Understanding the effects of epilepsy, a neurological disorder frequently beginning in childhood, is particularly important because it may disrupt the development of foundations for later cognitive and psychological functions. Despite the prevalence of seizure disorders and the importance of the developmental period in which seizures frequently begin, surprisingly little information about the effects of seizures with respect to cognitive and behavioral functioning is available. Moreover, understanding of the complex interactions between the pathological processes (bioelectric disturbance, neuropathology) and developmental, environmental, and psychological variables that contribute to the overall clinical picture is limited. In Cognitive and Behavioral Disorders of Epileptic Origin in Children, Thierry Deonna and Eliane Roulet-Perez take a unique approach to beginning to untangle these variables, drawing on their extensive clinical experience to present a series of cases that illustrate how seizures influence development.
In the foreword, Jean Aicardi reminds us that prior to the introduction of the scientific method, which relies on large samples of patients amenable to statistical analysis, careful observation of single cases and “anecdotal” evidence was the primary method of inquiry for understanding disease and discovering treatment effects. Despite the limitations inherent in case series, meticulous observations framed in the context of contemporary knowledge can still provide valuable insights into the effects of disease on the individual in multiple domains. The availability of advanced technology for studying structural and functional anomalies enhances the power of the case study as a means for understanding disease.
The authors begin with the premise that epilepsy's effect has on development is multidetermined, and that the seizures are important factors. The emphasis throughout the book is on this factor—that is, the seizure as a recurring bioelectric event is important not only in the transient behavioral disruption observed during a seizure but also because it produces changes in structure and function that contribute to ongoing problems later in development. While acknowledging the importance of other factors, they make the important point that not all of the behavioral and cognitive disturbances are caused by a static underlying neuropathological condition. Successful seizure treatment may, in some cases, be accompanied by amelioration of the accompanying cognitive problems.
The authors lay the foundation for the rest of the book in Chapters 1 and 2, tracing the development of their approach in historical context of emergent thinking about seizures in children. Subsequent chapters are organized around a central theme, with case studies from practice used to illustrate the authors' theses. In Chapter 3, the authors provide a brief review of how seizures alter the neurological landscape of the child at various stages of development. They explain that seizures tend to spread via established networks and, just as normal stimulation reinforces synaptic connections necessary for development of cognitive functions, abnormal stimulation can alter these same networks. In chapter 4, they begin to isolate the effects of the ictal discharge on cognitive development and function, arguing that epileptic discharges can have effects that are distinct from the effects of the underlying cause of seizures (e.g., mass lesion, MTS) or side effects of treatment with antiepileptic medications before moving on to discuss these effects in Chapter 5. Chapter 6 is a brief review of cognitive and behavioral disturbances in various epilepsy syndromes, again framing the value of the individual longitudinal case study to identify the direct effects of epileptic discharges on behavior.
The next three chapters provide brief reviews of neurocognitive function from three different approaches. In Chapter 7, a functional domain-by-domain approach to neuropsychological deficits begins with a cursory review of attention and memory in epilepsy. This is followed by a discussion of language and reading disturbance, with case presentations to illustrate the association of reading disorders and correlation of reading errors with active epileptic discharges. In Chapter 8, the approach shifts from functional domains to the spectrum of cognitive dysfunction in selected epileptic syndromes, with the most detailed discussion focusing on the benign partial epilepsies that, it turns out, may not be so benign when careful analysis of cognitive function is undertaken. In Chapter 9, brief discussion of specific underlying pathologies (developmental and acquired lesions) is punctuated by two illustrative cases.
In Chapter 10, the authors miss an opportunity to extensively discuss issues of plasticity in development following surgery, a topic that is ideally suited for the methods and direction that the rest of the text takes. A cursory overview of surgery is followed by a discussion of language development following dominant hemispherectomy. However, less extensive and less radical surgery is becoming increasingly seen as a viable option for children with focal epilepsies, and study of individual outcomes and more elaborate discussion of the controversial issue of early surgery would have been a valuable addition.
Chapters 11 and 12 take on the difficult topic of more severe cognitive (e.g., mental retardation) and developmental disorders (autistic spectrum disorders) and their possible association with epilepsy, noting that often the association is not causal but that the contribution of epileptiform activity needs further exploration.
The detailed testing and observations of individual cases depend on a structured approach to child assessment. In Chapter 13, the authors present an overview of their approach to child assessment, including a brief discussion of important issues such as test-retest effects, timing of assessments in relation to active seizures, and taking into account side effects of medication treatment. Whereas far from comprehensive, this chapter can be a helpful guide to the non-neuropsychologist regarding the structure and content of neuropsychological examination of the child with epilepsy. The next two chapters provide a similar overview of medications in epilepsy, and emotional/psychological aspects of epilepsy for the child.
The final chapter addresses a topic rarely discussed and in need of more attention—what happens to the children with epilepsy when they become adults? The authors present an optimistic picture, but clearly it is important that more work be done in this area. It is this that I think is the most important point of the book: that understanding the long-term outcome in all cases (chronic, developmental, treated, untreated) is needed to better understand the developmental consequences of epilepsy, and detailed follow-up can provide an important window for viewing the mechanisms of development and plasticity in the more general sense.
Throughout the book, the authors remind us that many children with epilepsy function normally with no disturbances in cognition or behavior. There is a great deal of diversity in the functions of children, even within “homogenous” diagnostic groups (e.g., Temporal Lobe Epilepsy). It is this diversity that makes application of group findings to the individual difficult, proving the value inherent in careful analysis of individual cases. Although their treatment of some topics is cursory, it does not seem that their intent was to provide a comprehensive overview. Instead, they briefly introduce problems and analyze individual cases to illustrate their points. By providing a different view on the fluctuating nature of seizure disorders and how factors such as the diversity of underlying pathology interact with the individual characteristics to produce the overall clinical picture, the authors have produced a work that can be a useful addition to a more comprehensive library for clinicians who work with children that have seizure disorders.
