48 Epilepsy

Epilepsy is characterized by the repeated occurrence of seizures that result from recurrent, abnormal, excessive, synchronous discharges of populations of cerebral neurons (Epilepsy Foundation of America 1981).

It is misleading to think of epilepsy as one disease. There are many causes of this symptom cluster, just as there are for the symptom cluster of nausea and vomiting. A better term would be “the epilepsies.” The epilepsies do, however, share certain physiologi­cal characteristics. Clusters of neurons in some parts of the brain begin to discharge impulses in a disorga­nized fashion. The parts of the body controlled by the affected neurons respond with disorganized activity such as convulsions or tremors, or by loss of normal function such as loss of consciousness, paralysis of a limb, or localized numbness. The condition is also chronic, marked by the recurrence of seizures. By monitoring the brain with electrodes, an electroen- Cephalographer can often detect abnormal brain waves, either localized in one part of the brain or coming from all parts at once.

Etiology

Although epilepsy can begin at any age, the major­ity of patients have their first seizure before the age of 20. In fact, the age of onset is often related to the cause.

other than the brain. Only a very small percentage of these febrile seizures persist after the age of 4, however. Head trauma is one of the most common causes of seizures among adults, although brain tu­mor must also be suspected, as about 40 percent of all patients with brain tumors have seizures. Later in life, seizures may be caused by cerebrovascular attacks.

Despite medicine’s increased ability to determine the various causes of epilepsy, no known cause can be found or reasonably presumed for a large propor­tion of seizures. Until a very few years ago, genetic predisposition was thought to be the cause of what was called “idiopathic” epilepsy. Today, most experts do not believe that heritability plays as large a role as the proportion of patients whose seizures have been diagnosed as idiopathic might suggest. That genetic factors are involved, however, is indicated by the fact that people with a family history of epilepsy have a higher incidence of seizures than the popula­tion in general. In addition, the electroencephalo­gram (EEG) tracings of asymptomatic relatives of patients with some forms of epilepsy show a higher incidence of abnormal discharge than is found among the rest of the population.

Epilepsy is characterized by recurrent seizures; therefore, an individual’s first seizure does not, of itself, indicate its presence. Nervous system infec­tions, metabolic imbalance, and transient reactions to head injury may all result in a seizure episode without putting the individual at risk for further seizures. Among epileptics an almost infinite num­ber of stimuli may trigger seizure activity.

Epileptics as well as nonepileptics may experience seizures that are not associated with abnormal brain wave activity and that have no known physiological cause. These pseudoseizures are often called hysteri­cal seizures or conversion reactions. Like epileptic seizures, pseudoseizures have characteristics that ap­pear repeatedly. Epileptics with pseudoseizures tend to exhibit the same signs and symptoms in the same sequence with each episode. Nonepileptics’ symp­toms may vary in site and nature if there are many episodes. Despite the fact that pseudoseizures are responsive to the social environment and appear to vary among cultures, they are often very difficult to distinguish from epileptic seizures. Between 8 and 20 percent of epileptics are thought to experience pseudoseizures in addition to their epileptic sei­zures, and it has been estimated that even experi­enced neurologists can identify pseudoseizures only 75 percent of the time (Lechtenberg 1984).

Epidemiology

Because epilepsy is a nonreportable disease, it is difficult to arrive at reasonable estimates of its inci­dence. Perhaps half the cases in the United States are preventable in the sense that they are the se­quelae of trauma, infections, birth injury, and so forth, with clear damage to the brain, the seizures appearing as a secondary symptom of the underlying brain damage. In cases of cerebral palsy or mental deficiency, epileptic seizures are often the least dra­matic of the symptoms. These secondary cases are more frequent when there is poor prenatal and perinatal care and in populations suffering from pov­erty with its attendant overcrowding, malnutrition, neglect, and violence.

Distribution and Incidence

In the United States the incidence of epilepsy is about 0.3 to 0.4 percent per year, or roughly one tenth the incidence of mental deficiency and perhaps one half the incidence of schizophrenia. The rate for males is slightly higher than that for females for all types of seizures combined, and is highest for ages 0 to 4 years, reaches a low level after adolescence, and peaks again after 70 years as the result of late cere­bral disease (Kurland 1949).

