Stroke after adult-onset epilepsy: a population-based retrospective cohort study

Epilepsy and brain health: a large prospective cohort study

BACKGROUND

Epilepsy, as a chronic noncommunicable disease with recurrent seizures, may be a marker of deterioration or alteration in other underlying neurological diseases. This study aimed to investigate the relationship of epilepsy with brain function, other common brain disorders, and their underlying mechanisms.

METHODS

The study was based on clinical diagnostic and test data from 426,527 participants in the UK Biobank, of whom 3,251 were diagnosed with epilepsy at baseline. Multiple linear and Cox regression models were used to explore the association between epilepsy, brain function, and other brain disorders.

RESULTS

This study demonstrated consistent deleterious effects of epilepsy on cognitive and motor function and mental health. The risk of neurological diseases and psychiatric disorders was significantly elevated in the epilepsy population during the 17-year follow-up period, according to the longitudinal analysis. We also identified several brain regions associated with epilepsy, including the pallidum, hippocampus, and precentral regions. Mediation analyses revealed mediating effects of peripheral markers and proteins (e.g., GGT, HDL, ACE2, and GDF15), suggesting that liver function and lipid metabolism may be involved in the development of other brain disorders in individuals with epilepsy.

CONCLUSIONS

Our study provides robust evidence of the association between epilepsy and poor brain health, underscoring the importance of early intervention for epilepsy.

Antiseizure Medications and Cardiovascular Events in Older People With Epilepsy in the Canadian Longitudinal Study on Aging

Importance

How epilepsy may promote cardiovascular disease remains poorly understood.

Objective

To estimate the odds of new-onset cardiovascular events (CVEs) over 6 years in older people with vs without epilepsy, exploring how enzyme-inducing antiseizure medications (EIASMs) and traditional cardiovascular risk factors mediate these odds.

Design, Setting, and Participants

This was a prospective cohort study using the comprehensive cohort of the Canadian Longitudinal Study on Aging (CLSA), with 6 years of follow-up (2015-2021, analysis performed in December 2023). The CLSA is an ongoing, national study of 51 338 adults aged 45 to 85 years at baseline who are recruited in Canada. The comprehensive cohort includes 30 097 individuals living near 1 of 11 data collection centers. Participation in the CLSA was voluntary; participation rate was 45%. Among those in the comprehensive cohort, individuals reporting no previous history of CVEs (ie, stroke, transient ischemic attack [TIA], or myocardial infarction [MI]) at baseline were excluded. No other exclusion criteria were applied. A total of 86% of participants completed follow-up.

Exposure

Lifetime history of epilepsy.

Main Outcomes and Measures

The primary outcome was new-onset CVEs over 6 years. Secondary outcomes were new-onset strokes, TIAs, and MIs. Logistic models were fitted for these outcomes as a function of epilepsy, age, sex, household income, and education level. Mediation analyses were conducted for strong EIASM use, weak EIASM use, Framingham score, Physical Activity Scale for the Elderly (PASE) score, and waist to hip ratio.

Results

Among the 30 097 individuals in the comprehensive cohort, a total of 27 230 individuals (mean [SD] age, 62.3 [10.1] years; 14 268 female [52.4%]) were included, 431 with a lifetime history of epilepsy. New-onset CVEs were more likely in epilepsy, with an adjusted odds ratio of 2.20 (95% CI, 1.48-3.27). The proportion of the effect of epilepsy on new-onset CVEs was mediated as follows by each of the following variables: strong EIASM use, 24.6% (95% CI, 6.5%-54.6%), weak EIASM use, 4.0% (95% CI, 0.8%-11.0%), Framingham score, 1.4% (95% CI, -1.6% to 4.5%), PASE score, 3.3% (95% CI, 1.4%-6.8%), and waist to hip ratio, 1.6% (95% CI, 0.4%-3.7%).

Conclusions and Relevance

Results of this cohort study reveal that epilepsy was associated with new-onset CVEs. Nearly one-third of this association can be explained by EIASMs. These findings should be considered when choosing an antiseizure medication for a person at risk for cardiovascular disease.

Pathophysiology, Diagnosis, Prognosis, and Prevention of Poststroke Epilepsy: Clinical and Research Implications

Poststroke epilepsy (PSE) is associated with higher mortality and poor functional and cognitive outcomes in patients with stroke. With the remarkable development of acute stroke treatment, there is a growing number of survivors with PSE. Although approximately 10% of patients with stroke develop PSE, given the significant burden of stroke worldwide, PSE is a significant problem in stroke survivors. Therefore, the attention of health policymakers and significant funding are required to promote PSE prevention research. The current PSE definition includes unprovoked seizures occurring more than 7 days after stroke onset, given the high recurrence risks of seizures. However, the pathologic cascade of stroke is not uniform, indicating the need for a tissue-based approach rather than a time-based one to distinguish early seizures from late seizures. EEG is a commonly used tool in the diagnostic work-up of PSE. EEG findings during the acute phase of stroke can potentially stratify the risk of subsequent seizures and predict the development of poststroke epileptogenesis. Recent reports suggest that cortical superficial siderosis, which may be involved in epileptogenesis, is a promising marker for PSE. By incorporating such markers, future risk-scoring models could guide treatment strategies, particularly for the primary prophylaxis of PSE. To date, drugs that prevent poststroke epileptogenesis are lacking. The primary challenge involves the substantial cost burden due to the difficulty of reliably enrolling patients who develop PSE. There is, therefore, a critical need to determine reliable biomarkers for PSE. The goal is to be able to use them for trial enrichment and as a surrogate outcome measure for epileptogenesis. Moreover, seizure prophylaxis is essential to prevent functional and cognitive decline in stroke survivors. Further elucidation of factors that contribute to poststroke epileptogenesis is eagerly awaited. Meanwhile, the regimen of antiseizure medications should be based on individual cardiovascular risk, psychosomatic comorbidities, and concomitant medications. This review summarizes the current understanding of poststroke epileptogenesis, its risks, prognostic models, prophylaxis, and strategies for secondary prevention of seizures and suggests strategies to advance research on PSE.

