal CA3 neurons in TBI-PTZ rats compared with TBI-saline or sham-operated rats. These results demonstrate that an induced period of post-traumatic seizures significantly exacerbates the structural damage caused by TBI. These findings emphasize the need to control seizures after TBI to limit even further damage to the injured brain.

Correlates of posttraumatic epilepsy 35 years following combat brain injury

BACKGROUND

The Vietnam Head Injury Study (VHIS) is a prospective, longitudinal follow-up of 1,221 Vietnam War veterans with mostly penetrating head injuries (PHIs). The high prevalence (45%-53%) of posttraumatic epilepsy (PTE) in this unique cohort makes it valuable for study.

METHODS

A standardized multidisciplinary neurologic, cognitive, behavioral, and brain imaging evaluation was conducted on 199 VHIS veterans plus uninjured controls, some 30 to 35 years after injury, as part of phase 3 of this study.

RESULTS

The prevalence of seizures (87 patients, 43.7%) was similar to that found during phase 2 evaluations 20 years earlier, but 11 of 87 (12.6%) reported very late onset of PTE after phase 2 (more than 14 years after injury). Those patients were not different from patients with earlier-onset PTE in any of the measures studied. Within the phase 3 cohort, the most common seizure type last experienced was complex partial seizures (31.0%), with increasing frequency after injury. Of subjects with PTE, 88% were receiving anticonvulsants. Left parietal lobe lesions and retained ferric metal fragments were associated with PTE in a logistic regression model. Total brain volume loss predicted seizure frequency.

CONCLUSIONS

Patients with PHI carry a high risk of PTE decades after their injury, and so require long-term medical follow-up. Lesion location, lesion size, and lesion type were predictors of PTE.

Post-traumatic seizures-A prospective study from a tertiary level trauma center in a developing country

RATIONALE

No large studies till date are available from India on post-traumatic seizures (PTS).

METHODS

This is a prospective observational study of 520 patients with traumatic brain injury (TBI) (July 2007-2008). Patients admitted after 24h of injury, with Glasgow coma scale (GCS)<or=4 were excluded.

RESULTS

At a median follow-up of 386 days, 59 (11.4%) patients developed PTS. Incidence of immediate, early and late onset seizure were 6.5%, 2.1% and 2.7% respectively. In children, incidence of PTS was 18.3%. On univariate analysis, females, of age <10 years, with associated medical problems and with delayed loss of consciousness and poor GCS (<9), following fall from height, had significantly higher odds of PTS. On multivariate analysis, the risk of PTS was 3.7 times higher in patients who had fallen from height, 4.4 times higher in associated medical problems, and 3.7 times higher in severe head injury (GCS<9) at presentation. PTS was associated with poor Glasgow outcome score and higher incidence of behavioral abnormality on follow up. 32% patient with PTS developed recurrent delayed seizures. Seizure recurrence was significantly higher in late onset PTS. PTS affected overall outcome of the patients in severe head injury.

CONCLUSION

The risk of PTS was higher in patients who sustained fall from height, in GCS<9, and associated medical problems. About 1/3rd of the patients with early PTS developed recurrent delayed seizures.

Global outcome, productivity and epilepsy 3--8 years after severe head injury. The impact of injury severity

OBJECTIVE

To assess long-term outcome in survivors after severe head injury and relate outcome to injury severity.

DESIGN

Follow-up 3-8 years post injury in a retrospectively collected sample.

SETTING

A neurosurgical department in a regional trauma centre.

SUBJECTS

Of 146 individuals admitted, 135 were actively treated. Twenty-four per cent of these died within six months. Ninety-three of the 94 (aged 1-88 years) who survived more than three years were included in the follow-up. They were separated into groups based on their level of consciousness at four weeks post injury: oriented (n = 39), confused (n = 22) or in a minimally conscious/vegetative state (MCS/VS) (n = 26) and not possible to assess (n = 6).

