Unraveling the shared genetics of common epilepsies and general cognitive ability

Objective

Cognitive impairment is prevalent among individuals with epilepsy, and it is possible that genetic factors can underlie this relationship. Here, we investigated the potential shared genetic basis of common epilepsies and general cognitive ability (COG).

Methods

We applied linkage disequilibrium score (LDSC) regression, MiXeR and conjunctional false discovery rate (conjFDR) to analyze different aspects of genetic overlap between COG and epilepsies. We used the largest available genome-wide association study data on COG (n = 269,867) and common epilepsies (n = 27,559 cases, 42,436 controls), including the broad phenotypes 'all epilepsy', focal epilepsies and genetic generalized epilepsies (GGE), and as well as specific subtypes. We functionally annotated the identified loci using a variety of biological resources and validated the results in independent samples.

Results

Using MiXeR, COG (11.2k variants) was estimated to be almost four times more polygenic than 'all epilepsy', GGE, juvenile myoclonic epilepsy (JME), and childhood absence epilepsy (CAE) (2.5k - 2.9k variants). The other epilepsy phenotypes were insufficiently powered for analysis. We show extensive genetic overlap between COG and epilepsies with significant negative genetic correlations (-0.23 to -0.04). COG was estimated to share 2.9k variants with both GGE and 'all epilepsy', and 2.3k variants with both JME and CAE. Using conjFDR, we identified 66 distinct loci shared between COG and epilepsies, including novel associations for GGE (27), 'all epilepsy' (5), JME (5) and CAE (5). The implicated genes were significantly expressed in multiple brain regions. The results were validated in independent samples (COG: p = 1.0 × 10-14; 'all epilepsy': p = 5.6 × 10-3).

Significance

Our study demonstrates a substantial genetic basis shared between epilepsies and COG and identifies novel overlapping genomic loci. Enhancing our understanding of the relationship between epilepsies and COG may lead to the development of novel comorbidity-targeted epilepsy treatments.

Treating status epilepticus in adults

This clinical review examines the treatment of status epilepticus, a condition in which epileptic seizures are prolonged and pose a significant risk of brain damage and death. International guidelines recommend the use of benzodiazepines as first-line treatment, and these should be administered promptly and in appropriate doses. Second-line treatment involves the use of high-dose anti-seizure medications to stop and prevent seizures. If seizure activity persists, general anaesthesia should be administered as soon as possible. All neurological hospital departments should have established and rehearsed protocols for treating status epilepticus.

Astrocytes as critical players of the fine balance between inhibition and excitation in the brain: spreading depolarization as a mechanism to curb epileptic activity

Spreading depolarizations (SD) are slow waves of complete depolarization of brain tissue followed by neuronal silencing that may play a role in seizure termination. Even though SD was first discovered in the context of epilepsy research, the link between SD and epileptic activity remains understudied. Both seizures and SD share fundamental pathophysiological features, and recent evidence highlights the frequent occurrence of SD in experimental seizure models. Human data on co-occurring seizures and SD are limited but suggestive. This mini-review addresses possible roles of SD during epileptiform activity, shedding light on SD as a potential mechanism for terminating epileptiform activity. A common denominator for many forms of epilepsy is reactive astrogliosis, a process characterized by morphological and functional changes to astrocytes. Data suggest that SD mechanisms are potentially perturbed in reactive astrogliosis and we propose that this may affect seizure pathophysiology.

Biological rhythms and epilepsy treatment

Approximately one-third of patients with epilepsy are drug-refractory, necessitating novel treatment approaches. Chronopharmacology, which adjusts pharmacological treatment to physiological variations in seizure susceptibility and drug responsiveness, offers a promising strategy to enhance efficacy and tolerance. This narrative review provides an overview of the biological foundations for rhythms in seizure activity, clinical implications of seizure patterns through case reports, and the potential of chronopharmacological strategies to improve treatment. Biological rhythms, including circadian and infradian rhythms, play an important role in epilepsy. Understanding seizure patterns may help individualize treatment decisions and optimize therapeutic outcomes. Altering drug concentrations based on seizure risk periods, adjusting administration times, and exploring hormone therapy are potential strategies. Large-scale randomized controlled trials are needed to evaluate the efficacy and safety of differential and intermittent treatment approaches. By tailoring treatment to individual seizure patterns and pharmacological properties, chronopharmacology offers a personalized approach to improve outcomes in patients with epilepsy.

Reliable evaluation of functional connectivity and graph theory measures in source-level EEG: How many electrodes are enough?

OBJECTIVE

Using EEG to characterise functional brain networks through graph theory has gained significant interest in clinical and basic research. However, the minimal requirements for reliable measures remain largely unaddressed. Here, we examined functional connectivity estimates and graph theory metrics obtained from EEG with varying electrode densities.

METHODS

EEG was recorded with 128 electrodes in 33 participants. The high-density EEG data were subsequently subsampled into three sparser montages (64, 32, and 19 electrodes). Four inverse solutions, four measures of functional connectivity, and five graph theory metrics were tested.

RESULTS

The correlation between the results obtained with 128-electrode and the subsampled montages decreased as a function of the number of electrodes. As a result of decreased electrode density, the network metrics became skewed: mean network strength and clustering coefficient were overestimated, while characteristic path length was underestimated.

CONCLUSIONS

Several graph theory metrics were altered when electrode density was reduced. Our results suggest that, for optimal balance between resource demand and result precision, a minimum of 64 electrodes should be utilised when graph theory metrics are used to characterise functional brain networks in source-reconstructed EEG data.

SIGNIFICANCE

Characterisation of functional brain networks derived from low-density EEG warrants careful consideration.

Temporal lobe epilepsy

The temporal lobes are the part of the brain most likely to give rise to epileptic seizures. Seizures originating in the temporal lobes vary greatly in character; some may be so unusual that they are not even recognised as epileptic. For patients who have been diagnosed with hippocampal sclerosis and whose seizures cannot be controlled with drugs, epilepsy surgery may be a good treatment option. In this brief clinical review, we summarise the key features of epilepsy and highlight the importance of accurate and early diagnosis for achieving good clinical outcomes.