Cerebral small vessel disease increases risk for epilepsy: a Mendelian randomization study

BACKGROUND

Despite previous research suggesting a potential association between cerebral small vessel disease (CSVD) and epilepsy, the precise causality and directionality between cerebral small vessel disease (CSVD) and epilepsy remain incompletely understood. We aimed to investigate the causal link between CSVD and epilepsy.

METHOD

A bidirectional two-sample Mendelian randomization (MR) analysis was performed to evaluate the causal relationship between CSVD and epilepsy. The analysis included five dimensions of CSVD, namely small vessel ischemic stroke (SVS), intracerebral hemorrhage (ICH), white matter damage (including white matter hyperintensity [WMH], fractional anisotropy, and mean diffusivity), lacunar stroke, and cerebral microbleeds. We also incorporated epilepsy encompassing both focal epilepsy and generalized epilepsy. Inverse variance weighted (IVW) was used as the primary estimate while other four MR techniques were used to validate the results. Pleiotropic effects were controlled by adjusting vascular risk factors through multivariable MR.

RESULT

The study found a significant association between SVS (odds ratio [OR] 1.117, PFDR = 0.022), fractional anisotropy (OR 0.961, PFDR = 0.005), mean diffusivity (OR 1.036, PFDR = 0.004), and lacunar stroke (OR 1.127, PFDR = 0.007) with an increased risk of epilepsy. The aforementioned correlations primarily occurred in focal epilepsy rather than generalized epilepsy on subgroup analysis and retained their significance in the multivariable MR analysis.

CONCLUSION

Our study demonstrated that genetic susceptibility to CSVD independently elevates the risk of epilepsy, especially focal epilepsy. Diffusion tensor imaging may help screen patients at high risk for epilepsy in CSVD. Improved management of CSVD may be a significant approach in reducing the overall prevalence of epilepsy.

Hypertension and other vascular risk factors in patients with functional seizures

OBJECTIVE

Recent literature has suggested that functional seizures are associated with an elevated risk for vascular disease and mortality. We investigated the prevalence of risk factors for vascular disease in patients who were admitted to the epilepsy monitoring unit.

METHODS

Patients who were admitted to the epilepsy monitoring unit and received a definitive diagnosis of either functional seizures or epilepsy were identified. Data collected included demographic, clinical characteristics, medication list, comorbidities, and scheduled blood pressure measurements that occurred every 12 h during the admission. The mean blood pressures were calculated and if they were above the American College of Cardiology and the American Heart Association guideline cutoff of 130/80 mm Hg or the patient had a documented history of hypertension the patient was counted as having the condition. A multiple logistic regression model was developed to evaluate the independent association of the patient's diagnosis (i.e., epilepsy or functional seizures) and vascular risk factors that controlled for the number of blood pressure measurements, age, sex, and if the patient was taking antihypertensive medications.

RESULTS

270 patients were included in this study of which 147 patients had epilepsy and 123 had functional seizures. Among those with functional seizures, 57.72 % had either a history of hypertension or a mean blood pressure above 130/80 compared to 38.78 % of those with epilepsy (p = 0.0022). In addition, 30.89 % of functional seizures patients had hyperlipidemia and 63.41 % were obese. The logistic regression model indicated that functional seizures were independently associated with high blood pressure (OR: 2.47, 95 % CI 1.10-5.69), hyperlipidemia (OR: 3.38, 95 % CI 1.35-8.86), and obesity (OR: 4.25, 95 % CI 2.22-8.36) compared to those with epilepsy. There was no significant difference in the prevalence of diabetes (OR: 0.81, 95 % CI 0.24-2.77) or current tobacco use (OR: 1.04, 95 % CI 0.48-2.25) between the groups.

SIGNIFICANCE

Patients with functional seizures had an elevated prevalence of several vascular risk factors. These findings may partially account for complications associated with functional seizures and have implications related to their pathophysiology.

Comparison of Cardiovascular Outcomes and All-Cause Mortality Between Patients With and Without Epilepsy: A Systematic Review and Meta-Analysis of Observational Studies

This meta-analysis aimed to assess the all-cause mortality and cardiovascular outcomes among patients diagnosed with epilepsy. The entire process of this systematic review and meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to ensure transparency and reporting completeness. A comprehensive search strategy was employed to identify relevant studies in electronic databases, including PubMed, Embase, and the Cumulative Index of Nursing and Allied Health Literature (CINAHL), from January 1, 2010, to January 15, 2024. Outcomes assessed in this meta-analysis included all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and arrhythmias. A total of 12 studies were included in this meta-analysis with a pooled sample size of 7,026,313. The majority of included studies were conducted in Taiwan (n=4). Our study revealed that individuals with epilepsy faced a higher risk of all-cause mortality, cardiovascular mortality, and stroke. Although there was a higher incidence of myocardial infarction and arrhythmias among epilepsy patients, this disparity did not reach statistical significance. There is a need for future research to explore the impact of epilepsy types, antiepileptic drugs, and lifestyle factors on cardiovascular outcomes.

Histopathological characterization of cerebral small vessel disease in epilepsy patients with temporal lobe epilepsy submitted to surgery: A case-control study

BACKGROUND

Cerebrovascular disease (CVD) is a major contributor to epilepsy; however, patients with epilepsy also have a significantly increased risk of stroke. The way in which epilepsy contributes to the increased risk of stroke is still uncertain and is ill-characterized in neuropathological studies. A neuropathological characterization of cerebral small vessel disease (cSVD) in patients with chronic epilepsy was performed.

METHODS

Thirty-three patients with refractory epilepsy and hippocampal sclerosis (HS) submitted to epilepsy surgery from a reference center were selected between 2010 and 2020 and compared with 19 autopsy controls. Five randomly selected arterioles from each patient were analyzed using a previously validated scale for cSVD. The presence of CVD disease imaging markers in pre-surgical brain magnetic resonance imaging (MRI) was studied.

