Presurgical language fMRI: Technical practices in epilepsy surgical planning

Area of Science:

• Neuroimaging
• Clinical Neuroscience
• Epileptology

Background:

• Language functional MRI (fMRI) is widely used in clinical practice, particularly for epilepsy surgery planning.
• However, the execution of language fMRI in real-world clinical settings remains poorly understood.
• Significant gaps may exist between evidence-based protocols and current clinical applications.

Purpose of the Study:

• To comprehensively document the current execution of language fMRI in epilepsy surgical planning.
• To identify variations in cognitive task design, image acquisition, data analysis, and interpretation.
• To highlight discrepancies between established best practices and routine clinical fMRI implementation.

Main Methods:

• A questionnaire was developed focusing on cognitive design, image acquisition, analysis, interpretation, and practical aspects of language fMRI.
• Responses were collected from individuals responsible for language fMRI data at 63 epilepsy surgical programs.
• Data were analyzed to identify commonalities and variations across different aspects of fMRI execution.

Main Results:

• Marked heterogeneity was observed across all aspects of language fMRI execution in epilepsy surgery planning.
• Most programs utilize multiple tasks, with significant variation in protocol variants, run durations, and specific tasks employed (e.g., noun-verb generation, verbal fluency).
• Data acquisition and analysis methods vary considerably, with few sites adhering to the most validated protocols; statistical thresholding is often patient-specific, and expertise is inconsistently integrated.

Conclusions:

• Current clinical practice of language fMRI in epilepsy surgery planning is characterized by substantial heterogeneity.
• There is a notable gap between the evidence supporting fMRI and its actual clinical application.
• Epilepsy surgical teams should evaluate their practices against validated protocols and ensure comprehensive expertise to optimize patient care.