Since the early 1970s, several good epidemiolog­ical surveys of epilepsy have been made in Iceland, England, and the United States, which report crude prevalence rates between 3.6 and 5.5 per 1,000 popu­lation (Kurland, Kurtzke, and Goldberg 1973). Epidemiological studies of epilepsy, however, are plagued by a variety of problems. Of prime impor­tance in this regard is the lack of agreement on the definition of epilepsy itself as well as what consti­tutes an active or an inactive case. In addition, there are difficulties involved in estimating the size of the population universe and the number of cases not identified by the case finding procedures. The most rigorous survey conducted in a community in the United States was done in Rochester, Minnesota (Hauser and Kurland 1975). The crude rate for all types of epilepsy was 5.7 per 1,000 population. Seventy-five percent of the patients’ seizures were of Imdetermined cause, and approximately 70 percent had generalized seizures. A prevalence rate of 2.8 per 1,000 population has been reported for Tokyo (Tsuboi 1988) and of 2.47 for rural Kashmir, India (Koul, Razdan, and Motta 1988).

Crude prevalence rates between 7.6 and 8.4 per 1,000 population have been reported for four North American Indian tribes (Levy, Neutra, and Parker 1987).

Classification, Clinical Manifestations, and Pathology

The growing emphasis on physiological mecha­nisms and electroclinical correlations has led to a classification of the epilepsies by the localization of the electrical abnormality in the brain. The major division is between generalized {centrencephalic) sei­zures, where the brain activity is spread over the entire cerebral cortex; and partial (focal) seizures, which occur when only one part of the brain is involved. Generalized seizures demonstrate bilat­eral motor activity and involve a loss of conscious­ness, which may or may not occur in partial sei­zures depending upon the part of the brain initially affected and the subsequent involvement of other structures. There is an approximate correspondence between the sites of the brain where electrical ab­normality occurs and the clinical manifestation of the seizure.

Generalized Seizures

The term “epilepsy” was first used to denote the symptoms of major, or grand mal seizure, currently referred to as a tonic-clonic seizure. To this day, over 60 percent of all individuals diagnosed as epileptic have tonic-clonic seizures. A sudden burst of dis­charges involving the whole brain occurs without warning. The patient falls to the ground uncon­scious. Then, in the tonic phase, the patient goes rigid and often gives a short cry, due to the contrac­tion of the diaphragm and chest muscles. The eyes may roll up or turn to one side, and the tongue may be bitten. After this, a period of jerky, clonic, spasms alternately flex and extend the muscles of the head, face, and extremities. During this phase, the patient may injure him- or herself as well as be incontinent.

A variety of other generalized seizures have also been recognized. Sometimes patients exhibit only the tonic or clonic aspects of the seizure. Between the ages of 4 and 12 years, absence seizures often occur. These have been known as petit mal because they are of such brief duration, no more than a few seconds, that they often go unrecognized and un­treated. During the brief lapse of consciousness, the child stares vacantly and neither speaks nor hears. Subsequently, activity is resumed with no period of stupor. Equally brief are atonic seizures, during which the child simply falls to the ground; myoclonic seizures, which are sudden, brief, and massive, in­volving either the entire body or confined to the extremities, face, or trunk; and infantile spasms, during which the child is jerked into a fetal position with the knees drawn up. Many children with infan­tile spasms are also mentally retarded.

Partial Seizures

All partial seizures begin in one part of the brain, and, because different parts of the brain control dif­ferent parts of the body as well as mental and sen­sory functions, their signs and symptoms are varied and, often, quite complex. Many patients exhibit behaviors easily mistaken as psychiatric problems which can make accurate diagnosis difficult. It is also among victims of partial seizures that one is most likely to observe displays of bizarre, learned, culturally conditioned behavior.

Simple partial seizures have been variously called focal, focal motor, or focal sensory seizures. Although the symptoms may be motor, autonomic, psychic, sensory, or a combination, they are all linked to the affected area of the brain. The patient does not lose consciousness as a general rule, and the attacks last no more than 30 seconds. One type of simple partial seizure has been called the Jacksonian. It character­istically begins with the twitching of one foot or hand, and the patient retains consciousness. Until very recently, seizures were classed as Jacksonian even if the activity subsequently spread to both sides of the body and involved loss of consciousness. Today, however, such seizures are classed as partial but secondarily generalized.