RESULTS

There were no differences in age (43.8 vs. 41.6 years; p = 0.547) or gender distribution (female gender 60.6% vs. male gender 52.6%; p = 0.575) between groups. Most CVD findings in brain MRI were mild. Patients had a mean time between the epilepsy onset and surgery of 26 ± 14.7 years and were medicated with a median number of three antiseizure medication (ASMs) [IQR 2-3]. Patients had higher median scores in arteriolosclerosis (3 vs. 1; p < 0.0001), microhemorrhages (4 vs. 1; p < 0.0001) and total score value (12 vs. 8.9; p = 0.031) in comparison with controls. No correlation was found between age, number of years until surgery, number of ASMs or cumulative defined daily dosage of ASM.

CONCLUSION

The present study provides evidence supporting the increased burden of cSVD in the neuropathological samples of patients with chronic epilepsy.

Epilepsy-Heart Syndrome: Incidence and Clinical Outcomes of Cardiac Complications in patients with Epilepsy

The risks of cardiovascular events (CVEs) in people with epilepsy (PWE) are not well understood. To establish the short- and long-term burden of CVEs in PWE. Electronic health records from a global federated health research network (TriNetX) were used to establish a cohort of PWE. Primary outcomes were: (1) the proportion of people experiencing a composite outcome of cardiac arrest, acute heart failure (HF), acute coronary syndrome (ACS), atrial fibrillation (AF), severe ventricular arrhythmia or all-cause death within 30 days of a seizure; and (2) the 5-year risk for a composite outcome of ischemic heart diseases, stroke, hospitalization, or all-cause death in the PWE experiencing early CVEs. Cox-regression analyses with propensity score matching was used to produce hazard ratios (HRs) and 95% confidence intervals (CI). In 271,172 PWE (mean age 50 ± 20 years; 52% females), the 30-day risk of CVEs following seizure was: 8.7% for the composite outcome, 0.9% for cardiac arrest, 0.8% for HF, 1.2% for ACS, 4.1% for AF, 0.7% for severe ventricular arrhythmias, and 1.6% for all-cause death. For the 15,120 PWE experiencing CVEs within 30 days of seizure, the 5-year adjusted risks for all composite outcomes measured were significantly increased (overall HR: 2.44, 95% CI 2.37-2.51), ischemic heart diseases HR 3.23 (95% CI 3.10-3.36), stroke HR 1.56 (95% CI 1.48-1.64), hospitalization HR 2.03 (95% CI 1.97-2.10), and all-cause death HR 2.75 (95% CI 2.61-2.89). The large proportions of PWE with active disease that experience CVEs and the poor long-term outcome associated suggest the existence of an "epilepsy-heart syndrome."

Tackling seizures in patients with Alzheimer's disease

INTRODUCTION

In past years, a possible bidirectional link between epilepsy and Alzheimer's disease (AD) has been proposed: if AD patients are more likely to develop epilepsy, people with late-onset epilepsy evidence an increased risk of dementia. Furthermore, current research suggested that subclinical epileptiform discharges may be more frequent in patients with AD and network hyperexcitability may hasten cognitive impairment.

AREAS COVERED

In this narrative review, the authors discuss the recent evidence linking AD and epilepsy as well as seizures semeiology and epileptiform activity observed in patients with AD. Finally, anti-seizure medications (ASMs) and therapeutic trials to tackle seizures and network hyperexcitability in this clinical scenario have been summarized.

EXPERT OPINION

There is growing experimental evidence demonstrating a strong connection between seizures, neuronal hyperexcitability, and AD. Epilepsy in AD has shown a good response to ASMs both at the late and prodromal stages. The new generation ASMs with fewer cognitive adverse effects seem to be a preferable option. Data on the possible effects of network hyperexcitability and ASMs on AD progression are still inconclusive. Further clinical trials are mandatory to identify clear guidelines about treatment of subclinical epileptiform discharges in patients with AD without seizures.

Detailed risks and characteristics of postepilepsy stroke in non-traumatic adult-onset epilepsy

BACKGROUND

Patients with epilepsy have an increased risk of stroke. However, the detailed risk and characteristics of postepilepsy stroke have not been investigated.

METHODS

This study utilized the National Health Insurance Research Database in Taiwan. We classified adult patients with newly diagnosed epilepsy from 2003 to 2016 as the epilepsy cohort. Patients in the nonepilepsy cohort were selected with propensity score matching at a case-control ratio of 1:5. The incidence, hazard ratio (HR), period-specific HR, recurrent HR in the Wei-Lin-Weissfeld model, stroke severity index, complications, and mortality of all stroke, ischemic stroke (IS) and hemorrhagic stroke events in the two cohorts were analyzed.

RESULTS

We enrolled 23,810 patients in the epilepsy cohort and 119,050 persons in the nonepilepsy cohort. The period-specific HRs of all stroke, IS and hemorrhagic stroke peaked immediately after epilepsy diagnosis and trended downward [Adjusted HRs of all stroke: 4.88 (3.88-6.14), 4.47 (3.50-5.70), 3.17 (2.62-3.84), 2.81 (2.27-3.48), 2.81 (2.36-3.34) and 2.33 (2.07-2.62) in 0-0.5, 0.5-1, 1-2, 2-3, 3-5 and ≥5 years after epilepsy diagnosis, respectively]. The recurrent stroke HRs in the epilepsy cohort were >1 from the first [3.06 (2.71-3.34)] to the fourth events [6.33 (1.08-37.03)]. IS events in the epilepsy cohort were associated with a younger onset age, a higher IS severity index, a higher rate of urinary tract infection, a lower in-hospital mortality, while 90-day stroke mortality was similar between the 2 cohorts.

CONCLUSION

Since the increased risk of stroke in epilepsy cohort peaked immediately after epilepsy diagnosis, early implementation of prevention strategies is considered.

