Structural and physiological MRI correlates of occult cerebrovascular disease in late-onset epilepsy

Epilepsy and the risk of adverse cardiovascular events: A nationwide cohort study

BACKGROUND AND PURPOSE

Epilepsy is associated with higher morbidity and mortality compared to people without epilepsy. We performed a retrospective cross-sectional and longitudinal cohort study to evaluate cardiovascular comorbidity and incident vascular events in people with epilepsy (PWE).

METHODS

Data were extracted from the French Hospital National Database. PWE (n = 682,349) who were hospitalized between January 2014 and December 2022 were matched on age, sex, and year of hospitalization with 682,349 patients without epilepsy. Follow-up was conducted from the date of first hospitalization with epilepsy until the date of each outcome or date of last news in the absence of the outcome. Primary outcome was the incidence of all-cause death, cardiovascular death, myocardial infarction, hospitalization for heart failure, ischaemic stroke (IS), new onset atrial fibrillation, sustained ventricular tachycardia or fibrillation (VT/VF), and cardiac arrest.

RESULTS

A diagnosis of epilepsy was associated with higher numbers of cardiovascular risk factors and adverse cardiovascular events compared to controls. People with epilepsy had a higher incidence of all-cause death (incidence rate ratio [IRR] = 2.69, 95% confidence interval [CI] = 2.67-2.72), cardiovascular death (IRR = 2.16, 95% CI = 2.11-2.20), heart failure (IRR = 1.26, 95% CI = 1.25-1.28), IS (IRR = 2.08, 95% CI = 2.04-2.13), VT/VF (IRR = 1.10, 95% CI = 1.04-1.16), and cardiac arrest (IRR = 2.12, 95% CI = 2.04-2.20). When accounting for all-cause death as a competing risk, subdistribution hazard ratios for ischaemic stroke of 1.59 (95% CI = 1.55-1.63) and for cardiac arrest of 1.73 (95% CI = 1.58-1.89) demonstrated higher risk in PWE.

CONCLUSIONS

The prevalence and incident rates of cardiovascular outcomes were significantly higher in PWE. Targeting cardiovascular health could help reduce excess morbidity and mortality in PWE.

Epileptogenicity of white matter lesions in cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

The epileptogenic properties of white matter lesions (WML) in cerebral small vessel disease (CSVD) are not yet understood. The aim of our systematic review and meta-analysis was to estimate the association between the extent of WML in CSVD and epilepsy, analyze whether these WML are associated with an increased risk of seizure recurrence, and evaluate if treatment with anti-seizure medication (ASM) is justified in first-seizure patients with WML and no cortical lesions.

METHODS

Following a pre-registered study protocol (PROSPERO-ID CRD42023390665), we systematically searched Pubmed and Embase for relevant literature comparing WML load between patients with epilepsy and controls as well as studies on seizure recurrence risk and ASM therapy in the presence vs. absence of WML. We calculated pooled estimates using a random effects model.

RESULTS

Eleven studies comprising 2983 patients were included in our study. Presence of WML (OR 2.14, 95% CI 1.38-3.33) and presence of relevant WML as assessed by visual rating scales (OR 3.96, 95% CI 2.55-6.16) but not WML volume (OR 1.30, 95% CI 0.91-1.85) were significantly associated with seizures. These results stayed robust in sensitivity analyses restricted to studies on patients with late-onset seizures/epilepsy. Only two studies assessed the association between WML and risk of seizure recurrence with conflicting results. Currently, there are no studies on the efficacy of ASM therapy in the presence of WML in CSVD.

CONCLUSIONS

This meta-analysis suggests an association between presence of WML in CSVD and seizures. More research is needed addressing the association between WML and risk of seizure recurrence and ASM therapy focusing on a population of patients with a first unprovoked seizure.

