- Common frontal lobe seizures depending on localization
- Mesial temporal lobe epilepsy with hippocampal sclerosis
- Lateral temporal lobe epilepsy
- Frontal lobe epilepsies
- Occipital lobe epilepsies
- Parietal lobe epilepsies
- Temporal lobe epilepsy (TLE)
Focal (anatomical, topographical, or localization-related) epilepsies are defined by seizures that emanate from an epileptogenic focus anywhere within the brain. These may be idiopathic, symptomatic, and cryptogenic (synonym: probably symptomatic).
Ictal symptoms, particularly at onset, are determined by localization and not by etiology. Anatomical origins of some epilepsies are difficult to assign to specific localizations or lobes and this is often the case with seizures originating from clinically silent epileptogenic regions.
The new ILAE diagnostic scheme considers ‘symptomatic (or probably symptomatic) focal epilepsies’ as a separate group from ‘idiopathic focal epilepsies’. This is because prognosis and treatment of idiopathic focal epilepsies differ significantly from the symptomatic ones. There is now concrete evidence to accept, diagnose, and treat certain focal epilepsies on the basis of etiology rather than simply localization. Mesial temporal lobe epilepsy with hippocampal sclerosis, among the more common and most distinct epileptic syndromes, is a striking example of this.
The ILAE Commission (1989) classifies focal epilepsies according to their topographical/anatomical origin as:
- Temporal lobe epilepsies
- Frontal lobe epilepsies
- Parietal lobe epilepsies
- Occipital lobe epilepsies
The epileptic syndromes and their significance
A major advance in recent epileptology is the recognition of epileptic syndromes that allows an accurate diagnosis and management of seizure disorders.[1-3]
Medical diagnosis is the identification of a disease by investigation of its symptoms and history, which provides a solid basis for the treatment and prognosis of the individual patient. An accurate diagnosis is the golden rule in medicine, and epilepsies should not be an exception to this. Like in any other disease, the recognition of non-fortuitous clustering of symptoms and signs in epilepsies requires the study of detailed clinical and laboratory data.[1-3] However, often in current practice, the diagnosis is limited to either epilepsy or seizures, which is unsatisfactory because this cannot provide guidance on important items such as severity of the disease, prognosis, short- and long-term therapeutic decisions, and genetics (research and counselling), which are all factors that crucially affect personal, family, and social life; education; and career choices of patients. Defining the type of epilepsy should now be considered mandatory as it offers the best guide to both management and prognosis. Most epileptic syndromes and diseases are well defined and easy to diagnose. The benefits of syndromic diagnosis over seizure/symptom diagnosis or an inclusive diagnosis such as epilepsy far outweigh any morbidity from incorrect categorization that may arise in difficult cases.[4]
Important clinical features of a syndrome include the type of seizures, their localization, frequency, sequence of events, circadian distribution, precipitating factors, age at onset, mode of inheritance, physical or mental symptoms and signs, prognosis, and response to treatment.
Epilepsies or epilepsy?
The clinical and practical significance of the syndromic diagnosis of epilepsies is well illustrated by 3 common epileptic disorders. Benign childhood focal epilepsies, juvenile myoclonic epilepsy (JME), and hippocampal epilepsy have nothing in common other than the fact that they may all be complicated by generalized tonic clonic seizures (GTCS), which are primarily GTCS in JME and secondarily GTCS in benign childhood focal epilepsies and hippocampal epilepsy.
Furthermore, the short-and long-term treatment strategies are entirely different for each disorder: benign childhood focal epilepsies may or may not require medication for a few years, appropriate anti-epileptic drug (AED) treatment is lifelong in JME while neurosurgery may be life-saving for patients with hippocampal epilepsy. What may be a life-saving drug such as carbamazepine for hippocampal epilepsy may be ill-advised for JME.
It should not be difficult to distinguish an intelligent child with benign focal seizures or childhood absence epilepsy from a child with Kozhevnikov-Rasmussen, Lennox-Gastaut, Down, or Sturge-Weber syndrome or a child with severe post-traumatic cerebral damage, brain anoxia, or catastrophic progressive myoclonic epilepsy. Describing all these children as simply having epilepsy just because they have seizures offers no more benefit than a diagnosis of febrile illness irrespective of cause, which may be a mild viral illness, a life-threatening acute bacterial meningitis, or a malignancy. Inappropriate generalizations with regard to terminology, diagnosis, and treatment are the single most important factor of mismanagement in epilepsies.[4]
C. P. Panayiotopoulos, MD, PhD, FRCP
Reviewed and revised June 2008 by Steven C. Schachter, MD
Back to topFrontal lobe seizures have greatly variable clinical and EEG manifestations depending on the origin and spread of the epileptogenic focus.
