The clinical concept of epilepsy

What caused Joan of Arc's neuropsychiatric symptoms? Medical hypotheses from 1882 to 2016

Between 1882 and 2016, the medical literature offered a variety of etiologic hypotheses to explain Joan of Arc's voices, visions, and unwavering belief that she was the instrument of God. Although Joan lived from 1412 to 1431, there is extensive primary documentation of her life, including transcripts of her testimony during the Trial of Condemnation. Once this source material was compiled and made available, physician-authors began to theorize about Joan's neuropsychiatric symptoms in the context of her remarkable achievements. This article summarizes all papers written by physician-authors about Joan of Arc. The historical flow of diagnostic speculation in the medical literature reflects the cultural context in which it was produced as well as the emergence of novel ideas and new technologies in psychiatry, neurology, and neuropsychiatry. The early literature offered psychological theories and addressed the question of whether Joan was sane. The later literature focused on the possibility that Joan might have had epilepsy, with discussions of seizure etiology and possible cerebral focus, and also reflections on the purview of science as well as spirituality and the brain. This article offers the first comprehensive review of the medical literature about Joan of Arc, making this scholarship more accessible.

The evolution of the concepts of seizures and epilepsy: What's in a name?

This review aims to highlight the historical hallmarks in the development of the concepts of seizures and epilepsy. It begins with a discussion of seizure semiology and terminology, followed by the pathophysiology of seizures. We then discuss the definition of epilepsy, its etiologies, and ultimately classification schemes. Each section starts with our current views and subsequently transports the reader back in time to understand how these views evolved and came to be what they are today. People living as early as in the prehistoric times may have been aware of the existence of seizures, and descriptions and terminology have been provided as early as 2500 BC. While names have been revised and updated through time, the meanings are seemingly unchanged. However, it is clearly evident that we have come a long way in understanding the pathophysiology and etiology of seizures and epilepsy, thus leading to our current classification schemes. No classification scheme will be perfect yet, until our understanding is advanced enough to create one based predominantly on scientific grounds. The goal is that it is relevant to clinical practice, leading to a more precise diagnosis to guide targeted treatments.

Systems biology, complexity, and the impact on antiepileptic drug discovery

The number of available anticonvulsant drugs increased in the period spanning over more than a century, amounting to the current panoply of nearly two dozen so-called antiepileptic drugs (AEDs). However, none of them actually prevents/reduces the post-brain insult development of epilepsy in man, and in no less than a third of patients with epilepsy, the seizures are not drug-controlled. Plausibly, the enduring limitation of AEDs' efficacy derives from the insufficient understanding of epileptic pathology. This review pinpoints the unbalanced reductionism of the analytic approaches that overlook the intrinsic complexity of epilepsy and of the drug resistance in epilepsy as the core conceptual flaw hampering the discovery of truly antiepileptogenic drugs. A rising awareness of the complexity of epileptic pathology is, however, brought about by the emergence of nonreductionist systems biology (SB) that considers the networks of interactions underlying the normal organismic functions and of SB-based systems (network) pharmacology that aims to restore pathological networks. By now, the systems pharmacology approaches of AED discovery are fairly meager, but their forthcoming development is both a necessity and a realistic prospect, explored in this review.

Association of serotonin transporter polymorphisms with responsiveness to adrenocorticotropic hormone in infantile spasm

BACKGROUND

Serotonin or 5-hydroxytryptamine (5-HT) is an important neurotransmitter in the central nervous system. The serotonin transporter (5-HTT) is a key regulator of the level of serotonergic neurotransmission. In the present study, the contribution of 5-HTT polymorphisms to the risk of infantile spasm (IS) and the responsiveness to adrenocorticotropic hormone (ACTH) were investigated.

METHODS

Two functional polymorphisms, the 44-bp insertion-deletion polymorphism in the promoter region (5-HTTLPR) and the variable number tandem repeat in the second intron (5-HTTVNTR), were genotyped in a Chinese case-control study involving 112 patients with IS and 120 controls.

RESULTS

Genotyping yielded valid data in 111 patients and 118 controls for 5-HTTLPR and 110 patients and 118 controls for 5-HTTVNTR. The polymorphisms were not found to have an allelic or genotypic association with IS. However, responsiveness to ACTH was higher in patients who were homozygous for L (91%) than in those with S/L (56%) or S/S (60%) (P=0.017). Haplotype analysis did not improve the observed association.

CONCLUSIONS

The results suggest that the 5-HTTLPR genotype may influence the responsiveness to ACTH. This interpretation deserves further study.

A possible association of responsiveness to adrenocorticotropic hormone with specific GRIN1 haplotypes in infantile spasms

AIM

Adrenocorticotropic hormone (ACTH) has been used as the major therapy for infantile spasms since 1958 because it effectively suppresses seizures; it also normalizes the electroencephalogram in the short-term treatment of infantile spasms. G protein-regulated inducer of neurite outgrowth 1 (GRIN1, also known as N-methyl-D-aspartate receptor 1, NMDAR1), a glutamate receptor, is the main component of functional N-methyl-D-aspartic acid receptors that are involved in the glucocorticoid-induced neuronal damage. Thus, it may be a candidate gene to be tested for responsiveness to ACTH in infantile spasms. In the present study, polymorphisms in the GRIN1 gene in infantile spasms were investigated using a case-control design.