The potential role of DNA methylation as preventive treatment target of epileptogenesis

Pharmacological therapy of epilepsy has so far been limited to symptomatic treatment aimed at neuronal targets, with the result of an unchanged high proportion of patients lacking seizure control. The dissection of the intricate pathological mechanisms that transform normal brain matter to a focus for epileptic seizures—the process of epileptogenesis—could yield targets for novel treatment strategies preventing the development or progression of epilepsy. While many pathological features of epileptogenesis have been identified, obvious shortcomings in drug development are now believed to be based on the lack of knowledge of molecular upstream mechanisms, such as DNA methylation (DNAm), and as well as a failure to recognize glial cell involvement in epileptogenesis. This article highlights the potential role of DNAm and related gene expression (GE) as a treatment target in epileptogenesis.

Prediction of Long-term Survival After Status Epilepticus Using the ACD Score

Importance

Early prediction of long-term mortality in status epilepticus is important given the high fatality rate in the years after diagnosis.

Objective

To improve prognostication of long-term mortality after status epilepticus diagnosis.

Design, Settings, and Participants

This retrospective, multicenter, multinational cohort study analyzed adult patients who were diagnosed with and treated for status epilepticus at university hospitals in Odense, Denmark, between January 1, 2008, and December 31, 2017, as well as in Oslo, Norway; Marburg, Germany; and Frankfurt, Germany. They were aged 18 years or older and had first-time, nonanoxic status epilepticus. A new scoring system, called the ACD score, for predicting 2-year (long-term) mortality after hospital discharge for status epilepticus was developed in the Danish cohort and validated in the German and Norwegian cohorts. The ACD score represents age at onset, level of consciousness at admission, and duration of status epilepticus. Data analysis was performed between September 1, 2019, and March 31, 2020.

Exposures

Long-term follow-up using data from national and local civil registries in Denmark, Norway, and Germany.

Main Outcomes and Measures

The predefined end point was 2-year survival for all patients and for a subgroup of patients with status epilepticus causes that were not damaging or were less damaging to the brain. Neurological deficits before and after onset, demographic characteristics, etiological categories of status epilepticus, comorbidities, survival, time points, treatments, and prognostic scores for different measures were assessed.

Results

A total of 261 patients (mean [SD] age, 67.2 [14.8] years; 132 women [50.6%]) were included, of whom 145 patients (mean [SD] age, 66.3 [15.0] years; 78 women [53.8%]) had status epilepticus causes that were not damaging or were less damaging to the brain. The validation cohort comprised patients from Norway (n = 139) and Germany (n = 906). At hospital discharge, 29.8% of patients (n = 64 of 215) had new moderate to severe neurological deficits compared with baseline. New neurological deficits were a major predictor of 2-year survival after hospital discharge (odds ratio, 5.1; 95% CI, 2.2-11.8); this association was independent of etiological category. Nonconvulsive status epilepticus in coma and duration of status epilepticus were associated with development of new neurological deficits, and a simple 3-factor score (ACD score) combining these 2 risk factors with age at onset was developed to estimate survival after status epilepticus diagnosis. The ACD score had a linear correlation with 2-year survival (Pearson r2 = 0.848), especially in the subset of patients with a low likelihood of brain damage.

Conclusions and Relevance

This study found that age, long duration, and nonconvulsive type of status epilepticus in coma were associated with the development of new neurological deficits, which were predictors of long-term mortality. Accounting for risk factors for new neurological deficits using the ACD score is a reliable method of prediction of long-term outcome in patients with status epilepticus causes that were not damaging or were less damaging to the brain.

Episodic Memory Dysfunction and Effective Connectivity in Adult Patients With Newly Diagnosed Nonlesional Temporal Lobe Epilepsy

Objective

Epilepsy is associated with both changes in brain connectivity and memory function, usually studied in the chronic patients. The aim of this study was to explore the presence of connectivity alterations measured by EEG in the parietofrontal network in patients with temporal lobe epilepsy (TLE), and to examine episodic memory, at the time point of diagnosis.

Methods

The parietofrontal network of newly diagnosed patients with TLE (N = 21) was assessed through electroencephalography (EEG) effective connectivity and compared with that of matched controls (N = 21). Furthermore, we assessed phenomenological aspects of episodic memory in both groups. Association between effective connectivity and episodic memory were assessed through correlation.

Results

Patients with TLE displayed decreased episodic (p ≤ 0.001, t = −5.18) memory scores compared with controls at the time point of diagnosis. The patients showed a decreased right parietofrontal connectivity (p = 0.03, F = 4.94) compared with controls, and significantly weaker connectivity in their right compared with their left hemisphere (p = 0.008, t = −2.93). There were no significant associations between effective connectivity and episodic memory scores.

Conclusions

We found changes in both memory function and connectivity at the time point of diagnosis, supporting the notion that TLE involves complex memory functions and brain networks beyond the seizure focus to strongly interconnected brain regions, already early in the disease course. Whether the observed connectivity changes can be interpreted as functionally important to the alterations in memory function, it remains speculative.

Astrocytic Ca2+ Signaling in Epilepsy

Epilepsy is one of the most common neurological disorders – estimated to affect at least 65 million worldwide. Most of the epilepsy research has so far focused on how to dampen neuronal discharges and to explain how changes in intrinsic neuronal activity or network function cause seizures. As a result, pharmacological therapy has largely been limited to symptomatic treatment targeted at neurons. Given the expanding spectrum of functions ascribed to the non-neuronal constituents of the brain, in both physiological brain function and in brain disorders, it is natural to closely consider the roles of astrocytes in epilepsy. It is now widely accepted that astrocytes are key controllers of the composition of the extracellular fluids, and may directly interact with neurons by releasing gliotransmitters. A central tenet is that astrocytic intracellular Ca²⁺ signals promote release of such signaling substances, either through synaptic or non-synaptic mechanisms. Accruing evidence suggests that astrocytic Ca²⁺ signals play important roles in both seizures and epilepsy, and this review aims to highlight the current knowledge of the roles of this central astrocytic signaling mechanism in ictogenesis and epileptogenesis.

The organization of functional neurocognitive networks in focal epilepsy correlates with domain-specific cognitive performance

Understanding and diagnosing cognitive impairment in epilepsy remains a prominent challenge. New etiological models suggest that cognitive difficulties might not be directly linked to seizure activity, but are rather a manifestation of a broader brain pathology. Consequently, treating seizures is not sufficient to alleviate cognitive symptoms, highlighting the need for novel diagnostic tools. Here, we investigated whether the organization of three intrinsic, resting-state functional connectivity networks was correlated with domain-specific cognitive test performance. Using individualized EEG source reconstruction and graph theory, we examined the association between network small worldness and cognitive test performance in 23 patients with focal epilepsy and 17 healthy controls, who underwent a series of standardized pencil-and-paper and digital cognitive tests. We observed that the specific networks robustly correlated with test performance in distinct cognitive domains. Specifically, correlations were evident between the default mode network and memory in patients, the central-executive network and executive functioning in controls, and the salience network and social cognition in both groups. Interestingly, the correlations were evident in both groups, but in different domains, suggesting an alteration in these functional neurocognitive networks in focal epilepsy. The present findings highlight the potential clinical relevance of functional brain network dysfunction in cognitive impairment.

