Many seizures arise from frontal, parietal, and occipital lobes, and these are collectively referred to as extratemporal seizures. They are commonly encountered, and merit recognition because some extratemporal seizures reflect the presence of specific syndromes. Some types are inherited, others are acquired, and both medical and surgical treatments may be used. This chapter will review the features of extratemporal seizures.

The prevalence of extratemporal complex partial seizures is not known due to limited epidemiologic data. Data exist for the epidemiology of extratemporal epilepsies, but the seizure type of those within the series is not included. In a prospective community-based study of 160 patients with localization related epilepsy, 36 (22.5%) were frontal, 43 (27%) were temporal, 9 (5.6%) were frontotemporal, 10 (6.2%) were parietal, 52 (32.5%) were central, and 10 (6.2%) were occipital.¹ In the Montreal surgical series, temporal lobe epilepsy represented 56%, frontal lobe 18%, central or sensorimotor 7%, parietal 6%, and occipital 1% of 2177 patients,² but this does not reflect prevalence. Parietal and occipital lobe seizures account for about 6% and 5-10%, respectively, of surgically treated epilepsy patients.^3–5 Seizures arising from frontal, parietal, and occipital lobes may start at any age, with both genders equally affected.

Associated Epilepsy Syndromes and the Syndrome’s Natural History

The International League Against Epilepsy has recognized three idiopathic benign epilepsies of childhood.⁶ The most common idiopathic benign epilepsy in childhood is benign childhood epilepsy with centrotemporal spikes (BECTS), or rolandic epilepsy, first described by Loiseau and Beaussant in 1958.⁷ This condition has a 15% prevalence rate among the epilepsies in the 1-to-15-year age group and a male predominance (∼60% male). The defining features are clinical manifestations emanating from the lower part of the pre- or postcentral gyri, onset between 3 and 13 years of age, centrotemporal spikes, and normal neurologic examination and developmental and cognitive skills. The ictal behavior consists of simple partial seizures with hemifacial or oropharyngeal sensorimotor symptoms or speech arrest; nighttime seizures may generalize secondarily. The interictal EEG shows centrotemporal spikes, high-amplitude sharp and slow wave complexes at C3 and C4, which are commonly bilateral and occur independently and increase in rate of occurrence during sleep. The spikes have a horizontal dipole with maximum electronegativity in centrotemporal regions and positivity in the frontal regions.⁸ Video-electroencephalographic monitoring (VEM) is rarely indicated in these children. Benign childhood epilepsy with centrotemporal spikes is genetically determined but heterogeneous in its manifestations. There is evidence for linkage to a region on chromosome 15q14.⁹ The prognosis is excellent, with remission within 2 to 4 years of onset and before age 16. The risk of having recurrent seizures after remission is 1 to 3%, similar to that of the normal population.

The benign occipital epilepsies include early- and late-onset forms. The late-onset type described by Gastaut and idiopathic photosensitive occipital lobe epilepsy account for 2 to 7% of all benign focal epilepsies of childhood.¹⁰ The seizures in idiopathic photosensitive occipital lobe epilepsy are provoked by varying degrees of light intensity and are described further in Seizure Triggers, on page 195. The early-onset type (Panayiotopoulos syndrome) is not uniformly considered an occipital epilepsy because seizures often begin with autonomic manifestations, and there is no clear demonstration of occipital origin; although there is a posterior predominance of epileptiform discharges, they involve all brain regions, and occipital spikes are not found in all cases.¹¹ The prognosis is excellent, with most patients having no more than five seizures and remission 1 to 2 years after onset.

Idiopathic childhood occipital epilepsy, also called benign epilepsy of childhood with occipital paroxysms, is a pure form of idiopathic occipital epilepsy, but with uncertain prognosis. Seizures begin between 15 months and 17 years and cause a variety of symptoms, including visual hallucinations, illusions, visual loss, other ocular symptoms of tonic eye deviation, eye pain or blinking, and postictal headache. The interictal occipital paroxysms or high-amplitude diphasic occipital spikes have an aftergoing slow wave and are not usually activated by sleep or photic stimulation. Seizures remit in 50 to 60% of patients 2 to 4 years after onset.¹² VEM is infrequently required.

Other inherited forms of benign partial epilepsies have been described but are less well characterized.¹³ Benign childhood epilepsy with parietal spikes and giant somatosensory evoked potentials is a benign epilepsy involving mainly the parietal lobe, with a peak age of onset between 4 and 6 years. Children may have versive seizures or generalized seizures during sleep, parietal lobe interictal spikes, and high-voltage potentials evoked by foot or hand tapping.¹⁴ Benign focal epilepsy in infants with central and vertex spikes and waves during sleep is characterized by behavioral arrest or focal tonic seizures and central and vertex spikes that are not specific to this syndrome.¹⁵ Patients with benign childhood focal seizures associated with frontal or midline spikes have onset of automotor or tonic seizures by age 10, midline spikes, and focal abnormalities in the frontal lobe.¹⁶ So far these partial epilepsies have been associated with a benign course, but they need to be better characterized. Ictal recording data are limited as well.