Clinical, imaging, and biomarker evidence of amyloid- and tau-related neurodegeneration in late-onset epilepsy of unknown etiology

Accumulating evidence suggests amyloid and tau-related neurodegeneration may play a role in development of late-onset epilepsy of unknown etiology (LOEU). In this article, we review recent evidence that epilepsy may be an initial manifestation of an amyloidopathy or tauopathy that precedes development of Alzheimer's disease (AD). Patients with LOEU demonstrate an increased risk of cognitive decline, and patients with AD have increased prevalence of preceding epilepsy. Moreover, investigations of LOEU that use CSF biomarkers and imaging techniques have identified preclinical neurodegeneration with evidence of amyloid and tau deposition. Overall, findings to date suggest a relationship between acquired, non-lesional late-onset epilepsy and amyloid and tau-related neurodegeneration, which supports that preclinical or prodromal AD is a distinct etiology of late-onset epilepsy. We propose criteria for assessing elevated risk of developing dementia in patients with late-onset epilepsy utilizing clinical features, available imaging techniques, and biomarker measurements. Further research is needed to validate these criteria and assess optimal treatment strategies for patients with probable epileptic preclinical AD and epileptic prodromal AD.

Late-onset epilepsy with cognitive symptoms: Comparison of cognitive and imaging profiles with probable Alzheimer's disease

OBJECTIVE

We aimed to (i) compare the clinical, neuropsychological, and neuroimaging characteristics of unprovoked late-onset epilepsy (LOE) patients with cognitive symptoms against probable Alzheimer's disease (AD) patients; (ii) clarify how neurodegeneration and other processes could be implicated in the cognitive symptoms of unprovoked LOE patients; and (iii) characterize the longitudinal trajectory of unprovoked LOE patients with cognitive symptoms.

METHODS

Twenty-six unprovoked LOE patients with cognitive symptoms and 26 probable AD were retrospectively recruited from epilepsy and memory clinics at a single tertiary referral center. The patients underwent comprehensive clinical, neuropsychological, and 18Fluorodeoxyglucose PET-CT assessments. All LOE patients had clinical follow-up and a subset of 17 patients had repeat neuropsychological assessments.

RESULTS

At baseline, 18% of LOE patients with cognitive symptoms had dementia-range cognitive impairment and one received a diagnosis of probable AD. Compared with the probable AD group, the LOE group did not perform significantly better in global measures of cognition (total ACE-III), neuropsychological tests for fluency, working memory, language, attention, or executive function, but performed better in naming, memory, and visuospatial ability. The commonest patterns of cognitive impairment in the LOE group were frontal and left temporal, whereas all AD patients exhibited parietotemporal patterns. The AD group had more 18Fluorodeoxyglucose PET-CT hypometabolism in the parietal and occipital, but not the temporal and frontal lobes. During the 3.0 ± 3.2 years follow-up, improved seizure frequency in the LOE group covaried with improved total ACE-III score, there was no further conversion to probable AD and no group-level cognitive decline.

CONCLUSION

Unprovoked LOE patients with cognitive symptoms had varying severities of cognitive impairment, and different patterns of cognitive and imaging abnormalities compared with AD patients. They were rarely diagnosed with probable AD at presentation or follow-up. Cognitive outcome in LOE may be related to seizure control. Cerebral small vessel disease may play a role in LOE-associated cognitive impairment.

Diagnosis and Treatment of Poststroke Epilepsy: Where Do We Stand?

Purpose of Review

Stroke is the most common cause of seizures and epilepsy in older adults. This educational paper aims to give an update on current clinical aspects of diagnosis and treatment of poststroke epilepsy.

Recent Findings

Regarding epileptic seizures related to stroke, it is important to distinguish between acute symptomatic seizures and unprovoked seizures as they differ in their risk for seizure recurrence. In fact, after a single unprovoked poststroke seizure, a diagnosis of epilepsy can be made because there is a greater than 60% risk for further seizures. Clinical models that can predict the development of epilepsy after a stroke have been successfully established. However, treatment with anti-seizure medications is advised only after a first unprovoked poststroke seizure, as current treatments are not known to be effective for primary prevention. The management of poststroke epilepsy requires consideration of aspects such as age, drug-drug interactions and secondary vascular prophylaxis, yet evidence for the use of anti-seizure medications specifically in poststroke epilepsy is limited.