Seizure control after late introduction of anakinra in a patient with adult onset Rasmussen's encephalitis

Neuroinflammation has been considered an important pathophysiological process involved in epileptogenesis and may provide possibilities for new treatment possibilities. We present the case of a 45-year-old female with drug resistant epilepsy and progressive right-sided cerebral hemiatrophy associated with adult onset Rasmussen's encephalitis. Over a period of 26 years, she was treated with 14 different antiseizure medications, intravenous immunoglobulins, glucocorticosteroids, underwent two operations with focal resection and subpial transections, and tried out trigeminal nerve stimulation. Extensive blood tests, including antibodies relevant for autoimmune encephalitis, and brain biopsy did not show any signs of neuroinflammation. Eventually, the patient received the interleukin-1 receptor antagonist, anakinra. Within 1-2 days after injection, seizure frequency decreased significantly, and, after one week, the seizures stopped completely. Anakinra treatment was continued for 2 months. Stopping medication led to a relapse of seizures after 2 weeks, with a frequency of up to 45 seizures per day. Reintroduction of anakinra led to rapid recovery. Treatment with anakinra was continued for 7 months. The treatment was discontinued in April 2020, and the patient has been completely seizure free since then. There have been no other changes in antiseizure medication.

Cognition in adult patients with newly diagnosed non-lesional temporal lobe epilepsy

OBJECTIVE

To evaluate whether cognitive performance is affected in newly diagnosed temporal lobe epilepsy (TLE) and to determine the most vulnerable cognitive domains.

METHODS

In this baseline longitudinal study, differences in memory and non-memory cognitive functions were assessed using comprehensive neuropsychological test batteries in 21 adult patients with newly diagnosed non-lesional TLE and individually matched controls. In addition, the analyses included ratings of self-perceived emotional status.

RESULTS

The patients performed more poorly than the control group regarding delayed visual memory (p = 0.013) and executive function tasks related to switching (Trail Making Test and verbal fluency shifting; p = 0.025 and p = 0.03, respectively). We found no differences in verbal learning and memory, attention/working memory/processing speed, and other executive functions.

SIGNIFICANCE

Our results show that patients with TLE often have specific cognitive deficits at time of diagnosis, even in the absence of structural brain abnormalities. This supports the hypothesis that memory dysfunction is linked to an underlying pathology rather than to the effect of recurrent seizures, long-term use of anti-seizure medication, or other epilepsy-related factors. As certain executive functions are affected at an early stage, the pathology may involve brain regions beyond the temporal lobe and may comprise larger brain networks. These results indicate the need for greater awareness of cognition at the time of diagnosis of TLE and before initiation of treatment, and integration of neuropsychological assessment into early routine clinical care.

Differential Glial Activation in Early Epileptogenesis-Insights From Cell-Specific Analysis of DNA Methylation and Gene Expression in the Contralateral Hippocampus

Background and Aims: Morphological changes in mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS) are well-characterized. Yet, it remains elusive whether these are a consequence of seizures or originate from a hitherto unknown underlying pathology. We recently published data on changes in gene expression and DNA methylation in the ipsilateral hippocampus (ILH) using the intracortical kainate mouse model of mTLE-HS. In order to explore the effects of epileptic activity alone and also to further disentangle what triggers morphological alterations, we investigated glial and neuronal changes in gene expression and DNA methylation in the contralateral hippocampus (CLH). Methods: The intracortical kainic acid mouse model of mTLE-HS was used to elicit status epilepticus. Hippocampi contralateral to the injection site from eight kainate-injected and eight sham mice were extracted and shock frozen at 24 h post-injection. Glial and neuronal nuclei were sorted by flow cytometry. Alterations in gene expression and DNA methylation were assessed using reduced representation bisulfite sequencing and RNA sequencing. The R package edgeR was used for statistical analysis. Results: The CLH featured substantial, mostly cell-specific changes in both gene expression and DNA methylation in glia and neurons. While changes in gene expression overlapped to a great degree between CLH and ILH, alterations in DNA methylation did not. In the CLH, we found a significantly lower number of glial genes up- and downregulated compared to previous results from the ILH. Furthermore, several genes and pathways potentially involved in anti-epileptogenic effects were upregulated in the CLH. By comparing gene expression data from the CLH to previous results from the ILH (featuring hippocampal sclerosis), we derive potential upstream targets for epileptogenesis, including glial Cox2 and Cxcl10. Conclusion: Despite the absence of morphological changes, the CLH displays substantial changes in gene expression and DNA methylation. We find that gene expression changes related to potential anti-epileptogenic effects seem to dominate compared to the pro-epileptogenic effects in the CLH and speculate whether this imbalance contributes to prevent morphological alterations like neuronal death and reactive gliosis.

Influence of valproate-induced hyperammonemia on treatment decision in an adult status epilepticus cohort

INTRODUCTION

Status epilepticus (SE) is a neurological emergency in which immediate intervention is required to prevent permanent brain damage and death. Intravenous (IV) valproic acid (VPA) is often used for the treatment of SE. However, IV VPA frequently increases the blood ammonia level. In this study, we explore the impact of IV VPA-induced hyperammonemia (HA) on treatment management of SE and discuss the challenges related to this particular condition.

METHODS

We used data from medical records of 31 adult patients (≥18 years) treated with IV VPA for SE at Oslo University Hospital between January 2006 and October 2019. Clinical and blood sample data and information about the influence of HA on treatment were collected. Correlations between ammonia levels and other continuous or categorical variables were tested using the Pearson's correlation coefficient. The Kruskal-Wallis H-test was used to analyze associations between different variables and treatment decisions.

