History
The majority of frontal lobe seizures are thought to be due to underlying structural lesions, although many patients with frontal lobe seizures have no obvious lesions on magnetic resonance imaging (MRI) scans.
A careful history should focus on specific characteristics of seizure episodes, including a detailed description by eyewitnesses, patterns of occurrence, precipitating factors, and response to medication. 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. [1] Awareness may appear unimpaired when seizures are brief, and paitents may have absent or minimal post-ictal state.
Features that help to distinguish frontal lobe seizures from nonepileptic events include stereotyped semiology, occurrence during sleep, brief duration (often < 30 seconds), rapid bilateral evolution, prominent motor manifestations, and complex automatisms. Other features of frontal lobe seizures include significant voice alterations in ictal speech, with elevated pitch during verbal communication. [8]
Even when such characteristics are present, however, distinguishing frontal lobe seizures from nonepileptic events remains difficult 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. [9, 10]
Other history findings may 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 focal motor seizures with clonic or myoclonic movements and preserved awareness; jacksonian spread to adjacent cortical areas may occur, and progression to bilateral tonic-clonic activity
-
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
Physical Examination
A general physical and thorough neurologic examination should be performed in all patients with epilepsy.
General examination
General examination may reveal 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, may also be found.
Neurologic examination
As structural lesions are common, neurologic abnormalities are common in patients with frontal lobe epilepsy. Pay particular attention to the motor examination.
