Late-onset epilepsy and 25-year cognitive change: The Atherosclerosis Risk in Communities (ARIC) study

Bidirectional relationship between late-onset epilepsy (LOE) and dementia: A systematic review and meta-analysis of cohort studies

OBJECTIVE

To explore the bidirectional relationship of late-onset epilepsy (LOE) with dementia and Alzheimer's disease (AD).

METHODS

Using the common electronic databases, including PubMed, Cochrane Library databases and EMBASE, we systematically reviewed published cohort studies that assessed the risk of LOE in individuals comorbid with dementia or AD, and those with dementia or AD comorbid with LOE that had been published up to 31 March 2023. The data extraction process was carried out independently by two authors. The summary adjusted relative ratio (aRR) was calculated by employing Rev Man 5.3 for the inclusion of studies. To investigate the origins of heterogeneity, we conducted both subgroup and sensitivity analyses. In the presence of heterogeneity, a random-effects model was employed. To evaluate potential publication bias, we utilized the funnel plot and conducted Begg's and Egger's tests.

RESULTS

We included 20 eligible studies in the final analysis after a rigorous screening process. Pooled results indicated that LOE was association with an increased risk of all-cause dementia (aRR: 1.34, 95% confidence interval [CI]: 1.13-1.59) and AD (aRR: 2.49, 95% CI: 1.16-5.32). In addition, the pooled effect size for LOE associated with baseline AD and all-cause dementia were 3.51 (95% CI: 3.47-3.56) and 2.53 (95% CI: 2.39-2.67), respectively. Both sensitivity and subgroup analyses showed that these positive correlations persisted. According to the results of the Egger's and Begg's tests, as well as visual inspection of funnel plots, none of the studies appeared to be biased by publication.

CONCLUSION

The findings suggested that LOE is a potential risk factor for dementia and AD, and vice versa, dementia and AD are both potential risk indicators for LOE. Since there is substantial heterogeneity among the cohorts analyzed and more cohort studies should be conducted to confirm the correlations found in the current study.

Neuropsychology of late-onset epilepsies

In an increasingly ageing society, patients ageing with epilepsy and those with late-onset epilepsies (LOE) represent a challenge for epilepsy care and treatment. Senescence itself bears risks of pathologies which in the form of acute focal damage (e.g. stroke) or slowly progressive degenerative damage can cause seizures and substantial cognitive impairment. There is converging evidence from studies in LOE that cognitive impairments are present from epilepsy onset before treatment is initiated and may even precede the emergence of seizures. This suggests that these impairments (like the seizures) are expressions of the underlying disease. Indeed, both seizures and cognitive impairments can be early indicators of disease conditions which lead to mental decline. Cognitive decline over time poses the challenge of disentangling the interrelation between seizures, treatment effects and underlying disease. This issue must be considered as some of the etiologies for causing neuropsychological decline can be addressed. Medication and active epilepsy can contribute to impairments and their impact may be reversible. Dementia is rare if seizures are what has brought the person to attention, and if this is not accompanied by other slowly developing features (such as cognitive of psychiatric changes). From a neuropsychological point of view choosing the right screening tools or assessments, obtaining the history and timeline of impairments in relation to epilepsy, and most importantly longitudinally following the patients regardless of whether epilepsy is ultimately controlled or not appear essential.

Alzheimer's disease and epilepsy: shared neuropathology guides current and future treatment strategies

Epilepsy is a cause of profound disability in patients with Alzheimer's disease (AD). The risk of being diagnosed with AD increases the risk for epilepsy, and in parallel, a history of epilepsy increases the likelihood of the development of AD. This bi-directional relationship may be due to underlying shared pathophysiologic hallmarks, including decreased cerebrospinal fluid amyloid beta 42 (Aβ42), increased hyperphosphorylated tau protein, and hippocampal hyperexcitability. Additionally, there are practical treatment considerations in patients with co-morbid AD and epilepsy-namely, there is a higher risk of seizures associated with medications commonly prescribed for Alzheimer's disease patients, including antidepressants and antipsychotics such as trazodone, serotonin norepinephrine reuptake inhibitors (SNRIs), and first-generation neuroleptics. Anti-amyloid antibodies like aducanumab and lecanemab present new and unique considerations in patients with co-morbid AD and epilepsy given the risk of seizures associated with amyloid-related imaging abnormalities (ARIA) seen with this drug class. Finally, we identify and detail five active studies, including two clinical trials of levetiracetam in the respective treatment of cognition and neuropsychiatric features of AD, a study characterizing the prevalence of epilepsy in AD via prolonged EEG monitoring, a study characterizing AD biomarkers in late-onset epilepsy, and a study evaluating hyperexcitability in AD. These ongoing trials may guide future clinical decision-making and the development of novel therapeutics.

