SEMINARS I N NEUROLOGY-VOLUME
10, NO. 4
DECEMBER 1990
Epileptic Seizures and Syndromes in Adults
Every patient with a seizure disorder needs three levels of diagnosis: clinical seizure type, epileptic syndrome, and etiology. The first is based on clinical and (to a lesser degree) electroencephalographic (EEG) observation and is of primary importance for choosing drug therapy. The second combines the clinical seizure classification with genetic, historical, and laboratory data. The value of the epilepsy syndrome diagnosis is that it may suggest a patient's prognosis, as well as the best lines of overall treatment, and the extent to which additional investigations to determine an underlying cause for the seizures should be pursued. The classifications of epileptic seizures and ~yndromes,'-~ which evolved in concert, are discussed in detail in an earlier article, by Thadani and Williamson. In this article, the seizure types and epileptic syndromes seen in adults will be described, and their clinical implications discussed. Specific treatment is addressed more fully in later articles.
PREVALENCE OF SEIZURE TYPES IN ADULTS Classification of seizures is pheriomenologic, although EEG data are often considered, but the diagnosis of a specific epileptic syndrome depends on all the data available and may change if additional information is obtained. In adults, the number of distinct epileptic syndromes encountered tends to be less than in children, and the seizure types assume more significance. Thus, in this article seizures will be emphasized more than syndromes. Gastaut et a l h e r e able to classify seizure types and, by inference, epileptic syndromes, in 75% of their patients in Marseilles on the basis of clinical and EEG data (in most cases only a 30-minute tracing). Seventy-eight percent of patients over the age
of 15 years had partial, and only 22%, generalized epilepsy. Similar results (70 to 80% partial seizures in adults, less frequent in children) were found in studies from India, Denmark, and Nigeria.6-8 Granieri et al" reviewed medical records and contacted potential cases for interview and neurologic examination in the Copparo district of Italy. Both adults and children were studied. Total prevalence of epilepsy, defined as a history of two or more nonfebrile seizures, with at least one in the past 5 years, or patients taking antiepileptic drugs, was 6.211000. Clinical data alone were used for classification according to the 1981 International Classification of Epileptic Syndromes (ICES). Of 278 cases identified, 18 were unclassifiable, 165 had simple partial seizures (SPS), 29 had complex partial seizures (CPS), 43 had partial seizures secondarily generalized, and three, "unspecified" partial seizures. Eleven had simple and 25, complex absences, 125 tonic, clonic, or tonic-clonic seizures, and eight, other types of generalized epilepsy." The incidence figures were age dependent: the rates for partial seizures were 18.8, 25.1, and 10.41 100,000lyear in 0-9, 10-19, and 20-39 year olds, respectively, and corresponding figures for generalized seizures were 62, 20.8, and 6.5. A clear etiology for seizures was ascertainable in about 40% of patients. A similar population study in Aarhus, Denmark, found that 37% of patients had partial arid 37%, generalized seizures. "' Goodridge and Shorvon" identified 122 patients with a history of seizures (including those who had a single episode) in an English general practice of 6000. Partial seizures with o r without secondary generalization were present in 29%, and primary generalized seizures in 65%. EEG data were not reviewed. Only 5% of the study patients were less than 10 years old on prevalence day, although 31% had been at seizure onset. This population may have been skewed toward children.
Chief, Clinical Epilepsy Section NINDS, NIH, Bethesda, Maryland Reprint requests: Dr. Theodore, Clinical Epilepsy Section, NIH 1015 N-248, Bethesda, MD 20892
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William H. Theodore, M.D.
Keranen et all2 used the 1981 ICES to classify seizure types in patients over 15 years old at Kupio University Hospital, Finland. EEG records, and in some cases prolonged video-EEG monitoring, were used as well as clinical data. Seizures could be classified in 82.5% of 1220 cases: 7.5% had SPS; 23%, CPS; 25.5%, CPS with secondary generalization; 23%, generalized tonic-clonic seizures (GTCS); and about 1% each, atonic, absence, tonic, or myoclonic seizures. Age-related differences in frequency of seizure types were less, even in the adult population, than in the report of Granieri et al.99'2 Differences in proportions of partial and generalized epilepsies in surveys of adult populations may be due to several factors. Focal onset in seizures thought to be generalized may be detected only after extensive investigation. Secondary generalization may be very rapid; observers may remember only the more dramatic GTCS, and not subtle initial manifestations of CPS. In some studies, EEG data were not included in the classification. The age range of the population studied may be important as well. Partial seizures of all types, and localization-related epilepsies, may be more likely to persist into adult life than primary generalized seizures and epilepsies. Studies of hospital clinic populations, rather than regional surveys, may be more likely to include higher numbers of patients with partial seizures, since these may be more resistant to treatment than GTCS or absence. Nevertheless, these figures clearly show that most adults with epilepsy have partial seizures with or without secondary generalization, and fit into the syndrome of localization-related epilepsy. Several conclusions follow. In patients with partial seizures, an underlying cerebral lesion is presumed to be present, which may range from a malignant tumor to a small region of gliosis and neuronal loss. A systematic effort should be made to detect such a focus in each patient, using EEG, magnetic resonance scans, and possibly single photon or positron emission tomography. When all imaging modalities are combined, it is likely that nearly 75% of patients with partial seizures will have a detectable abnormality.I3
VOLUME 10, NUMBER 4 DECEMBER 1990
hood. GTCS first appearing after the age of 18 or 20 years are more likely to fit into the syndrome of "situation-related" (drugs, alcohol, systemic disease) than "age-related" seizures.14 There may be important differences in seizure etiology with increasing age between 20 and 80 (Table 1). Cerebrovascular disease, drug toxicity, and systemic metabolic derangements probably become more common causes, whereas alcohol abuse declines.I5 The frequency of brain tumors as the cause of new-onset epilepsy appears to peak in the sixth and seventh decades, depending in addition on the specific population studied, the seizure types included, and the diagnostic tests performed.15 Currie et all%tudied 666 patients (75% had seizure onset at age 15 years or older) at the London Hospital from 1949 to 1967 who met clinical or EEG criteria for "temporal lobe epilepsy." Only 25% had a definite seizure etiology; 10% had tumors. Even in the computerized tomography (CT) scan era, tumors account for less than 20% of new-onset seizures in adults, and 40 to 50% still have no definite etiology.14 It is important to remember that CT may not detect a small low-grade glioma, especially in the temporal lobe, on initial scan, and many years may pass before a definite diagnosis can be made. Magnetic resonance imaging (MRI) may be more sensitive, but it is still important to reassess patients with periodical clinical examination and imaging studies, especially when clear localization-related epilepsy and partial seizures are present. Astrocytomas are more likely to present with seizures in young and weakness in older adults." Tumors become less common as a cause of seizures after 70, representing less than 5% of new-onset ~ a s e s . ' ~ The incidence of cerebrovascular diseases as a cause of seizures is uncertain. Seizures may be attributed to cerebrovascular disease on the basis of weak or circumstantial evidence. Although discrete abnormalities appear on CT in the elderly presenting with seizures more frequently than in the normal population, their etiologic role is unclear.lg Table 1. Common Etiologies of Seizures Presenting in Adult Life
Yo
ETIOLOGY OF SEIZURES IN ADULTS Although the distinction between childhood and adult epilepsy is artificial, the etiology of seizures presenting for the first time in adult life may be significantly different from that in children. "Localization-related epilepsy," for example, beginning in adult life, is more likely to be due to a tumor than the same syndrome starting in child-
Unknown
40-50
Drugs or alcohol
10-20
Ischemic Tumor Head injury Metabolic Infection
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SEMINARS IN NEUROLOGY
Based on historical evidence alone, Goodridge and Shorvon" thought that trauma accounted for seizures in 10% and cerebrovascular disease in 9% of their population." In a hospital outpatient population of adults studied with EEG and CT, these figures were 4 and 14%.14Degenerative conditions such as Alzheimer's disease or Creutzfeldt-Jakob syndrome will account for only a small percentage in any series. T h e range of possible etiologies also varies with clinical seizure type. A patient with chronic CPS and normal neurologic examination is likely to have an old structural lesion (hemorhage, arteriovenous malformation), focal gliosis, or a small tumor. Tumors and cerebrovascular disease are more frequent in patients with extratemporal SPS than with CPS and unusual in true primary generalized GTCS.I4 An adult with new-onset GTCS and no evidence of secondary generalization may have a metabolic derangement, such as hyponatremia, alcohol withdrawal, or drug toxicity (for example, theophylline or a psychotherapeutic agent).
