Recent advancements in molecular genetics have expanded our understanding of the etiology of many neurological diseases and neurodevelopmental abnormalities. Having a comprehensive understanding of genetics is essential in treating patients with metabolic epilepsies. Genetic counseling has been defined as a process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease. Some of the components of a genetic counseling interaction include interpretation of family and medical histories to assess the chance of disease occurrence or recurrence; education about inheritance, testing, management, prevention, resources, and research; and counseling to promote informed choices and adaptation to the risk or condition. The genetic counselor may also educate patients and their families about the underlying genetics of their epilepsy and the relevance of a genetic cause of epilepsy for family members, including recurrence risk, reproductive options and the possible teratogenic effect of antiepileptic drugs.

This chapter presents a brief review of the enzymes, transporters, and cofactor producers of the urea cycle. Seizures have long been associated with urea cycle disorders (UCDs), thought to be caused by high levels of ammonia. Furthermore, the brain damage obtained during metabolic crisis has been thought to damage critical structures, leading to epilepsy after the conclusion of the crisis. The first and most critical step of successful treatment of UCDs is recognition. Neurologic monitoring is an essential part of the emergency management of UCDs. The neurological abnormalities observed in patients with urea cycle defects are vast. Controlling ammonia levels by dialysis and complementary medication are needed. EEG monitoring should be initiated early, as this may be very useful for clinical management and indication of untreated metabolic crises. Furthermore, aggressive treatment of clinical and subclinical seizure activity may be helpful in optimizing outcomes for these patients.

Stereoelectroencephalography (SEEG) has become an increasingly important technique in epilepsy surgery. Multiple methods exist for the implantation of SEEG electrodes. This chapter summarizes the technique of using a stereotactic frame for this purpose, as well as discusses the major stereotactic frame systems used and their relative advantages and disadvantages. The localization and targeting of intracerebral structures has been a project that has engaged neurosurgeons since the earliest origins of the specialty. The unique nature of the brain makes minimization of disruption to surrounding tissue and definition of the safest trajectory an imperative for reducing neurologic deficits caused by surgical procedures. While newer technologies, such as robotic assistance, have emerged, stereotactic frames continue to be a familiar, accurate, and efficient method of placing SEEG electrodes. As with any technique, a proper understanding of the technical nuances and limitation is important for minimization of complications.

Posterior cortex epilepsies are a group of epilepsies arising from the occipital, parietal, or posterior temporal cortices, or from any combination of these topographies. Parietal lobe epilepsy (PLE) is considered the great imitator among focal epilepsies because of the prominent connectivity underlying the parietal cortex leading to highly variable seizure semiology and nonspecific scalp electroencephalography (EEG) findings. Additional testing, such as magnetoencephalography (MEG) and invasive EEG, are usually required—especially in nonlesional cases. Because of its rich connectivity, coupled with particular anatomical features shared by posterior cortices, scalp EEG is generally unhelpful or misleading in this subset of patients. As a result, diagnosing posterior cortex epilepsies is significantly challenging. Additional diagnostic workup with MEG, nuclear medicine studies, and invasive EEG monitoring is often required. This chapter seeks to review each posterior cortex epilepsy subtype as well as discusses two cases in order to highlight important key concepts.

The goal of intracerebral depth electrode electroencephalography (EEG) recording is to record seizures and the propagation pattern of the seizures in order to delineate the extent of the epileptogenic zone (EZ). This chapter focuses on the interpretation of IEDs recorded by chronically implanted depth electrodes and discusses its role in the epilepsy presurgical evaluation. Combining interictal epileptiform discharges (IEDs) with high frequency oscillations and functional MRI could potentially increase the value of IEDs in localizing the EZ. Quantitative EEG could increase efficiency and improve interreader reliability. Ultimately, the usefulness of stereoelectroencephalography IEDs in localization is limited by the areas sampled by depth electrodes, which in turn are driven by where the electrodes are implanted. Fundamental to IED assessment, therefore, is a set of meaningful hypotheses for the location of the seizure onset zone (SOZ) prior to electrode implantation.