Prevalence of dementia in a level 4 university epilepsy center: how big is the problem?

Background

The relationship between epilepsy and dementia is currently a topic of great interest. Our study aimed to determine the prevalence of dementia diagnoses among patients of a large level 4 university epilepsy center.

Methods

In this retrospective monocentric study conducted at the Department of Epileptology of the University Hospital Bonn, we searched for dementia-related terms in a total of 145,501 medical letters from 40,360 adult patients who were seen between 2003 and 2021. Files with at least one hit were selected and analyzed with regard to diagnoses, age, age at epilepsy onset, and the question as to whether epilepsy preceded or followed the dementia diagnosis.

Results

Among the medical letters of 513 patients, dementia-related terms were found. The letters of 12.7% of these patients stated a dementia diagnosis, 6.6% were suspected of having dementia, 4.9% had mild cognitive impairment, and 6.6% had other neurodegenerative diseases without dementia. Taking all 40,360 patients into account, the prevalence of diagnosed or suspected dementia was 0.25%. An older age (≥60 years) and late-onset epilepsy (≥60 years), but not a longer epilepsy duration, increased the odds of dementia by 6.1 (CI 3.5-10.7) and 2.9 (CI 1.7-4.7), respectively. Additionally, vascular, metabolic, inflammatory, and behavioral mood-related comorbidities were commonly observed. Epilepsy tended to precede (23.2%) rather than follow (8.1%) the dementia diagnosis.

Conclusion

Despite the clear limitations of a selection bias and the potential underdiagnosis of dementia and underestimation of its prevalence when relying on the medical letters from a specialized center which rather focuses on epilepsy-related issues, the findings of this study offer valuable insights from the perspective of an epilepsy center. In this setting, the prevalence of dementia in epilepsy is rather low. However, physicians should be aware that the risk of dementia is higher in the elderly, in late-onset epilepsies, and when comorbid risk factors exist. Seizures can also be an early sign of a neurodegenerative disease. Future research should explicitly screen for dementia in patients with epilepsy and stratify them according to their underlying pathologies and comorbidities.

Cognitive phenotypes in late-onset epilepsy: results from the atherosclerosis risk in communities study

Introduction

Cognitive phenotyping is a widely used approach to characterize the heterogeneity of deficits in patients with a range of neurological disorders but has only recently been applied to patients with epilepsy. In this study, we identify cognitive phenotypes in older adults with late-onset epilepsy (LOE) and examine their demographic, clinical, and vascular profiles. Further, we examine whether specific phenotypes pose an increased risk for progressive cognitive decline.

Methods

Participants were part of the Atherosclerosis Risk in Communities Study (ARIC), a prospective longitudinal community-based cohort study of 15,792 individuals initially enrolled in 1987-1989. LOE was identified from linked Centers for Medicare and Medicaid Services claims data. Ninety-one participants with LOE completed comprehensive testing either prior to or after seizure onset as part of a larger cohort in the ARIC Neurocognitive Study in either 2011-2013 or 2016-2017 (follow-up mean = 4.9 years). Cognitive phenotypes in individuals with LOE were derived by calculating test-level impairments for each participant (i.e., ≤1 SD below cognitively normal participants on measures of language, memory, and executive function/processing speed); and then assigning participants to phenotypes if they were impaired on at least two tests within a domain. The total number of impaired domains was used to determine the cognitive phenotypes (i.e., Minimal/No Impairment, Single Domain, or Multidomain).