SEIZURE TYPES IN ADULTS Many epileptic syndromes and their seizure types, appearing first in childhood, persist into adult life. Patients with childhood or juvenile absence may continue to have their typical attacks or develop GTCS as adults. Most patients with juvenile myoclonic epilepsy, although well-controlled by antiepileptic drugs (AEDs), will have seizures as adults if drugs are stopped. Patients with the Lennox-Gastaut syndrome rarely achieve complete seizure remission, although seizure types may change and the pure atonic spells seen in early childhood may be replaced by GTCS or more complex events reminiscent of partial seizures. A large proportion of patients with "localization-related" epilepsies have seizure onset in childhood. GENERALIZED SEIZURES
GTCS are the most common type of generalized seizures seen in adults." Other generalized seizures such as absence, atonic, or myoclonic account for less than 5% of all adult seizures. Although at least 50% of the GTCS appear to be secondarily generalized, intensive investigation may be needed to detect the focus.20From a pharmacotherapeutic point of view, there is little need to distinguish between primary and secondary GTCS, since carbamazepine and phenytoin seem to be equally effective in both types (see article by Mattson in this issue of Seminars). Both partial and ab-
sence seizures may progress to GTCS, and the extent of generalization may vary not only between patients but even from seizure to seizure in the same patient.20Although GTCS are usually easy to diagnose clinically, patient or observer reports may emphasize features that seem to reflect focal onset but are in fact due to fragmentary forms. These may occur particularly when patients are taking antiepileptic drugs. Absence seizures nearly all begin before age 15 years and usually age 10; about 15 to 20% may have persistent episodes beyond age 20.21 Both GTCS and absence seizures accompanied by various generalized spike-wave discharge patterns have been found in association with focal intracranial lesions, although most patients have had some clinical suggestion of the presence of a lesion." Frontal lobe lesions in particular have been associated with apparent "primary" GTCS or absence, and both have been evoked by frontal lobe or cingulate gyrus electrical stimulation via implanted elect r o d e ~ . ~ "Nevertheless, ~~ etiologic and neuroimaging investigation is unrevealing in the vast majority of patients with either absence or GTCS.22 Diagnostic confusion may arise between absence and CPS, especially in a patient who has had epilepsy since childhood. Clinical as well as EEG patterns distinguish these two seizure types. Absence seizures do not begin with an aura, and they end abruptly without a period of postictal confusion.'TPS last a mean of 2 minutes, compared ~~.~~ compowith 10 seconds for a b s e n ~ e . Clonic nents, especially eye blinking, are more common in absence attacks, but automatisms tend to occur in the longer episodes only, and to be restricted to the face and hand^.'^ Absence status epilepticus has been reported rarely to occur in adult life without a previous history of seizures, but most adults with nonconvulsive status will have localization-related epilepsy." Autonomic features such as increased blood pressure, tachycardia, and increased esophageal and decreased gastric motility are frequent in CPS and may precede loss of consciou~ness.~~ These autonomic phenomena, possibly leading to neurogenic pulmonary edema and cardiac arrhythmias, may be associated with sudden unexplained death in patients with epilepsy. Other forms of generalized seizures, such as atonic, or purely tonic or clonic attacks in adult life occur in the context of childhood onset epilepsy usually associated with a severe static encephalopathy or underlying metabolic disease (a "generalized, symptomatic" epilepsy). Myoclonic jerks appearing in an adult without a previous history of epilepsy suggest either a relatively benign or a grim prognosis. Juvenile myo39 1
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EPILEPTIC SEIZURES A N D SYNDROMES-THEODORE
SEMINARS I N NEUROLOGY
PARTIAL SEIZURES
SPS often precede CPS or GTCS in the form of an aura. The surface EEG during SPS is often normal.31T h e episodes, which can last several minutes, may show a variety of motor or more subtle autonomic, emotional, or perceptual phenomena that may seem nonspecific in the absence of a definite history of seizures. COMPLEX PARTIAL SEZZURES OF TEMPORAL LOBE ORIGIN
In adults, CPS of anterior temporal origin are the most frequently encountered partial seizure type. Many patients have seizure onset in adolescence or earlier; it is not unusual to experience a seizure-free period for several years (on or even off medication) before recurrence in late teens or early 20s. T h e seizures may begin with an aura (gastrointestinal discomfort is the most common) followed by loss of consciousness and a variety of automatisms, such as lip smacking, chewing, and fumbling with clothes or objects. Occasionally patients may walk around or perform fragments of more complex normal activity, but clearly organized, directed behavior is exceptional. Secondary generalization is part of the syndrome, but is more likely to be suppressed by AED therapy than are the partial seizures themselves. There may be varying degrees of neuropsychologic impairment. Although historical evidence for specific etiology may be meager, and neurologic examination usually is normal, modern techniques such as MRI and positron emission tomography are showing focal abnormalities in an increasing number of patients. At surgery, most will have focal temporal gliosis and neuronal loss. A minority have a low-grade tumor, small arteriovenous malformation, or other lesion. 392
FRONTAL LOBE SEIZURES
Clinical distinctions among partial seizures may suggest autonomic origin. Certain specific clinical patterns are characteristic of origin in different portions of frontal lobe and less likely to be confused with CPS of temporal origin. Much of this information comes from stimulation studies, which may or may not be an accurate guide to spontaneous clinical attacks. Frontal lobe seizures include focal motor seizures of rolandic origin and various kinds of supplementary motor seiz u r e ~ , including ~ ~ - ~ ~ the characteristic posture of the arm contralateral to seizure onset described .~~ by Ajmone-Marsan and R a l ~ t o n Unfortunately, similar events may be associated with seizures beginning in other brain regions.35 Rapid secondary generalization was early suggested as a feature of CPS emanating from frontal foci.'"eported clinical characteristics differentiating CPS of frontal from temporal origin include clusters of short attacks, a higher incidence of partial status, vague warnings rather than characteristic auras, minimal postictal confusion, bizarre attacks, including "sexual" automatisms, and bimanual and bipedal "bicycling" movements that may be mistaken for psychogenic spells, speech arrest and forced vocalization, shouting, laughing, deep or irregular breathing, and head and eye deviati~n.~~-~~ Geier et a139thought that patients tended to be more aware of automatisms occurring during CPS of frontal than temporal origin. When automatic behavior is induced by cingulate gyrus stimulation, patients may retain consciousness.40Auras involving complex psychic or emotional content may be less frequent in CPS of frontal origin.41In 40 patients with CPS of frontal origin, a traumatic etiology was found in 50%; a clear structural lesion may be more common in this patient group.