Summary

This text reviews the epidemiology and risk factors for poststroke epilepsy, explains the role of EEG and neuroimaging in patients with stroke and seizures and provides an overview on the clinical management of stroke-related acute symptomatic seizures and poststroke epilepsy.

Late-onset epilepsy and the risk of dementia: a systematic review and meta-analysis

BACKGROUND

Patients with dementia have higher risk of epilepsy. However, it remains not comprehensively evaluated if late-onset epilepsy (LOE) is associated with higher risk of dementia. We, therefore, performed a meta-analysis to systematically evaluate the association.

METHODS

Relevant cohort studies were identified by search of electronic databases including PubMed, Embase, and Web of Science. A randomized-effect model incorporating the possible between-study heterogeneity was used to pool the results.

RESULTS

Overall, seven cohort studies including 873,438 adults were included, and 16,036 (1.8%) of them had LOE. With a mean follow-up duration of 8.7 years, 33,727 of them were diagnosed as dementia. Pooled results showed that LOE was associated with a higher risk of dementia (risk ratio [RR] 2.39, 95% confidence interval [CI] 2.04-2.81, p < 0.001, I² = 67%). Results of subgroup analysis showed that the association between LOE and the risk of dementia was stronger in hospital-derived participants (RR 4.23, 95% CI 2.67-6.70, p < 0.001) than that in community-derived population (RR 2.25, 95% CI 1.93-2.63, p < 0.001; p for subgroup difference = 0.01). Pooled results of three studies showed that LOE was associated with a higher risk of Alzheimer's disease (RR 2.35, 95% CI 1.08-5.08, p = 0.03, I² = 85%). One study suggested a significant association between LOE and risk of vascular dementia (RR 2.0, 95% CI 1.77-2.26, p < 0.001).

CONCLUSIONS

Evidence from cohort studies suggests that LOE may be a risk factor of dementia.

Late-Onset Focal Epilepsy: Electroclinical Features and Prognostic Role of Leukoaraiosis

The aim of this study was to describe the electroclinical and prognostic characteristics, and to investigate the role of leukoaraiosis in outpatients with new-onset elderly focal epilepsy aged ≥60 years, referred to a tertiary epilepsy center between 2005 and December 31, 2020. Among the 720 patients who were referred to the center, we retrospectively selected 162 consecutive outpatients, with a first referral for recent-onset focal epilepsy of unknown cause (UC) or structural cause (SC), and collected a clinical and standard-Electroencephalogram (S-EEG), 24-h ambulatory EEG (A-EEG), and neuroimaging data. We also analyzed the seizure prognosis after titration of the first antiseizure medication (ASM). One hundred and four UC and 58 SC patients, followed up for 5.8 ± 5.3 years (mean ± SD), were included. Compared with the SC group, the patients with UC showed a predominance of focal seizures with impaired awareness (51.9% of cases) and focal to bilateral tonic-clonic seizures during sleep (25%); conversely, the SC group, more frequently, had focal to bilateral tonic-clonic seizures during wakefulness (39.6%) and focal aware seizures (25.8%) (p < 0.0001). Oral or gestural automatisms were prevalent in UC epilepsy (20.2 vs. 6.9% in the SC group, p = 0.04). In UC compared to patients with SC, interictal epileptiform discharges showed a preferential temporal lobe localization (p = 0.0007), low expression on S-EEG, and marked activation during deep Non-Rapid Eye Movement (NREM) sleep (p = 0.003). An overall good treatment response was found in the whole sample, with a probability of seizure freedom of 68.9% for 1 year. The cumulative probability of seizure freedom was significantly higher in the UC compared with the SC group (p < 0.0001). The prognosis was worsened by leukoaraiosis (p = 0.012). In the late-onset focal epilepsy of unknown cause, electroclinical findings suggest a temporal lobe origin of the seizures. This group showed a better prognosis compared with the patients with structural epilepsy. Leukoaraiosis, per se, negatively impacted on seizure prognosis.