Results

At our baseline (Visit 5), 36.3% met criteria for Minimal/No Impairment, 35% for Single Domain Impairment (with executive functioning/ processing speed impaired in 53.6%), and 28.7% for Multidomain Impairment. The Minimal/No Impairment group had higher education and occupational complexity. There were no differences in clinical or vascular risk factors across phenotypes. Of those participants with longitudinal data (Visit 6; n = 24), 62.5% declined (i.e., progressed to a more impaired phenotype) and 37.5% remained stable. Those who remained stable were more highly educated compared to those that declined.

Discussion

Our results demonstrate the presence of identifiable cognitive phenotypes in older adults with LOE. These results also highlight the high prevalence of cognitive impairments across domains, with deficits in executive function/processing speed the most common isolated impairment. We also demonstrate that higher education was associated with a Minimal/No Impairment phenotype and lower risk for cognitive decline over time.

Early cognitive comorbidities before disease onset: A common symptom towards prevention of related brain diseases?

Brain diseases are very heterogeneous; however they also display multiple common risk factors and comorbidities. With a paucity of disease-modifying therapies, prevention became a health priority. Towards prevention, one strategy is to focus on similar symptoms of brain diseases occurring before disease onset. Cognitive deficits are a promising candidate as they occur across brain diseases before disease onset. Based on recent research, this review highlights the similarity of brain diseases and discusses how early cognitive deficits can be exploited to tackle disease prevention. After briefly introducing common risk factors, I review common comorbidities across brain diseases, with a focus on cognitive deficits before disease onset, reporting both experimental and clinical findings. Next, I describe network abnormalities associated with early cognitive deficits and discuss how these abnormalities can be targeted to prevent disease onset. A scenario on brain disease etiology with the idea that early cognitive deficits may constitute a common symptom of brain diseases is proposed.

The clinical correlation between Alzheimer's disease and epilepsy

Alzheimer's disease and epilepsy are common nervous system diseases in older adults, and their incidence rates tend to increase with age. Patients with mild cognitive impairment and Alzheimer's disease are more prone to have seizures. In patients older than 65 years, neurodegenerative conditions accounted for ~10% of all late-onset epilepsy cases, most of which are Alzheimer's disease. Epilepsy and seizure can occur in the early and late stages of Alzheimer's disease, leading to functional deterioration and behavioral alterations. Seizures promote amyloid-β and tau deposits, leading to neurodegenerative processes. Thus, there is a bi-directional association between Alzheimer's disease and epilepsy. Epilepsy is a risk factor for Alzheimer's disease and, in turn, Alzheimer's disease is an independent risk factor for developing epilepsy in old age. Many studies have evaluated the shared pathogenesis and clinical relevance of Alzheimer's disease and epilepsy. In this review, we discuss the clinical associations between Alzheimer's disease and epilepsy, including their incidence, clinical features, and electroencephalogram abnormalities. Clinical studies of the two disorders in recent years are summarized, and new antiepileptic drugs used for treating Alzheimer's disease are reviewed.

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.

Highlights From AES2020, a Virtual American Epilepsy Society Experience

Due to COVID-19 a live, in-person meeting was not possible for the American Epilepsy Society in 2020. An alternative, virtual event, the AES2020, was held instead. AES2020 was a great success with 4679 attendees from 70 countries. The educational content was outstanding and spanned the causes, treatments, and outcomes from epileptic encephalopathy to the iatrogenicity of epilepsy interventions to neurocognitive disabilities to the approach to neocortical epilepsies. New gene therapy approaches such as antisense oligonucleotide treatment for Dravet syndrome were introduced and neuromodulation devices were discussed. There were many other topics discussed in special interest groups and investigators' workshops. A highlight was having a Nobel prize winner speak about memory processing. Human intracranial electrophysiology contributes insights into memory processing and complements animal work. In a special COVID symposium, the impact of COVID on patients with epilepsy was reviewed. Telehealth has been expanded rapidly and may be well suited for some parts of epilepsy care. In summary, the epilepsy community was alive and engaged despite being limited to a virtual platform.

Efficacy of phenobarbital in treating elderly epilepsy patients in rural northeast China: A community-based intervention trial

OBJECT

To provide information on the characteristics of elderly epilepsy patients in rural Northeast China.