CLINICAL DISTINCTION OF FRONTAL AND TEMPORAL LOBE SEIZURES Delgado-Escueta and c o l l e a g ~ e s have ~ ~ - ~at~ tempted to divide CPS into specific clinical subtypes. Type 1 attacks had three phases, a motionless stare lasting about 10 seconds, unresponsiveess with stereotyped automatisms lasting about 60 seconds, and confusion or a "cloudy" state with "reactive" automatisms, which could last 10 to 15 minutes. Type 2 attacks did not begin with a motionless stare and included only a very brief period of stereotyped automatisms or none at all. Coordinated .motor activity, such as drinking water, could occur
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clonic epilepsy has a usual age of onset of 13 to 15 . . years but may begin as l a t e i s the early 20s." Patients often have GTCS as well, but these may start several years after the myoclonic jerks appear. Although needing prolonged, if not lifelong, treatment, the syndrome responds well to valproic acid in most cases. In an older adult, myoclonic jerks may be associated with a fatal disorder, 'such as CreutzfeldtJakob syndrome or Alzheimer's disease, but are very rarely the presenting manifestation.I5 They may occasionally accompany sleep disorders or derangement of systemic chemistry. Adult onset of metabolic diseases such as Unverricht-Lundborg syndrome will be found very rarely.
V O L U M E 10, NUMBER 4 DECEMBER 1990
EPI1,EPTIC SEIZURES AND SYNDROMES-THEODORE
PARTIAL SEIZURES AND SPEECH DYSFUNCTION T h e relationship of ictal and postictal speech and language dysfunction to side of seizure is complex. Gabr et al" studied 35 patients whose site of seizure origin had been localized using prolonged scalp and subdural EEG recordings, and who had had intracarotid amobarbital tests for determination of hemispheric dominance for speech. Postictal dysphasia was strongly correlated with dominant hemisphere seizure onset, but 83% of patients with identifiable speech during seizures themselves had nondominant seizure foci. Currie et al'%lso found that dysphasia was more common in patients with dominant foci. King and AjmoneMarsan3' reported that postictal dysphasia was more common in patients with left than right hemisphere foci, but ictal speech was nonlateralizing. Some studies have reported no correlation between side of speech dominance and ictal or postictal speech phenomena.'; These studies did not
have as complete documentation of site of seizure onset as that of Gabr et al, but it is important to remember that CPS spread to contralateral temporal as well as ipsilateral extratemporal structures and ictal clinical manifestations may reflect activation of secondary sites as well as the focus itself.
PARIETAL AND OCCIPITAL LOBE SEIZURES Because of the wide overlap with symptoms of seizures originating in other regions, parietal CPS cannot be distinguished reliably on clinical ground^."^ Occipital lobe CPS usually have visual or oculomotor features suggesting their origin, although some features, such as head and eye deviation, may of both parietal and occipbe less s~ecific.~%pread ital CPS to involve temporal regions may be responsible for observed clinical phenomena. Other partial seizure types rarely seen in adults include benign rolandic epilepsy, which spontaneously disappears at puberty in almost all cases." Clinical features, including speech arrest with preserved consciousness, hemifacial and ipsilateral arm clonic jerking, and a tendency for seizures to occur at night, distinguish them from CPS.60EEG discharges, often bilateral, occur at F8T 4 or C4-T4.
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during the period of' reactive automatisms in either seizure type. Type 1 CPS were associated with EEG discharges of mesial-anterior temporal origin; the patients had good results from anterior temporal lobe~tomy.~"Type 2 seizures, however, had diffuse surface EEG discharges and did not respond to r features in temporal l ~ b e c t o m y . ~ W t h eclinical type 2 patients, such as postural changes, contraversive head and eye movements, "bicycling," or "fishing," suggested frontal ~rigin.~"n a subsequent study, however, the same investigators concluded that only 60% of CPS of hippocampalamygdalar origin began with an initial motionless stare.lWther reports have also suggested that the initial motionless stare was not a constant feature of any group of CPS."'48 W e i ~ e described r~~ several subvarieties of CPS: temporobasal-limbic, temporopolar, opercular, posterior temporal neocortical, and frontobasal cingulate. Although there was great deal of overlap between the subtypes, Weiser was able, using cluster and principal components analysis, to discern clinical patterns associated with each anatomic sublocalization. The temporobasal-limbic type was by far the most freq~ent.~"he clinical distinction might be important, since these patients might respond to a more restricted form of surgery, selective amygdalo-hippocampectomy, with less postoperative neuropsychologic impairment.jO However, Weiser's results suggested that it would be difficult in any individual case to make an anatomic localization based on clinical data alone.49
PARTIAL SEIZURES AND PSYCHIATRIC ILLNESS: "RIGHT" AND "LEFT" TEMPORAL LOBE EPILEPSY Patients with CPS are thought by many investigators to be more likely than those with other seizure types to have psychologic problems such as depression, personality disorders, and schizophreniform psychoses. Patients with CPS and secondary GTCS may be more likely to develop psychopathology than those with CPS alone.55 Differences in psychiatric manifestations and interictal personality may exist between patients with right and left temporal Patients with right temporal EEG foci were more likely to have wide swings of emotion and exaggerated positive social traits, whereas those with left temporal foci were excessively philosophical and introspective, investing apparently chance events with particular personal significance, and had a negative view of t h e m s e l v e ~ . ~ ~ I o r - H e nsuggested ry~~ that right temporal lobe foci were associated with a clinical syndrome of a manic-depressive disorder, whereas left temporal foci were more likely to be associated with schizophreniform psychoses.57 Subtle differ393
SEMINARS I N NEUROLOGY VOLUME 10, NUMBER 4 DECEMBER 1990
CONCLUSION
394
Proper seizure and epilepsy classification is important to both treatment and clinical research. The effects of experimental antiepileptic drugs, and surgery for uncontrolled epilepsy, cannot be assessed unless uniform patient groups are studied. Enough information, starting with history and EEG, should be obtained in each case to allow proper classification. Prolonged video-EEG monitoring may be necessary to identify seizure type,
and neuroimaging as well as other laboratory tests to assign patients to an appropriate epilepsy syndrome. One should be wary particularly of a diagnosis of primary generalized epilepsy in adults and make sure that evidence for a focal lesion or underlying toxic or metabolic disorder has not been overlooked.