The causes of symptomatic extratemporal lobe epilepsies are diverse and include neoplasm, trauma, vascular insults, malformations of cortical development (dysplasia, neurofibromatosis, and tuberous sclerosis), infections, inflammatory disease, inborn errors of metabolism, and systemic causes (e.g., celiac disease). Cortical malformations often require high-resolution magnetic resonance imaging (MRI) to be visualized;¹⁷ some non-population-based studies report these as the most common cause of uncontrolled seizures of extratemporal origin.^18–23 A surgical series of 70 patients with frontal lobe epilepsy reported dysplasias in 41% of patients with abnormal MRI and in 17% of patients with normal MRI; in this series, 19% had tumors, 3% had vascular malformations, and 10% were cryptogenic based on MRI and surgical pathology.¹⁹ In another surgical series of 25 patients who underwent frontal lobe surgery, 32% of patients had dysplasias, and 20% had low-grade neoplasms, with four gangliogliomas and one dysembryoplastic neuroepithelial tumor.¹⁸

Tumors have been reported as a common etiology in parietal lobe epilepsy.^3,24,25 In two other surgical series, 48% and 63% of parietal lobe seizures were associated with tumors.^3,24 The most common tumors were gliomas and astrocytomas. Williamson et al. reported low-grade gliomas in 7 of 10 patients who underwent resection of parietal lobe lesions.²⁵ In a study of 34 patients with parietal lobe epilepsy and tumors, 62% were astrocytomas, 14% meningiomas, 9% hemangiomas, 9% oligodendrogliomas, and 3% ependymoblastomas.²⁶ In a study of 82 nontumoral patients with parietal lobe epilepsy, 43% (35) had a history of head trauma.²⁴ Other etiologies were encephalitis, forme fruste of tuberous sclerosis, hamartoma, vascular malformations, tuberculoma, cystic lesions, microgyria, and ischemia; 20% were cryptogenic, similar to other studies.^25,28 These statistics probably reflect selection bias, as patients with well-defined lesions are more likely to have surgery.

In recent surgical series, cortical malformations are more common than tumors or trauma in patients with occipital lobe epilepsy,²⁹ with heterotopias, focal cortical dysplasia, and polymicrogyria being the most common lesions.²³ Perinatal injury, specifically anoxic-ischemic encephalopathy causing porencephaly, periventricular leukomalacia, or infarction, is more likely to affect the occipital lobes. In older adults, primary intracerebral hemorrhage occurs more commonly in the parietal region, and cerebral infarctions involve the middle cerebral arteries are more likely to cause frontal or parietal seizures.³⁰ Head trauma with loss of consciousness has been reported in ∼20% of patients with symptomatic occipital lobe epilepsy.³¹ Occipital lobe seizures may be the presenting symptom of reversible posterior leukoencephalopathy, Lafora disease, or asymptomatic celiac disease. Other less common causes of occipital lobe seizures are metabolic encephalopathies and infections, such as Rasmussen encephalitis, inherited disorders, such as neurofibromatosis, Sturge-Weber syndrome, forme fruste of tuberous sclerosis, Kuf disease, and mitochondrial disorders.

Ictal Behavior

Frontal Lobe Seizures

Frontal lobe seizures are challenging to diagnose and can be mistaken for nonepileptic events, such as psychogenic seizures, parasomnias, and movement disorders. The clinical manifestations are diverse, and none are absolutely specific for one region in the frontal lobe, with the possible exception of focal clonic jerking. The various clinical symptoms and signs occur because of the complexity and variability of the patterns of spread of epileptic discharges and possibly individual differences in somatotopic organization.³² A single frontal focus can be associated with multiple ictal behaviors due to multiple spread patterns and variable seizure generators. Moreover, the first behavioral change from seizures that arise in clinically silent regions occurs only after spread of the ictal discharge to an eloquent cerebral area. Many types of frontal lobe seizures have features that distinguish them from temporal lobe seizures. Frontal lobe seizures often occur during sleep and in clusters and produce early motor manifestations with vocalizations (Table 10-1).³³ Approximately 50% of patients who had surgical evaluations had an aura and typically brief seizures (10–30 s) with minimal or no postictal confusion. Kotagal et al. compared the behavior in patients with mesial temporal lobe epilepsy with that in patients with frontal lobe epilepsy and found that repetitive, proximal upper extremity movements, complete loss of consciousness, and complex motor and hypermotor activity were more common in frontal lobe seizures.³⁴

Frontal lobe seizures can be divided into perirolandic, supplementary sensorimotor area, dorsolateral, orbitofrontal, anterior frontopolar, opercular, and cingulate types (Table 10-2).³⁵ Perirolandic seizures are characterized by motor activity that typically starts unilaterally in the face with subsequent unilateral eye blinking, then spreads to the arm, followed by speech arrest with preservation of consciousness.³⁶ The behavior is a result of activation of the primary motor cortex, or Brodmann area 4.³⁷ An example of a brief clonic seizure involving the throat motor cortex in a 31-year-old man with refractory frontal lobe epilepsy starting at age 29 is shown in Video 10-1 (EEG in Figure 10-1). This example demonstrates how VEM may differentiate frontal lobe epilepsy from nonepileptic disorders, such as sleep-related laryngospasm and gastroesophageal reflux.