METHOD

Consecutive patients (aged >60) who were diagnosed with convulsive epilepsy in seven counties in Jilin Province, Northeast China, between January 2010 and December 2019 were included in the program and were divided into the EOE (early-onset epilepsy) group and the LOE (late-onset epilepsy) group. The patients were followed up once a month, and demographics and clinical data were recorded.

RESULT

There were 471 patients enrolled in this study, with 329 patients classified into the EOE group and 142 patients recruited into the LOE group. At baseline, the EOE group was younger than the LOE group (t=-9.007, p < 0.001). The most common etiologies for the EOE and LOE groups were post-trauma (4.0%, n=13) and stroke (9.2%, n=13). Elderly epilepsy patients had a good response to PB monotherapy, and no significant difference was found between the two groups (p > 0.05). EOE patients complained of more serious adverse events (p < 0.05), and drowsiness (52%) and ataxia (28%) were the most common adverse events reported by the EOE and LOE groups, respectively; however, more LOE patients were prone to withdrawal due to side effects (p = 0.036). A total of 63 patients withdrew from the study, and nonadherence was the commonest cause for withdrawal (56% in EOE and 50% in LOE). In the entire follow-up period, 112 patients (63 in the EOE group and 49 in the LOE group) died; the most common causes of death were stroke (n=44, 39%) and heart disease (n=36, 32%). The LOE group had a shorter survival time than the EOE group (χ²=42.216, p < 0.001). The LOE group (HR=3.47, 95% CI: 2.36-5.09) and higher seizure frequency (HR=1.72, 95% CI: 1.17-2.52) were the risk factors for death.

CONCLUSION

Elderly epilepsy patients had a good response to PB monotherapy. EOE patients complained of more serious adverse events, but more LOE patients were prone to withdrawal due to side effects. Nonadherence was the commonest cause of drug withdrawal, and it reflects the limited education regarding the impact of seizures and the differences in priorities of rural communities. EOE patients survive longer than LOE patients.

Ten year cumulative incidence of dementia after late onset epilepsy of unknown etiology

Recent epidemiological studies suggest late life onset epilepsy of unknown etiology (LOEU) is a risk factor for future dementia. These studies rely on inclusion and exclusion of multiple diagnostic codes rather than structured data and neuroimaging findings, and thus challenging to interpret clinically. We assessed the cumulative incidence of dementia in patients with LOEU diagnosed through admission data and neuroimaging over a 10-year follow-up and compared baseline characteristics that distinguish group level incident dementia. We screened our hospital records for patients aged 55-69 with new epilepsy, admitted between 2000 and 2008, and excluded patients diagnosed with epilepsy from an underlying cause on medical records or neuroimaging. We used retrospective hospital data to follow patients for incident dementia or mortality at 10 years and compared baseline (demographics, depression or anxiety, vascular risk factors, results of electroencephalogram (EEG) studies, antidepressant use and type of ant seizure medication) and follow up (seizure recurrence, incident cerebrovascular disease) characteristics for patients with and without incident dementia. Fifty-four LOEU cases were screened, age at first seizure was 61 ± 5. The 10-year cumulative incidence of dementia was 22.20% (95% Confidence Interval 22.08-23.10%) and time to dementia diagnosis was 5.4 ± 3.9 years. Patients with incident dementia were more likely to be women (83% vs 38%, p = 0.002), have interictal epileptic form discharges (IED) on baseline EEG (70% vs 29%, p = 0.011) and depression or anxiety (50% vs 18%, p = 0.026). No differences were found in other baseline or follow up characteristics. Our results support recent findings of dementia incidence in LOEU. Prospective studies on LOEU should evaluate phenotypic determinants of individuals with late life epilepsy and the rate of progression to dementia.