Effect of late-onset epilepsy on cognitive functioning in patients with small vessel disease

RATIONALE

Late-onset epilepsy (LOE) often has underlying cerebrovascular cause and has been associated with neurocognitive deficits and dementia. Nevertheless, the interplay between these factors has not been studied thus far. Hence, we conducted a retrospective cross-sectional study aimed to explore how unprovoked epileptic seizures along with vascular-related factors contribute to neurocognitive impairments in patients with cerebral small vessel disease.

METHODS

Twenty-seven patients with LOE aged > 60 years with concomitant cerebral small vessel disease (cSVD) and a matched group of cSVD without epilepsy were cognitively assessed. Demographic, clinical, and vascular information were obtained and vascular burden score was calculated for each patient. Multiple linear regression models were used to explore the relationship between epilepsy and cognitive measures adjusting for demographic and vascular risk factors.

RESULTS

Compared with cSVD, cSVD-LOE group showed a poorer performance on verbal memory measures, visuomotor tracking and speed processing and phonetic fluency. In the multiple regression analysis, the presence of epilepsy was found to be the major predictor for verbal memory dysfunction, specifically in verbal short recall (p = 0.008) and verbal learning (p < 0.001). No interactions between vascular burden and epilepsy were found.

CONCLUSION

Patients who had cSVD with concurrent LOE showed poorer performance on memory function compared with patients with cSVD without epilepsy, and they showed a different cognitive profile from that typically manifested by patients with cSVD. The presence of epilepsy, but not seizure localization nor vascular burden, was the major contributor to the decrease in verbal memory.

Cerebrovascular Reactivity Measurement Using Magnetic Resonance Imaging: A Systematic Review

Cerebrovascular reactivity (CVR) magnetic resonance imaging (MRI) probes cerebral haemodynamic changes in response to a vasodilatory stimulus. CVR closely relates to the health of the vasculature and is therefore a key parameter for studying cerebrovascular diseases such as stroke, small vessel disease and dementias. MRI allows in vivo measurement of CVR but several different methods have been presented in the literature, differing in pulse sequence, hardware requirements, stimulus and image processing technique. We systematically reviewed publications measuring CVR using MRI up to June 2020, identifying 235 relevant papers. We summarised the acquisition methods, experimental parameters, hardware and CVR quantification approaches used, clinical populations investigated, and corresponding summary CVR measures. CVR was investigated in many pathologies such as steno-occlusive diseases, dementia and small vessel disease and is generally lower in patients than in healthy controls. Blood oxygen level dependent (BOLD) acquisitions with fixed inspired CO₂ gas or end-tidal CO₂ forcing stimulus are the most commonly used methods. General linear modelling of the MRI signal with end-tidal CO₂ as the regressor is the most frequently used method to compute CVR. Our survey of CVR measurement approaches and applications will help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.

Seizures in the context of occult cerebrovascular disease

There is an important bidirectional relationship between seizures and cerebrovascular disease (CVD). Aside from poststroke epilepsy, Occult CVD is an important cause of late-onset seizures (LOS) and late-onset epilepsy (LOE). Late-onset seizures/LOE are associated with a threefold increased risk of subsequent clinical stroke. This relationship exists not only in later life, but with 'late-onset' seizures or epilepsy occurring from the fourth decade of life onwards. There is increasing evidence for the importance of hypertension and cerebral small vessel disease (SVD) in epileptogenesis, but there is a considerable need for further work to elucidate underlying mechanisms. There may be a disproportionately increased risk of intracerebral hemorrhage (ICH) after LOS/LOE; this too requires further study. There is also a bidirectional relationship between LOS/LOE and cognitive impairment/dementia: it is likely that there are important interactions between vascular and neurodegenerative pathological processes mediating LOE, stroke, and dementia. There is a pressing need for better epidemiological and natural history data as well as elucidation of epileptogenic mechanisms, in order to progress our understanding and to better inform clinical practice.