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ences in interictal, but not ictal, "fear" have been reported between patients with right and left temporal foci: patients with left. temporal foci reported more fear of social and sexual situations, but not of animals or physical injury.58 Gupta et aI5' reported that "psychic" and "autonomic" (epigastric, cardiovascular, or genitourinary) auras, as well as auras in general, were more common in patients with right than left temporal foci. Not all investigators have reported similar results, and the EEG localization techniques used may not always have been optimal, either to distinguish right from left temporal foci o r primary from secondary GTCS. In many studies only a single EEG was performed, and only weak evidence of lateralization taken as definitive. Master et a160 found no difference on an interictal personality index between patients with partial and generalized epilepsy, and no left-right differences, although the patient group did show more psychologic dysfunction than normal controls. However, when subjects with overt psychiatric disorders are excluded from analysis, differences in interictal personality between patients with epilepsy and normal controls largely di~appear.~' It is interesting that, despite reports of different effects of site of seizure onset on sexuality, there were no differences in postictal prolactin measurements between patients with right o r left temporal lobe focL6' Psychopathology in patients with epilepsy may be due to a combination of factors, including social, economic, and educational disadvantage, cultural milieu, drug toxicity (which has been associated with episodes of psychosis, depression, and impaired sexual function), in addition to seizure type and localization of the EEG focus.62Underlying etiology and overall neuropsychologic dysfunction may be important as well. One of the most important factors leading to psychiatric disturbance in patients with seizures is the presence of significant cerebral changes.63Too little information is available to attempt to define anatomic-clinical syndromes of right or left temporal lobe epilepsy, or CPS with and without psychopathology.
21. Dalby MA. Epilepsy and 3 per second spike and wave rhythms. Acta Neurol Scand 1969;45(Suppl40): 1-183 22. Theodore WH. Cerebral metabolism in absence seizures and related syndromes. I n Myslobodsky MS, Mirsky AF, eds. Elements of petit ma1 epilepsy. New York: Peter Lang, 1988: 131-58 23. Goldring S. T h e role of prefrontal cortex in grand ma1 convulsion. Arch Neurol 1972;26: 109-19 24. Mazars G. Cingulate gyrus epileptic foci as a n origin for generalized seizures. In Gastaut H, Jasper H , Bancaud J, Waltregny A, eds. Physiopathogenesis of the epilepsies. Springfield, IL: Charles C Thomas, 1969 25. Bancaud J , Talairach J , Morle P, et al. Generalized epileptic seizures elicited by electrical stimulation of the frontal lobe in man. Electroencephalogr Clin Neurophysiol 1974;37:275-82 26. Penry JK, Porter RJ, Dreifuss FE. Simultaneous recording of absence seizures with videotapes and electroencephalography. Brain 1975;98:427-40 27. Theodore WH, Porter RJ, Penry JK. Complex partial seizures: clinical characteristics and differential diagnosis. Neurology (Cleve) 1983;33: 11 15-21 28. Porter RJ, Penry JK. Petit ma1 status. Adv Neurol 1983;34:61-7 29. Van Buren JM, Ajmone-Marsan C. A correlation of autonomic and EEG components in temporal lobe epilepsy. Arch Neurol 1960;3:683-703 30. Dreifuss FE. Juvenile myoclonic epilepsy: characteristics of a primary generalized epilepsy. Epilepsia 1989;30 (Suppl 4):s 1-7 31. Devinsky 0, Kelley K, Porter RJ, Theodore WH. Clinical and electrographic features of simple partial seizures. Neurology (Cleve) 1988;38: 1347-52 32. Van Buren JM, Fedio P. Functional representation on the medial aspect of the frontal lobes in man. J Neurosurg 1976;44:275-89 33. Waterman K, Purves SJ, Hosaka B, et al. An epileptic syndrome caused by mesial frontal lobe seizure foci. Neurology (Cleve) 1987;37:577-82 34. Geier S, Bancaud J , Talairach J , et al. T h e seizures of frontal lobe epilepsy: a study of clinical manifestations. Neurology (Minneap) 1977;27:951-8 35. Ajmone-Marsan C, Ralston B. T h e epileptic seizure: its functional morphology and diagnostic significance. Springfield, IL: Charles C Thomas, 1957 36. Ludwig B, Ajmone-Marsan C, Van Burne JM. Cerebral seizures of probable orbito-frontal origin. Epilepsia 1975;16:141-58 37. Williamson PD, Spencer DD, Spencer SS, et al. Complex partial seizures of frontal lobe origin. Ann Neurol 1985; 18:497-504 38. Spencer SS, Spencer DD, William PD, Mattson RH. Sexual automatisms in complex partial seizures. Neurology (Cleve) 1983;33:527-33 39. Geier S, Bancaud J , Talairach J , et al. Automatisms during frontal lobe epileptic seizures. Brain 1976;99: 447-58 40. Talairach J , Bancaud J , Geier S, et al. T h e cingulate gyrus and human behavior. Electroencephalogr Clin Neurophysiol 1973;34:45-52 4 1. Rasmussen T. Characteristics of a pure culture of frontal lobe epilepsy. Epilepsia 1983;24:482-93 42. Escueta AV, Kunze U , Waddell G, et al. Lapse of consciousness and automatisms in temporal lobe epilepsy: a videotape analysis. Neurology (Minneap) 1977;27: 144-55