Seizures arising from the primary motor cortex and the supplementary motor area have been relatively well defined:
- Frontal seizures from the motor cortex
- Simple focal motor clonic or tonic-clonic seizures with or without Jacksonian march to neighboring motor regions. Hand and mainly thumb, face, and lips are preferentially affected (per the motor homunculus).
- Myoclonic seizures are unilateral or bilateral such as in epilepsia partialis continua of Kozhevnikov.
- Tonic postural motor with clonic movements.
- Frontal seizures from the supplementary sensorimotor area (SMA)
- Stereotyped hypermotor seizures of bilateral and asymmetric tonic posturing of limb girdles, often with contraversion of the eyes and head, vocalizations, or speech arrest.
- Brief for sec.
- Abrupt onset and termination.
- Nocturnal circadian distribution; rarely occur in awake states.
- High frequency, sometimes many per night.
- Lack of post-ictal confusion.
- Somatosensory and ill-defined auras (not epigastric) are common.
Epileptic seizures generated in frontal lobe regions other than the motor cortex and the SMA are less well specified. These are:
- Cingulate. Cingulate seizure patterns are complex partial with complex motor gestural automatisms at onset. Autonomic signs are common, as are changes in mood and affect. Gelastic seizures of frontal lobe origin emanate from this region.
- Anterior frontopolar. Anterior frontopolar seizure patterns include forced thinking or initial loss of contact and adversive movements of head and eyes, with possible progression including contraversive movements and axial clonic jerks and falls and autonomic signs.
- Orbitofrontal. The orbitofrontal seizure pattern is one of complex partial seizures with initial motor and gestural automatisms, olfactory hallucinations and illusions, and autonomic signs.
- Dorsolateral. Dorsolateral seizure patterns may be tonic or, less commonly, clonic with versive eye and head movements and speech arrest. Seizures characterized by unusual symptoms of “forced thinking” and “forced acts” usually emanate from the dorsolateral intermediate frontal lobe.
- Opercular. Opercular seizure characteristics include mastication, salivation, swallowing, laryngeal symptoms, speech arrest, epigastric aura, fear, and autonomic phenomena. Simple partial seizures, particularly partial clonic facial seizures, are common and may be ipsilateral. If secondary sensory changes occur, numbness may be a symptom, particularly in the hands. Gustatory hallucinations are particularly common in this area.
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
~20% of patients with epilepsies; 65% of mesial TLE.
Age at onset
Late childhood or adolescence.
Sex
Males = females.
Neurological and mental state
Usually normal prior to seizure onset.
Etiology
Hippocampal sclerosis.
Clinical manifestations
Pre-existing complex febrile convulsions are common. Simple focal seizures are the initial non-febrile seizures followed by complex focal seizures or generalized convulsions.
Main ictal manifestations include ascending epigastric aura and fear in simple focal seizures. Oro-alimentary automatisms typically occur in complex focal seizures (~70%).
Complex internal sensations and illusions occur but not as common as in extra-hippocampal epilepsies. Olfactory and gustatory hallucinations are less often.
Post-ictal symptoms are frequent and often severe.
Secondarily generalized tonic-clonic seizures (GTCS) are infrequent in properly treated patients.
Complex focal status epilepticus occur, particularly in untreated patients. Less common than absence status epilepticus.
Diagnostic procedures
MRI provides in vivo visualization of hippocampal sclerosis in all patients. ‘Double pathology’ such as malformations of cortical development may co-exist.
Functional brain imaging and other new methodologies offer significant insights and practically eliminate the need for invasive techniques in neurosurgical evaluation.
Inter-ictal EEG
In half of patients, single routine EEG is normal or with non-specific abnormalities. Only 1/3 show the classic spike or sharp and slow-wave focus in the anterior temporal electrode. Prolonged EEG monitoring, along with sleep EEG, increases the yield to 70% to 80%. Half have regional temporal inter-ictal runs of slow waves, which are of lateralizing value.
Ictal EEG
Rhythmic 4 to 7 Hz slow activity over the affected temporal lobe, before or simultaneously with clinical events. Fast spiking is exceptional.
