Ictal fear during parietal seizures

Area of Science:

• Neuroscience
• Epileptology
• Clinical Neurology

Background:

• Ictal fear, a distinct seizure manifestation, is infrequently associated with parietal lobe epilepsy.
• Understanding the neuroanatomical underpinnings of ictal fear is crucial for accurate localization and treatment of epilepsy.

Purpose of the Study:

• To investigate the electroclinical correlations of ictal fear in a patient with parietal seizures.
• To explore the potential role of the parietal cortex in generating ictal fear, independent of limbic structures.

Main Methods:

• Stereoelectroencephalography (SEEG) was used to record seizure activity and precise localization of the seizure onset zone.
• The Connectivity Epileptogenicity Index (cEI) was employed to quantify the epileptogenic zone.
• Detailed analysis of clinical semiology, specifically the occurrence and characteristics of ictal fear.

Main Results:

• The seizure onset zone was identified within the left inferior parietal cortex and superior temporal gyrus.
• Prominent ictal fear was observed during SEEG-recorded seizures originating from these parietal regions.
• Crucially, the amygdala was not involved in the seizure network during the episodes of ictal fear.

Conclusions:

• Parietal lobe seizures can generate significant ictal fear.
• Ictal fear in this case was associated with the involvement of the inferior parietal cortex and superior temporal gyrus.
• This finding challenges the traditional view that ictal fear exclusively involves limbic structures, demonstrating its potential origin in the parietal cortex.