Ann Neurol. 2025 Aug 16. doi: 10.1002/ana.70002. Online ahead of print.
ABSTRACT
OBJECTIVE: Intracranial language localization with electrical stimulation mapping (ESM) and high-gamma modulation (HGM) mapping relies on artificial, repetitive tasks, requiring sustained cooperation from patients. Herein, we tested the validity of unstructured, interpersonal, naturalistic conversation for language localization, using a novel methodology: Behavior-iEEG-Spectral-Power correlation (BESPoC). We first validated BESPoC against ESM, HGM, and neuropsychological outcomes using well-established language tasks, then demonstrated the validity of naturalistic conversation.
METHODS: We included 134 patients (59 females), aged 2-29 years, undergoing standard-of-care stereo-electroencephalography monitoring who engaged in picture naming, auditory naming, story listening, and conversed with a family member. ESM and HGM analysis were performed using established methods. BESPoC methodology quantified correlation between stereo-electroencephalography spectral power from task recordings, obviating the need for any trial-based epochs, and behavioral markers. The large sample size allowed mixed-effects modeling to compare BESPoC with HGM and ESM.
RESULTS: BESPoC showed high specificity (0.79-0.83) and sensitivity (0.64-0.86) for localizing HGM language sites across the tasks. BESPoC also compared well with HGM across all language tasks for localizing ESM speech/language sites. With conventional tasks, BESPoC was superior to HGM for modeling neuropsychological deficits seen, despite preserving ESM speech/language sites. Naturalistic conversation compared well with standard tasks for localization of HGM and ESM language sites, and determined neuropsychological outcomes better than conventional tasks.
INTERPRETATION: Using BESPoC methodology naturalistic conversation is shown to produce valid cortical language maps of both expressive and receptive language, and determine neuropsychological outcomes after epilepsy surgery. ANN NEUROL 2025.
PMID:40817733 | DOI:10.1002/ana.70002