Pearls and Oy-sters: De Novo Seizure and Stroke in the Elderly: The Issue of Chicken and Egg

Seizures immediately preceding the occurrence of an ischemic or hemorrhagic stroke are a rare but well documented phenomenon, for which the term "heraldic seizure" has been proposed. Cerebrovascular disease is the most common cause of epileptic seizures in elderly patients, thus screening and management of vascular risk factors should be done systematically in cases of late-onset epilepsy. MRI may help to distinguish heraldic seizure from stroke-elicited seizure by showing abnormalities confined to the cortex that spare vascular territories, increased MRA flow in the ipsilateral cerebral arteries and enhancement of the leptomeninges on postcontrast MRI. Here we present a case report that illustrates the difficulty of making the diagnosis of a heraldic seizure at onset.

Mortality in Patients With Late-Onset Epilepsy: Results From the Atherosclerosis Risk in Communities Study

OBJECTIVE

To determine the risk of mortality and causes of death in persons with late-onset epilepsy (LOE) compared to those without epilepsy in a community-based sample, adjusting for demographics and comorbid conditions.

METHODS

This is an analysis of the prospective Atherosclerosis Risk in Communities (ARIC) study, initiated in 1987-1989 among 15,792 mostly black and white men and women in 4 U.S. communities. We used Centers for Medicare Services fee-for-service claims codes to identify cases of incident epilepsy starting at or after age 67. We used Cox proportional hazards analysis to identify the hazard of mortality associated with LOE and to adjust for demographics and vascular risk factors. We used death certificate data to identify dates and causes of death.

RESULTS

Analyses included 9090 participants, of whom 678 developed LOE during median 11.5 years of follow-up after age 67. Participants who developed LOE were at an increased hazard of mortality compared to those who did not, with adjusted hazard ratio 2.39 (95% CI 2.12-2.71). We observed excess mortality due to stroke, dementia, neurologic conditions, and end-stage renal disease in participants with compared to without LOE. Only 4 deaths (1.1%) were directly attributed to seizure-related causes.

CONCLUSIONS

Persons who develop LOE are at increased risk of death compared to those without epilepsy, even after adjusting for comorbidities. The majority of this excess mortality is due to stroke and dementia.

Epilepsy, antiepileptic drugs, and the risk of major cardiovascular events

OBJECTIVE

This study was undertaken to determine whether epilepsy and antiepileptic drugs (including enzyme-inducing and non-enzyme-inducing drugs) are associated with major cardiovascular events using population-level, routinely collected data.

METHODS

Using anonymized, routinely collected, health care data in Wales, UK, we performed a retrospective matched cohort study (2003-2017) of adults with epilepsy prescribed an antiepileptic drug. Controls were matched with replacement on age, gender, deprivation quintile, and year of entry into the study. Participants were followed to the end of the study for the occurrence of a major cardiovascular event, and survival models were constructed to compare the time to a major cardiovascular event (cardiac arrest, myocardial infarction, stroke, ischemic heart disease, clinically significant arrhythmia, thromboembolism, onset of heart failure, or a cardiovascular death) for individuals in the case group versus the control group.

RESULTS

There were 10 241 cases (mean age = 49.6 years, 52.2% male, mean follow-up = 6.1 years) matched to 35 145 controls. A total of 3180 (31.1%) cases received enzyme-inducing antiepileptic drugs, and 7061 (68.9%) received non-enzyme-inducing antiepileptic drugs. Cases had an increased risk of experiencing a major cardiovascular event compared to controls (adjusted hazard ratio = 1.58, 95% confidence interval [CI] = 1.51-1.63, p < .001). There was no notable difference in major cardiovascular events between those treated with enzyme-inducing antiepileptic drugs and those treated with non-enzyme-inducing antiepileptic drugs (adjusted hazard ratio = .95, 95% CI = .86-1.05, p = .300).

SIGNIFICANCE

Individuals with epilepsy prescribed antiepileptic drugs are at an increased risk of major cardiovascular events compared with population controls. Being prescribed an enzyme-inducing antiepileptic drug is not associated with a greater risk of a major cardiovascular event compared to treatment with other antiepileptic drugs. Our data emphasize the importance of cardiovascular risk management in the clinical care of people with epilepsy.

Late-onset epilepsy predicts stroke: Systematic review and meta-analysis

OBJECTIVE

Late-onset epilepsy (LOE) is closely associated with cerebrovascular disease, acting as both a marker of cerebrovascular disease (CVD) and occurring as a direct consequence. Despite this, our understanding of LOE as a cerebrovascular phenomenon is in its infancy. LOE also appears to be a harbinger of dementia.

METHODS

A systematic review was performed to identify publications relating to LOE and identified observational studies, clinical studies, and radiological studies.

RESULTS

A meta-analysis of observational studies demonstrated that patients presenting with LOE experience an increased risk of subsequent stroke (weighted OR 3.88 (95% CI 2.76-5.46)). The additional studies demonstrated clinical and radiological evidence to support the premise that LOE is likely to reflect underlying cerebrovascular disease.

SIGNIFICANCE

Cerebrovascular disease risk factors convey increased risk of LOE and LOE can precede stroke and dementia, acting as an early marker for cerebrovascular risk. This may represent a potential point for intervention. There are a number of suggested mechanisms relating LOE to stroke; however, there is limited understanding of the natural history of LOE. Current data support the need for prospective research in order to understand the natural history of LOE and modify disease, in order to reduce the apparent sequelae of stroke and dementia.

