Epilepsy is a neurological condition in which an individual experiences chronic abnormal bursts of electrical discharge in the brain. These seizures can cause a variety symptoms depending on the areas of the brain affected. Symptoms can vary from mild to severe and can include complete or partial loss of consciousness, loss of speech, uncontrollable motor behavior, and/or unusual sensory experiences. From various studies worldwide6, approximately 0.5% of the population is reported to be affected by active epilepsy

Koyama, Alain

English

CogPrints Cognitive Sciences Eprint Archive

Epilepsy – A Brief Overview

Cognitive Sciences ePrint Archive

 1
Epilepsy – A Brief Overview 
 
©2005 Alain Koyama; Completed: April 2005; For correspondences, email to: alain.koyama@gmail.com 
 
 
 Epilepsy is a neurological condition in which an individual experiences chronic abnormal 
bursts of electrical discharge in the brain. These seizures can cause a variety symptoms 
depending on the areas of the brain affected. Symptoms can vary from mild to severe and can 
include complete or partial loss of consciousness, loss of speech, uncontrollable motor 
behavior, and/or unusual sensory experiences. From various studies worldwide6, 20, 22, 24, 26, 
approximately 0.5% of the population is reported to be affected by active epilepsy. 
 It is also important to dispel a common myth that epilepsy and seizures are the same 
thing. Although seizures are the primary symptom of epilepsy, they can have other causes, such 
as high fever, malignant hypertension, or drug abuse. In these cases, the seizures stop when 
the condition improves, whereas seizures in epilepsy are a chronic long-term condition. Another 
common myth is that epilepsy occurs only in children. Although much media coverage focuses 
on epilepsy in children, people of all ages can be affected by epilepsy. 
 Epileptic seizures are caused parts of the brain eliciting abnormal electrical activity. The 
region of seizure generating tissue, or the epileptogenic focus, can be due to structural 
abnormalities that disrupt normal neural circuitry. These abnormalities may be genetic, caused 
by head injury, infection, stroke or tumor. In such cases when the cause is known, it is termed 
symptomatic epilepsy. Other classifications include idiopathic epilepsy, when there is no 
identifiable cause but a genetic basis is presumed, and cryptogenic epilepsy, when neither 
classification fits and the cause in unknown. 
 Just as there can be multiple causes, individuals can be affected by one or more types 
of seizures. Partial seizures begin in a localized area, while generalized seizures develop over a 
widespread area on the cortex of the brain. Partial seizures can be further subdivided into 
simple and complex, where only complex seizures can cause loss of consciousness. 
Generalized seizures are grouped into six major categories. Absence seizures (also known as 
petit mal) are characterized by a partial loss of consciousness when the individual briefly 
appears vacant and unresponsive. Involuntary muscle twitches, particularly in the face, are 
often seen. Myoclonic seizures consist of very brief and sporadic arrhythmic movements. Tonic 
seizures consist of sudden stiffening movements involving the head, body, or extremities that 
often occur during sleep. Clonic seizures are characterized by repeated, rhythmic motor 
movements, often involving a large portion of the body as well as causing unconsciousness. 
Tonic-clonic seizures (also called grand mal) begin with the tonic phase of sudden stiffening 
movements when the individual may experience symptoms such as loss of orofacial motor 
control resulting in tongue biting or clenched teeth and/or urinary incontinence. This is followed 
by the clonic phase of rhythmic body movements. After the seizure, the individual may be 
emotionally distraught, feeling confused or sleepy. Atonic seizures consist of a sudden loss of 
muscle tone. A brief atonic seizure may elicit mild symptoms such as drooping of the head, but 
often the seizure is prolonged and the individual falls down from loss of postural tone. Status 
eplilepticus is the term given to describe the life-threatening condition when an individual 
experiences prolonged or successive seizures with no recovery time. Depending on the medical 
professional, seizure activity can be considered status epilepticus if it lasts a minimum of 5 
minutes up to a more conservative 30 minutes.  
 Dozens of epileptic syndromes exist, classified based on the symptoms and brain 
regions affected. One of the more common forms of epilepsy is temporal lobe epilepsy (TLE). 
The most striking symptoms are often not the typical motor behavior seen in partial seizures. 
