Cognitive-metabolic relationship in temporal lobe epilepsy: A systematic review

Area of Science:

• Neurology
• Neuroimaging
• Epilepsy Research

Background:

• Cognitive decline is a significant cause of disability in temporal lobe epilepsy (TLE).
• The underlying pathophysiology of cognitive impairment in TLE is not well understood.
• Identifying metabolic changes may lead to new biomarkers and treatments for TLE-associated cognitive decline.

Purpose of the Study:

• To systematically review current literature on neurometabolic dysfunction in TLE using brain imaging.
• To explore the relationship between identified metabolic changes and cognitive deficits in TLE patients.

Main Methods:

• A systematic review of five databases was conducted, adhering to PRISMA guidelines.
• Included observational studies published through December 2024 that linked metabolic imaging findings with cognitive measures in TLE.
• Analyzed 38 studies involving 1161 TLE patients (aged 5-66).

Main Results:

• Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) was the most common imaging technique (22 studies).
• Proton magnetic resonance spectroscopy (¹H-MRS) was used in 14 studies to quantify brain metabolites.
• Verbal memory impairment correlated with left temporal lobe metabolite changes; non-memory deficits linked to metabolism in temporal and extratemporal regions.

Conclusions:

• ¹⁸F-FDG PET is widely used, but other PET tracers and ¹H-MRS are underutilized for assessing cognitive-metabolic correlates in TLE.
• Left temporal dysmetabolism strongly correlates with verbal memory impairment.
• Multifaceted cognitive impairment in TLE is associated with measurable metabolic changes, suggesting potential biomarkers for cognitive decline risk.