New anti-seizure medication for elderly epilepsy patients - a critical narrative review

Introduction: The number of elderly patients with epilepsy is growing in resource rich countries due to demographic changes and increased longevity. Management in these patients is challenging as underlying etiology, co-morbidities, polypharmacy, age-related pharmacokinetic and pharmacodynamic changes need to be considered.Areas covered: Lacosamide, eslicarbazepine acetate, brivaracetam, and perampanel have been approved in the USA and Europe for monotherapy and/or adjunctive treatment of seizures in the last few years. The authors review the pharmacological properties and safety profile of these drugs and provide recommendations for their use in in the elderly.Expert opinion: There are only limited data available on more recent antiseizure medications (ASMs). Drugs with a low risk of interaction (lacosamide, brivaracetam) are preferred choices. Once daily formulations (perampanel and eslicarbazepine acetate) have the advantage of increased compliance. Intravenous formulations (brivaracetam and lacosamide) are useful in emergency situations and in patients who have difficulties to swallow. Dose adjustments are necessary for all ASMs used in the elderly with slow titration and lower target doses than in the regulatory trials. The adverse event profile does not significantly differ from that found in the general adult population.

Risk of stroke after new-onset seizures

PURPOSE

Observational cohort studies have reported a potentially increased risk of stroke in patients with epileptic seizures. Whether late-onset seizures merit primary stroke prophylaxis is not known, and more information on stroke risk is needed for the planning of RCTs. We performed a case-control study based on Swedish national registers to quantify the risk of stroke after epileptic seizures.

METHODS

Cases ≤100 years of age with a first-ever stroke 2001-2009 were identified through the Swedish Stroke Register, and stroke-free controls (matched for age and sex) were obtained from the Population Register. The National Patient Register provided information on diagnostic codes for seizures, epilepsy and comorbidities. 123 105 stroke cases and 250 506 controls were included.

RESULTS

Epileptic seizures prior to index stroke date were detected in 1559 (1.27 %) cases and 1806 (0.72 %) controls, yielding an odds ratio (95 % confidence interval) for stroke of 1.77 (1.65-1.89). ORs were similar in men and women, but higher below the age of 75. An onset of seizures in the year preceding stroke date resulted in a higher risk for stroke (OR = 2.21, 95 % CI = 1.79-2.72) compared to when more than 5 years had passed since the first seizure (OR = 1.57, 95 % CI = 1.43-1.72).

CONCLUSION

A history of epileptic seizures was associated with an increased risk of subsequent stroke. The risk seems to be particularly high in the first year following seizure diagnosis, which supports the notion that unexplained late-onset seizures may merit swift assessment of vascular risk profile. The nature of stroke prevention requires further study.

Dementia in late-onset epilepsy: The Atherosclerosis Risk in Communities study

OBJECTIVE

To determine the risk of dementia after the development of late-onset epilepsy.

METHODS

We used data from the Atherosclerosis Risk in Communities (ARIC) cohort study, which started in 1987 to 1989 with 15,792 mostly Black and White men and women from 4 US communities. We identified late-onset epilepsy (LOE; seizures starting at age 67 or later) from linked Medicare claims data. We used a Cox proportional hazards regression model to evaluate associations between LOE and dementia through 2017 as ascertained from neuropsychological testing, interviews, and hospital discharge surveillance, and we used multinomial logistic regression to assess the risk of dementia and mild cognitive impairment in the subset with full neuropsychological assessments available. We adjusted for demographics and vascular and Alzheimer disease risk factors.

RESULTS

Of 9,033 ARIC participants with sufficient Medicare coverage data (4,980 [55.1%] female, 1993 [22.1%] Black), 671 met the definition of LOE. Two hundred seventy-nine (41.6%) participants with and 1,408 (16.8%) without LOE developed dementia (p < 0.001). After a diagnosis of LOE, the adjusted hazard ratio for developing subsequent dementia was 3.05 (95% confidence interval 2.65-3.51). The median time to dementia ascertainment after the onset of LOE was 3.66 years (quartile 1-3, 1.28-8.28 years).

INTERPRETATION

The risk of incident dementia is substantially elevated in individuals with LOE. Further work is needed to explore causes for the increased risk of dementia in this growing population.

CDC-supported epilepsy surveillance and epidemiologic studies: A review of progress since 1994

To report progress, to identify gaps, and to plan epilepsy surveillance and research activities more effectively, the Centers for Disease Control and Prevention (CDC) Epilepsy Program has summarized findings from selected CDC-supported surveillance and epidemiologic studies about epilepsy from 1994 through 2019. We identified publications supported by CDC funding and publications conducted by the CDC Epilepsy Program alone or with partners. We included only epilepsy surveillance and epidemiologic studies focusing on epilepsy burden, epilepsy-related outcomes, and healthcare utilization. We describe the findings of these studies in the following order: 1)prevalence; 2)incidence; 3)epilepsy-related outcomes by selected demographic characteristics; 4)cysticercosis or neurocysticercosis (NCC); 5)traumatic brain injury (TBI); 6)comorbidity; 7)mortality; 8)access to care; 9)quality of care; and 10) cost. We have characterized these findings in relation to the scope of the first three domains of the 2012 Institute of Medicine report on epilepsy and its relevant first four recommendations. From 1994 through 2019, 76 publications on epilepsy-related epidemiologic and surveillance studies were identified. Over the past 25 years, CDC has expanded community, state, and national surveillance on epilepsy and supported epidemiologic studies by using multiple assessment methods and validated case-ascertainment criteria to identify epilepsy burden, epilepsy-related outcomes, and healthcare utilization in the general population or in population subgroups. Among identified research opportunities, studies on epilepsy incidence and risk factors, mortality, and cost are considered as important surveillance gaps. Other remaining gaps and suggested surveillance strategies are also proposed. Findings from this review may help epilepsy researchers and other stakeholders reference and prioritize future activities for epidemiologic and surveillance studies in epilepsy.

Increased risk of stroke and myocardial infarction in patients with epilepsy: A systematic review of population-based cohort studies

OBJECTIVE

The objective of the study was to review the current epidemiological evidence about the relationship between epilepsy and increased risk of cardio- and cerebrovascular events.

METHODS

We systematically searched MEDLINE (from inception to 19th October 2018) to identify population-based cohort studies evaluating the risk of subsequent stroke or myocardial infarction (MI) in patients with epilepsy without history of prior cerebrovascular disease in comparison with subjects without epilepsy.

