Absence seizures and the frontal lobe

Area of Science:

• Neuroscience
• Epileptology
• Cognitive Neurology

Background:

• Absence seizures, particularly the 3-second spike-wave pattern, have been debated regarding their origin (cortical vs. thalamic).
• Primary generalized epilepsy (PGE) in humans is characterized by these seizures, impacting cognitive functions.

Purpose of the Study:

• To resolve the controversy surrounding the origin of spike-wave discharges in human absence seizures.
• To elucidate the role of the frontal lobe in the pathophysiology and cognitive manifestations of absence seizures.

Main Methods:

• Review and synthesis of existing literature on human primary generalized epilepsy and absence seizures.
• Analysis of the electroencephalographic (EEG) patterns, specifically the 3-second spike-wave, and their topographical distribution.
• Correlation of seizure semiology with known functions of the frontal lobe, particularly working memory.

Main Results:

• The origin of 3-second spike-wave absence seizures in humans with PGE is definitively cortical, with maximal involvement of the frontal lobe.
• The frontal lobe, including prefrontal and frontomotor areas, is maximally implicated in the 3-second spike-wave pattern.
• Absence seizures are characterized by a suspension of working memory, an executive function predominantly managed by the frontal lobe.

Conclusions:

• The cortical origin of human absence seizures, with a frontal lobe focus, is established, resolving prior controversies.
• The frontal lobe's role in working memory provides a neurocognitive explanation for the clinical features and rapid recovery observed in absence seizures.
• This frontal lobe-centric model applies to classical absence seizures in PGE and secondary bilateral synchrony with frontal epileptogenic foci.