eMedicine Specialties > Neurology > Seizures and Epilepsy

Frontal Lobe Epilepsy

Author: Sheryl Haut, MD, Director, Adult Epilepsy, Associate Professor of Clinical Neurology, Departments of Neurology, Comprehensive Epilepsy Management Center, Montefiore Medical Center, Albert Einstein College of Medicine
Contributor Information and Disclosures

Updated: May 7, 2009

Introduction

Background

Frontal lobe epilepsy is characterized by recurrent seizures arising from the frontal lobes. Frequently, seizure types are simple partial or complex partial, often with secondary generalization. Clinical manifestations tend to reflect the specific area of seizure onset and range from behavioral to motor or tonic/postural changes. Status epilepticus may be associated more commonly with frontal lobe seizures than with seizures arising from other areas.

See eMedicine articles Simple Partial Seizures, Complex Partial Seizures, and Status Epilepticus.

Pathophysiology

Seizures may arise from any of the frontal lobe areas, including orbitofrontal, frontopolar, dorsolateral, opercular, supplementary motor area, motor cortex, or cingulate gyrus.

Disease conditions commonly associated with frontal lobe epilepsy are frequently symptomatic, including congenital causes such as cortical dysgenesis, gliosis, or vascular malformations; neoplasms; head trauma; infections; and anoxia.

With recent advances in genetic analysis, an expanded number of genetically inherited frontal lobe epilepsy syndromes have been described. Many of these syndromes are characterized by autosomal dominant inheritance.

Frequency

United States

The exact incidence of frontal lobe epilepsy is not known. In most centers frontal lobe epilepsy accounts for 20-30% of operative procedures involving intractable epilepsy.

Sex

No significant gender-based frequency difference has been reported for frontal lobe epilepsy in epidemiologic studies. However, a comparison of frontal lobe versus temporal lobe seizures captured during epilepsy monitoring has suggested a male predominance in frontal lobe seizures.¹

Age

• Symptomatic frontal lobe epilepsy may affect patients of all ages.
• In a large series of cases, mean subject age was 28.5 years with age of epilepsy onset 9.3 years for left frontal epilepsy and 11.1 years for right frontal epilepsy.

Clinical

History

• Patients with frontal lobe seizures may present with a clear epileptic syndrome or with unusual behavioral or motor manifestations that are not immediately recognizable as seizures.^2,3 A careful history should focus on specific characteristics of the episodes, including a detailed description by eyewitnesses, time and pattern of occurrence, precipitating factors, and response to medication.
• Features that help to distinguish frontal lobe seizures from nonepileptic events include stereotyped semiology, occurrence during sleep, brief duration (often <30 seconds), rapid secondary generalization, prominent motor manifestations, and complex automatisms. Despite this, the distinction remains difficult to make based on history alone, and patients with frontal lobe epilepsy are often directed first to psychiatrists rather than to neurologists. Details obtained about the seizure semiology may help to identify the specific frontal region of onset.^4,5
  • Prominent speech disturbances - May indicate dominant hemisphere involvement
  • Supplementary motor area (SMA) - Typically involve unilateral or asymmetric bilateral tonic posturing; may be associated with facial grimacing, vocalization, or speech arrest; seizures frequently preceded by a somatosensory aura; complex automatisms such as kicking, laughing, or pelvic thrusting may be present; responsiveness often preserved
  • Primary motor cortex - Usually simple partial motor seizures with clonic or myoclonic movements and preserved consciousness; jacksonian spread to adjacent cortical areas may occur, and secondary generalization is frequent; speech arrest and contralateral adversive or dystonic posturing may be present
  • Medial frontal, cingulate gyrus, orbitofrontal, or frontopolar regions - Complex behavioral events characterized by motor agitation and gestural automatisms; viscerosensory symptoms and strong emotional feelings often described; motor activity repetitive and may involve pelvic thrusting, pedaling, or thrashing, often accompanied by vocalizations or laughter/crying; seizures often bizarre and may be diagnosed incorrectly as psychogenic
  • Dorsolateral cortex - Tonic posturing or clonic movements often associated with either contralateral head and eye deviation, or less commonly, ipsilateral head turn
  • Operculum - Swallowing, salivation, mastication, epigastric aura, fear, and speech arrest often associated with clonic facial movements; gustatory hallucinations also may occur
  • Nonlocalizable frontal seizures - Rare, manifesting as brief staring spells accompanied by generalized spike/wave on EEG, which may be difficult to distinguish from primarily generalized absence seizures; may present as generalized tonic-clonic seizures without obvious focal onset
  • Nocturnal frontal lobe epilepsy - Autosomal dominant inheritance; seizures occur mainly during sleep; characterized by marked motor manifestations, including dystonic posturing, jerking, bending, and rocking; difficult to distinguish from parasomnias