Individuals may perceive sounds or smells that are not present, or visual disturbances, such as 
objects appearing larger or smaller than they are. Psychological symptoms can often be the 
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most striking, when derealization or strong spiritual sensations may be experienced. One of the 
most common epileptic syndromes in childhood is benign childhood epilepsy with 
centrotemporal spikes. It is considered benign as seizures are infrequent, often responsive to 
treatment, and typically subside in adolescence. Despite the optimistic prognosis, 
neuropsychiatric testing shows that cognitive difficulties can exist in areas such as language 
and memory5, 13. Another common syndrome is childhood absence epilepsy. As the name 
implies, it consists of absence seizures usually starting around or slightly after the preschool 
years, and has a similar prognosis to benign childhood epilepsy. Less frequent and more severe 
is Lennox-Gastaut Syndrome (LGS), which can consist of multiple types of seizures, 
developmental delay, and a high prevalence of status epilepticus. Prognosis is often poor, 
especially those with earlier onset4, 16, although some can have near complete remission of 
symptoms. Another more rare form of epilepsy, with only around 200 reported cases since 
19572, is Landau-Kleffner Syndrome (LKS). Initial symptoms consist of the abrupt onset of 
seizures and regression of language skills. Medication may alleviate seizure activity, but 
language impairment is difficult to treat and may continue even if the patient recovers. 
 Antiepileptic drugs (AED) are the main form of treatment for epilepsy. Although many 
AED’s have been developed, approximately one-third of epilepsy patients are not responsive to 
pharmaceutical treatments12. If non-responsive to medication, surgical options can be 
considered. One common method is the removal or resection of epileptogenic tissue. Before 
resection, the patient undergoes extensive electrophysiological, neuroimaging and 
neuropsychiatric testing to strictly localize the epileptogenic tissue. Brain tissue can also be 
lesioned such as in a corpus callosotomy, where the main tract of fibers connecting the two 
hemispheres of the brain is severed to disrupt the pathways responsible for propagating 
generalized seizures. 
 A newer surgical method is multiple subpial transections (MST), where multiple parallel 
incisions are made in a restricted region of cortex in order to disrupt synchronous neural activity 
responsible for seizure generation. MST can be a viable alternative to resection when the 
epileptogenic tissue transcends critical areas in the brain, and removal of the tissue may result 
in serious cognitive impairment. MST is sometimes combined with resection to improve seizure 
activity slightly more effectively than MST alone19, 27.  
 A less invasive surgical treatment is vagus nerve stimulation (VNS), where an electrical 
stimulator implanted in the neck directs intermittent pulses to the vagus nerve. The patient can 
also activate the stimulator magnetically if they feel a seizure about to begin in order to prevent 
the seizure or reduce its severity. Common side effects of this treatment, such as voice 
alterations and tingling sensations, tend to be mild to moderate, and subside with time3. 
 One increasingly used noninvasive treatment for children is the ketogenic diet. It 
consists of low carbohydrate, high protein, and high fat consumption, similar to the popularized 
Atkins diet but more strict. Although it can be an effective alternative11, 18, the child’s growth 
should be closely monitored as it may be negatively affected by the restrictive diet14, 17. 
 Neurofeedback is a method in which a patient attempts to regulate the abnormal brain 
activity responsible for seizures. Scalp electrodes relay the brain’s electrical activity usually in 
visual form on a screen, providing feedback for the patient’s progress. Neurofeedback can be a 
low-cost noninvasive solution with long term benefits, shown in repeated studies to have 
consistent positive results21, 23, 25. 
 In addition to physiological symptoms, epilepsy can also adversely affect quality of life by 
incurring mood disorders. Of particular concern is the high prevalence of depression7, 10 and 
suicide8. Depression can result from the location of the epileptic foci, with left TLE patients most 
affected1, 15, as a side effect from medication, or as a reaction from the personal, social, and 
professional difficulties from seizure activity. It has also been theorized that as several studies 
have reported, high prevalence rates of depression preceding epilepsy suggest that rather than 
a side effect, depression can be a contributing factor to the development of epilepsy9.  
 3
 
 
 
References: 
 