The main goal of stimulation studies during stereoelectroencephalography (SEEG) is to trigger habitual seizures, in order to help define the epileptogenic zone (EZ). Direct electrical stimulation (DES) studies during SEEG represent a key component of methodology for defining the EZ. On the one hand, habitual seizures triggered by stimulation are considered evidence in favor of an epileptogenic role for the stimulated structure, and tend to show cortical epileptic discharge involving the same structures as observed for spontaneous seizures, associated with partial or complete habitual semiology. On the other hand, relatively little work has explored underlying physiological mechanisms and many aspects of DES in general remain poorly understood. This chapter describes clinical approaches to stimulation for seizure induction during SEEG and discusses how stimulation studies can help in defining EZ, as well as highlighting potential pitfalls and areas for future research.

This chapter describes the development and typical developmental tasks of toddlers and preschool children, both with and without disabilities. Children with disabilities (CWDs) must learn to manage the disability away from home, communicate their needs to adults, and often encounter prejudice and stigma for the first time. The chapter describes disabilities such as traumatic brain injuries, seizure disorders, childhood infections, asthma, and autism spectrum disorder. Early intervention programs, inclusive preschools, speech and language services, and respite care for parents are examples of services for toddlers and CWDs. CWDs must complete all the typical developmental tasks with added responsibilities of learning how to manage the disability away from home and asserting themselves with adults in order to explain their needs.

Interictal epileptiform discharges (IEDs) represent a distinct group of waveforms that are characteristically seen in people with epilepsy. Scalp detection of IEDs is based upon dipole localization and the surrounding field. The interictal electroencephalogram (EEG) plays a pivotal role in providing ancillary support for a clinical diagnosis of epilepsy. Abnormal focal IEDs on EEG represent a heightened predisposition for the expression of focal seizures. Epileptiform discharges appear in different morphologies. Both spikes and sharp waves are referred to as IEDs and are defined by their duration. Mid-temporal IEDs occur in patients with temporal lobe epilepsy. Benign childhood epilepsy with centrotemporal spikes is a common childhood genetic localization related epilepsy syndrome. Frontal spikes are often found in patients with frontal lobe epilepsy, although they may be absent in up to one-third of patients. Central IEDs can occur with symptomatic focal epilepsies at any age.

Epileptogenic zone (EZ) has become a trivialized term, and so much overused that any precise sense has been lost. In the recent literature, it has either been used as a synonym for epileptogenic lesion or held equivalent to a fluorodeoxyglucose-PET hypometabolic area or delineated by interictal equivalent current dipoles in high density EEG or magnetoencephalography. The EZ is not a theoretical concept in stereoelectroencephalography. Tailored surgical strategy is based on its delineation and its relation with a possible or patent lesion. Irritative zone(s) is a distinct entity though they may overlap at least in part. Criteria for EZ definition have become more precise with time, but have remained basically the same for the last 50 years. They ally synchrony with signal frequency parameters. Conditions like EZ extent, anatomical location, lesion histology, and their variations explain its multiple electrical pattern expressions.

Stereoelectroencephalography (SEEG) was invented in the late 50s by Jean Talairach, a neurosurgeon, and Jean Bancaud, a neuropsychiatrist and electroencephalographer. This method was based upon recording of brain electrical activity by intracerebral electrodes, stereotactically implanted in preidentified cortical and subcortical structures. SEEG offered high spatial and temporal resolution and a high power of localization. The ultimate objective of SEEG is to provide the surgeon with an integrated view of the epileptogenic process, based on the definition of the epileptogenic zone and its overlap with the lesional zone. SEEG interpretation was based on ictal anatomo-electro-clinical correlations. A better comprehension of seizure build-up in the human brain led to major pathophysiological advances. SEEG-guided epilepsy surgery was performed only in Paris during the first 25 years, and then adopted in Switzerland and Canada. Its recent worldwide expansion confirms its universally recognized rationality and its perfect adjustment to brain imaging.