Complex partial seizures are characterized by com­plex symptoms and, unlike simple partial seizures, by impairment of consciousness. Often the patient appears to be conscious but later has no recollection of the episode. These seizures are usually associated with the temporal or frontal lobe and often begin with an aura that warns of the impending attack. Auras may include any of a large variety of sensa­tions. Some of those most commonly reported are nausea; faintness; dizziness; numbness of the hands, lips, and tongue; choking sensations; and chest pain. Less often, patients have reported visions, palpita­tion, or disturbances of smell or hearing. Some pa­tients have sensations that may begin hours or even days before the seizure. These symptoms are called the prodrome and most often involve irritability or feelings of uneasiness. When psychomotor symp­toms appear during a seizure, they are generally semipurposeful and inappropriate actions such as clumsy attempts to disrobe. Patients often stagger about uttering guttural sounds. Such behavior is often confused with psychiatric disorder and is often alarming to those present.

Secondarily generalized partial seizures occur when seizures with a focal onset spread throughout the brain and produce generalized tonic-clonic sei­zures. Because the generalized phase is so dramatic, patients and their families often overlook the focal onset. The presence of an aura indicates the pres­ence of the focal onset and the need to observe the initial phase more closely.

The diagnosis of epilepsy and the classification of the type of seizure depend primarily on information obtained from the medical history. The first task is to determine whether the patient has epilepsy or has experienced another kind of brief, reversible alter­ation of consciousness or behavior. Subsequently, specifying the type of epileptic seizure is important for confirming the diagnosis and as a major guide in choosing the initial antiepileptic medication. Be­cause the physician is most often unable to observe the patient or obtain an EEG reading during a sei­zure, an accurate medical history is of crucial impor­tance. EEGs administered between seizures may or may not reveal patterns suggestive of epilepsy. Nev­ertheless, because they often do reveal abnormal discharges, routine administration of EEGs is of sig­nificant value in the evaluation of any patient with a history suggestive of epilepsy.

By conservative estimates, some 50 percent of pa­tients can have their recurrent seizures controlled without side effects when optimal medical treatment is available. Another 30 percent can achieve seizure control but experience some side effects of the medi­cation. For some patients whose seizures cannot be controlled by medication, surgery may be an option if a distinct piece of brain tissue that is causing the seizures can be identified, and if its removal will not cause unacceptable neurological deficits such as speech difficulty or memory loss.

History

Antiquity

The antiquity of epilepsy is attested to by an ancient Akkadian text that speaks of a person whose neck turns left, whose hands and feet are tense and eyes wide open, from whose mouth froth flowed, and who lost consciousness. The Greeks referred to it as “the sacred disease” as well as “epilepsy,” which means seizure and which may derive from the idea that all diseases represented attacks by supernatural be­ings. The term “sacred disease” is found first in the writings OfHeraclitus and Herodotus, but its identifi­cation with epilepsy is made explicit in the book On the Sacred Disease, part of the Hippocratic collection of medical writings from about the year 400 B.C. and the first monograph on epilepsy we possess.

Underlying the great variety of explanations of­fered by the ancients lies the basic belief that epi­lepsy is an affliction or possession by a higher power and that its cure must be supernatural. The Ro­mans called epilepsy morbus coτnitalis because the attack spoiled the day of the comitia, the assembly of the people. There was also the idea that the disease was contagious: The epileptic was unclean and whoever touched him or her might become prey to the demon. The idea that epilepsy was contagious was one of the factors that made the epileptic’s life miserable and gave him or her a social stigma. To the ancients the epileptic was an object of horror and disgust and not a saint or prophet as has some­times been contended. Wherever the physicians of antiquity wrote of the sacred disease, they meant epilepsy and differentiated it from hysterical at­tacks as well as from madness.

In the struggle between supernatural and scien­tific explanations of disease, science has gradually emerged victorious in the Western world. The fight, however, has been long and eventful, and in it epi­lepsy held one of the key positions. Showing both physical and psychic symptoms, epilepsy more than any other disease was open to interpretation both as a physiological process and as the effect of supernatu­ral influences. The first record we have of the battle is in On the Sacred Disease, an attack on popular superstition that called epilepsy the “sacred” dis­ease. It maintained that epilepsy was hereditary, that its cause lay in the brain, and its treatment was to be by diet and drugs as long as it had not yet become chronic. It is here we first find the fundamen­tal statement that the seat of the disease is in the brain and that the brain is the organ of all psychic processes both normal and pathological. Moreover, according to the author of this work, not only epi­lepsy but all mental diseases were to be explained by disturbances in the brain.