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3. Ben-Menachem, E. (2002). Vagus-nerve stimulation for the treatment of epilepsy. Lancet Neurol, 
1(8): p. 477-82. 
4. Chevrie, J.J. and J. Aicardi (1972). Childhood epileptic encephalopathy with slow spike-wave. A 
statistical study of 80 cases. Epilepsia, 13(2): p. 259-71. 
5. Croona, C., et al. (1999). Neuropsychological findings in children with benign childhood epilepsy 
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Curr, 3(6): p. 202-203. 
10. Kanner, A.M. and S. Palac (2000). Depression in Epilepsy: A Common but Often Unrecognized 
Comorbid Malady. Epilepsy Behav, 1(1): p. 37-51. 
11. Kossoff, E.H., et al. (2003). Efficacy of the Atkins diet as therapy for intractable epilepsy. 
Neurology, 61(12): p. 1789-91. 
12. Kwan, P. and M.J. Brodie (2000). Early identification of refractory epilepsy. N Engl J Med, 342(5): 
p. 314-9. 
13. Monjauze, C., et al. (2005). Language in benign childhood epilepsy with centro-temporal spikes 
abbreviated form: rolandic epilepsy and language. Brain Lang, 92(3): p. 300-8. 
14. Peterson, S.J., et al. (2005). Changes in growth and seizure reduction in children on the 
ketogenic diet as a treatment for intractable epilepsy. J Am Diet Assoc, 105(5): p. 718-25. 
15. Piazzini, A., et al. (2001). Depression and Anxiety in Patients with Epilepsy. Epilepsy Behav, 2(5): 
p. 481-489. 
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international meta-analysis. Epilepsia, 43(2): p. 141-5. 
20. Sridharan, R. and B.N. Murthy (1999). Prevalence and pattern of epilepsy in India. Epilepsia, 
40(5): p. 631-6. 
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with EEG operant conditioning. Clin Electroencephalogr, 31(1): p. 45-55. 
22. Tellez-Zenteno, J.F., et al. (2004). National and regional prevalence of self-reported epilepsy in 
Canada. Epilepsia, 45(12): p. 1623-9. 
23. Uhlmann, C. and W. Froscher (2001). Biofeedback treatment in patients with refractory epilepsy: 
changes in depression and control orientation. Seizure, 10(1): p. 34-8. 
24. (unknown) (1994). Current Trends Prevalence of Self-Reported Epilepsy -- United States, 1986-
1990. CDC Morbidity and Mortality Weekly Report, 43(44): p. 810-811,817-818. 
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25. Walker, J.E. and G.P. Kozlowski (2005). Neurofeedback treatment of epilepsy. Child Adolesc 
Psychiatr Clin N Am, 14(1): p. 163-76, viii. 
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[Lennox-Gastaut syndrome in the adult].

About continuous or subcontinuous spikewave activity during wakefulness: electroclinical correlations. Continuous spikes and waves during slow sleep electrical status epilepticus during slow sleep.,

Basic concepts and clinical findings in the treatment of seizure disorders with EEG operant conditioning.

Changes in growth and seizure reduction in children on the ketogenic diet as a treatment for intractable epilepsy.

Childhood epileptic encephalopathy with slow spike-wave. A statistical study of 80 cases.

Children and the ketogenic diet.

Depression in Epilepsy Is Much More Than a Reactive Process.

Depression in Epilepsy:

Depression, anxiety, and temporal lobe epilepsy. Laterality of focus and symptoms.

Early identification of refractory epilepsy.

Efficacy of the Atkins diet as therapy for intractable epilepsy.

Language in benign childhood epilepsy with centro-temporal spikes abbreviated form: rolandic epilepsy and language.

Multiple subpial transection for intractable partial epilepsy: an international meta-analysis.

Neuropsychological findings in children with benign childhood epilepsy with centrotemporal spikes.

Prevalence and pattern of epilepsy in

Psychiatric comorbidity in chronic epilepsy: identification, consequences, and treatment of major depression.

Rates and risk factors for suicide, suicidal ideation, and suicide attempts in chronic epilepsy.

The epidemiology of epilepsy in Europe - a systematic review.

The ketogenic diet.

Vagus-nerve stimulation for the treatment of epilepsy.

Epilepsy – A Brief Overview

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