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  • Updated 08.28.2020
  • Released 06.17.2003
  • Expires For CME 08.28.2023

Frontal lobe seizures

Introduction

Overview

Frontal lobe seizures can have bizarre manifestations; however, they are easily recognizable if the clinician is well aware of the clinical presentation. Frontal lobe seizures are typically brief, nocturnal, and without loss of consciousness. Focal clonic seizures, asymmetric tonic seizures, hyperkinetic seizures, absence type seizures, and masticatory seizures originate in different subregions of the frontal lobes. Treatment includes medical as well as surgical options.

Key points

• Focal clonic seizures originate in the primary motor area; asymmetric tonic seizures involve the supplementary motor area; and prefrontal seizures often manifest as hyperactive seizures.

• Frontal lobe seizures may have bizarre manifestations with hyperactive behavior and preserved consciousness.

• Frontal lobe seizures can be misdiagnosed as psychiatric disease or sleep disorders.

• Frontal lobe seizures are brief and nocturnal and occur in clusters.

Historical note and terminology

The first detailed description of focal clonic seizures, a type of seizure originating in the posterior frontal lobes, was published by JF Bravais in 1827 (16). Hughlings Jackson, in 1867, related clonic seizures to electric discharges in the contralateral prerolandic region (105). He described seizures with a “march of spasm” and wrote: “We may first see movement of the index-finger, then of the hand, then the whole arm, then of the face, leg, then of bilateral muscles” (63). The Commission on Classification and Terminology of the International League Against Epilepsy still classified these seizures as “Jacksonian seizures” in 1989 (03). In later classifications by the International League Against Epilepsy, those seizures are listed as “focal clonic seizure (without spread)” and “Jacksonian march seizures (with local spread)” (30; 31). They are also referred to as “focal motor seizures with elementary clonic motor signs” (30; 31), “clonic seizures” (64), “simple motor seizures,” or “somatomotor seizures.” If they involve the entire hemibody they are termed “hemiclonic seizures” (30). If focal clonic seizures persist for a prolonged time the term “epilepsia partialis continua” is applied (31).

Penfield and Welch performed stimulation experiments of the human and monkey cortex. They defined the supplementary motor area (Brodmann area 6) as a region of the brain that mediates speech and behavioral arrest, vocalization, and asymmetric contralateral posturing when stimulated (78). They described supplementary motor area seizures as seizures with speech arrest, unilateral arm posturing, and head or eye deviation, later referred to as "fencing posture" (77; 76). In a detailed study of pharmacologically induced seizures, Ajmone-Marsan created the term "M2e" to describe tonic abduction and external rotation of the shoulder with flexion of the elbow with or without head turning. He described supplementary motor involvement if M2e posturing occurred without loss of consciousness and without progression into a secondarily generalized tonic-clonic seizure (02). With the introduction of intracranial long-term EEG recordings, supplementary motor area seizures again became the focus of scientific interest in the late 1980s and early 1990s and were described in greater detail (26; 70; 69; 37; 108; 61; 23; 86; 08; 46; 35). The terms “adversive seizure” and “supplementary sensorimotor seizures” were also used to describe supplementary motor area seizures (02; 01). They were also listed as “focal (asymmetrical) tonic seizures” by previous publications (30; 31).

Focal unaware seizures of frontal lobe origin with bizarre automatisms were initially recognized by Tharp, who described three patients that were misdiagnosed as having psychogenic attacks (107). Using stereoencephalography, Geier, Bancaud, and Talairach defined frontal lobe automatisms further (40; Geier et al 1977), and detailed descriptions of focal impaired awareness seizures of frontal lobe origin followed (115; 111). The term "hypermotor seizure" was proposed for this type of seizure (64). These seizures are also termed "frontal lobe seizures with hypermotor automatisms," "frontal lobe seizures with frenetic automatisms," "complex partial seizures frontal lobe type," "frontal lobe seizures with agitated behavior," or "seizures with hyperactive automatisms" (113). They were also termed “hyperkinetic seizures” or “focal motor seizures with hyperkinetic automatisms” in some classification publications (30; 31).

In a later report of the International League Against Epilepsy (ILAE) on revised terminology and concepts for organization of seizures and epilepsy, frontal lobe seizures are classified as “focal seizures” with further descriptors such as “with or without impairment of consciousness” or “with or without observable motor components” (11). The latest iteration outlines the ILAE operational classification of seizure types with focal seizures described as either aware or with impaired awareness (34). Frontal lobe seizures with secondary generalization are now described as focal seizures evolving to bilateral tonic-clonic.

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