Neurovascular Uncoupling During Language Tasks in Patients With Epilepsy Undergoing Temporal Lobectomy Presurgical Evaluation ALFF‐Based NVU Correction in Epilepsy
Sydnie Hom, Alex Prusky, Shaghayegh Poursabbagh, Khuram Kazmi, Ron Gefen, Joseph Ifrach, Thomas Ross, Todd Siegal, Evren Burakgazi‐Dalkilic, Melissa Carran, Eric Nagele, Ignacio Valencia, Islam Fayed, Mahdi AlizadehABSTRACT
Background and Purpose
Neurovascular uncoupling (NVU) disrupts the relationship between neuronal activity and the blood oxygen level‐dependent (BOLD) signal, potentially reducing the accuracy of presurgical language mapping in epilepsy. While amplitude of low frequency fluctuations (ALFF)‐based NVU correction has been validated in brain tumor patients, its application to task‐based fMRI in epilepsy remains unexplored. This pilot study evaluates the effect of ALFF‐based NVU correction on task‐related activation in patients with temporal lobe epilepsy (TLE).
Methods
Seven patients with refractory TLE (5 female, 2 male; age 18–48 years) underwent resting‐state and task‐based BOLD fMRI on a 3.0T Siemens Prisma scanner. Language mapping included four block‐design paradigms: rhyming, sentence completion, word generation, and verb generation. Voxel‐wise Z ‐score maps were computed using a general linear model, and suprathreshold voxels were identified using an activation mapping as a percentage of local excitation threshold. ALFF maps were calculated, and correction factors based on voxel‐wise ALFF ratios to contralateral homologues were applied.
Results
ALFF correction reduced suprathreshold voxel counts across all tasks. The temporal lobe and cerebellum showed the largest changes across all tasks: mediapercent decrease in suprathreshold voxels—temporal: 19.1% [95% CI 12.6%–24.7%], cerebellum: 10.3% [9.5%–14.5%], occipital: 7.6% [4.5%–10.3%], parietal: 6.3% [4.2%–7.0%], frontal: 5.7% [3.5%–7.0%])).
Conclusions
In this pilot cohort, ALFF‐based NVU correction was associated with reduced task‐related activation, suggesting ALFF‐based correction may influence the localization of task‐related activation.