OUTCOME MEASURES

Glasgow Outcome Scale Extended (GOSE), participation in work/education (productivity) and posttraumatic epilepsy.

RESULTS

GOSE scores were: vegetative state: 3%, severe disability: 28% (22% lower level, 6% upper level), moderate disability: 39% (22% lower level, 17% upper level) and good recovery: 27% (10% lower level, 17% upper level). Productivity was 34% (aged 7-64 years). The three severity groups had different GOSE scores (P<0.001) and different proportion of productive individuals (P<0.001). Twenty-three per cent experienced posttraumatic epilepsy and this was significantly associated with the highest injury severity (P<0.001) and intracranial surgery (P = 0.01).

CONCLUSIONS

Being independent in daily life but unable to work was the typical long-term outcome. Stratifying the patients based on consciousness at four weeks we found different outcomes. Among oriented patients, almost all regained independency, whereas in the most severe group, poor outcomes and posttraumatic epilepsy was common.

The impact of prophylactic treatment on post-traumatic epilepsy after severe traumatic brain injury

AIM

To assess the incidence of late post-traumatic epilepsy (PTE) in patients with very severe traumatic brain injury (TBI) who either received or did not receive anti-epileptic prophylactic treatment.

METHODS

Two populations were studied: 55 patients retrospectively and 82 subjects prospectively.

RESULTS

Ten patients (18%) in the first population showed late PTE. Although the incidence was lower in patients who did not receive prophylactic treatment, the difference between the treated and the non-treated group was not statistically significant. Sixty-nine patients in the second group (84%) had prophylactic treatment. Twenty-seven patients (39%) suffered from late PTE during the 2-year follow-up period and 17 of them (63%) showed EEG epileptic abnormalities. No patient who did not receive preventive therapy suffered from late PTE during the observation period.

CONCLUSIONS

Due to the negative cognitive effects of anti-epileptic drugs, the preliminary results are of considerable interest for the rehabilitation of patients with very severe TBI.

Prognostic factors of long-term functioning and productivity after traumatic brain injury: a systematic review of prospective cohort studies

OBJECTIVE

To systematically review prospective cohort studies that investigated prognostic factors associated with long-term activity limitations or participation restrictions and productivity after a traumatic brain injury.

DATA SOURCES

PubMed and Psychinfo were searched from 1995 to April 2005, and references were checked.

REVIEW METHODS

Publications were selected if the study assessed prognostic factors for activity limitations or participation restrictions at least one year post injury; outcome was measured with another or additional measure besides the Glasgow Outcome Scale; the design was a prospective cohort study of adult traumatic brain injury patients; the article was a full-text article written in English, French, German or Dutch. Two reviewers independently assessed methodological quality. A study was considered as 'high quality' if it satisfied at least half of the maximum available quality score.

RESULTS

Thirty-five articles reporting on 14 cohorts were included. Due to heterogeneity in prognostic factors and outcome measures, a best-evidence synthesis was performed. All cohorts were of high quality. Strong evidence for predicting disability was found for older age, pre-injury unemployment, pre-injury substance abuse, and more disability at rehabilitation discharge. Strong prognostic factors for being non-productive were pre-injury unemployment, longer post-traumatic amnesia, more disability at rehabilitation admission, and pre-injury substance abuse.

CONCLUSION

Older age, pre-injury unemployment, pre-injury substance abuse and more disability at rehabilitation discharge are important predictors of long-term disability. Pre-injury unemployment, longer post-traumatic amnesia, more disability at rehabilitation admission and pre-injury substance abuse are important predictors of being non-productive.

Prevention and treatment of post-traumatic epilepsy

Post-traumatic epilepsy is reported after 2-5% of closed head injuries but up to 50% or more following penetrating head injury. Despite several studies, no drug strategy has been able, to date, to quench the biochemical events leading to epileptogenesis. One possibility is that treatment with available antiepileptic drugs has been implemented too late, and thus, ultra-early treatment might still be able to stop the neurochemical epileptogenic cascade dead in its tracks. However, currently drug therapy should be instituted only after the first late unprovoked seizure.