43. Delgado-Escueta AV, Bocsal FE, Treiman DM. Complex partial seizures o n closed circuit television and EEG; a study of 691 attacks in 79 patients. Ann Neurol 1981; 11:292-300 44. Delgado-Escueta AV, Walsh GO. Type 1 complex partial seizures of hippocampal origin: excellent results of anterior temporal lobectomy. Neurology (Cleve) 1985;35: 143-54 45. Walsh GO, Delgado-Escueta AV. Type 2 complex partial seizures: poor results of anterior temporal lobectomy. Neurology (Cleve) 1984;34: 1-13 46. Maldonado HM, Delgado-Escueta AV, Walsh GO, et al. Complex partial seizures of hippocampal and amygdalar origin. Epilepsia 1988;29:420-33 47. Brey R, Laxer KD. Type 112 complex partial seizures: no correlation with surgical outcome. Epilepsia 1985;26: 657-60 48. Williams LB, Thompson EA, Lewis DV. Intractable complex partial seizures: the "initial motionless stare" and surgical outcome following temporal lobectomy. Neurology (Cleve) 1987;37: 1255-8 49. Weiser HG. Electroclinical features of the complex partial seizure. Stuttgart: Gustav Fischer, 1983 50. Weiser HG. Selective amygdalo-hippocampectomy for temporal lobe epilepsy. Epilepsia 1988;29(Suppl 2): S100-13 51. Gabr M, Luders H , Dinner D, Morris H , Wyllie E. Speech manifestations in lateralization of temporal lobe epilepsy. Ann Neurol 1989;25:82-7 52. King DW, Ajmone-Marsan C. Clinical features and ictal patterns in epileptic patients with EEG temporal lobe foci. Ann Neurol 1977;2: 138-47 53. Williamson PD, Spencer SS. Clinical and EEG features of complex partial seizures of extratemporal origin. Epilepsia 1986;27(Suppl 2):S46-63 54. Loiseau P, Pestre M, Dartigues JF, et al. Long-term prognosis in two forms of childhood epilepsy: typical absence seizures and epilepsy with rolandic (centrotemporal) EEG foci. Ann Neurol 1983; 13:642-8 55. Hermann BP, Dikmen S, Wilensky AJ. Increased psychopathology associated with multiple seizure types: fact o r artifact? Epilepsia 1982;23:587-96 56. Bear DM, Fedio P. Quantitative analysis of interictal behavior in temporal lobe epilepsy. Arch Neurol 1977; 34:454-67 57. Flor-Henry P. Psychosis and temporal lobe epilepsy. Epilepsia 1969; 10:363-95 58. Strauss E, Risser A, Jones MW. Fear responses in patients with epilepsy. Arch Neurol 1982;39:629-30 59. Gupta AK, Jeavons PM, Hughes RC, Covanis A. Aura in temporal lobe epilepsy; clinical and electroencephalographic correlation. J Neurol Neurosurg Psychiatry 1983;46: 1079-83 60. Master DR, Toone BK, Scott DF. lnterictal behavior in temporal lobe epilepsy. Adv Epileptol 1984; 15:556-65 61. Laxer KD, Mullooley JP, Howell B. Prolactin changes after seizures classified by EEG monitoring. Neurology (Cleve) 1985;35:31-5 62. Rodin E, Schmaltz S, Twitty G. What does the Bear-Fedio inventory measure? in Adv Epileptol 1984;15:551-5 63. Stevens JR, Hermann BP. Temporal lobe epilepsy, psychopathology and violence: the state of the evidence. Neurology (NY) 1981;31:1127-32
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EPILEPTIC SEIZURES AND S Y N D R O M E S T H E O D O R E
10, NO. 4
DECEMBER 1990
Epileptic Seizures and Syndromes in Adults
Every patient with a seizure disorder needs three levels of diagnosis: clinical seizure type, epileptic syndrome, and etiology. The first is based on clinical and (to a lesser degree) electroencephalographic (EEG) observation and is of primary importance for choosing drug therapy. The second combines the clinical seizure classification with genetic, historical, and laboratory data. The value of the epilepsy syndrome diagnosis is that it may suggest a patient's prognosis, as well as the best lines of overall treatment, and the extent to which additional investigations to determine an underlying cause for the seizures should be pursued. The classifications of epileptic seizures and ~yndromes,'-~ which evolved in concert, are discussed in detail in an earlier article, by Thadani and Williamson. In this article, the seizure types and epileptic syndromes seen in adults will be described, and their clinical implications discussed. Specific treatment is addressed more fully in later articles.
PREVALENCE OF SEIZURE TYPES IN ADULTS Classification of seizures is pheriomenologic, although EEG data are often considered, but the diagnosis of a specific epileptic syndrome depends on all the data available and may change if additional information is obtained. In adults, the number of distinct epileptic syndromes encountered tends to be less than in children, and the seizure types assume more significance. Thus, in this article seizures will be emphasized more than syndromes. Gastaut et a l h e r e able to classify seizure types and, by inference, epileptic syndromes, in 75% of their patients in Marseilles on the basis of clinical and EEG data (in most cases only a 30-minute tracing). Seventy-eight percent of patients over the age
of 15 years had partial, and only 22%, generalized epilepsy. Similar results (70 to 80% partial seizures in adults, less frequent in children) were found in studies from India, Denmark, and Nigeria.6-8 Granieri et al" reviewed medical records and contacted potential cases for interview and neurologic examination in the Copparo district of Italy. Both adults and children were studied. Total prevalence of epilepsy, defined as a history of two or more nonfebrile seizures, with at least one in the past 5 years, or patients taking antiepileptic drugs, was 6.211000. Clinical data alone were used for classification according to the 1981 International Classification of Epileptic Syndromes (ICES). Of 278 cases identified, 18 were unclassifiable, 165 had simple partial seizures (SPS), 29 had complex partial seizures (CPS), 43 had partial seizures secondarily generalized, and three, "unspecified" partial seizures. Eleven had simple and 25, complex absences, 125 tonic, clonic, or tonic-clonic seizures, and eight, other types of generalized epilepsy." The incidence figures were age dependent: the rates for partial seizures were 18.8, 25.1, and 10.41 100,000lyear in 0-9, 10-19, and 20-39 year olds, respectively, and corresponding figures for generalized seizures were 62, 20.8, and 6.5. A clear etiology for seizures was ascertainable in about 40% of patients. A similar population study in Aarhus, Denmark, found that 37% of patients had partial arid 37%, generalized seizures. "' Goodridge and Shorvon" identified 122 patients with a history of seizures (including those who had a single episode) in an English general practice of 6000. Partial seizures with o r without secondary generalization were present in 29%, and primary generalized seizures in 65%. EEG data were not reviewed. Only 5% of the study patients were less than 10 years old on prevalence day, although 31% had been at seizure onset. This population may have been skewed toward children.