Epilepsy in older people

Globally, as populations age there will be challenges and opportunities to deliver optimal health care to senior citizens. Epilepsy, a condition characterised by spontaneous recurrent seizures, is common in older adults (aged >65 years) and yet has received comparatively little attention in this age group. In this Review, we evaluate the underlying causes of epilepsy in older people, explore difficulties in establishing a diagnosis of epilepsy in this population, discuss appropriate antiseizure medications, and evaluate potential surgical treatment options. We consider cognitive, psychological, and psychosocial comorbidities and the effect that epilepsy might have on an older person's broader social or care network in high-income versus middle-income and low-income countries. We emphasise the need for clinical trials to be more inclusive of older people with epilepsy to help inform therapeutic decision making and discuss whether measures to improve vascular risk factors might be an important strategy to reduce the probability of developing epilepsy.

Late-onset unexplained epilepsy: What are we missing?

With the aging of the US population, the incidence of epilepsy will increase, with 25 to 50% of new cases with no identifiable etiology diagnosed as late-onset unexplained epilepsy (LOUE). In the current targeted review, we discuss the possible role of cerebral small vessel ischemic disease, accumulation of amyloidβ and hyperphosphorylated tau, and sleep apnea as potential pathophysiologic mechanisms explaining LOUE. We highlight the impact of these processes on cognition and avenues for diagnosis and treatment.

Association between white matter hyperintensities, cortical volumes, and late-onset epilepsy

OBJECTIVE

To identify the association between brain vascular changes and cortical volumes on MRI and late-onset epilepsy.

METHODS

In 1993-1995, 1,920 participants (median age 62.7, 59.9% female) in the community-based Atherosclerosis Risk in Communities (ARIC) Study underwent MRI, and white matter hyperintensities were measured. In addition, in 2011-2013, 1,964 ARIC participants (median age 72.4, 61.1% female) underwent MRI, and cortical volumes and white matter hyperintensities were measured. We identified cases of late-onset epilepsy (starting at age 60 or later) from ARIC hospitalization records and Medicare claims data. Using the 1993-1995 MRI, we evaluated the association between white matter hyperintensities and subsequent epilepsy using survival analysis. We used the 2011-2013 MRI to conduct cross-sectional logistic regression to examine the association of cortical volumes and white matter hyperintensities with late-onset epilepsy. All models were adjusted for demographics, hypertension, diabetes, smoking, and APOE ε4 allele status.

RESULTS

Ninety-seven ARIC participants developed epilepsy after having an MRI in 1993-1995 (incidence 3.34 per 1,000 person-years). The degree of white matter hyperintensities measured at ages 49-72 years was associated with the risk of late-onset epilepsy (hazard ratio 1.27 per age-adjusted SD, 95% confidence interval [CI] 1.06-1.54). Lower cortical volume scores were associated cross-sectionally with higher odds of late-onset epilepsy (odds ratio 1.87, 95% CI 1.16-3.02) per age-adjusted SD.

CONCLUSIONS

This study demonstrates associations between earlier-life white matter hyperintensities on MRI and later-life incident epilepsy, and between cortical volumes measured later in life and late-onset epilepsy. These findings may help illuminate the causes of late-onset epilepsy.