Ventricular enlargement after moderate or severe head injury: a frequent and neglected problem

The primary goal of this study was to determine the incidence of post-traumatic ventriculomegaly (Evans' index > or = 0.30) in 95 head-injured patients with a Glasgow Coma Scale (GCS) score of < or =13 at admission. Additional objectives were to determine the relationship between an increase in ventricular size and several clinical and radiological features and outcome. A planimetric study was carried out in the sequential control computed tomography (CT) scans of 34 moderately head-injured (GCS 9-13) and 61 severely head-injured (GCS 3-8) patients with a minimum follow-up of 2 months. Between two and six CT scans were evaluated in each patient. The presence of subarachnoid hemorrhage (SAH) was registered. Evans' index was determined in all CT scans. In the final CT scan of each patient, ventricular size was related to the admission GCS score, age, the presence of SAH in the initial CT scans, type of brain lesion (classified according to the final diagnosis in the Traumatic Coma Data Bank classification), and outcome. Ventriculomegaly was found in 39.3% of patients with severe head injury and in 27.3% of those with a moderate head injury. Increased ventricular size was evident 4 weeks after injury in 57.6% and 2 months after injury in 69.7%. No relationship was found between post-traumatic ventriculomegaly and age, initial GCS score, the presence of SAH, or type of lesion (focal or diffuse). Post-traumatic ventriculomegaly was significantly correlated with outcome. Post-traumatic ventriculomegaly is a frequent and early finding in patients with moderate or severe traumatic brain injury.

Behaviour, cognition and epilepsy

Cognitive and behavioural impairments have been observed as a consequence even of single seizures. In individuals with high seizure frequency, such impairments may accumulate and have a much greater impact on daily life than hitherto suspected. In addition, the risk of behavioural impairments is increased for some seizure types, such as secondary generalized seizures. Moreover, for all epilepsy types, increased risk is associated with persistent or poorly controlled seizures. Clinical studies show that cognitive impairments induced by seizures are reversible for most seizure types when seizures are controlled adequately. Additionally, for some seizure types there may be a kind of time window within which impairments are reversible. Exceeding the time window may result in irreversible impairment. These studies suggest that antiepileptic drug treatment can thus protect against such secondary behavioural impairments or at least correct these when seizures are controlled. This emphasizes the need to achieve complete and early seizure control. On the contrary, all antiepileptic drugs have a detrimental effect on the central nervous system and may affect cognitive function, behaviour and mood to some extent. Some treatments may undo the beneficial effects of antiepileptic drug treatment by inducing new or other cognitive impairments. This once more illustrates the need for the emphasis of clinical practice to evolve from mere seizure control to a more comprehensive approach, in which the prevention of central cognitive effects and effects on daily life of both seizures and drugs is given due attention. Optimal management requires a careful balance between, on the one hand, the desire to reach early and maximal seizure control and, on the other, the need to avoid tolerability problems related to cognitive and behavioural impairments. This article reviews how this balance can be achieved for older and newer antiepileptic drugs.

Predicting posttraumatic epilepsy with MRI: prospective longitudinal morphologic study in adults

PURPOSE

Evaluation of morphologic risk factors for posttraumatic epilepsy (PTE) by using brain magnetic resonance imaging (MRI) in serial assessments <or=2 years after traumatic brain injury (TBI).

METHODS

Brain MRI hyperintense (gliosis) or hypointense (hemosiderin) areas or both were assessed in the images of 135 adult TBI inpatients who completed a 2-year clinical, EEG, and MRI study protocol. Overall clinical follow-up for the development of PTE was 5-10 years (median, 102 months). Morphologic risk factors for PTE were evaluated by using Kaplan-Meier curves and Cox regression analysis.

