Increased microstructural white matter correlations in left, but not right, temporal lobe epilepsy

Area of Science:

• Neuroimaging
• Neuroscience
• Epilepsy Research

Background:

• White matter tract correlations in healthy subjects reflect phylogenetic development and functional specialization.
• Temporal lobe epilepsy (TLE) may exhibit deviations in these intertract correlations.

Purpose of the Study:

• Establish normal intertract correlations in healthy controls.
• Examine deviations from normal intertract correlations in left TLE (LTLE) and right TLE (RTLE).
• Assess the potential of tract correlations to differentiate between LTLE and RTLE.

Main Methods:

• Investigated intertract correlations in 28 healthy controls, 21 LTLE patients, and 23 RTLE patients.
• Analyzed nine specific white matter tracts, including parahippocampal fasciculi, uncinate fasciculi, arcuate fasciculi, frontoparietal tracts, and the fornix.
• Employed cluster and discriminant analyses, comparing tract correlations and fractional anisotropy (FA) values.

Main Results:

• LTLE demonstrated an abnormal increase in intertract correlations, while RTLE showed correlations similar to controls.
• In controls, tract correlations increased with increasing FA; in TLE groups, they increased with decreasing FA.
• Cluster analyses revealed separated homologous tracts in LTLE and RTLE groups, unlike the agglomeration in controls.
• Discriminant analyses showed tract correlations were more effective than FA values in classifying LTLE versus RTLE.

Conclusions:

• LTLE patients exhibit more extensive microstructural orientation losses and aberrant intertract correlations compared to RTLE patients.
• Aberrant correlations in LTLE may stem from pathological processes like seizure spread or adaptive mechanisms.
• Tract correlations show predictive value in distinguishing LTLE from RTLE, potentially enhancing the clinical role of diffusion imaging.