Structural brain abnormalities in genetic generalized epilepsies: A systematic review and meta-analysis

Area of Science:

• Neuroimaging
• Epilepsy Research
• Quantitative MRI

Background:

• The International League Against Epilepsy (ILAE) definition posits no standard MRI structural abnormalities in genetic generalized epilepsy (GGE).
• Emerging quantitative magnetic resonance imaging (qMRI) techniques suggest potential structural differences in GGE patients.
• Contradictory evidence necessitates a systematic review to clarify structural brain abnormalities in GGE.

Purpose of the Study:

• To systematically review and quantitatively analyze structural brain abnormalities in genetic generalized epilepsy (GGE) using quantitative MRI.
• To compare structural findings between GGE patients and healthy controls.
• To evaluate the consistency of findings with existing hypotheses on GGE pathophysiology.

Main Methods:

• Systematic literature review adhering to PRISMA guidelines.
• Quantitative meta-analysis using a random-effect model.
• Inclusion of 28 peer-reviewed, case-control studies published after 1989.

Main Results:

• Significant structural differences identified between GGE patients and controls.
• Observed volume reductions in whole brain, thalamus, putamen, caudate, pallidum, and supplementary motor area.
• Gray matter volume reductions in hemispheres, thalamus, insula; surface area reduction in caudal anterior cingulate cortex; and gray matter increase in medial frontal gyrus.

Conclusions:

• Contrary to the current ILAE definition, structural brain abnormalities may be present in GGE patients.
• Findings support the involvement of thalamocortical networks in GGE but suggest abnormalities extend to other cognitive domains.
• Methodological variations necessitate cautious interpretation of results.