Defining clinico-neuropathological subtypes of mesial temporal lobe epilepsy with hippocampal sclerosis

Area of Science:

• Neurology
• Epileptology
• Pathology

Background:

• Hippocampal sclerosis (HS) is the leading cause of drug-resistant focal epilepsies, particularly mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS).
• Despite surgical interventions, a significant percentage of patients experience persistent or recurrent seizures due to surgical failure.
• The condition exhibits diverse electroclinical, structural, and molecular pathology patterns, complicating treatment and prognosis.

Purpose of the Study:

• To discuss the varied pathological patterns contributing to the epileptogenic network in mTLE-HS.
• To highlight the need for international consensus on terminology for mTLE-HS subtypes.
• To emphasize the role of advanced diagnostic tools in predicting surgical success.

Main Methods:

• Review of existing literature on hippocampal sclerosis and mesial temporal lobe epilepsy.
• Discussion of pathological patterns including hippocampal cell loss and involvement of adjacent brain structures.
• Consideration of advanced neuroimaging, histopathology, neurophysiology, and molecular genetics.

Main Results:

• HS presents a wide spectrum of pathological findings, influencing the extent of the epileptogenic network.
• Involvement of other mesial temporal structures and temporal neocortex, such as focal cortical dysplasia, can impact seizure control.
• Current understanding necessitates clearer classification of mTLE-HS subtypes.

Conclusions:

• Accurate classification and understanding of HS pathology are essential for improving surgical outcomes in mTLE-HS.
• International consensus on terminology is required to standardize diagnosis and research.
• Future advancements in high-resolution imaging, histopathology, and molecular diagnostics will aid in predicting patient prognosis and optimizing epilepsy management.