RESULTS

In 20 patients, PTE developed. Kaplan-Meier curves showed that gliomesenchymal sequelae of focal brain lesions (subdural hematomas/contusions) that required surgical treatment (sSDH-C) were a PTE risk factor (p<0.001), as were sequelae of nonsurgical hemorrhagic contusions with gliosis wall incompletely surrounding hemosiderin dregs (IW) (p=0.039) and mainly those with time-related changes from incomplete to complete gliosis wall around hemosiderin (I/CW) (p=0.005); those with early hemosiderin completely surrounded by gliosis (CW) were not (p=0.821). Cox regression analysis showed that for patients with sequelae of sSDH-C, the PTE risk was 4.38 (p=0.023) times higher than for those who did not require surgical treatment or underwent surgery because of purely extradural hematoma; for those with IW and I/CW lesions, considered pooled, it was 6.61 times higher (p=0.014) than for those with CW lesions.

CONCLUSIONS

MRI follow-up examination in the early chronic stage can differentiate among low-, intermediate-, and high-risk sequelae of TBI. These findings yield new evidence for, but do not resolve, the debate on posttraumatic epileptogenesis.

Severe brain injuries in children

Authors present a seven years retrospective study on 85 cases of severe brain injuries (SBI) in children (GCS </= 8) treated in the Pediatric and ICU Departments of the Clinic Hospital "Bagdasar-Arseni" Bucharest, Romania. The relationship between ICP, GCS on admission, the CT-scan/MRI alteration and the outcome evaluated by the Glasgow Outcome Scale (GOS) were studied in order to highlight the most important factors to improve prognosis. An overall mortality of 25.9% was found in this series. Authors concluded that the ICP values at admission >/= 20 mmHg, the Diffuse Axonal Injury (DAI) on MRI and the GCS on admission are factors of prognosis in SBI in children. The politrauma context is an aggravating factor for SBI in this age group. Other factors which influence GCS on admission may have prognostic importance i.e.: prehospital care, transport time and adequate transport conditions.

Head injury and dementia

PURPOSE OF REVIEW

The link between head injury and dementia/Alzheimer's disease is controversial. This review discusses some recent epidemiological, human autopsy and experimental studies on the relationship between traumatic head injury and dementia.

RECENT FINDINGS

Recent epidemiological studies have shown that head injury is a risk factor for the development of dementia/Alzheimer's disease, whereas others have not. After experimental brain trauma the long-term accumulation of amyloid beta peptide suggests that neurodegeneration is influenced by apolipoprotein E epsilon 4, and after human brain injury both amyloid beta peptide deposition and tau pathology are seen, even in younger patients. Amyloid beta peptide levels in the cerebrospinal fluid and the overproduction of beta amyloid precursor protein in humans and animals after traumatic brain injury are increased. Repeated mild head trauma in both animals and humans accelerates amyloid beta peptide accumulation and cognitive impairment. Retrospective autopsy data support clinical studies suggesting that severe traumatic brain injury with long-lasting morphological residuals are a risk factor for the development of dementia/Alzheimer's disease. The influence of the apolipoprotein E genotype on the prognosis of traumatic brain injury is under discussion.

SUMMARY

Although epidemiological studies and retrospective autopsy data provide evidence that a later cognitive decline may occur after severe traumatic brain injury, the relationship between dementia after head/brain trauma and apolipoprotein E status is still ambiguous. Both human postmortem and experimental studies showing apolipoprotein beta deposition and tau pathology after head injury support the link between traumatic brain injury and dementia, and further studies are warranted to clarify this relationship.

Epilepsy after head injury

PURPOSE OF REVIEW

The purpose of this short review is to provide an update on the epidemiology of posttraumatic epilepsy, associated risk factors, data from prevention studies, and recent breakthroughs in experimental research.

