fMRI language dominance and FDG-PET hypometabolism

Area of Science:

• Neuroscience
• Epilepsy Research
• Medical Imaging

Background:

• Atypical language dominance is frequently observed in patients with temporal lobe epilepsy (TLE).
• Understanding the relationship between brain metabolism and language lateralization in TLE is crucial for patient management.

Purpose of the Study:

• To investigate the association between left temporal hypometabolism and language processing lateralization using functional magnetic resonance imaging (fMRI).
• To determine if hypometabolism in specific temporal regions correlates with language network activation patterns.

Main Methods:

• Thirty TLE patients underwent (18)fluoro-deoxyglucose (FDG)-PET to assess regional glucose metabolism.
• fMRI was employed to evaluate language dominance using an auditory definition decision paradigm.
• Statistical analyses, including correlation and regression, were performed to link metabolic data with fMRI activation patterns.

Main Results:

• Nineteen patients exhibited ipsilateral temporal hypometabolism.
• Left midtemporal hypometabolism correlated significantly with reduced laterality index in the middle frontal gyrus (MFG) and showed trends with Wernicke area (WA) and inferior frontal gyrus (IFG).
• Hypometabolism was associated with altered voxel activation in the WA, with fewer ipsilateral and more contralateral activated voxels.

Conclusions:

• No evidence of impaired blood oxygenation level-dependent (BOLD) response was found in hypometabolic cortex.
• Regional hypometabolism in the temporal lobe may serve as a marker for dysfunction leading to language function displacement in TLE.