Association of Posttraumatic Epilepsy With Long-term Functional Outcomes in Individuals With Severe Traumatic Brain Injury

Traumatic brain injury: molecular biomarkers, genetics, secondary consequences, and medical management

Traumatic brain injury (TBI) has reached epidemic proportions worldwide. The consequences of TBI can be severe even with repetitive mild trauma. If death and coma are avoided, the consequences of TBI in the long term typically involve dizziness, sleep disturbances, headache, seizures, cognitive impairment, focal deficits, depression, and anxiety. The severity of brain injury is a significant predictor of outcome. However, the heterogenous nature of the injury makes prognosis difficult. The present review of the literature focuses on the genetics of TBI including genome wide (GWAS) data and candidate gene associations, among them brain-derived neurotrophic factor (BDNF) with TBI and development of post-traumatic epilepsy (PTE). Molecular biomarkers of TBI are also discussed with a focus on proteins and the inflammatory protein IL1-β. The secondary medical sequela to TBI of cognitive impairment, PTE, headache and risk for neurodegenerative disorders is also discussed. This overview of TBI concludes with a review and discussion of the medical management of TBI and the medicines used for and being developed at the preclinical and clinical stages for the treatment of TBI and its host of life-debilitating symptoms.

EEG biomarkers for the prediction of post-traumatic epilepsy - a systematic review of an emerging field

Traumatic brain injury (TBI) is often followed by post-traumatic epilepsy (PTE), a condition often difficult to treat and leading to a substantial decline in quality of life as well as increased long-term mortality. The latent period between TBI and the emergence of spontaneous recurrent seizures provides an opportunity for pharmacological intervention to prevent epileptogenesis. Biomarkers capable of predicting PTE development are urgently needed to facilitate clinical trials of putative anti-epileptogenic drugs. EEG is a widely available and flexible diagnostic modality that plays a fundamental role in epileptology. We systematically review the advances in the field of the discovery of EEG biomarkers for the prediction of PTE in humans. Despite recent progress, the field faces several challenges including short observation periods, a focus on early post-injury monitoring, difficulties in translating findings from animal models to scalp EEG, and emerging evidence indicating the importance of assessing altered background scalp EEG activity alongside epileptiform activity using quantitative EEG methods while also considering sleep abnormalities in future studies.

Risk of epilepsy after traumatic brain injury: a nationwide Norwegian matched cohort study

Background

Post-traumatic epilepsy (PTE) is a well-known complication of traumatic brain injury (TBI). Although several risk factors have been identified, prediction of PTE is difficult. Changing demographics and advances in TBI treatment may affect the risk of PTE. Our aim was to provide an up-to-date estimate of the incidence of PTE by linking multiple nationwide registers.

Methods

Patients with TBI admitted to hospital 2015-2018 were identified in the Norwegian Trauma Registry and matched to trauma-free controls on sex and birth year according to a matched cohort design. They were followed up for epilepsy in nationwide registers 2015-2020. Cumulative incidence of epilepsy in TBI patients and controls was estimated taking competing risks into account. Analyses stratified by the Abbreviated Injury Scale (AIS) severity score, Glasgow Coma Scale score and age were conducted for the TBI group. Occurrence of PTE in different injury types was visualized using UpSet plots.

Results

In total, 8,660 patients and 84,024 controls were included in the study. Of the patients, 3,029 (35%) had moderate to severe TBI. The cumulative incidence of epilepsy in the TBI group was 3.1% (95% Confidence Interval [CI] 2.8-3.5%) after 2 years and 4.0% (3.6-4.5%) after 5 years. Corresponding cumulative incidences in the control group were 0.2% (95% CI 0.2-0.3%) and 0.5% (0.5-0.6%). The highest incidence was observed in patients with severe TBI according to AIS (11.8% [95% CI 9.7-14.4%] after 2 years and 13.2% [10.8-16.0%] after 5 years) and in patients >40 years of age.

Conclusion

Patients with TBI have significantly higher risk of developing epilepsy compared to population controls. However, PTE incidence following moderate-severe TBI was notably lower than what has been reported in several previously published studies.

Predictors of follow-up care for critically-ill patients with seizures and epileptiform abnormalities on EEG monitoring

OBJECTIVE

Post-hospitalization follow-up visits are crucial for preventing long-term complications. Patients with electrographic epileptiform abnormalities (EA) including seizures and periodic and rhythmic patterns are especially in need of follow-up for long-term seizure risk stratification and medication management. We sought to identify predictors of follow-up.