Supplementary motor seizures are clinically distinct because of tonic posturing of one or more extremities on both sides (mainly proximal muscles affected) and preserved awareness. They are brief (<30 s), frequent, may occur only during sleep, and can be preceded by a sensory aura. Supplementary motor seizures can produce ipsilateral or contralateral head turning or limb posturing, so lateralization of the focus is often uncertain. Contralateral tonic extension is not a reliable finding.

In contrast, seizures arising from the premotor nonsupplementary motor cortex produce contralateral tonic posturing, which is a reliable lateralizing sign.³⁸ An example of a brief tonic seizure involving the left arm with preserved awareness in a 22-year-old man with refractory frontal lobe epilepsy starting at age 13 is shown in Video 10-2 (EEG in Figure 10-2). It can be associated with speech arrest or vocalization and followed by clonic movements.³⁹ The head usually turns contralaterally, but without secondary generalization, head turning is an unreliable lateralizing sign,^40,41 and versive movements are rare.³⁷ In an 18-year-old woman, Video 10-3 shows a supplementary sensorimotor seizure with right arm and leg tonic posturing, screaming, and asymmetric bilateral tonic posturing starting at age 8 (Figure 10-3). Video 10-4 shows another example of a supplementary sensorimotor seizure with left leg stiffening, followed by clonic activity because of spread to the primary motor cortex in a 31-year-old right-handed woman with refractory frontal lobe seizures starting at age 5 (Figure 10-4).

Dorsolateral, orbitofrontal, frontopolar, and cingulate seizures have more variable clinical manifestations. Seizures originating from these regions are not as well characterized as primary and supplementary motor cortex seizures probably because significant overlap among these areas makes them difficult to localize. Seizures arising from these regions do not always produce loss of awareness, but often remain complex partial (without generalization) when awareness is lost.

Focal tonic or clonic movements, versive movements of the head or eyes, and speech arrest characterize dorsolateral seizures. Version is characterized by clonic or tonic head and eye deviation that is forced, sustained, and unnatural. It is activated by discharges in a frontal eye field or Brodmann areas 6 and 8, located in the posterior part of the middle frontal gyrus, with lateralizing significance to the hemisphere contralateral to the field of movements.⁴⁰ However, ipsilateral head turning can occur prior to version. Video 10-5 shows an example of a dorsolateral frontal seizure in an 18-year-old woman with version of the head to the left whose evaluation identified a focal cortical dysplasia in the right middle frontal gyrus (EEG in Figure 10-5). Auras of nonvertiginous dizziness, fear, or epigastric sensations have been reported in half of all patients with dorsolateral seizures,⁴² and this probably reflects propagation. Dorsolateral seizures have been associated with multiple seizure types depending on pattern of spread.¹⁸

Epileptic involvement of the frontal operculum can produce chewing, salivation, swallowing, and gustatory hallucinations, or autonomic manifestations, such as flushing, pallor, tachycardia, pupillary dilation, or apnea. Activation of the Broca area can produce difficulty with speech output, including speech arrest, dysphasia, or comprehension difficulty. Akinetic seizures can cause speech arrest or an inability to initiate or sustain movement and are associated with activation of the negative motor areas anterior to the primary motor face area. In a few patients, the paretic limb was found to be contralateral to the seizure focus.^43–46

Seizures originating in the anterior cingulate gyrus have variable semiology depending on the ictal spread pattern. They are usually brief and rapidly propagate to other lobes of the brain.⁴⁷ The anterior cingulate cortex is part of an interconnected system to assess the motivational content of internal and external stimuli and regulate goal directed behavior,⁴⁸ and seizures are characterized by complex motor behavior, screaming, fear, emotional or autonomic symptoms.

Complex partial seizures arising from the orbitofrontal region are characterized by unresponsiveness or behavioral arrest, sometimes with vigorous motor automatisms,^49–52 but the behavior can vary depending on the spread pattern. In contrast to typical complex partial seizures of temporal lobe origin, the typical motor automatisms during frontal lobe complex partial seizures are bilateral and complex and can be quite bizarre.⁵³ Alimentary automatisms can occur, but these are more common in temporal lobe epilepsy.³⁴ The behavior may be preceded by a nonspecific, cephalic sensation. The motor activity frequently involves both legs, as in thrashing, rocking, thrusting, bicycling, or running. When the automatisms involve the arms, the movements involve the proximal muscles. Vocalizations, including laughing, crying, and screaming, can be associated with the behavior and have no lateralizing value. They often occur during sleep and last <1 min. Video 10-6 shows an example of an orbitofrontal seizure in a 27-year-old man preceded by an aura of anxiety and palpitations (Figure 10-6). These bilateral, complex motor seizures have classically been thought to arise from the orbitofrontal, anterior cingulate, and mesial frontal regions,⁵⁴ but they can arise from any area in the frontal lobe. Video 10-7 shows an example of a complex frontal lobe seizure in a 14-year-old young man with rocking and bouncing movements from sleep (EEG in Figure 10-7).