RESULTS

A total of 16,641 records were screened, and 6 studies were included. Data on the risk of subsequent stroke and MI were provided by five and two studies, respectively. The adjusted hazard ratios (_adjHRs) of subsequent ischemic stroke for patients with epilepsy ranged from 1.09 (95% confidence interval (CI): 1.00-1.19) to 2.85 (95% CI: 2.49-3.26). Two studies assessing the incidence of hemorrhagic stroke showed an increased risk in patients with epilepsy (_adjHR: 3.30; 95% CI: 2.46-4.43 and _adjHR: 2.27; 95% CI: 1.80-2.85). The _adjHRs of subsequent MI ranged between 1.09 (95% CI: 1.00 to 1.19) and 1.48 (95% CI: 1.31-1.67). Age, hypertension, MI, diabetes, hyperlipidemia, and arteriosclerosis were significantly associated with the increase in stroke risk. A gradient between the antiepileptic drug (AED) dose and risk of subsequent stroke was found. In comparison with carbamazepine (CBZ), oxcarbazepine (OXC) was associated with an increased risk of stroke and valproate (VPA) with a reduction in risk of stroke and MI, whereas no significant associations with vascular disease were found for phenobarbital (PB), lamotrigine (LMT), phenytoin (PHT), clonazepam (CLZ), and clobazam (CLB).

CONCLUSIONS

Patients with epilepsy are at higher risk of subsequent stroke and MI in comparison with subjects without epilepsy. Although individual AEDs may carry different risks of cardio- and cerebrovascular disease, the clinical relevance of the metabolic effects of the enzyme-inducing AEDs is still uncertain. This article is part of the Special Issue "Seizures & Stroke".

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.

Medicare claims can identify post-stroke epilepsy

OBJECTIVE

There have been no validated Medicare claims-based algorithms available to identify epilepsy by discrete etiology of stroke (e.g., post-stroke epilepsy, PSE) in community-dwelling elderly individuals, despite the increasing availability of large datasets. Our objective was to validate algorithms that detect which patients have true PSE.

METHODS

We linked electronic health records (EHR) to Medicare claims from a Medicare Pioneer Accountable Care Organization (ACO) to identify PSE. A neurologist reviewed 01/2012-12/2014 EHR data from a stratified sample of Medicare patients aged 65+ years to adjudicate a reference-standard to develop an algorithm for identifying patients with PSE. Patient sampling strata included those with: A) epilepsy-related claims diagnosis (n = 534 [all]); B) no diagnosis but neurologist visit (n = 500 [randomly sampled from 4346]); C) all others (n = 500 [randomly sampled from 16,065]). We reconstructed the full sample using inverse probability sampling weights; then used half to derive algorithms and assess performance, and the remainder to confirm performance. We evaluated predictive performance across several measures, e.g., specificity, sensitivity, negative and positive predictive values (NPV, PPV). We selected our best performing algorithms based on the greatest specificity and sensitivity.

RESULTS

Of 20,943 patients in the reconstructed sample, 13.6% of patients with epilepsy had reference-standard PSE diagnosis, which represents a 3-year overall prevalence of 0.28% or 28/10,000, and a prevalence within the subpopulation with stroke of 3%. The best algorithm included three conditions: (a) at least one cerebrovascular claim AND one epilepsy-specific anticonvulsant OR (b) at least one cerebrovascular claim AND one electroencephalography claim (specificity 100.0% [95% CI 99.9%-100.0%], NPV 98.8% [98.6%-99.0%], sensitivity 20.6% [95% CI 14.6%-27.9%], PPV 86.5% [95% CI 71.2%-95.5%]).

CONCLUSION

Medicare claims can identify elderly Medicare beneficiaries with PSE with high accuracy. Future epidemiological surveillance of epilepsy could incorporate similar algorithms to accurately identify epilepsy by varying etiologies.

Epilepsy after stroke: Definitions, problems and a practical approach for clinicians

Stroke, whether ischemic or hemorrhagic, is the main etiology of epilepsy in the elderly. However, incidences and outcomes differ according to stroke subtype and delay of onset following the stroke. While the medical literature is extensive, it is not always consistent, and many questions still remain regarding risk factors and management of vascular epilepsy. Thus, the present report here is an overview of the clinical aspects of vascular epilepsy using a practical approach that integrates data from meta-analyses and the more recently published expert recommendations.

Myocardial infarction after epilepsy onset: A population-based retrospective cohort study

INTRODUCTION

Cardiovascular comorbidities of epilepsy such as hypertension, hyperlipidemia, and diabetes are associated with myocardial infarction (MI). Little data on the development of subsequent cardiovascular disease (CVD) in persons with epilepsy (PWE) are available, with inconsistent findings regarding the association between epilepsy and subsequent MI. A higher risk of MI among adults (without prior MI) following epilepsy diagnosis compared with that among controls was hypothesized.

METHODS

This retrospective cohort study used statewide hospital and emergency department (ED) encounter data from 2000-2013 for South Carolina residents aged >18 years without prior MI at the onset of epilepsy, or the first encounter for controls. Persons with epilepsy were compared with 1) persons with migraine (PWM), whose neurological condition has characteristics similar to epilepsy; and 2) persons with isolated lower extremity fracture (PWLF). Subsequent MI was defined as a diagnosis of MI after the first clinical encounter for epilepsy, migraine, or lower extremity fracture (LEF); the association was evaluated with Cox proportional hazard modeling methods.

RESULTS

In this study, 2.2% of PWE, 0.6% of PWM, and 1.2% of PWLF had a subsequent MI. Persons with epilepsy were significantly more likely to be non-Hispanic Black (NHB), be covered by Medicaid, and reside in a rural or low income area compared with PWM and PWLF. Specific cardiovascular disease risk factors were more prevalent in PWE than in PWM and PWLF. After adjustment, the hazard of subsequent MI in PWE was 48% higher than in PWM (hazard ratio (HR) = 1.48; 95% confidence intervals (CI) = 1.31-1.67) and 24% higher than in PWLF (HR = 1.24; 95% CI = 1.10-1.39). The hazard of MI increased with increasing age and number of additional comorbidities and was higher in males, those living in rural areas, and those with specific cardiovascular risk factors.