Physical

A general physical and thorough neurologic examination should be performed in all patients with epilepsy.

• General examination
  • Signs suggestive of syndromes that may be associated with epilepsy, such as facial dysmorphisms
  • Skin abnormalities such as cafe-au-lait spots, hypomelanotic macules, or neurofibromas suggesting neurocutaneous syndromes
• Neurologic examination
  • As structural lesions are common, high incidence of neurologic abnormalities in patients with frontal lobe epilepsy
  • Particular emphasis on the motor examination

Causes

The majority of frontal lobe seizures are thought to be symptomatic, although many patients with frontal lobe seizures have no obvious lesions on MRI.

Significant advances in molecular genetic approaches have identified the genetic defects related to a family of frontal lobe epilepsies known as autosomal dominant nocturnal frontal lobe epilepsies (ADNFLE).

• Tumors
  • Recent reviews indicate that the epileptogenic lesion in approximately one third of patients with refractory frontal lobe seizures is a tumor.
  • Common pathologies include gangliogliomas, low-grade gliomas, and epidermoid tumors. High-grade tumors more often present with headache or focal deficits, but many are associated with seizures at some time in their course.
• Head trauma
  • Head trauma is a very frequent cause of damage to the frontal lobes. Risk of later epilepsy depends largely on the severity of trauma. The first seizure usually occurs within months, but may not occur for many years.
  • Pathologic examination of the frontal lobe frequently reveals meningocerebral cicatrix.
• Vascular malformations
  • Three main types are recognized—arteriovenous malformations, cavernous angiomas, and venous angiomas.
  • Arteriovenous malformations and cavernous angiomas are more likely to cause seizures than venous angiomas.
• Developmental lesions
  • With improvements in neuroimaging, cortical dysplasias increasingly are being recognized as epileptogenic lesions.
  • Other common developmental causes of frontal lobe seizures include hamartomas and nodular heterotopias.
• Gliosis
  • Gliosis is identified in many pathologic specimens following surgical resection for frontal lobe epilepsy.
  • It may follow head trauma, neonatal anoxia, or previous resection; often no cause is identified.
• Encephalitis: While encephalitis commonly produces temporal lobe epilepsy, frontal lobe seizures may occur.
• Inherited frontal lobe epilepsy
  • Three types of ADNFLE have been described. They are clinically characterized by brief nocturnal motor seizures that often occur in clusters, mainly during non-REM sleep.⁶ Seizures may also occur during daytime naps. A brief aura is typically followed by hyperkinetic or tonic activity, and typically shows a good response to carbamazepine. Differentiation from parasomnias remains a challenge.
  • ADNFLE was the first partial epilepsy identified as a single gene disorder. Mutations in 2 nicotinic acetylcholine receptor genes (nAChR alpha4 and beta2 subunits) have been associated with ADNFLE, with a third potential locus identified.^7,8 Nicotine use is reported to be associated with decreased seizure frequency in patients with these mutations.⁹ Positron emission tomography studies in ADNFLE demonstrate decreased nAChR density in the right dorsolateral prefrontal region, but increased density in mesencephalon. Recently, dopaminergic pathways in the striatum have been shown to be altered in ADNFLE.¹⁰
  • Other familial frontal lobe epilepsies have been identified, including a familial partial epilepsy with variable foci linked to chromosome 22.

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