RESULTS

Thirty of 31 patients had increased ammonia level during IV VPA treatment. In 16/30 patients, VPA was discontinued, and in 6/30 patients, the dose was reduced. We found a difference in the median peak ammonia level among the groups where VPA was discontinued (99 μmol/l), reduced (71 μmol/l), and continued (55.5 μmol/l) (P = 0.008). Also clinical status, measured by West Haven Criteria, varied among the groups where VPA was discontinued (3.5), reduced (2.5), and continued (2.0) (P = 0.01). Treatment decisions at peak ammonia were not associated with the level of liver enzymes and bilirubin.

CONCLUSION

Hyperammonemia had a substantial impact on further management. To date, no recommendations exist on how to manage VPA-induced HA in SE. We call for systematic prospective studies and evidence-based guidelines.

Assessment of cardiac structure and function in a murine model of temporal lobe epilepsy

Sudden unexpected death in epilepsy (SUDEP) is a significant cause of premature seizure-related death. An association between SUDEP and cardiac remodeling has been suggested. However, whether SUDEP is a direct consequence of acute or recurrent seizures is unsettled. The purpose of this study was to evaluate the impact of status epilepticus (SE) and chronic seizures on myocardial structure and function. We used the intracortical kainate injection model of temporal lobe epilepsy to elicit SE and chronic epilepsy in mice. In total, 24 C57/BL6 mice (13 kainate, 11 sham) were studied 2 and 30 days post-injection. Cardiac structure and function were investigated in-vivo with a 9.4 T MRI, electrocardiography (ECG), echocardiography, and histology [Haematoxylin/Eosin (HE) and Martius Scarlet Blue (MSB)] for staining of collagen proliferation and fibrin accumulation. In conclusion, we did not detect any significant changes in cardiac structure and function neither in mice 2 days nor 30 days post-injection.

Neuronal and glial DNA methylation and gene expression changes in early epileptogenesis

BACKGROUND AND AIMS

Mesial Temporal Lobe Epilepsy is characterized by progressive changes of both neurons and glia, also referred to as epileptogenesis. No curative treatment options, apart from surgery, are available. DNA methylation (DNAm) is a potential upstream mechanism in epileptogenesis and may serve as a novel therapeutic target. To our knowledge, this is the first study to investigate epilepsy-related DNAm, gene expression (GE) and their relationship, in neurons and glia.

METHODS

We used the intracortical kainic acid injection model to elicit status epilepticus. At 24 hours post injection, hippocampi from eight kainic acid- (KA) and eight saline-injected (SH) mice were extracted and shock frozen. Separation into neurons and glial nuclei was performed by flow cytometry. Changes in DNAm and gene expression were measured with reduced representation bisulfite sequencing (RRBS) and mRNA-sequencing (mRNAseq). Statistical analyses were performed in R with the edgeR package.

RESULTS

We observed fulminant DNAm- and GE changes in both neurons and glia at 24 hours after initiation of status epilepticus. The vast majority of these changes were specific for either neurons or glia. At several epilepsy-related genes, like HDAC11, SPP1, GAL, DRD1 and SV2C, significant differential methylation and differential gene expression coincided.

CONCLUSION

We found neuron- and glia-specific changes in DNAm and gene expression in early epileptogenesis. We detected single genetic loci in several epilepsy-related genes, where DNAm and GE changes coincide, worth further investigation. Further, our results may serve as an information source for neuronal and glial alterations in both DNAm and GE in early epileptogenesis.

Ca2+ Signals in Astrocytes Facilitate Spread of Epileptiform Activity

Epileptic seizures are associated with increased astrocytic Ca²⁺ signaling, but the fine spatiotemporal kinetics of the ictal astrocyte–neuron interplay remains elusive. By using 2-photon imaging of awake head-fixed mice with chronic hippocampal windows we demonstrate that astrocytic Ca²⁺ signals precede neuronal Ca²⁺ elevations during the initial bout of kainate-induced seizures. On average, astrocytic Ca²⁺ elevations preceded neuronal activity in CA1 by about 8 s. In subsequent bouts of epileptic seizures, astrocytes and neurons were activated simultaneously. The initial astrocytic Ca²⁺ elevation was abolished in mice lacking the type 2 inositol-1,4,5-trisphosphate-receptor (Itpr2^−/−). Furthermore, we found that Itpr2^−/− mice exhibited 60% less epileptiform activity compared with wild-type mice when assessed by telemetric EEG monitoring. In both genotypes we also demonstrate that spreading depression waves may play a part in seizure termination. Our findings imply a role for astrocytic Ca²⁺ signals in ictogenesis.

Predictive performances of STESS and EMSE in a Norwegian adult status epilepticus cohort

PURPOSE

"Status Epilepticus Severity Score" (STESS) and "Epidemiology-based Mortality Score in Status Epilepticus" (EMSE) are two clinical scoring systems aiming to predict mortality in status epilepticus (SE). The objective of this study was to compare their predictive performances in a cohort of 151 SE-patients from Oslo University Hospital in the period 2001-2017.

METHOD

Variables used to calculate STESS (age, previous seizures, worst SE-semiology, level of consciousness) and two different versions of EMSE, EMSE-EAC (etiology, age, comorbidities) and EMSE-EACE (etiology, age, comorbidities, EEG-pattern), as well as outcome were collected retrospectively. Receiver Operating Characteristic (ROC)-analyses, determination of best cut-off values, sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were performed. In addition, Precision-Recall curves (PRC) were produced, plotting PPV as a function of Se.

RESULTS

Thirteen patients (9%) died during their hospital stay. STESS did not accurately predict mortality, with a ROC-curve showing an area under the curve (AUC) of 0.625(95%CI = 0.472-0.783), p = 0.15. EMSE-EAC performed better with an AUC of 0.714(95%CI = 0.552-0.873), p = 0.01 and a best cut-off value of 37. Se was 69.2%, Sp 72.1%, PPV 19% and NPV 96.2%. EMSE-EACE performed best with an AUC of 0.855(95%CI = 0.736-0.976), p < 0.0005 and a best cut-off value of 79. Se was 77.8%, Sp 87.8%, PPV 36.8% and NPV 97.7%. The PRC showed areas under the PRC of 0.23 for EMSE-EAC and 0.46 for EMSE-EACE.

CONCLUSIONS

EMSE-EAC and EMSE-EACE performed better than STESS and may be useful in identifying the patients at risk of death in SE. PRC may give a more relevant visual representation of predictive utility than ROC-curves in situations of imbalanced datasets.

Evaluation of long-term antiepileptic drug use in patients with temporal lobe epilepsy: Assessment of risk factors for drug resistance and polypharmacy

PURPOSE

To evaluate risk factors for drug resistance and polypharmacy in patients with temporal lobe epilepsy.