Chief, Clinical Epilepsy Section NINDS, NIH, Bethesda, Maryland Reprint requests: Dr. Theodore, Clinical Epilepsy Section, NIH 1015 N-248, Bethesda, MD 20892
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William H. Theodore, M.D.
Keranen et all2 used the 1981 ICES to classify seizure types in patients over 15 years old at Kupio University Hospital, Finland. EEG records, and in some cases prolonged video-EEG monitoring, were used as well as clinical data. Seizures could be classified in 82.5% of 1220 cases: 7.5% had SPS; 23%, CPS; 25.5%, CPS with secondary generalization; 23%, generalized tonic-clonic seizures (GTCS); and about 1% each, atonic, absence, tonic, or myoclonic seizures. Age-related differences in frequency of seizure types were less, even in the adult population, than in the report of Granieri et al.99'2 Differences in proportions of partial and generalized epilepsies in surveys of adult populations may be due to several factors. Focal onset in seizures thought to be generalized may be detected only after extensive investigation. Secondary generalization may be very rapid; observers may remember only the more dramatic GTCS, and not subtle initial manifestations of CPS. In some studies, EEG data were not included in the classification. The age range of the population studied may be important as well. Partial seizures of all types, and localization-related epilepsies, may be more likely to persist into adult life than primary generalized seizures and epilepsies. Studies of hospital clinic populations, rather than regional surveys, may be more likely to include higher numbers of patients with partial seizures, since these may be more resistant to treatment than GTCS or absence. Nevertheless, these figures clearly show that most adults with epilepsy have partial seizures with or without secondary generalization, and fit into the syndrome of localization-related epilepsy. Several conclusions follow. In patients with partial seizures, an underlying cerebral lesion is presumed to be present, which may range from a malignant tumor to a small region of gliosis and neuronal loss. A systematic effort should be made to detect such a focus in each patient, using EEG, magnetic resonance scans, and possibly single photon or positron emission tomography. When all imaging modalities are combined, it is likely that nearly 75% of patients with partial seizures will have a detectable abnormality.I3
VOLUME 10, NUMBER 4 DECEMBER 1990
hood. GTCS first appearing after the age of 18 or 20 years are more likely to fit into the syndrome of "situation-related" (drugs, alcohol, systemic disease) than "age-related" seizures.14 There may be important differences in seizure etiology with increasing age between 20 and 80 (Table 1). Cerebrovascular disease, drug toxicity, and systemic metabolic derangements probably become more common causes, whereas alcohol abuse declines.I5 The frequency of brain tumors as the cause of new-onset epilepsy appears to peak in the sixth and seventh decades, depending in addition on the specific population studied, the seizure types included, and the diagnostic tests performed.15 Currie et all%tudied 666 patients (75% had seizure onset at age 15 years or older) at the London Hospital from 1949 to 1967 who met clinical or EEG criteria for "temporal lobe epilepsy." Only 25% had a definite seizure etiology; 10% had tumors. Even in the computerized tomography (CT) scan era, tumors account for less than 20% of new-onset seizures in adults, and 40 to 50% still have no definite etiology.14 It is important to remember that CT may not detect a small low-grade glioma, especially in the temporal lobe, on initial scan, and many years may pass before a definite diagnosis can be made. Magnetic resonance imaging (MRI) may be more sensitive, but it is still important to reassess patients with periodical clinical examination and imaging studies, especially when clear localization-related epilepsy and partial seizures are present. Astrocytomas are more likely to present with seizures in young and weakness in older adults." Tumors become less common as a cause of seizures after 70, representing less than 5% of new-onset ~ a s e s . ' ~ The incidence of cerebrovascular diseases as a cause of seizures is uncertain. Seizures may be attributed to cerebrovascular disease on the basis of weak or circumstantial evidence. Although discrete abnormalities appear on CT in the elderly presenting with seizures more frequently than in the normal population, their etiologic role is unclear.lg Table 1. Common Etiologies of Seizures Presenting in Adult Life
Yo
ETIOLOGY OF SEIZURES IN ADULTS Although the distinction between childhood and adult epilepsy is artificial, the etiology of seizures presenting for the first time in adult life may be significantly different from that in children. "Localization-related epilepsy," for example, beginning in adult life, is more likely to be due to a tumor than the same syndrome starting in child-
Unknown
40-50
Drugs or alcohol
10-20
Ischemic Tumor Head injury Metabolic Infection
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SEMINARS IN NEUROLOGY
Based on historical evidence alone, Goodridge and Shorvon" thought that trauma accounted for seizures in 10% and cerebrovascular disease in 9% of their population." In a hospital outpatient population of adults studied with EEG and CT, these figures were 4 and 14%.14Degenerative conditions such as Alzheimer's disease or Creutzfeldt-Jakob syndrome will account for only a small percentage in any series. T h e range of possible etiologies also varies with clinical seizure type. A patient with chronic CPS and normal neurologic examination is likely to have an old structural lesion (hemorhage, arteriovenous malformation), focal gliosis, or a small tumor. Tumors and cerebrovascular disease are more frequent in patients with extratemporal SPS than with CPS and unusual in true primary generalized GTCS.I4 An adult with new-onset GTCS and no evidence of secondary generalization may have a metabolic derangement, such as hyponatremia, alcohol withdrawal, or drug toxicity (for example, theophylline or a psychotherapeutic agent).
