Frontal Lobe Epilepsy
- Author: Sheryl Haut, MD; Chief Editor: Selim R Benbadis, MD more...
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. Status epilepticus may be associated more commonly with frontal lobe seizures than with seizures arising from other areas.
Signs and symptoms
Time of day is an important characteristic for seizures originating in the frontal lobe, as the majority of these seizures occur between the hours of 2 am and noon. The following features help to distinguish frontal lobe seizures from nonepileptic events:
Occurrence during sleep
Brief duration (often < 30 seconds)
Rapid secondary generalization
Prominent motor manifestations
Other history findings may vary according to the site of involvement, include the following:
Dominant hemisphere involvement - May be indicated by prominent speech disturbances
Supplementary motor area (SMA) - Typically involves unilateral or asymmetrical, 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 examination may reveal signs suggestive of syndromes that may be associated with epilepsy, such as the following:
Cafe-au-lait spots, hypomelanotic macules, or neurofibromas
See Clinical Presentation for more detail.
For new-onset seizures, blood tests should be performed to rule out a metabolic cause (eg, hypoglycemia, hypomagnesemia). For patients with an established diagnosis of epilepsy, blood testing for complications may include the following:
CBC - Monitor for neutropenia and thrombocytopenia
Liver function tests
MRI is the imaging modality of choice in patients with frontal lobe seizures
Underlying lesions are reported to be present in up to 50% of patients with frontal lobe epilepsy
Optimally, MRI with gadolinium should be obtained with high resolution, 1 mm thick slices, and multiple sequences; if EEG or other testing indicates a potential epileptogenic zone, thin slices through the area of interest should be requested
A field strength of 3 Tesla (3T) can further increase the identification of lesions 
PET scanning is being increasingly used in the presurgical evaluation of patients with extratemporal epilepsy.
On PET scans, interictal hypometabolism, reflective of focal dysfunction, may be seen in areas that were normal on MRI
SPECT scans may be obtained during prolonged video-EEG monitoring; hyperperfusion on ictal SPECT scanning suggests an area of seizure onset
Indicated for all patients with frontal lobe epilepsy
Patients with intractable epilepsy, or in whom the diagnosis is doubtful, should undergo prolonged video-EEG monitoring
If the events are primarily or exclusively nocturnal, polysomnography should be considered, with extended EEG montages if available
Interictal EEGs may be normal
On interictal EEG, spikes or sharp waves may be absent; may appear maximal unilaterally, bilaterally, or in the midline; or may appear generalized due to secondary bilateral synchrony; background rhythm abnormalities, with or without focal slowing, may be present
Ictal onset often is seen poorly from the scalp and is highly variable in appearance
Postictal slowing can be confirmatory, and at times, localizing or lateralizing
Patients with suspected frontal lobe epilepsy frequently require invasive EEG monitoring
On intracranial EEG, Ictal onset most often appears as a low-voltage, high-frequency discharge (ie, buzz), although rhythmic activity at alpha, theta, or delta frequencies may be seen
See Workup for more detail.
Anticonvulsant therapy should be initiated once the diagnosis of epilepsy is established. Many nocturnal episodes with prominent motor manifestations respond extremely well to carbamazepine. Monotherapy is desirable, some patients require polytherapy.
Patients with medically intractable epilepsy should be considered for resective epilepsy surgery. Other treatment options include the following:
Modified Atkins diet
Vagal nerve stimulator
Multiple subpial transections
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.
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, vascular malformations), neoplasms, head trauma, infections, and anoxia.
Owing to 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, belonging to a group known as the autosomal dominant nocturnal frontal lobe epilepsies (ADNFLE).
Quality-of-life issues for patients with epilepsy can include the following:
Coping with the social stigma of epilepsy
Living with restrictions
Living with long-term medical therapy
Go to Epilepsy and Seizures for an overview of this topic.
Reviews indicate that the epileptogenic lesion in approximately one third of patients with refractory frontal lobe seizures is a tumor.
Common tumors causing frontal lobe epilepsy 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 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.
Three main types are recognized: arteriovenous malformations, cavernous angiomas, and venous angiomas. Arteriovenous malformations and cavernous angiomas are more likely to cause seizures than are venous angiomas.
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 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.
Although 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. 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. Nicotine use is reported to be associated with decreased seizure frequency in patients with these mutations.
Positron emission tomography (PET) scan studies in ADNFLE demonstrate decreased nAChR density in the right dorsolateral prefrontal region, but increased density in mesencephalon. Dopaminergic pathways in the striatum have been shown to be altered in ADNFLE.
Other familial frontal lobe epilepsies have been identified, including a familial partial epilepsy with variable foci linked to chromosome 22.
The exact incidence of frontal lobe epilepsy is not known. In most centers, however, frontal lobe epilepsy accounts for 20-30% of operative procedures involving intractable epilepsy.
No significant sex-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.
Symptomatic frontal lobe epilepsy may affect patients of all ages.
In a large series of cases, the 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.
Complications of frontal lobe epilepsy may include status epilepticus or a comorbid psychiatric or behavioral disturbance.
Status epilepticus is reported in up to 25% of patients with frontal lobe epilepsy. The episodes may be convulsive, nonconvulsive, or simple partial.
Approximately 65-75% of patients with frontal lobe seizures respond to appropriate anticonvulsants and become seizure free.
The proportion of patients with medically refractory frontal lobe epilepsy who become seizure free from additional medications or surgical options is lower than in patients with temporal lobe epilepsy.
An important feature in prognosis is the early recognition of frontal lobe seizures as an epileptic syndrome rather than as a parasomnia or a psychiatric condition.
Patient education is important for all patients with epilepsy. Many patients benefit from joining one of the national or regional epilepsy support groups.
Patients with epilepsy who are not seizure free have the following restrictions:
Driving - Duration of restriction varies by state
Operating heavy machinery
Activities that involve unprotected heights
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FDA approves Aptiom to treat seizures in adults. US Food and Drug Administration. Available at http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm374358.htm. Accessed: November 12, 2013.