Chapter 8
Analysis of EEG in Medically Intractable
Epilepsy
Ki-Young Jung
Abstract EEG is an electrophysiologic technique that directly measures neural
activity from the brain with high temporal resolution. EEG has been used in various
neurological disorders to monitor functional brain states such as impaired consciousness including brain death, epilepsy, sleep disorders and cerebrovascular diseases.
Epilepsy is a neurological disorder characterized by producing epileptic seizure
caused by abnormal excessive or synchronous neuronal activity in the brain. EEG
is an essential method to make diagnosis, classification, and localization of seizure
focus in epilepsy, and is actually most commonly used in epilepsy and seizure disorders. In this chapter, I’ll focus on how EEG analysis can contribute to the clinical
diagnosis and treatment of epilepsy, particularly to epilepsy surgery. As detailed theoretical and technological aspects of EEG analyses are introduced in other chapters,
only clinical applicability and significance of these methods will be reviewed here.
8.1 Overview of Epilepsy and Epilepsy Surgery
Epilepsy is a chronic, neurologic disorder characterized by spontaneous, recurrent
seizures. The prevalence of epilepsy is ranging from 2 to 10 per 1000 people, affecting approximately 70 million people of all ages worldwide [25]. About 20–40% of
people with epilepsy are medically intractable or drug-resistant despite that a variety of antiepileptic drugs have been developed for the past two decades. Epilepsy
surgery has been the gold standard therapeutic option for cases in which medications
have failed [31]. About two third of patients who had surgical treatment exhibited
good outcome [44]. The aim of resective epilepsy surgery is to achieve freedom of
seizure by means of complete elimination of epileptogenic zone in the epileptic brain.
Epileptogenic zone is a theoretical concept indicating brain area that is necessary and
sufficient for initiating seizures and whose removal or disconnection is necessary for
abolition of seizures [12]. We can only identify epileptogenic zone after achieving
K.-Y. Jung (B)
Department of Neurology, Seoul National University, Seoul, Republic of Korea
e-mail: jungky@snu.ac.kr
© Springer Nature Singapore Pte Ltd. 2018
C.-H. Im (ed.), Computational EEG Analysis, Biological and Medical Physics,
Biomedical Engineering, https://doi.org/10.1007/978-981-13-0908-3_8
177
Analysis of EEG in Medically Intractable
Epilepsy
Ki-Young Jung
Abstract EEG is an electrophysiologic technique that directly measures neural
activity from the brain with high temporal resolution. EEG has been used in various
neurological disorders to monitor functional brain states such as impaired consciousness including brain death, epilepsy, sleep disorders and cerebrovascular diseases.
Epilepsy is a neurological disorder characterized by producing epileptic seizure
caused by abnormal excessive or synchronous neuronal activity in the brain. EEG
is an essential method to make diagnosis, classification, and localization of seizure
focus in epilepsy, and is actually most commonly used in epilepsy and seizure disorders. In this chapter, I’ll focus on how EEG analysis can contribute to the clinical
diagnosis and treatment of epilepsy, particularly to epilepsy surgery. As detailed theoretical and technological aspects of EEG analyses are introduced in other chapters,
only clinical applicability and significance of these methods will be reviewed here.
8.1 Overview of Epilepsy and Epilepsy Surgery
Epilepsy is a chronic, neurologic disorder characterized by spontaneous, recurrent
seizures. The prevalence of epilepsy is ranging from 2 to 10 per 1000 people, affecting approximately 70 million people of all ages worldwide [25]. About 20–40% of
people with epilepsy are medically intractable or drug-resistant despite that a variety of antiepileptic drugs have been developed for the past two decades. Epilepsy
surgery has been the gold standard therapeutic option for cases in which medications
have failed [31]. About two third of patients who had surgical treatment exhibited
good outcome [44]. The aim of resective epilepsy surgery is to achieve freedom of
seizure by means of complete elimination of epileptogenic zone in the epileptic brain.
Epileptogenic zone is a theoretical concept indicating brain area that is necessary and
sufficient for initiating seizures and whose removal or disconnection is necessary for
abolition of seizures [12]. We can only identify epileptogenic zone after achieving
K.-Y. Jung (B)
Department of Neurology, Seoul National University, Seoul, Republic of Korea
e-mail: jungky@snu.ac.kr
© Springer Nature Singapore Pte Ltd. 2018
C.-H. Im (ed.), Computational EEG Analysis, Biological and Medical Physics,
Biomedical Engineering, https://doi.org/10.1007/978-981-13-0908-3_8
177