Senile myoclonic epilepsy in Down syndrome

Epilepsy in Down Syndrome: A Highly Prevalent Comorbidity

Individuals with Down syndrome (DS) have an increased risk for epilepsy during the whole lifespan, but especially after age 40 years. The increase in the number of individuals with DS living into late middle age due to improved health care is resulting in an increase in epilepsy prevalence in this population. However, these epileptic seizures are probably underdiagnosed and inadequately treated. This late onset epilepsy is linked to the development of symptomatic Alzheimer's disease (AD), which is the main comorbidity in adults with DS with a cumulative incidence of more than 90% of adults by the seventh decade. More than 50% of patients with DS and AD dementia will most likely develop epilepsy, which in this context has a specific clinical presentation in the form of generalized myoclonic epilepsy. This epilepsy, named late onset myoclonic epilepsy (LOMEDS) affects the quality of life, might be associated with worse cognitive and functional outcomes in patients with AD dementia and has an impact on mortality. This review aims to summarize the current knowledge about the clinical and electrophysiological characteristics, diagnosis and treatment of epileptic seizures in the DS population, with a special emphasis on LOMEDS. Raised awareness and a better understanding of epilepsy in DS from families, caregivers and clinicians could enable earlier diagnoses and better treatments for individuals with DS.

The overlap between epilepsy and Alzheimer's disease and the consequences for treatment

Introduction: Alzheimer's disease may be associated with both clinical and subclinical epileptic seizure activity. Once regarded as an epiphenomenon, epileptiform activity may, in fact, be an integral part of the Alzheimer's phenotype, and may be not only a symptomatic therapeutic target but also a possible mechanism to retard or prevent disease progression. Areas covered: The authors review clinical research articles with a focus on the semiology, epidemiology, and treatment of seizures in Alzheimer's disease, and also look at some experimental animal model studies which have informed clinical thinking on seizure aetiopathogenesis. The evidence base for treatment decisions is sparse. A brief overview of the clinical assessment of Alzheimer's disease patients considering relevant differential diagnoses and diagnostic pitfalls is presented. Expert opinion: Studies of epileptic seizures in Alzheimer's disease have become more frequent over the last 5-10 years. Understanding of seizure semiology, epidemiology, and possible pathogenesis has increased. However, the optimal management of seizures in this context remains unknown, largely due to the paucity of studies sufficient to examine this question. Clearly, such studies will be required, not only to inform clinicians about symptomatic control of seizures in Alzheimer's disease but also to investigate whether this might impact on disease progression.

Presenilin-1 mutation Alzheimer's disease: a genetic epilepsy syndrome?

Mutations in the presenilin-1 gene (PSEN1) on chromosome 14 are the most common cause of autosomal dominant Alzheimer's disease (AD), with around 180 mutations described to date. PSEN1 AD has a broad clinical phenotype, encompassing not only dementia but a variety of other neurological features which may include epileptic seizures. Around 20% of recorded PSEN1 mutations have been reported to be associated with epileptic seizures, sometimes occurring as an early feature of disease, sometimes late. The epilepsy-associated PSEN1 mutations are spread throughout the PSEN1 gene. This frequency of seizure-associated PSEN1 mutations may be an underestimate, as epileptic seizures may not be recognized as such in the context of a dementing disorder, perhaps being labeled as "confusion" or delirious episodes. A high index of clinical suspicion for epileptic seizures in PSEN1 AD is therefore appropriate. The neuropathological substrates of PSEN1 AD-related seizures remain to be determined, as few such cases have undergone detailed neuropathological examination. Nevertheless, PSEN1 AD should now be recognized, using the new International League Against Epilepsy nomenclature, as a genetic epilepsy syndrome.