CONCLUSION

Persons with epilepsy had moderately elevated risk of subsequent MI compared with PWM or PWLF. The association between epilepsy and MI needs to be further investigated, and clinical care of PWE should include evaluation and management of risk factors for MI.

Antiphospholipid antibodies in epilepsy: A systematic review and meta-analysis

BACKGROUND

Autoimmunity is believed to play an important causative role in the pathogenesis of epilepsy. There are evidences for the presence of autoantibodies in patients with epilepsy. To date, many studies have assessed the presence of antiphospholipid antibodies (aPLs) in epilepsy patients, though the relationship has been inconclusive.

AIMS

The aim of this systematic review and meta-analysis was to evaluate the presence of aPLs in epileptic patients as compared to healthy controls.

METHODS

Five electronic databases (PubMed, Web of Science, Embase, Scopus and Google Scholar) were searched systematically. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. Quality assessment was carried out by using the modified 9-star Newcastle-Ottawa Scale (NOS). L'Abbé plots were generated to visually inspect heterogeneity while publication bias was evaluated via visualization of contour- enhanced funnel plots, and Begg's and Egger's tests.

RESULTS

Based on the inclusion criteria, 14 studies were selected involving 1248 epilepsy patients and 800 healthy controls. The majority of epilepsy was categorised as generalised or partial and none had comorbidity with autoimmune diseases. Significant presence of both anticardiolipin (aCL) antibodies (OR: 5.16, 95% CI: 3.21-8.28, p < 0.00001) and anti-β2- glycoprotein I (anti-β2-GPI) antibodies (OR: 2.95, 95% CI: 1.07-8.11, p = 0.04) exhibited comorbid association with epilepsy patients as compared to healthy controls. Subgroup analyses revealed that presence of aCL antibodies was more specifically observed in paediatrics (OR: 4.57, 95% CI: 2.57-8.15, p < 0.00001) than adults (OR: 4.24, 95% CI: 1.80-10.01, p = 0.001). The odds of aCL antibody presence was higher in partial epilepsy patients (OR: 7.88, 95% CI: 3.23-19.24, p < 0.00001) than that of generalised (OR: 3.76, 95% CI: 2.15-6.59, p < 0.00001) and in Asian epileptic patients (OR: 9.56, 95% CI: 2.69-33.95, p = 0.0005) than Europeans (OR: 4.35, 95% CI: 2.74-6.92, p < 0.00001). The presence of anti-β2-GPI antibodies was significant in paediatric (OR: 6.44, 95% CI: 1.39-29.89, p = 0.02) and African population with epilepsies (OR: 10.59, 95% CI: 1.22-92.25, p = 0.03). NOS of the majority of the studies (11/14) indicated a high methodological quality. No substantial heterogeneity was observed either from the quantitative analysis or from the L'Abbé plots while no significant publication bias was detected from funnel plots; Begg's and Egger's tests.

CONCLUSION

Since none of the epilepsy subjects exhibited any comorbid autoimmune disorders, significant presence of aCL and anti-β2-GPI antibodies indicate towards their contribution in immune-mediated general pathogenesis of 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.

Validity of health insurance data to identify people with epilepsy

BACKGROUND

Large administrative databases may prove useful to assess epilepsy-related comorbidity and mortality. Despite their increased use, their validity as data source in epilepsy is yet under-ascertained.

METHODS

Achmea is a large Dutch health insurance company covering about 25% of the population. We performed a retrospective cohort study using data from the Achmea Health Insurance Database (AHID) over the period 2006-2009. To assess the validity of epilepsy codes in the AHID, we randomly invited 1000 individuals (age 18-75 years insured by Achmea), attending an epilepsy centre or a district hospital during 2006-2009, to participate. Informed consent was provided and 293 were eligible for inclusion. We compared the diagnostic codes for epilepsy in AHID with the diagnosis in their case-notes (reference standard). As additional measure of validity, we compared prevalence of epilepsy codes in AHID (based on anonymized data of all 26.297 subjects with this code in AHID) with epilepsy prevalence rates in the general Dutch population to estimate an age-specific standardized prevalence ratio.

RESULTS

We identified 293 participants with an epilepsy code in AHID. The majority (278) of them had a definite or possible diagnosis of epilepsy in the case-notes; i.e. a positive predictive value of 0.95 (95% CI 0.92-0.97). The overall prevalence of epilepsy codes in the AHID was slightly higher than the putative prevalence in the general Dutch population (7.4/1.000 vs. 6.8/1.000) with a Standardized Prevalence Ratio of 1.08 (95% CI: 1.08-1.09).

CONCLUSIONS

Our findings demonstrate the validity of AHID data for a diagnosis of epilepsy and confirm previous work on using administrative data for epilepsy research.

An update on the prevalence and incidence of epilepsy among older adults

OBJECTIVE

To estimate the prevalence and incidence of epilepsy among beneficiaries of Arizona Medicare aged 65 and over.

METHODS

An analysis of Medicare administrative claims data for 2009-2011 for the State of Arizona was conducted. Epilepsy was defined as a beneficiary who had either≥one claim with diagnostic code of 345.xx (epilepsy) or at least two claims with diagnosis code of 780.3x (seizure) ≥30days apart. Stroke-related and psychiatric comorbidities were determined by diagnostic codes. Average annual prevalence and incidence were calculated and stratified by demographic characteristics and comorbidities. Odds ratios (OR) and 95% confidence intervals (CI) were calculated as measures of effect for prevalence and incidence and the chi-square statistic was calculated to compare the proportions of epilepsy cases with and without comorbidities (alpha=0.05).