Prognosis
Largely unknown. In neurosurgical series, initially, patients have a rather mild or uneventful course of hippocampal seizures that may be controlled with medication. Later, within years, seizures become worse and intractable; memory and psychological abnormalities appear. However, the neurosurgical cases may be the iceberg (~20%). The vast majority of cases (~80%) are not seen in these specialized centers and some of them may be very mild and easily controlled with proper AEDs.
Differential diagnosis
Non-epileptic conditions and seizures from other brain locations.
Management options
AEDs indicated for focal epilepsies. Early surgical intervention provides excellent chance of cure and subsequent normal life: ~60% become seizure free, 20% have reduced numbers of seizures, 10% show no benefit, and 10% have neurosurgical complications or get worse.
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
1/3 of TLE or 10% to 15% of all epilepsies.
Age at onset
Mainly late childhood to adolescence.
Sex
Males = females.
Neurological and mental state
Depends on etiology.
Etiology
Symptomatic, cryptogenic, idiopathic. Structural causes include malformations of cortical development, tumors, vascular, traumatic, viral and other infectious and parasitic disorders, and cerebrovascular disease.
Clinical manifestations
Seizures manifest with auditory hallucinations or illusions, vestibular phenomena, experiential symptoms, visual hallucinations, and visual misperceptions. Language disturbances in dominant hemispheric focus. Motor ictal symptoms include clonic movements of facial muscles, grimacing, finger and hand automatisms, dystonic posturing of an upper extremity, leg automatisms, restlessness, and unformed vocalizations. Rotation of the whole body is frequent and of differentiation value from mesial TLE.
These symptoms may progress to complex focal seizures through spreading to mesial temporal or extra-temporal structures. Impairment of consciousness is not as pronounced as with mesial TLE.
Secondarily generalized tonic-clonic seizures (GTCS) are infrequent in properly treated patients.
Complex focal status epilepticus occurs particularly in untreated patients. It is less common than absence status epilepticus of idiopathic generalized epilepsy.
Diagnostic procedures
MRI is abnormal in >90% of symptomatic cases.
Inter-ictal EEG
In symptomatic cases, background is usually abnormal, with posterior lateralized slow waves, and half show mid-temporal or posterior temporal spikes.
Ictal EEG
Rhythmic slow activity (around 4 to 7 Hz) that appears over the affected temporal lobe, before or simultaneously with clinical events. Fast spiking is more common in lateral TLE than in mesial TLE.
Prognosis
Frequency, severity, and response to treatment vary considerably from good to intractable and may be progressive, depending mainly on the underlying cause.
Differential diagnosis
Non-epileptic conditions and seizures arising from other brain locations.
Lateral temporal lobe seizures usually lack features commonly exhibited in mesial TLE such as (1) ascending epigastric aura or fear; (2) eye blinking and aggressive behavior; and (3) contralateral dystonia, searching head movements, body shifting, hyperventilation, and post-ictal cough or sigh.
Management options
Drug treatment is similar to that for any other types of focal seizure.
Neurosurgical treatment provides an excellent chance of cure and a subsequent normal life in certain pathological conditions of lateral TLE.
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
~1% to 2% of all epilepsies; 22.5% among focal epilepsies in community studies; second, after temporal lobe epilepsy (TLE) in neurosurgical series.
Age at onset
Any age.
Sex
Males = females.
Neurological and mental state
Depends on etiology.
Etiology
Symptomatic, cryptogenic, and idiopathic. In neurosurgical series, 2/3 of patients are symptomatic from malformations of cortical development (57.4%), tumors (16.4%), traumatic and other lesions (26.2%). Autosomal dominant nocturnal frontal lobe epilepsy is genetic.
Clinical manifestations
Motor manifestations are most common and most characteristic ictal symptom (90%). Frontal lobe seizures: (1) manifest with prominent motor manifestations (tonic, clonic, or postural); show frequent complex gestural automatisms at onset; (2) last usually for several sec; (3) progress to rapid secondary generalization (more common than in TLE); (4) show no or minimal post-ictal confusion; and (5) are frequent (several times a day and mainly during sleep).
See types of frontal lobe seizures according to main localization.
Diagnostic procedures
MRI often determines structural causes in ~60%. Functional neuroimaging is important for localization.
Inter-ictal EEG
Often normal; if abnormal, there may be background asymmetry, frontal spikes, or sharp waves (either unilateral or frequently bilateral or unilateral multilobar).