One-Year Analysis of Risk Factors Associated With Cognitive Impairment in Newly Diagnosed Epilepsy in Adults

Cognitive impairment (CI) occurs in people with epilepsy, affecting their quality of life. This study aimed to identify factors associated with CI in adult patients with newly diagnosed epilepsy. Additionally, we sought to determine whether any particular cognitive function is impaired predominantly by anti-seizure medications or by other factors. We enrolled 229 patients with newly diagnosed epilepsy and 191 participants were followed up for 1 y. We used the Montreal Cognitive Assessment as a tool to quantify CI. The sub-item scores were also collected to assess whether any aspects of CI are predominantly affected by anti-seizure medication treatment. Subjective memory decline due to anti-seizure medications was also recorded. One-hundred-and-two participants (44.5%) had CI onset before anti-seizure medication treatment. Aging, low education level, stroke or brain surgery etiology, and anxious symptoms were identified as risk factors for CI before anti-seizure medications use. Brain surgery for the young, anxious status for the middle-aged, and depressive status for the elderly were risk factors for CI at different ages. The elderly PWE had worse memory than the others. PWE with TLE had worse cognition, especially in memory and naming. The overall impact of anti-seizure medications on cognition was mild. Refractory epilepsy was a predictor of cognitive decline. Subjective memory decline was predicted by high-risk treatment and by a finding of refractory epilepsy. Clarifying the risk factors for CI can help the physician to assess the probable risk of CI for each individual before the start of anti-seizure medication treatment, which may lead to better compliance.

Cognitive decline in older adults with epilepsy: The Cardiovascular Health Study

OBJECTIVE

Cognitive decline is a major concern for older adults with epilepsy. Whether and how much faster older adults with epilepsy experience cognitive decline beyond expected age-related cognitive change remain unclear. We sought to estimate and compare rates of cognitive decline in older adults with and without epilepsy.

METHODS

The Cardiovascular Health Study is a population-based longitudinal cohort study of 5888 US adults aged 65+. Cognitive function was assessed annually with Modified Mini-Mental State Exam (3MS) and Digit Symbol Substitution Test (DSST). We used linear mixed models to estimate average rates of decline in 3MS and DSST scores by epilepsy status (prevalent, incident, or no epilepsy), adjusted for risk factors associated with cognitive decline.

RESULTS

The rate of decline in 3MS was significantly faster in prevalent epilepsy (P < .001) and after incident epilepsy (P = .002) compared with no epilepsy. Prevalent epilepsy and apolipoprotein E gene (APOE) ε4 (ApoE4) had a synergistic interaction, whereby prevalent epilepsy and ApoE4 together were associated with 1.51 points faster annual decline in 3MS than would be expected if prevalent epilepsy and ApoE4 did not interact (P < .001). Older adults with prevalent epilepsy had a significantly lower initial DSST score and faster rate of decline compared to those with no epilepsy (P < .001).

SIGNIFICANCE

Faster decline in global cognitive ability seen in this study validates concerns of patients. ApoE4 allele status was an effect modifier of the relationship between cognitive decline and prevalent epilepsy. Further research is warranted to explore biological mechanisms and possible interventions to mitigate cognitive decline.

Cognitive disorders in epilepsy II: Clinical targets, indications and selection of test instruments

This is the second of two narrative reviews on cognitive disorders in epilepsy (companion manuscript: Cognitive disorders in epilepsy I: Clinical experience, real-world evidence and recommendations). Its focus is on the clinical targets, indications, and the selection of neuropsychological test instruments. Cognitive assessment has become an essential tool for the diagnosis and outcome control in the clinical management of epilepsy. The diagnostics of basic and higher brain functions can provide valuable information on lateralized and localized brain dysfunctions associated with epilepsy, its underlying pathologies and treatment. In addition to the detection or verification of deficits, neuropsychology reveals the patient's cognitive strengths and, thus, information about the patient reserve capacities for functional restitution and compensation. Neuropsychology is an integral part of diagnostic evaluations mainly in the context of epilepsy surgery to avoid new or additional damage to preexisting neurocognitive impairments. In addition and increasingly, neuropsychology is being used as a tool for monitoring of the disease and its underlying pathologies, and it is suited for the quality and outcome control of pharmacological or other non-invasive medical intervention. This narrative review summarizes the present state of neuropsychological assessments in epilepsy, reveals diagnostic gaps, and shows the great need for education, homogenization, translation and standardization of instruments.