Middle Ages Through the Eighteenth Century During the Middle Ages, the literature on epilepsy propounded two contrasting views. On the one hand, the “falling evil” was bound to demoniac beliefs and theological speculations; on the other, physicians clung to the idea of a definite natural disease. Little effort was made to force the issue, however; physi­cians rarely discussed the theological aspects and seem, moreover, to have been unable to rid them­selves of traditional definitions and explanations. By the end of the sixteenth century, this appears to have changed, the debate became open, involving the role of the devil, witchcraft, and various types of magical treatment. Despite many efforts to define epilepsy and classify types of seizures, little progress was made medically, although, gradually, the idea that epilepsy was a natural disease did gain more cre­dence, especially after the Age of Enlightenment.

Nineteenth Century

By the beginning of the nineteenth century, epilep­tics were hospitalized, but unlike the insane, were allowed to go to mass on Sundays. Confined epilep­tics, however, became the object of systematic medi­cal attention only in the early nineteenth century. The care of epileptics, especially children, pro­gressed slowly. Only in 1838 were epileptic children in Paris transferred from the Hospital of the Incur­ably Ill to the Bicetre, where some kind of education was provided for them. The separation of hospital­ized epileptics from the insane was motivated less from solicitude for the epileptics who might suffer from contact with the insane than from the belief that epilepsy was an infectious disease that would affect the insane even more than it did the healthy. The confinement of epileptics in separate wards of lunatic asylums became established procedure in Eu­rope around 1850 and was soon followed by requests for special institutions for epileptics.

During the early part of the nineteenth century, the most valuable contributions to the medical his­tory of epilepsy were made by physicians associated with hospitals and lunatic asylums, and it was then that new terminology, increased use of statistics, and interest in the psychiatric side of epilepsy devel­oped. The terms grand and petit mal, absence, status epilepticus, and aura, for example, were in common usage and survive to this day. The growing use of statistics fostered investigations into the inheritabil­ity of epilepsy and determination of the various causes of the illness, prominent among which were fright, sorrow, and masturbation. Despite the in­creased attention paid to epilepsy, however, modern medicine’s understanding is usually said to have begun around 1880, when the impact of John Hughlings Jackson’s work in England and that of Jean Charcot in France began to be felt. Jackson outlined a neurological theory of epilepsy, while Charcot separated epilepsy from hysteria more em­phatically than any of his predecessors. Jackson’s principles were publicly demonstrated in 1888, by William Macewan, who was “probably the first sur­geon to localize the cerebral focus by inference from the motor or sensory signs of the epileptic seizure” (Temkin 1971).

Jerrold E. Levy

Bibliography

Epilepsy Foundations of America. 1981. How to recognize and classify seizures. Landover, Maryland: Epilepsy Foundation of America.

Ervin, Frank R. 1967. Brain disorders. IV: Associated with convulsions (epilepsy). In Comprehensive text­book of psychiatry, ed. Alfred M. Freedman and Har­old I. Kaplan, 795-816. Baltimore.

Hauser, W. Allen, and Leonard T. Kurland. 1975. The epidemiology of epilepsy in Rochester, Minnesota, 1935 through 1967. Epilepsia 16: 1—66.

Koul, Roshan, S. Razdan, and Anil Motta. 1988. Preva­lence and pattern of epilepsy (LathZMirgiZLaran) in rural Kashmir, India. Epilepsia 29: 116-22.

Kurland, Leonard T. 1949. The incidence and prevalence of convulsive disorders in a small urban community. Epilepsia 1: 143.

Kurland, Leonard T., John F. Kurtzke, and Irving D. Gold­berg. 1973. Epidemiology of neurologic and sense or­gan disorders. Cambridge.

Lechtenberg, Richard. 1984. Epilepsy and the family. Cambridge.

Levy, Jerrold E., Raymond Neutra, and Dennis Parker. 1987. Hand trembling, frenzy witchcraft, and moth madness: A study of Navajo seizure disorders. Tucson.

Temkin, Owsei. 1971. The falling sickness: A history of epilepsy from the Greeks to the beginnings of modern neurology, 2d edition. Baltimore.

Tsuboi₁ Takayuki 1988. Prevalence and incidence of epi­lepsy in Tokyo. Epilepsia 29: 103-10.