Ictal EEG
Usually normal. Ictal patterns consist of (1) frontal or multilobar, often bilateral, low-amplitude fast activity, mixed spikes, rhythmic spikes, rhythmic spike waves, or rhythmic slow waves or (2) bilateral high-amplitude single sharp waves followed by diffuse flattening. Uncommonly, the EEG abnormality precedes the seizure onset, providing important localizing information.
Prognosis
Usually unfavorable with regard to seizure frequency and response to drug treatment.
Differential diagnosis
Hypermotor seizures are frequently misdiagnosed as psychogenic movement disorders, familial paroxysmal dystonic choreoathetosis, paroxysmal kinesigenic choreoathetosis, or episodic ataxia.
Symptomatic frontal lobe absences may have similar clinical and EEG features of some typical absence seizures.
Management options
Drug treatment is the same as that for focal epilepsies. Seizures are usually resistant to AEDs. Their use is usually to protect the patients for secondarily generalized tonic-clonic seizures (GTCS).
Neurosurgery has limited success.
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
~5% to 10% of epilepsies, both in neurosurgical series and demographic studies.
Age at onset
Any age. Idiopathic occipital epilepsy appears in late childhood.
Sex
Males = females.
Neurological and mental state
Normal or abnormal depending on etiology.
Etiology
Symptomatic, cryptogenic, idiopathic, or metabolic. Symptomatic causes are congenital, residual, or progressive (malformations of cortical development, vascular, neoplastic, metabolic, hereditary, congenital, inflammatory, parasitic infections). Metabolic or other derangement such as eclampsia may have a particular predilection for the occipital lobes. There is an association between coeliac disease and occipital lobe epilepsy. Occipital seizures may be the first manifestation of Lafora disease or mitochondrial disorders.
Clinical manifestations
The cardinal symptoms are mainly visual and oculomotor. Visual symptoms are (1) elementary and less often complex visual hallucinations; (2) blindness; (3) visual illusions; and (4) palinopsia. Ictal oculomotor symptoms are (1) tonic deviation of the eyes (pursuit-like than oculotonic); (2) oculoclonic or nystagmus; and (3) repetitive eyelid closure or eyelid fluttering.
Elementary visual hallucinations mainly consist of multicolored circular patterns that develop fast in sec and they are usually brief for several sec to rarely 1 to 3 min.
Seizures may spread to anterior regions, generating symptoms from the temporal, parietal, and frontal lobes and secondarily hemiconvulsions or generalized convulsions.
Typically post-ictal headache often indistinguishable from migraine occurs in 1/3 to 1/2 of patients.
Frequent, sometimes many per day, and often in multiple clusters.
Timing
Predominantly diurnal.
Diagnostic procedures
MRI for all patients. Hematology, biochemistry, screening for metabolic disorders, molecular DNA analysis, or even skin or other tissue biopsy may be needed for cases of undetermined cause.
Inter-ictal EEG
Background of symptomatic cases is usually abnormal, with posterior lateralized slow waves, asymmetrical alpha and photic following, and often unilateral occipital spikes.
Background of idiopathic cases is normal, often with occipital spikes or occipital paroxysms.
Ictal EEG
Occipital paroxysmal fast activity, fast spiking, or both; brief occipital flattening may occur prior to this.
1/3 of occipital seizures do not show appreciable changes.
Prognosis
Frequency, severity, and response to treatment vary considerably from good to intractable or may be progressive, depending mainly on the underlying cause.
Differential diagnosis
Migraine, normal phenomena, and psychogenic or other causes unrelated to seizures. Migraine visual aura is fundamentally different from visual seizures.
Management options*
AEDs indicated for focal seizures. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice. Neurosurgery for severe symptomatic cases may be selectively effective.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Relatively small; ~6% in neurosurgical series.
Age at onset
Any age.
Sex
Males = females.
Neurological and mental state
Depends on etiology.
Etiology
Symptomatic, cryptogenic, or idiopathic.
Clinical manifestations
Simple focal seizures predominate. Subjective symptoms are somatosensory, disturbances of body image (somatic illusions), vertiginous, visual illusions, or complex formed visual hallucinations.
Somatosensory seizures (2/3): Paresthetic, dysesthetic, and painful sensations (numbness, thermal, pricking, tight, electric). Pain is sometimes exacerbating. Face, hand, and arm (per the sensory homunculus) are mainly involved. Symptoms may be static or march in Jacksonian manner.