RECENT FINDINGS

There is increasing evidence that neuroimaging findings, stratification by neurosurgical procedures performed, and genomic information (e.g. apolipoprotein E and haptoglobin genotypes) may provide useful predictors of the individual risk of developing posttraumatic epilepsy. While antiepileptic drug prophylaxis can be effective in protecting against acute (provoked) seizures occurring within 7 days after injury, no antiepileptic drug treatment has been found to protect against the development of posttraumatic epilepsy and therefore long-term anticonvulsant prophylaxis is not recommended. Glucocorticoid administration early after head injury also has not been found to reduce the risk of posttraumatic epilepsy. At the basic research level, there have been advances in the understanding of pathophysiological changes in posttraumatic excitatory and inhibitory synapses, and the critical period for epileptogenesis after head injury has been better defined. Finally, the development of a novel animal model, which mimicks more closely human posttraumatic epilepsy, may facilitate efforts to characterize relevant epileptogenic mechanisms and to identify clinically effective antiepileptogenic treatments.

SUMMARY

Despite the continuing lack of clinically effective agents for posttraumatic epilepsy prophylaxis, recent advances in basic and clinical research offer new hope for success in the development of new strategies for prevention and treatment.

Phenotyping the untouchables: environmental enhancement of behavioral and physiological activation in seizure-prone El mice

The onset and frequency of spontaneous and tail suspension-induced seizures in El mice appear to be influenced strongly by developmental and experiential factors over the first 3 months of life. To assess the impact of social factors on behavioral characteristics of El mice prior to the age of seizure susceptibility, locomotor activity and exploratory measures of arousal were recorded in 40-day-old El and control DDY mice exposed to group and isolation housing conditions. Once mice reached maturity, physiological reactivity to a tail suspension stressor was evaluated. The locomotor activity measure revealed circadian entrainment in both strains, nocturnal hyperactivity in El mice, and a locomotor activity-attenuating effect of group housing in El mice. In the two-compartment model of exploration, latency to enter, transitions to and from, and rearing in a brightly lit compartment were 50% higher in El relative to DDY mice, again suggesting a hyperactive phenotype. Finally, an acute 2-minute tail suspension stressor applied to 75-day-old mice implanted with radiotelemetry transmitters revealed a reactive tachycardia in El, but not DDY, mice. No seizures were observed during any of the experimental manipulations. Taken together, these results suggest that spontaneously occurring deviations in behavioral and cardiovascular measures of arousal characterize preseizure El mice and that motor features of hyperarousal can be exaggerated by the environmental manipulation of isolation housing.

Neuropsychological aspects of type of epilepsy and etiological factors in adults

Whether certain types of epilepsies and etiologies are related to profiles of cognitive impairment is of interest for diagnostics and treatment. The dichotomy between generalized and focal epilepsies (mesial temporal lobe, frontal lobe, parietal, and occipital lobe epilepsies) is considered. Then the most frequent etiologies are discussed. We conclude that specific associations between neuropsychological deficits and type of epilepsy and etiology are rather exceptions. However, knowledge of the type of epilepsy and pathology provides eminent information to evaluate the nature of deficits, to estimate chances of functional recovery, to provide rehabilitation recommendations, and to support decisions about treatment options.

Epilepsy and cognition

Patients with epilepsy are more prone to cognitive and behavioral deficits. Epilepsy per se may induce or exacerbate an underlying cognitive impairment, a variety of factors contribute to such deficits, i.e., underlying neuropathology, seizure type, age of onset, psychosocial problems, and treatment side effects. Epilepsy treatment may offset the cognitive and behavioral impairments by stopping or decreasing the seizures, but it may also induce untoward effects on cognition and behavior. The neurocognitive burden of epilepsy may even start through in utero exposure to medications. Epilepsy surgery can also induce certain cognitive deficits, although in most cases this can be minimized. Clinicians should consider cognitive side effect profiles of antiepileptic medications, particularly in extreme age groups. While no effective treatments are available for cognitive and behavioral impairments in epilepsy, comprehensive pretreatment evaluation and meticulous selection of antiepileptic drugs or surgical approach may minimize such untoward effects.