Cognition and dementia in older patients with epilepsy

With advances in healthcare and an ageing population, the number of older adults with epilepsy is set to rise substantially across the world. In developed countries the highest incidence of epilepsy is already in people over 65 and, as life expectancy increases, individuals who developed epilepsy at a young age are also living longer. Recent findings show that older persons with epilepsy are more likely to suffer from cognitive dysfunction and that there might be an important bidirectional relationship between epilepsy and dementia. Thus some people with epilepsy may be at a higher risk of developing dementia, while individuals with some forms of dementia, particularly Alzheimer's disease and vascular dementia, are at significantly higher risk of developing epilepsy. Consistent with this emerging view, epidemiological findings reveal that people with epilepsy and individuals with Alzheimer's disease share common risk factors. Recent studies in Alzheimer's disease and late-onset epilepsy also suggest common pathological links mediated by underlying vascular changes and/or tau pathology. Meanwhile electrophysiological and neuroimaging investigations in epilepsy, Alzheimer's disease, and vascular dementia have focused interest on network level dysfunction, which might be important in mediating cognitive dysfunction across all three of these conditions. In this review we consider whether seizures promote dementia, whether dementia causes seizures, or if common underlying pathophysiological mechanisms cause both. We examine the evidence that cognitive impairment is associated with epilepsy in older people (aged over 65) and the prognosis for patients with epilepsy developing dementia, with a specific emphasis on common mechanisms that might underlie the cognitive deficits observed in epilepsy and Alzheimer's disease. Our analyses suggest that there is considerable intersection between epilepsy, Alzheimer's disease and cerebrovascular disease raising the possibility that better understanding of shared mechanisms in these conditions might help to ameliorate not just seizures, but also epileptogenesis and cognitive dysfunction.

New onset epilepsy in the elderly: clinical, radiological and electroencephalographic features and treatment responses

OBJECTIVE

To evaluate new onset epilepsy characteristics, etiology, radiological and electroencephalographic features and to document treatment response in the elderly.

METHODS

This was a retrospective study carried out in King Fahd Medical City, Riyadh, Kingdom of Saudi Arabia, from 2010 to 2013. Medical records were searched to recruit patients. Hundred and nineteen patients were enrolled who fulfill the inclusion criteria. Clinical data with respect to seizure semiology, etiology, electroencephalographic findings, radiological findings, co-morbidities, and anti-epileptic drug (AED) therapy were assessed.

RESULTS

Cerebrovascular disease was the most common etiology, followed by occult cerebrovascular disease (oCVD). Focal onset seizures were the most common clinical presentation in this group of cohort. Electroencephalogram (EEG) showed generalized slowing in majority of patients (45.5%), with 21.8% interictal epileptiform activity. Patients required lower doses of AEDs to control seizures, gain better seizure control. Common co-morbidities were hypertension and diabetes mellitus.

CONCLUSION

Patients presenting with LOE, should have search for any other cerebrovascular risk factors. Further research is needed to determine the prevalence of oCVD in LOE, and to investigate whether addressing cerebrovascular risk factors in this cohort of patients can reduce the incidence of stroke.

High incidence of obstructive sleep apnea syndrome in patients with late-onset epilepsy

OBJECTIVES

The objective of the present study was to evaluate the prevalence of obstructive sleep apnea (OSA) in patients with late-onset epilepsy (LOE) who were considered at higher risk of cardiovascular disease.

METHODS

Polysomnography was performed on 27 patients with LOE. Berlin questionnaires and Epworth sleepiness score were performed on all patients. We compared clinical, demographic and anthropometric characteristics, questionnaire scores on the patients with no or mild OSA (group 1) and the patients with moderate or severe OSA (group 2). Patients eligible for continuous positive airway pressure (CPAP) therapy were reviewed in consultation.

RESULTS

Twenty-four patients (88.9%) had OSA and 55.6% had moderate or severe OSA. Patients in group 2 (n=15) were older than patients in group 1 (n=12). The two groups were similar in terms of body mass index (BMI), neck circumference, nocturnal seizure frequency, vascular cardiovascular risk factors and excessive daytime sleepiness. Leukoaraiosis in MRI was highly prevalent in our patients (40.7%), especially in group 2 patients. Eighty percent of the patients who had begun CPAP therapy experienced decreased seizure frequency.

CONCLUSION

Patients with LOE should be screened for the presence of OSA and treated accordingly.