METHODS

This is a retrospective cohort study of all patients (age ≥ 18 years) admitted to intensive care units that underwent continuous EEG (cEEG) monitoring at a single center between 01/2016-12/2019. Patients with EAs were included. Clinical and demographic variables were recorded. Follow-up status was determined using visit records 6-month post discharge, and visits were stratified as outpatient follow-up, neurology follow-up, and inpatient readmission. Lasso feature selection analysis was performed.

RESULTS

723 patients (53 % female, mean (std) age of 62.3 (16.4) years) were identified from cEEG records with 575 (79 %) surviving to discharge. Of those discharged, 450 (78 %) had outpatient follow-up, 316 (55 %) had a neurology follow-up, and 288 (50 %) were readmitted during the 6-month period. Discharge on antiseizure medications (ASM), younger age, admission to neurosurgery, and proximity to the hospital were predictors of neurology follow-up visits. Discharge on ASMs, along with longer length of stay, younger age, emergency admissions, and higher illness severity were predictors of readmission.

SIGNIFICANCE

ASMs at discharge, demographics (age, address), hospital care teams, and illness severity determine probability of follow-up. Parameters identified in this study may help healthcare systems develop interventions to improve care transitions for critically-ill patients with seizures and other EA.

Early Seizure Prophylaxis in Mild and Moderate Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Importance

Guidelines recommend seizure prophylaxis for early posttraumatic seizures (PTS) after severe traumatic brain injury (TBI). Use of antiseizure medications for early seizure prophylaxis after mild or moderate TBI remains controversial.

Objective

To determine the association between seizure prophylaxis and risk reduction for early PTS in mild and moderate TBI.

Data Sources

PubMed, Google Scholar, and Web of Science (January 1, 1991, to April 18, 2023) were systematically searched.

Study Selection

Observational studies of adult patients presenting to trauma centers in high-income countries with mild (Glasgow Coma Scale [GCS], 13-15) and moderate (GCS, 9-12) TBI comparing rates of early PTS among patients with seizure prophylaxis with those without seizure prophylaxis.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) reporting guidelines were used. Two authors independently reviewed all titles and abstracts, and 3 authors reviewed final studies for inclusion. A meta-analysis was performed using a random-effects model with absolute risk reduction.

Main Outcome Measures

The main outcome was absolute risk reduction of early PTS, defined as seizures within 7 days of initial injury, in patients with mild or moderate TBI receiving seizure prophylaxis in the first week after injury. A secondary analysis was performed in patients with only mild TBI.

Results

A total of 64 full articles were reviewed after screening; 8 studies (including 5637 patients) were included for the mild and moderate TBI analysis, and 5 studies (including 3803 patients) were included for the mild TBI analysis. The absolute risk reduction of seizure prophylaxis for early PTS in mild to moderate TBI (GCS, 9-15) was 0.6% (95% CI, 0.1%-1.2%; P = .02). The absolute risk reduction for mild TBI alone was similar 0.6% (95% CI, 0.01%-1.2%; P = .04). The number needed to treat to prevent 1 seizure was 167 patients.

Conclusion and Relevance

Seizure prophylaxis after mild and moderate TBI was associated with a small but statistically significant reduced risk of early posttraumatic seizures after mild and moderate TBI. The small absolute risk reduction and low prevalence of early seizures should be weighed against potential acute risks of antiseizure medications as well as the risk of inappropriate continuation beyond 7 days.

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 in chronic disorders of consciousness due to severe traumatic brain injury after traffic accidents

PURPOSE

To evaluate the clinical state of posttraumatic epilepsy (PTE) in patients with chronic disorders of consciousness (CDC) due to severe traumatic brain injury (STBI) after traffic accidents and clarify the risk factors for seizure occurrence in such patients.

METHODS

Two hundred ninety-three patients with CDC due to STBI (mean age at admission [±standard deviation]: 36.4 ± 17.9 years; men: 71.7 %; mean duration of injury to admission: 416 ± 732 days; mean hospitalization time: 899 ± 319 days) were enrolled in this study. We retrospectively investigated the relationship between seizure conditions (type and frequency) and clinical data, including age, sex, pathological types of brain injury, with/without surgical intervention, degree of CDC, and administration of antiseizure medications (ASMs).

RESULTS

Overall, 52.9 % (n = 155/293) and 64.2 % of the patients (n = 183/of 285 patients surviving at discharge) were administered ASMs at admission and discharge, respectively. One hundred thirty-two patients (45.1 %) experienced epileptic seizures during hospitalization, and the mean seizure frequency was 4.0 ± 0.4 times per year. In multivariate analysis, significant and independent risk factors of seizure occurrence were revealed to be male sex, high National Agency for Automotive Safety and Victims' Aid score, hypoxic encephalopathy, and history of the neurosurgical operations.