METHODS

Patients with temporal lobe epilepsy, treated for more than 5 years, completed questionnaires on antiepileptic drug use and effect. Logistic regression models were used for analysis of risk factors.

RESULTS

Of 135 patients included in the study, 65% were classified as drug resistant and 41% identified as using polypharmacy. Poor effects associated with first-choice antiepileptic drug were reported by 59% of the patients, and 70% reported poor effects of second-line treatment. The most frequently used first-generation antiepileptic drugs had a similar mean effect to those of second-generation. Univariate regression analyses showed a significant association between drug resistance and mesial temporal sclerosis, seizure onset below 18 years, and lack of family history of epilepsy. However, multivariate regression analysis showed no association with any demographic or clinical features. Unsuccessful treatment with the first antiepileptic drug increased the risk of drug resistance by 18 times, and the risk of poor effect from the second antiepileptic drug by 9 times. Disease duration was associated with annual risk for drug resistance of 7% and for polypharmacy of 5%.

CONCLUSIONS

A poor effect from initial pharmacotherapy is the only early risk factor for drug resistance found in this study. Long disease duration increases the risk of drug resistance and polypharmacy. Second-generation antiepileptic drugs provide no additional effect for poor responders to first-generation drugs.

Cerebral microvascular abnormalities in patients with idiopathic intracranial hypertension

AIM

Idiopathic intracranial hypertension (IIH) is characterized by symptoms indicative of increased intracranial pressure (ICP), such as headache and visual impairment. We have previously reported that brain biopsies from IIH patients show patchy astrogliosis and increased expression of the water channel aquaporin-4 (AQP4) at perivascular astrocytic endfeet.

METHODS

The present study was undertaken to investigate for ultrastructural changes of the cerebral capillaries in individuals with IIH. We examined by electron microscopy (EM) biopsies from the cortical parenchyma of 10 IIH patients and 8 reference subjects (patients, not healthy individuals), in whom tissue was retrieved from other elective and necessary brain surgeries (epilepsy, tumors or vascular diseases). IIH patients were diagnosed on the basis of typical clinical symptoms and abnormal intracranial pressure wave amplitudes during overnight ICP monitoring.

RESULTS

All 10 IIH patients underwent shunt surgery followed by favorable clinical outcome. EM revealed abnormal pericyte processes in IIH. The basement membrane (BM) showed more frequently evidence of degeneration in IIH, but neither the BM dimensions nor the pericyte coverage differed between IIH and reference tissue. The BM thickness increased significantly with increasing age. Reference individuals were older than IIH cases; observations may to some extent be age-related.

CONCLUSION

The present study disclosed marked changes of the cerebral cortical capillaries in IIH patients, suggesting that microvascular alterations are involved in the evolvement of IIH.

Brain Capillary Ultrastructure in Idiopathic Normal Pressure Hydrocephalus: Relationship With Static and Pulsatile Intracranial Pressure

Idiopathic normal pressure hydrocephalus (iNPH) is a neurodegenerative disease of unknown cause. We investigated the morphology of capillaries in frontal cortex biopsies from iNPH patients and related the observations to overnight intracranial pressure (ICP) scores. A biopsy (0.9×10 mm) was taken from where the ICP sensor subsequently was inserted. Brain capillaries were investigated by electron microscopy of biopsies from 27 iNPH patients and 10 reference subjects, i.e. patients (not healthy individuals) without cerebrospinal fluid circulation disturbances, in whom normal brain tissue was removed as part of necessary neurosurgical treatment. Degenerating and degenerated pericyte processes were identified in 23/27 (85%) iNPH and 6/10 (60%) of reference specimens. Extensive disintegration of pericyte processes were recognized in 11/27 (41%) iNPH and 1/10 (10%) reference specimens. There were no differences in basement membrane (BM) thickness or pericyte coverage between iNPH and reference subjects. The pulsatile or static ICP scores did neither correlate with the BM thickness nor with pericyte coverage. We found increased prevalence of degenerating pericytes in iNPH while the BM thickness and pericyte coverage did not differ from the reference individuals. Observations in iNPH may to some extent be age-related since the iNPH patients were significantly older than the reference individuals.

[What causes febrile convulsions?]

Febrile convulsions affect 2-5% of children in the age group from 6 months to 5 years. The convulsions seldom have negative consequences for the child's development, but may in rare cases constitute a debut symptom of epilepsy.

Augmentation of Ca(2+) signaling in astrocytic endfeet in the latent phase of temporal lobe epilepsy

Astrocytic endfeet are specialized cell compartments whose important homeostatic roles depend on their enrichment of water and ion channels anchored by the dystrophin associated protein complex (DAPC). This protein complex is known to disassemble in patients with mesial temporal lobe epilepsy and in the latent phase of experimental epilepsies. The mechanistic underpinning of this disassembly is an obvious target of future therapies, but remains unresolved. Here we show in a kainate model of temporal lobe epilepsy that astrocytic endfeet display an enhanced stimulation-evoked Ca(2+) signal that outlast the Ca(2+) signal in the cell bodies. While the amplitude of this Ca(2+) signal is reduced following group I/II metabotropic receptor (mGluR) blockade, the duration is sustained. Based on previous studies it has been hypothesized that the molecular disassembly in astrocytic endfeet is caused by dystrophin cleavage mediated by Ca(2+) dependent proteases. Using a newly developed genetically encoded Ca(2+) sensor, the present study bolsters this hypothesis by demonstrating long-lasting, enhanced stimulation-evoked Ca(2+) signals in astrocytic endfeet.

Identification of Srp9 as a febrile seizure susceptibility gene

OBJECTIVE

Febrile seizures (FS) are the most common seizure type in young children. Complex FS are a risk factor for mesial temporal lobe epilepsy (mTLE). To identify new FS susceptibility genes we used a forward genetic strategy in mice and subsequently analyzed candidate genes in humans.

METHODS

We mapped a quantitative trait locus (QTL1) for hyperthermia-induced FS on mouse chromosome 1, containing the signal recognition particle 9 (Srp9) gene. Effects of differential Srp9 expression were assessed in vivo and in vitro. Hippocampal SRP9 expression and genetic association were analyzed in FS and mTLE patients.