METHOD

Twelve single nucleotide polymorphisms in the GRIN1 gene were genotyped in a Chinese case-control set consisting of 97 unrelated patients with infantile spasms (60 males, 37 females; mean age 6.4 mo, SD 2.7) and 96 healthy individuals (63 males, 33 females; mean age 7.3 mo, SD 3.8). Association analysis was performed on the genotyped data.

RESULTS

Five estimated haplotypes with a frequency of more than 3% were detected. Results of the study showed that responsiveness to treatment with ACTH in homozygous carriers of the CTA haplotype was higher than that in heterozygous carriers and non-carriers (p=0.022). Furthermore, CTG, a rare haplotype, was strongly associated with infantile spasms (p=0.013).

INTERPRETATION

The results suggest that haplotypes of GRIN1 may influence responsiveness to ACTH. The findings necessitate further study for confirmation.

Autism spectrum disorders and epilepsy: moving towards a comprehensive approach to treatment

The biological and phenotypic heterogeneity of children with autism spectrum disorders (ASD) and epilepsy presents a significant challenge to the development of effective treatment protocols. There is no single treatment or treatment protocol for children with ASD or epilepsy. Children with co-occurring ASD and epilepsy should undergo a comprehensive assessment that includes investigation of underlying biological etiologies as well assessment of cognitive, language, affective, social and behavioral function prior to initiating treatment. The comprehensive treatment of children with ASD is based on a combination of therapeutic psychosocial interventions in combination with pharmacological agents. A process-oriented approach to assessment and intervention allows careful analysis of the child's response to treatment such that treatment protocols may be revised secondary to any changes in developmental trajectory of the child with ASD and epilepsy. The possibility of developing pharmacological interventions that target both ASD and epilepsy awaits definitive evidence. The best hope for good developmental outcomes in children with ASD and epilepsy is early recognition and comprehensive treatment of both the ASD and epilepsy.

Autism and epilepsy: historical perspective

Autism spectrum disorders (ASD) and epilepsy co-occur in approximately 30% of individuals with either ASD or epilepsy. While there is no single unifying ASD-epilepsy phenotype, understanding potential commonalities in subgroups of children with an ASD-epilepsy phenotype will help us disentangle the pathophysiology of both ASD and epilepsy. Throughout this brief historical perspective we selectively review critical trends in ASD-epilepsy research and highlight challenges to clinical and research efforts including terminology, heterogeneity of both ASD and epilepsy, and lack of careful characterization of children affected with both ASD and epilepsy. These complex issues continue to burden research on the diagnosis, neurobiology and management of children with ASD and epilepsy. A key concept that has emerged during the past 40 years is the strong association between intellectual disability and a higher prevalence of epilepsy in individuals with ASD. In addition, the two peaks of seizure onset, one in early childhood and one in adolescence and continuing through adulthood may be unique to individuals with ASD. The overlap of language and autistic regression to epilepsy, EEG epileptiform activity, sleep, and to epileptic encephalopathies such as Landau-Kleffner syndrome continue to be controversial areas of research and of clinical interest. An emerging consensus is that shared developmental genetic, molecular and pathophysiological mechanisms exist and account for the common co-occurrence of ASD and epilepsy.

Spikes and epilepsy

Digital EEG analysis provides significantly more information to the clinical electroencephalographer (EEGer) for scalp as well as for intracranial monitoring than is currently being routinely utilized. When modern data analysis software is used, interictal spikes contain considerably more information than had previously been ascribed to them. To optimize the diagnostic value of the EEG, sleep recordings after sleep deprivation is valuable because focal spikes, unless abundant, are relatively rare in the waking state. Recording time should also be sufficiently long to allow spikes to emerge. Spikes are always pathologic and can be associated with impaired cerebral perfusion, metabolic changes and concomitant behavioral changes. They can also be separated into simple and complex forms which may allow prognostic statements. The simplest way to accomplish this is by placing a cursor on the peak of the spike and see whether or not other channels show latency differences. More precise methods are: comparisons of voltage maps with current source density maps, principal component analysis and distinctions between stationary versus moving dipoles. Averaging of spikes is valuable but care must be taken that only those spikes which have the same distribution are averaged, and when the average is obtained only from the spike peak, propagation may already have occurred. It has been recommended that the midpoint of the ascending negative phase be used as the point for averaging. In intracranial recordings the frequencies above the gamma range should also be assessed. Their small electrical field allows a differentiation between locally generated events from those which are volume conducted and can thereby more accurately reflect the epileptogenic zone(s). High frequency activity can also be recorded from foramen ovale electrodes which enhances their diagnostic utility. It is emphasized that for centers which perform pre-surgical evaluations the software supplied by instrument manufacturers is inadequate and needs to be supplemented by additional commercially available programs. Furthermore, archived data should be used for retrospective investigations and follow-up studies of patients who have undergone either excisions, resections, or multiple subpial transections to evaluate the success rates by taking into account all the properties of interictal and ictal recordings which are mentioned in this article.