SEIZURE TYPES IN ADULTS Many epileptic syndromes and their seizure types, appearing first in childhood, persist into adult life. Patients with childhood or juvenile absence may continue to have their typical attacks or develop GTCS as adults. Most patients with juvenile myoclonic epilepsy, although well-controlled by antiepileptic drugs (AEDs), will have seizures as adults if drugs are stopped. Patients with the Lennox-Gastaut syndrome rarely achieve complete seizure remission, although seizure types may change and the pure atonic spells seen in early childhood may be replaced by GTCS or more complex events reminiscent of partial seizures. A large proportion of patients with "localization-related" epilepsies have seizure onset in childhood. GENERALIZED SEIZURES
GTCS are the most common type of generalized seizures seen in adults." Other generalized seizures such as absence, atonic, or myoclonic account for less than 5% of all adult seizures. Although at least 50% of the GTCS appear to be secondarily generalized, intensive investigation may be needed to detect the focus.20From a pharmacotherapeutic point of view, there is little need to distinguish between primary and secondary GTCS, since carbamazepine and phenytoin seem to be equally effective in both types (see article by Mattson in this issue of Seminars). Both partial and ab-
sence seizures may progress to GTCS, and the extent of generalization may vary not only between patients but even from seizure to seizure in the same patient.20Although GTCS are usually easy to diagnose clinically, patient or observer reports may emphasize features that seem to reflect focal onset but are in fact due to fragmentary forms. These may occur particularly when patients are taking antiepileptic drugs. Absence seizures nearly all begin before age 15 years and usually age 10; about 15 to 20% may have persistent episodes beyond age 20.21 Both GTCS and absence seizures accompanied by various generalized spike-wave discharge patterns have been found in association with focal intracranial lesions, although most patients have had some clinical suggestion of the presence of a lesion." Frontal lobe lesions in particular have been associated with apparent "primary" GTCS or absence, and both have been evoked by frontal lobe or cingulate gyrus electrical stimulation via implanted elect r o d e ~ . ~ "Nevertheless, ~~ etiologic and neuroimaging investigation is unrevealing in the vast majority of patients with either absence or GTCS.22 Diagnostic confusion may arise between absence and CPS, especially in a patient who has had epilepsy since childhood. Clinical as well as EEG patterns distinguish these two seizure types. Absence seizures do not begin with an aura, and they end abruptly without a period of postictal confusion.'TPS last a mean of 2 minutes, compared ~~.~~ compowith 10 seconds for a b s e n ~ e . Clonic nents, especially eye blinking, are more common in absence attacks, but automatisms tend to occur in the longer episodes only, and to be restricted to the face and hand^.'^ Absence status epilepticus has been reported rarely to occur in adult life without a previous history of seizures, but most adults with nonconvulsive status will have localization-related epilepsy." Autonomic features such as increased blood pressure, tachycardia, and increased esophageal and decreased gastric motility are frequent in CPS and may precede loss of consciou~ness.~~ These autonomic phenomena, possibly leading to neurogenic pulmonary edema and cardiac arrhythmias, may be associated with sudden unexplained death in patients with epilepsy. Other forms of generalized seizures, such as atonic, or purely tonic or clonic attacks in adult life occur in the context of childhood onset epilepsy usually associated with a severe static encephalopathy or underlying metabolic disease (a "generalized, symptomatic" epilepsy). Myoclonic jerks appearing in an adult without a previous history of epilepsy suggest either a relatively benign or a grim prognosis. Juvenile myo39 1
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EPILEPTIC SEIZURES A N D SYNDROMES-THEODORE
SEMINARS I N NEUROLOGY
PARTIAL SEIZURES
SPS often precede CPS or GTCS in the form of an aura. The surface EEG during SPS is often normal.31T h e episodes, which can last several minutes, may show a variety of motor or more subtle autonomic, emotional, or perceptual phenomena that may seem nonspecific in the absence of a definite history of seizures. COMPLEX PARTIAL SEZZURES OF TEMPORAL LOBE ORIGIN
In adults, CPS of anterior temporal origin are the most frequently encountered partial seizure type. Many patients have seizure onset in adolescence or earlier; it is not unusual to experience a seizure-free period for several years (on or even off medication) before recurrence in late teens or early 20s. T h e seizures may begin with an aura (gastrointestinal discomfort is the most common) followed by loss of consciousness and a variety of automatisms, such as lip smacking, chewing, and fumbling with clothes or objects. Occasionally patients may walk around or perform fragments of more complex normal activity, but clearly organized, directed behavior is exceptional. Secondary generalization is part of the syndrome, but is more likely to be suppressed by AED therapy than are the partial seizures themselves. There may be varying degrees of neuropsychologic impairment. Although historical evidence for specific etiology may be meager, and neurologic examination usually is normal, modern techniques such as MRI and positron emission tomography are showing focal abnormalities in an increasing number of patients. At surgery, most will have focal temporal gliosis and neuronal loss. A minority have a low-grade tumor, small arteriovenous malformation, or other lesion. 392
FRONTAL LOBE SEIZURES
Clinical distinctions among partial seizures may suggest autonomic origin. Certain specific clinical patterns are characteristic of origin in different portions of frontal lobe and less likely to be confused with CPS of temporal origin. Much of this information comes from stimulation studies, which may or may not be an accurate guide to spontaneous clinical attacks. Frontal lobe seizures include focal motor seizures of rolandic origin and various kinds of supplementary motor seiz u r e ~ , including ~ ~ - ~ ~ the characteristic posture of the arm contralateral to seizure onset described .~~ by Ajmone-Marsan and R a l ~ t o n Unfortunately, similar events may be associated with seizures beginning in other brain regions.35 Rapid secondary generalization was early suggested as a feature of CPS emanating from frontal foci.'"eported clinical characteristics differentiating CPS of frontal from temporal origin include clusters of short attacks, a higher incidence of partial status, vague warnings rather than characteristic auras, minimal postictal confusion, bizarre attacks, including "sexual" automatisms, and bimanual and bipedal "bicycling" movements that may be mistaken for psychogenic spells, speech arrest and forced vocalization, shouting, laughing, deep or irregular breathing, and head and eye deviati~n.~~-~~ Geier et a139thought that patients tended to be more aware of automatisms occurring during CPS of frontal than temporal origin. When automatic behavior is induced by cingulate gyrus stimulation, patients may retain consciousness.40Auras involving complex psychic or emotional content may be less frequent in CPS of frontal origin.41In 40 patients with CPS of frontal origin, a traumatic etiology was found in 50%; a clear structural lesion may be more common in this patient group.
CLINICAL DISTINCTION OF FRONTAL AND TEMPORAL LOBE SEIZURES Delgado-Escueta and c o l l e a g ~ e s have ~ ~ - ~at~ tempted to divide CPS into specific clinical subtypes. Type 1 attacks had three phases, a motionless stare lasting about 10 seconds, unresponsiveess with stereotyped automatisms lasting about 60 seconds, and confusion or a "cloudy" state with "reactive" automatisms, which could last 10 to 15 minutes. Type 2 attacks did not begin with a motionless stare and included only a very brief period of stereotyped automatisms or none at all. Coordinated .motor activity, such as drinking water, could occur
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clonic epilepsy has a usual age of onset of 13 to 15 . . years but may begin as l a t e i s the early 20s." Patients often have GTCS as well, but these may start several years after the myoclonic jerks appear. Although needing prolonged, if not lifelong, treatment, the syndrome responds well to valproic acid in most cases. In an older adult, myoclonic jerks may be associated with a fatal disorder, 'such as CreutzfeldtJakob syndrome or Alzheimer's disease, but are very rarely the presenting manifestation.I5 They may occasionally accompany sleep disorders or derangement of systemic chemistry. Adult onset of metabolic diseases such as Unverricht-Lundborg syndrome will be found very rarely.