RESULTS

Srp9 was differentially expressed between parental strains C57BL/6J and A/J. Chromosome substitution strain 1 (CSS1) mice exhibited lower FS susceptibility and Srp9 expression than C57BL/6J mice. In vivo knockdown of brain Srp9 reduced FS susceptibility. Mice with reduced Srp9 expression and FS susceptibility, exhibited reduced hippocampal AMPA and NMDA currents. Downregulation of neuronal Srp9 reduced surface expression of AMPA receptor subunit GluA1. mTLE patients with antecedent FS had higher SRP9 expression than patients without. SRP9 promoter SNP rs12403575(G/A) was genetically associated with FS and mTLE.

INTERPRETATION

Our findings identify SRP9 as a novel FS susceptibility gene and indicate that SRP9 conveys its effects through endoplasmic reticulum (ER)-dependent synthesis and trafficking of membrane proteins, such as glutamate receptors. Discovery of this new FS gene and mechanism may provide new leads for early diagnosis and treatment of children with complex FS at risk for mTLE.

The role of glial cells in epilepsy

BACKGROUND

Brain research in the last century was mainly directed at neurons, with the role of glia assumed to be limited to repair, supplying nutrients and above all acting as a packing material between neurons. In recent years, the importance of glial cells for normal brain function has been recognised. This article summarizes knowledge of glial cells of relevance to epilepsy.

METHOD

The article is based on a literature search in PubMed as well as the authors' clinical and research experience.

RESULTS

Astrocytes are the largest subgroup of glial cells and, in common with neurons, have diverse membrane transporters, ion channels and receptors. Among the most important roles of astrocytes are the uptake and redistribution of ions and water, glucose metabolism and communication with nerve cells. Disturbances in all of these functions have been associated with epilepsy.

INTERPRETATION

Epilepsy has previously been regarded as exclusively a disturbance in the functioning of neurons and especially of their contact points, the synapses. The mechanisms of action of today's anti-epileptic drugs are therefore primarily directed at neuronal channels and receptors. New knowledge of the role played by glial cells could increase our understanding of how epilepsy arises and could lead to new treatment strategies.

[How do antiepileptic drugs work?]

BACKGROUND

There are currently around 25 antiepileptic drugs in use in Norway, of which 15 have entered the market in the last 20 years. All have somewhat different effect- and adverse effect profiles and mechanisms of action. Here we present a brief overview of current knowledge regarding the basic mechanisms of action of these drugs.

METHOD

The review is based on a discretionary selection of relevant articles found through a literature search in PubMed and our own clinical and research experience.

RESULTS

There are, roughly speaking, four main mechanisms; 1) modulation of ion channels (sodium and calcium channel blockers, potassium channel openers), 2) potentiation of GABAergic inhibition, 3) reduction of glutamatergic excitation and 4) modulation of presynaptic neurotransmitter release. Some of the drugs have several mechanisms of action, and for some of them it is unclear which mechanism is clinically most important. To some extent, the drugs' mechanisms of action predict their effect against different types of epilepsy and seizures. For instance, sodium channel blockers work best against focal seizures, while calcium channel blockers work best against absences, a type of generalised seizure.

INTERPRETATION

Optimal treatment of patients with epilepsy requires not only thorough knowledge of seizure- and epilepsy classification, but also insight into the mechanisms of action of antiepileptic drugs.

Is the brain water channel aquaporin-4 a pathogenetic factor in idiopathic intracranial hypertension? Results from a combined clinical and genetic study in a Norwegian cohort

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure of unknown aetiology. Patients with IIH usually suffer from headache and visual disturbances. High intracranial pressure despite normal ventricle size and negative MRI indicate perturbed water flux across cellular membranes, which is provided by the brain water channel aquaporin-4 (AQP4). IIH could be associated with malfunctioning intracerebral water homeostasis and cerebrospinal fluid (CSF) reabsorption based on functional or regulatory alterations of AQP4.

METHODS

Clinical data, blood and CSF samples were collected from 28 patients with IIH. Clinical characteristics were assessed, and a genetic association study was performed by sequencing the AQP4 gene on chromosome 18. Genetic data were compared with 52 healthy controls and matched by age, sex and ethnicity. Chi-square test and linear discriminant analysis (LDA) were used in the search of a genotype-phenotype association.

RESULTS

While the majority of patients responded to medical treatment, four required shunt application. All, except one, had a good visual outcome. The 24 AQP4 gene SNPs showed no association with IIH. Full cross-validation of the LDA modelling resulted in only 55.1% correct classification of the cases and controls, with a corresponding estimated p-value 0.37.

CONCLUSIONS

Our genetic case-control study did not indicate an association between AQP4 gene variants and IIH. However, the theory of an etiopathogenic link between IIH and AQP4 is tempting, and discussed in this article. Association studies with large sample size are difficult to perform owing is the rarity of the condition.

Redistribution of monocarboxylate transporter 2 on the surface of astrocytes in the human epileptogenic hippocampus

Emerging evidence points to monocarboxylates as key players in the pathophysiology of temporal lobe epilepsy (TLE) with hippocampal sclerosis (mesial temporal lobe epilepsy, MTLE). Monocarboxylate transporters (MCTs) 1 and 2, which are abundantly present on brain endothelial cells and perivascular astrocyte endfeet, respectively, facilitate the transport of monocarboxylates and protons across cell membranes. Recently, we reported that the density of MCT1 protein is reduced on endothelial cells and increased on astrocyte plasma membranes in the hippocampal formation in patients with MTLE and in several animal models of the disorder. Because the perivascular astrocyte endfeet comprise an important part of the neurovascular unit, we now assessed the distribution of the MCT2 in hippocampal formations in TLE patients with (MTLE) or without hippocampal sclerosis (non-MTLE). Light microscopic immunohistochemistry revealed significantly less perivascular MCT2 immunoreactivity in the hippocampal formation in MTLE (n = 6) than in non-MTLE (n = 6) patients, and to a lesser degree in non-MTLE than in nonepilepsy patients (n = 4). Immunogold electron microscopy indicated that the loss of MCT2 protein occurred on perivascular astrocyte endfeet. Interestingly, the loss of MCT2 on astrocyte endfeet in MTLE (n = 3) was accompanied by an upregulation of the protein on astrocyte membranes facing synapses in the neuropil, when compared with non-MTLE (n = 3). We propose that the altered distribution of MCT1 and MCT2 in TLE (especially MTLE) limits the flux of monocarboxylates across the blood-brain barrier and enhances the exchange of monocarboxylates within the brain parenchyma.