RESULTS

The overall average annual prevalence and incidence over the study period was 15.2/1000 and 6.1/1000, respectively. Relative to the 65-69 age group and White beneficiaries, the highest prevalence was observed for beneficiaries 85 years or older (19.8/1000, OR 1.66, 95% CI 1.53-1.81) and Native Americans (21.2/1000, OR 1.42, 95% CI 1.25-1.62). In contrast, the highest incidence rates were observed for beneficiaries 85 years and older (8.5/1000, OR 1.82, 95% CI 1.60-2.07) and for Black beneficiaries (8.7/1000, OR 1.44, 95% CI 1.12-1.86). The incidence rate for Native Americans was not significantly different from that for White beneficiaries (6.2/1000, OR 1.02, 95% CI 0.81-1.29). More than one quarter of all cases (25.7%) and 31% of incident cases had either stroke-related and/or psychiatric comorbidities (all p-values < 0.001).

CONCLUSIONS

Epilepsy is a significant neurological disease among Medicare beneficiaries 65 years and older. Beneficiaries aged 85 and older and Black and Native Americans experienced higher rates of epilepsy than other demographic subgroups compared to White beneficiaries.

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.

From 'Big 4' to 'Big 5': a review and epidemiological study on the relationship between psychiatric disorders and World Health Organization preventable diseases

PURPOSE OF REVIEW

This study outlines the rationale and provides evidence in support of including psychiatric disorders in the World Health Organization's classification of preventable diseases. The methods used represent a novel approach to describe clinical pathways, highlighting the importance of considering the full range of comorbid disorders within an integrated population-based data repository.

RECENT FINDINGS

Review of literature focused on comorbidity in relation to the four preventable diseases identified by the World Health Organization. This revealed that only 29 publications over the last 5 years focus on populations and tend only to consider one or two comorbid disorders simultaneously in regard to any main preventable disease class.

SUMMARY

This article draws attention to the importance of physical and psychiatric comorbidity and illustrates the complexity related to describing clinical pathways in terms of understanding the etiological and prognostic clinical profile for patients. Developing a consistent and standardized approach to describe these features of disease has the potential to dramatically shift the format of both clinical practice and medical education when taking into account the complex relationships between and among diseases, such as psychiatric and physical disease, that, hitherto, have been largely unrelated in research.

The New Antiepileptic Drugs: Their Neuropharmacology and Clinical Indications

The administration of antiepileptic drugs (AEDs) is the first treatment of epilepsy, one of the most common neurological diseases. Therapeutic guidelines include newer AEDs as front-line drugs; monotherapy with new AEDs is delivered in Japan. While about 70% of patients obtain good seizure control by taking one to three AEDs, about 60% experience adverse effects and 33% have to change drugs. Compared to traditional AEDs, the prolonged administration of new AEDs elicits fewer adverse effects and fewer drug interactions and their teratogenicity may be lower. These characteristics increase drug compliance and allow combination therapy for drug-resistant epilepsy, although the antiepileptic effects of the new AEDs are not greater than of traditional AEDs. Comorbidities are not rare in epileptics; many adult patients present with stroke and brain tumors. In stroke patients requiring risk control and in chemotherapy-treated brain tumor patients, their fewer drug interactions render the new AEDs advantageous. Also, new AEDs offer favorable side benefits for concurrent diseases and conditions. Patients with stroke and traumatic brain injury often present with psychiatric/behavioral symptoms and cognitive impairment and some new AEDs alleviate such symptoms. This review presents an outline of the new AEDs used to treat adult patients based on the pharmacological activity of the drugs and discusses possible clinical indications from the perspective of underlying causative diseases and comorbidities.

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

Late-onset epilepsy (LOE), with onset after 50 years of age, is often attributed to underlying occult cerebrovascular disease. LOE is associated with a three-fold increase in subsequent stroke risk, therefore it is important to improve our understanding of pathophysiology. In this exploratory study, we aimed to determine whether established structural magnetic resonance imaging markers and novel physiological imaging markers of occult cerebrovascular disease were more common in patients with LOE than age-matched controls.

Sixteen patients with LOE (mean age ± SD: 67.6 ± 6.5 years) and 15 age-matched control subjects (mean age: 65.1 ± 3.9 years) underwent a 3 T MRI scan protocol. T₁-weighted images and T₂-weighted fluid attenuated inversion recovery (FLAIR) images were used to determine cortical grey matter volume and white matter hyperintensity (WMH) volume respectively, whilst multiple delay time arterial spin labelling (ASL) images were collected at rest and during a hypercapnic challenge. Cerebral blood flow (CBF) and arterial arrival time (AAT) were calculated from ASL data under both normocapnic and hypercapnic conditions. Cerebrovascular reactivity was also calculated for both CBF and AAT relative to the change in end-tidal CO₂.

Patients with LOE were found to have significantly lower cortical volume than control subjects (33.8 ± 3.8% of intracranial volume vs. 38.0 ± 5.5%, p = 0.02) and significantly higher WMH volume (1339 ± 1408 mm³ vs. 514 ± 481 mm³, p = 0.047). Baseline whole brain AAT was found to be significantly prolonged in patients with LOE in comparison to control subjects (1539 ± 129 ms vs. 1363 ± 167 ms, p = 0.005). Voxel-based analysis showed the significant prolongation of AAT to be predominantly distributed in the frontal and temporal lobes. Voxel-based morphometry showed the lower cortical volume to be localised primarily to temporal lobes. No significant differences in CBF or cerebrovascular reactivity were found between the two groups. Baseline whole brain AAT and cortical volume differences persisted upon further analysis to take account of differences in smoking history between patients and control subjects.

These findings suggest that occult cerebrovascular disease is relevant to the pathophysiology of LOE.

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LOE patients were found to have increased WMHs and reduced GM volume on MRI imaging in comparison to HC.

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Baseline arterial arrival time was significantly longer in LOE patients than HC.

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Baseline cerebral blood flow did not differ between LOE patients and HC.

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Cerebrovascular reactivity did not differ between LOE patients and HC.