V O L U M E 10, NUMBER 4 DECEMBER 1990
EPI1,EPTIC SEIZURES AND SYNDROMES-THEODORE
PARTIAL SEIZURES AND SPEECH DYSFUNCTION T h e relationship of ictal and postictal speech and language dysfunction to side of seizure is complex. Gabr et al" studied 35 patients whose site of seizure origin had been localized using prolonged scalp and subdural EEG recordings, and who had had intracarotid amobarbital tests for determination of hemispheric dominance for speech. Postictal dysphasia was strongly correlated with dominant hemisphere seizure onset, but 83% of patients with identifiable speech during seizures themselves had nondominant seizure foci. Currie et al'%lso found that dysphasia was more common in patients with dominant foci. King and AjmoneMarsan3' reported that postictal dysphasia was more common in patients with left than right hemisphere foci, but ictal speech was nonlateralizing. Some studies have reported no correlation between side of speech dominance and ictal or postictal speech phenomena.'; These studies did not
have as complete documentation of site of seizure onset as that of Gabr et al, but it is important to remember that CPS spread to contralateral temporal as well as ipsilateral extratemporal structures and ictal clinical manifestations may reflect activation of secondary sites as well as the focus itself.
PARIETAL AND OCCIPITAL LOBE SEIZURES Because of the wide overlap with symptoms of seizures originating in other regions, parietal CPS cannot be distinguished reliably on clinical ground^."^ Occipital lobe CPS usually have visual or oculomotor features suggesting their origin, although some features, such as head and eye deviation, may of both parietal and occipbe less s~ecific.~%pread ital CPS to involve temporal regions may be responsible for observed clinical phenomena. Other partial seizure types rarely seen in adults include benign rolandic epilepsy, which spontaneously disappears at puberty in almost all cases." Clinical features, including speech arrest with preserved consciousness, hemifacial and ipsilateral arm clonic jerking, and a tendency for seizures to occur at night, distinguish them from CPS.60EEG discharges, often bilateral, occur at F8T 4 or C4-T4.
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during the period of' reactive automatisms in either seizure type. Type 1 CPS were associated with EEG discharges of mesial-anterior temporal origin; the patients had good results from anterior temporal lobe~tomy.~"Type 2 seizures, however, had diffuse surface EEG discharges and did not respond to r features in temporal l ~ b e c t o m y . ~ W t h eclinical type 2 patients, such as postural changes, contraversive head and eye movements, "bicycling," or "fishing," suggested frontal ~rigin.~"n a subsequent study, however, the same investigators concluded that only 60% of CPS of hippocampalamygdalar origin began with an initial motionless stare.lWther reports have also suggested that the initial motionless stare was not a constant feature of any group of CPS."'48 W e i ~ e described r~~ several subvarieties of CPS: temporobasal-limbic, temporopolar, opercular, posterior temporal neocortical, and frontobasal cingulate. Although there was great deal of overlap between the subtypes, Weiser was able, using cluster and principal components analysis, to discern clinical patterns associated with each anatomic sublocalization. The temporobasal-limbic type was by far the most freq~ent.~"he clinical distinction might be important, since these patients might respond to a more restricted form of surgery, selective amygdalo-hippocampectomy, with less postoperative neuropsychologic impairment.jO However, Weiser's results suggested that it would be difficult in any individual case to make an anatomic localization based on clinical data alone.49
PARTIAL SEIZURES AND PSYCHIATRIC ILLNESS: "RIGHT" AND "LEFT" TEMPORAL LOBE EPILEPSY Patients with CPS are thought by many investigators to be more likely than those with other seizure types to have psychologic problems such as depression, personality disorders, and schizophreniform psychoses. Patients with CPS and secondary GTCS may be more likely to develop psychopathology than those with CPS alone.55 Differences in psychiatric manifestations and interictal personality may exist between patients with right and left temporal Patients with right temporal EEG foci were more likely to have wide swings of emotion and exaggerated positive social traits, whereas those with left temporal foci were excessively philosophical and introspective, investing apparently chance events with particular personal significance, and had a negative view of t h e m s e l v e ~ . ~ ~ I o r - H e nsuggested ry~~ that right temporal lobe foci were associated with a clinical syndrome of a manic-depressive disorder, whereas left temporal foci were more likely to be associated with schizophreniform psychoses.57 Subtle differ393
SEMINARS I N NEUROLOGY VOLUME 10, NUMBER 4 DECEMBER 1990
CONCLUSION
394
Proper seizure and epilepsy classification is important to both treatment and clinical research. The effects of experimental antiepileptic drugs, and surgery for uncontrolled epilepsy, cannot be assessed unless uniform patient groups are studied. Enough information, starting with history and EEG, should be obtained in each case to allow proper classification. Prolonged video-EEG monitoring may be necessary to identify seizure type,
and neuroimaging as well as other laboratory tests to assign patients to an appropriate epilepsy syndrome. One should be wary particularly of a diagnosis of primary generalized epilepsy in adults and make sure that evidence for a focal lesion or underlying toxic or metabolic disorder has not been overlooked.
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ences in interictal, but not ictal, "fear" have been reported between patients with right and left temporal foci: patients with left. temporal foci reported more fear of social and sexual situations, but not of animals or physical injury.58 Gupta et aI5' reported that "psychic" and "autonomic" (epigastric, cardiovascular, or genitourinary) auras, as well as auras in general, were more common in patients with right than left temporal foci. Not all investigators have reported similar results, and the EEG localization techniques used may not always have been optimal, either to distinguish right from left temporal foci o r primary from secondary GTCS. In many studies only a single EEG was performed, and only weak evidence of lateralization taken as definitive. Master et a160 found no difference on an interictal personality index between patients with partial and generalized epilepsy, and no left-right differences, although the patient group did show more psychologic dysfunction than normal controls. However, when subjects with overt psychiatric disorders are excluded from analysis, differences in interictal personality between patients with epilepsy and normal controls largely di~appear.~' It is interesting that, despite reports of different effects of site of seizure onset on sexuality, there were no differences in postictal prolactin measurements between patients with right o r left temporal lobe focL6' Psychopathology in patients with epilepsy may be due to a combination of factors, including social, economic, and educational disadvantage, cultural milieu, drug toxicity (which has been associated with episodes of psychosis, depression, and impaired sexual function), in addition to seizure type and localization of the EEG focus.62Underlying etiology and overall neuropsychologic dysfunction may be important as well. One of the most important factors leading to psychiatric disturbance in patients with seizures is the presence of significant cerebral changes.63Too little information is available to attempt to define anatomic-clinical syndromes of right or left temporal lobe epilepsy, or CPS with and without psychopathology.
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EPILEPTIC SEIZURES AND S Y N D R O M E S T H E O D O R E