Common genetic variation and susceptibility to partial epilepsies: a genome-wide association study

Partial epilepsies have a substantial heritability. However, the actual genetic causes are largely unknown. In contrast to many other common diseases for which genetic association-studies have successfully revealed common variants associated with disease risk, the role of common variation in partial epilepsies has not yet been explored in a well-powered study. We undertook a genome-wide association-study to identify common variants which influence risk for epilepsy shared amongst partial epilepsy syndromes, in 3445 patients and 6935 controls of European ancestry. We did not identify any genome-wide significant association. A few single nucleotide polymorphisms may warrant further investigation. We exclude common genetic variants with effect sizes above a modest 1.3 odds ratio for a single variant as contributors to genetic susceptibility shared across the partial epilepsies. We show that, at best, common genetic variation can only have a modest role in predisposition to the partial epilepsies when considered across syndromes in Europeans. The genetic architecture of the partial epilepsies is likely to be very complex, reflecting genotypic and phenotypic heterogeneity. Larger meta-analyses are required to identify variants of smaller effect sizes (odds ratio <1.3) or syndrome-specific variants. Further, our results suggest research efforts should also be directed towards identifying the multiple rare variants likely to account for at least part of the heritability of the partial epilepsies. Data emerging from genome-wide association-studies will be valuable during the next serious challenge of interpreting all the genetic variation emerging from whole-genome sequencing studies.

Variants of the genes encoding AQP4 and Kir4.1 are associated with subgroups of patients with temporal lobe epilepsy

OBJECTIVE

The etiopathogenesis of temporal lobe epilepsy (TLE) and its subgroups - mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and TLE with antecedent febrile seizures (TLE-FS) - is poorly understood. It has been proposed that the water channel aquaporin-4 (AQP4) and the potassium channel Kir4.1 (KCNJ10 gene) act in concert to regulate extracellular K(+) homeostasis and that functional alterations of these channels influence neuronal excitability. The current study was designed to identify variants of the AQP4 and KCNJ10 genes associated with TLE and subgroups of this condition.

MATERIAL AND METHODS

We included 218 Norwegian patients with TLE and 181 ethnically matched healthy controls. An association study was established in which all TLE patients were compared with healthy controls. Additionally, subgroups of 56 MTLE-HS patients were compared with 162 TLE patients without HS, and 102 TLE-FS patients were compared with 105 TLE without FS.

RESULTS

We found eight single SNPs, seven in KCNJ10 and one between KCNJ10 and KCNJ9, associated with TLE-FS (nominal p-values from 0.009 to 0.041). Seven of the SNPs segregate into one large haplotype block expanding from KCNJ10 to KCNJ9, including the region interposed those genes. One haplotype was overrepresented in the TLE-FS cases (nominal p-value 0.014). These results were confirmed by explorative multivariate analysis indicating that a combination of SNPs from KCNJ10, the region between KCNJ10 and KCNJ9, and the AQP4 gene is associated with TLE-FS. For the TLE cohort as a whole, explorative multivariate analysis indicated a combination of SNPs from the KCNJ10 and AQP4 genes in association with TLE.

CONCLUSION

Variations in the AQP4 and the KCNJ10/KCNJ9 region are likely to be associated with TLE, particularly TLE-FS, supporting the suggestion that perturbations of water and K(+) transport are involved in the etiopathogenesis of TLE.

Phenotypic characteristics of temporal lobe epilepsy: the impact of hippocampal sclerosis

OBJECTIVES

Whether mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is a condition with a unique biological background that can be delineated from other TLE, is unresolved. Here we performed a comparative analysis of two TLE patient cohorts - one cohort with HS and one without HS - in order to identify phenotypic characteristics specifically associated with MTLE-HS.

METHODS

Epidemiological data and clinical and diagnostic features were compared between patients with MTLE-HS and TLE patients without HS. When appropriate, data were compared with healthy controls.

RESULTS

Fifty-six (26%) patients were diagnosed with MTLE-HS and 162 (74%) with other TLE. Age at epilepsy onset was lower in patients with MTLE-HS (P = 0.003) than in TLE patients without HS. Incidence of simple partial seizures was higher in the MTLE-HS group (P = 0.006), as were complex partial seizures (P = 0.001), ictal psychiatric symptoms (P = 0.015), and autonomic symptoms (P < 0.001). Interictal psychiatric symptoms, including depression, were less frequent in MTLE-HS (P = 0.043). MTLE-HS patients had a higher incidence of childhood febrile seizures (FS; P = 0.043) than TLE patients without HS. In contrast, the former group had the lower frequency of first-grade family members with childhood FS (P = 0.019).

CONCLUSIONS

We identified phenotypic characteristics that distinguish MTLE-HS from other types of TLE. These characteristics will be important in diagnostics, treatment, and determination of prognosis, and provide a basis for future phenotype-genotype studies.

Microvascular decompression for hemifacial spasm: postoperative neurologic follow-up and evaluation of life quality

Microvascular decompression (MVD) is an effective and safe treatment in hemifacial spasm (HFS). Postoperative evaluations are usually made by neurosurgeons. Follow-up studies performed by neurologists and postoperative quality of life (QoL) investigations are lacking. All 25 HFS patients operated with MVD in our centre between 2000 and 2004 were evaluated with the recently validated HFS-7 scheme, extended with the item 'sleep disturbance due to HFS' (HFS-8). The patients underwent a careful neurological examination median 3 years after the operation. The evaluation focused on clinical aspects, changes in blood pressure and time until observable effect of MVD. The evaluation of HFS-7 questionnaire and the extended form (HFS-8) showed significant improvement in QoL after MVD. Neurological outcome was in almost all cases excellent or good. Eleven (44%) patients had no neurological deficits at all. Only one patient had serious complications with ipsilateral facial palsy, deafness, balance problems and vertigo. The other patients had minor neurological findings or symptoms. Eighteen (72%) patients experienced early effect within 3 months after MVD; seven (28%) patients had late effect between 6 and 14 months. Median age of the patients with late effect (62.6 years) was significantly higher than in those with early effect (52.7 years).

Neuro-ophthalmological findings in sarcoidosis

PURPOSE

This review emphasizes the importance of neuro-ophthalmological signs and symptoms in sarcoidosis. The presence of ophthalmological and neuro-ophthalmological findings may lead to diagnosis of the disease and the initiation of adequate treatment.