Somatic illusions (second most common): Distorted posture, limb position, or of movement, an extremity or a body part being alien or absent. They mainly emanate from the non-language-dominant cerebral hemisphere. Inability to move one extremity or a feeling of weakness in the hand is contralateral to the epileptogenic zone.
Vertigo and other vertiginous sensations (~10%).
Visual illusions and complex formed visual hallucinations (~12%); images look larger or smaller, close or far away, or moving although static; metamorphopsia, palinopsia.
Genital sensations or orgasm may occur.
Dominant temporal-parietal regions: Linguistic disturbances of alexia with agraphia and miscalculations.
Non-dominant parietal-occipital-temporal regions: Spatial disorientation.
Simple focal seizures often spread to extra-parietal regions, producing unilateral focal motor clonic manifestations (57% of patients), head and eye deviation (41%), tonic posturing of usually one extremity (28%), and automatisms (21%).
Most of the patients also suffer from secondarily generalized tonic-clonic seizures (GTCS).
Post-ictal symptoms include Todd’s paralysis (22%) and dysphasia (7%).
Duration is several sec to 2 min. Sensory epilepsia partialis continua is rare.
Frequent, sometimes many per day, and often in multiple clusters.
Precipitating factors
Movements of the affected part of the body, tapping, or other somatosensory stimuli.
Timing
Predominantly diurnal.
Diagnostic procedures
MRI is abnormal in ~60%.
Inter-ictal EEG
Usually normal or focal slow waves and spikes.
Ictal EEG
80% of simple focal sensory seizures do not show appreciable changes.
Prognosis
Frequency, severity, and response to treatment vary considerably from good to intractable or may be progressive, depending mainly on the underlying cause.
Differential diagnosis
Somatosensory seizures are often misdiagnosed as psychogenic, transient ischemic attacks, or migraine with aura, in that order.
Management options*
AEDs indicated for focal seizures are usually effective. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice. Neurosurgery for symptomatic cases: 65% become seizure free or have rarer seizures.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Prevalence
~30% to 50% of all epilepsies; 2/3 mesial and 1/3 lateral TLE.
Age at onset
Mainly late childhood to adolescence.
Sex
Males = females.
Neurological and mental state
Depends on etiology.
Etiology
Symptomatic, cryptogenic, idiopathic. Hippocampal sclerosis is the most common. Other structural causes: tumors, vascular, malformations of cortical development, traumatic, viral and other infectious and parasitic disorders, and cerebrovascular disease.
Clinical manifestations
These depend on whether the seizures are of mesial TLE or lateral TLE.
Post-ictal symptoms are very frequent and often severe.
Secondarily generalized tonic-clonic seizures (GTCS) are infrequent in properly treated patients.
Complex focal status epilepticus occur, particularly in untreated patients. It is less common than absence status epilepticus of idiopathic generalized epilepsy.
Diagnostic procedures
MRI is abnormal in >90% of symptomatic cases.
Inter-ictal EEG
Background of symptomatic cases is usually abnormal, with posterior lateralized slow waves in lateral TLE. In mesial TLE, 1/3 show unilateral or bilateral anterior temporal spikes. In lateral TLE, half show mid-temporal or posterior temporal spikes. A single routine EEG may be normal or show mild and non-specific abnormalities in half of the mesial TLE. Regional temporal inter-ictal runs of slow waves, which are of lateralizing value, are recorded in about half of patients.
Ictal EEG
Rhythmic slow activity (around 4 to 7 Hz) that appears over the affected temporal lobe, before or simultaneously with clinical events. Fast spiking is more common in lateral TLE than in mesial TLE.
In 1/3 of mesial TLE cases, no appreciable changes occur.
Prognosis
Frequency, severity, and response to treatment vary considerably from good to intractable and may be progressive, depending mainly on the underlying cause.
Differential diagnosis
Non-epileptic conditions and seizures arising from other brain locations.
Lateral temporal lobe seizures usually lack features usually exhibited in mesial TLE such as (1) ascending epigastric aura or fear; (2) eye blinking and aggressive behavior; and (3) contralateral dystonia, searching head movements, body shifting, hyperventilation, and post-ictal cough or sigh.
Management options*
Drug treatment, similar to any other type for focal seizures, is usually effective and this should be initiated as soon as possible. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice.
Neurosurgical treatment provides excellent chance of cure in hippocampal and other localized pathological conditions.
*Expert opinion, please check FDA-approved indications and prescribing information
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
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