Delayed seizures after intracerebral haemorrhage

Late seizures after intracerebral haemorrhage occur after the initial acute haemorrhagic insult subsides, and represent one of its most feared long-term sequelae. Both susceptibility to late seizures and their functional impact remain poorly characterized. We sought to: (i) compare patients with new-onset late seizures (i.e. delayed seizures), with those who experienced a recurrent late seizure following an immediately post-haemorrhagic seizure; and (ii) investigate the effect of late seizures on long-term functional performance after intracerebral haemorrhage. We performed prospective longitudinal follow-up of consecutive intracerebral haemorrhage survivors presenting to a single tertiary care centre. We tested for association with seizures the following neuroimaging and genetic markers of cerebral small vessel disease: APOE variants ε2/ε4, computer tomography-defined white matter disease, magnetic resonance imaging-defined white matter hyperintensities volume and cerebral microbleeds. Cognitive performance was measured using the Modified Telephone Interview for Cognitive Status, and functional performance using structured questionnaires obtained every 6 months. We performed time-to-event analysis using separate Cox models for risk to develop delayed and recurrent seizures, as well as for functional decline risk (mortality, incident dementia, and loss of functional independence) after intracerebral haemorrhage. A total of 872 survivors of intracerebral haemorrhage were enrolled and followed for a median of 3.9 years. Early seizure developed in 86 patients, 42 of whom went on to experience recurrent seizures. Admission Glasgow Coma Scale, increasing haematoma volume and cortical involvement were associated with recurrent seizure risk (all P < 0.01). Recurrent seizures were not associated with long-term functional outcome (P = 0.67). Delayed seizures occurred in 37 patients, corresponding to an estimated incidence of 0.8% per year (95% confidence interval 0.5-1.2%). Factors associated with delayed seizures included cortical involvement on index haemorrhage (hazard ratio 1.63, P = 0.036), pre-haemorrhage dementia (hazard ratio 1.36, P = 0.044), history of multiple prior lobar haemorrhages (hazard ratio 2.50, P = 0.038), exclusively lobar microbleeds (hazard ratio 2.22, P = 0.008) and presence of ≥ 1 APOE ε4 copies (hazard ratio 1.95, P = 0.020). Delayed seizures were associated with worse long-term functional outcome (hazard ratio 1.83, P = 0.005), but the association was removed by adjusting for neuroimaging and genetic markers of cerebral small vessel disease. Delayed seizures after intracerebral haemorrhage are associated with different risk factors, when compared to recurrent seizures. They are also associated with worse functional outcome, but this finding appears to be related to underlying small vessel disease. Further investigations into the connections between small vessel disease and delayed seizures are warranted.

Patterns of postictal cerebral perfusion in idiopathic generalized epilepsy: a multi-delay multi-parametric arterial spin labelling perfusion MRI study

The cerebral haemodynamic status of idiopathic generalized epilepsy (IGE) is a very complicated process. Little attention has been paid to cerebral blood flow (CBF) alterations in IGE detected by arterial spin labelling (ASL) perfusion magnetic resonance imaging (MRI). However, the selection of an optimal delay time is difficult for single-delay ASL. Multi-delay multi-parametric ASL perfusion MRI overcomes the limitations of single-delay ASL. We applied multi-delay multi-parametric ASL perfusion MRI to investigate the patterns of postictal cerebral perfusion in IGE patients with absence seizures. A total of 21 IGE patients with absence seizures and 24 healthy control subjects were enrolled. IGE patients exhibited prolonged arterial transit time (ATT) in the left superior temporal gyrus. The mean CBF of IGE patients was significantly increased in the left middle temporal gyrus, left parahippocampal gyrus and left fusiform gyrus. Prolonged ATT in the left superior temporal gyrus was negatively correlated with the age at onset in IGE patients. This study demonstrated that cortical dysfunction in the temporal lobe and fusiform gyrus may be related to epileptic activity in IGE patients with absence seizures. This information can play an important role in elucidating the pathophysiological mechanism of IGE from a cerebral haemodynamic perspective.