MATERIAL AND METHODS

Patients who had been diagnosed with neurosarcoidosis during the period 1990 - 2001 were identified from the departmental diagnostic index. The history, clinical, laboratory and imaging data of patients were analysed.

RESULTS

Fifteen patients were identified, four men and 11 women, with a mean age of 44.1 years (range 26-65 years). In six of the 15 (40%), neurological deficits were the initial symptoms. Nine (60%) had known sarcoidosis at the time of presentation. Ten patients (66%) had ophthalmological/neuro-ophthalmological symptoms and signs.

CONCLUSION

Neuro-ophthalmological symptoms may develop early in neurosarcoidosis. If neuro-ophthalmological symptoms arise in patients with established biopsy-proven sarcoidosis, the diagnosis is usually easy to make. However, a number of patients with neurosarcoidosis may present with neuro-ophthalmic symptoms before systemic involvement becomes obvious. In this situation the diagnosis is challenging, and the major goal is to establish the presence of systemic sarcoidosis.

Grüneisen ratio divergence at the quantum critical point in CeCu(6-x)Agx

The heavy-fermion system CeCu6-xAgx is studied at its antiferromagnetic quantum critical point, xc=0.2, by low-temperature (T> or =50 mK) specific heat, C(T), and volume thermal expansion, beta(T), measurements. Whereas C/T proportional to log((T0/T) would be compatible with the predictions of the itinerant spin-density-wave (SDW) theory for two-dimensional critical spin fluctuations, beta(T)/T and the Grüneisen ratio, Gamma(T) proportional to beta/C, diverge much weaker than expected, in strong contrast to this model. Both C and beta, plotted as a function of the reduced temperature t=T/T0 with T0=4.6 K, are similar to what was observed for YbRh2(Si(0.95)Ge(0.05))2 (T0=23.3 K), indicating a striking discrepancy to the SDW prediction in both systems.

TP53 gene mutations, nuclear p53 accumulation, expression of Waf/p21, Bcl-2, and CD95 (APO-1/Fas) proteins are not prognostic factors in de novo glioblastoma multiforme

Glioblastoma multiforme (WHO grade IV; GBM) is the most common primary brain tumor with a median survival of less than one year despite multimodal treatment regimens. However, a small subgroup of GBM patients has a better clinical outcome, with a small number of patients surviving several years. Apoptosis, a genetically determined program of cell suicide, may be induced as a consequence of critical DNA damage. However, due to defects in the signaling pathways, cancer cells may escape apoptosis, despite carrying irreversible DNA damage. In the present study, we have analyzed tumors of two age-matched, equally treated groups of GBM patients with different postoperative time to tumor progression (TTP), defined as 'short-term' for TTP of less than 6 months (n = 54), and 'long-term' for TTP of more than 12 months (n = 39) for alterations in apoptosis regulatory pathways: Mutations of the TP53 tumor suppressor gene and/or nuclear accumulation of its gene product p53, expression of Waf/p21, CD95 (Apo1/Fas), and Bcl-2. TP53 mutations were found in 12 out of 54 (22%) GBMs of short-term survivors and 8 out of 35 (23%) tumors of long-term survivors; the respective numbers for nuclear p53 protein accumulation were 12/53 (23%) and 10/37 (27%). Waf1/p21 expression was found in 13/53 (25%) tumors of short-term survivors and 9/35 (26%) GBMs of long-term survivors. The respective numbers for Bcl-2 expression were 25/42 (60%) and 22/36 (61%) and for CD95 (Apo1/Fas) expression 20/49 (41%) and 14/36 (39%) GBMs. The percentage of alterations in genes/proteins involved in the apoptotic pathway investigated here was virtually identical in the two groups of clinically different GBM patients. Thus, our data imply that none of these alterations investigated per se has a strong impact on the overall survival of GBM patients.

Long-term survival of glioblastoma multiforme: importance of histopathological reevaluation

The overall prognosis for patients with glioblastoma multiforme is extremely poor. However, a small proportion of patients enjoy prolonged survival. This study investigated retrospectively the extent to which erroneous histopathological classification may contribute to long-term survival of patients initially diagnosed with "glioblastoma multiforme." We compared two age- and gender-matched patient groups with different postoperative time to tumor progression (TTP), defined as "short-term" for TTP of less than 6 months (n = 54), and "long-term" for TTP of more than 12 months (n = 52). Histological specimens of the corresponding tumors, all primarily diagnosed as glioblastoma multiforme, were reevaluated according to the current World Health Organization (WHO) classification of central nervous system tumors, with the investigators being blinded to clinical outcome. Among the tumors from short-term TTP patients, one tumor (2%) was reclassified as anaplastic oligoastrocytoma (WHO grade III) while the remaining 53 were confirmed as glioblastoma multiforme. In contrast, 13 tumors (25%) from the long-term TTP patients were reclassified, mostly as anaplastic oligodendroglioma (WHO grade III; n = 7) or anaplastic oligoastrocytoma (WHO grade III, n = 2), respectively. In addition, three were reclassified as anaplastic astrocytoma (WHO grade III), and one was identified as anaplastic pilocytic astrocytoma (WHO grade III). Our data indicate that a sizable proportion of glioblastoma patients with long-term survival actually carry malignant gliomas with oligodendroglial features. The correct histopathological recognition of these tumors has not only prognostic but also therapeutic implications, since oligodendroglial tumors are more likely to respond favorably to chemotherapy.

Dramatic development of quadriplegia in a young man while engaged in heavy manual labour: a post-traumatic spinal cord injury?

A healthy 16-year-old male suddenly developed paraesthesiae in his hands during heavy manual labour. He was able to walk to the nearest doctor's practice himself. The symptoms worsened dramatically, and within a short period of time cardiac arrest occurred. After resuscitation and intensive care, quadriplegia due to a high cervical cord lesion was diagnosed. The patient died 70 days later without any changes in the neurological symptoms. Post mortem revealed severe focal ischaemic lesions in the cervical spinal cord in a mixed arterial/venous distribution, but no evidence of direct traumatic changes in the spinal cord, the spine or the soft tissues. All other possible causes than trauma were excluded. The clinical development of the symptoms suggest that this spinal cord lesion should be classified as a secondary traumatic spinal cord injury caused by a subluxation of the cervical spine. The pathogenesis of post-traumatic ischaemic damage to the spinal cord appears to be related to localized hypercoagulability resulting in the formation of microthrombi. Impaired microcirculation in a limited area and for a limited period of time may have caused the irregularly distributed ischaemic necrosis.