CONCLUSION

The high prevalence of PTE in patients with CDC due to STBI, and the significant and independent risk factors for seizure occurrence in the chronic clinical phase were revealed. We expect that this study will aid toward improving clinical assessment and management of epileptic seizures in the population.

Curcumin Lowers the Accelerated Speed of Epileptogenesis by Traumatic Brain Injury

Background

Traumatic brain injury or TBI can underlie epilepsy. Prevention of PTE has been of great interest to scientists. Given the antiepileptic, antioxidant and anti-inflammatory activities of curcumin, we examined whether this compound can affect epileptogenesis in rats after TBI.

Methods

Curcumin was injected once a day for two weeks. TBI was induced in the temporal cortex of anesthetized rats using a controlled cortical impact device. One day after TBI, pentylenetetrazole (PTZ), 35 mg/kg, was injected i.p. every other day until manifestation of generalized seizures. The number of PTZ injections was then recorded. Moreover, the extent of cortical and hippocampal IL-1β and glial fibrillary acidic protein (GFAP) expression in the epileptic rats were measured by Western blot analysis.

Results

Curcumin 50 and 150 mg/kg prevented the development of kindling, whereas TBI accelerated the rate of kindling. Curcumin 20 mg/kg prohibited kindling facilitation by TBI, and reduced the expression of IL-1β and GFAP induced by TBI.

Conclusion

Curcumin can stop the acceleration of epileptogenesis after TBI in rats. Inhibiting hippocampal and cortical overexpression of IL-1β and GFAP seems to be involved in this activity.

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.

Clinical complications after a traumatic brain injury and its relation with brain biomarkers

We aimed to find out which are the most frequent complications for patients who suffer a traumatic brain injury (TBI) and its relation with brain biomarker levels. We conducted a hospital cohort study with patients who attended the Hospital Emergency Department between 1 June 2018 and 31 December 2020. Different variables were collected such as biomarkers levels after 6 h and 12 h of TBI (S100, NSE, UCHL1 and GFAP), clinical and sociodemographic variables, complementary tests, and complications 48 h and 7 days after TBI. Qualitative variables were analysed with Pearson's chi-square test, and quantitative variables with the Mann-Whitney U test. A multivariate logistic regression model for the existence of complications one week after discharge was performed to assess the discriminatory capacity of the clinical variables. A total of 51 controls and 540 patients were included in this study. In the TBI group, the mean age was 83 years, and 53.9% of the patients were male. Complications at seven days were associated with the severity of TBI (p < 0.05) and the number of platelets (p = 0.016). All biomarkers except GFAP showed significant differences in their distribution of values according to gender, with significantly higher values of the three biomarkers for women with respect to men. Patients with complications presented significantly higher S100 values (p < 0.05). The patient's baseline status, the severity of the TBI and the S100 levels can be very important elements in determining whether a patient may develop complications in the few hours after TBI.

Predicting posttraumatic epilepsy using admission electroencephalography after severe traumatic brain injury

OBJECTIVE

Posttraumatic epilepsy (PTE) develops in as many as one third of severe traumatic brain injury (TBI) patients, often years after injury. Analysis of early electroencephalographic (EEG) features, by both standardized visual interpretation (viEEG) and quantitative EEG (qEEG) analysis, may aid early identification of patients at high risk for PTE.

METHODS

We performed a case-control study using a prospective database of severe TBI patients treated at a single center from 2011 to 2018. We identified patients who survived 2 years postinjury and matched patients with PTE to those without using age and admission Glasgow Coma Scale score. A neuropsychologist recorded outcomes at 1 year using the Expanded Glasgow Outcomes Scale (GOSE). All patients underwent continuous EEG for 3-5 days. A board-certified epileptologist, blinded to outcomes, described viEEG features using standardized descriptions. We extracted 14 qEEG features from an early 5-min epoch, described them using qualitative statistics, then developed two multivariable models to predict long-term risk of PTE (random forest and logistic regression).

RESULTS

We identified 27 patients with and 35 without PTE. GOSE scores were similar at 1 year (p = .93). The median time to onset of PTE was 7.2 months posttrauma (interquartile range = 2.2-22.2 months). None of the viEEG features was different between the groups. On qEEG, the PTE cohort had higher spectral power in the delta frequencies, more power variance in the delta and theta frequencies, and higher peak envelope (all p < .01). Using random forest, combining qEEG and clinical features produced an area under the curve of .76. Using logistic regression, increases in the delta:theta power ratio (odds ratio [OR] = 1.3, p < .01) and peak envelope (OR = 1.1, p < .01) predicted risk for PTE.

SIGNIFICANCE

In a cohort of severe TBI patients, acute phase EEG features may predict PTE. Predictive models, as applied to this study, may help identify patients at high risk for PTE, assist early clinical management, and guide patient selection for clinical trials.