Spatial-temporal functional mapping of language at the bedside with electrocorticography
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Updated: Mar 24, 2026

Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping
Published on: June 26, 2012
Yujing Wang1, Matthew S Fifer2, Adeen Flinker2
1From the Departments of Neurology (Y.W., A.K., M.C.C., D.F.B.-R., N.E.C.), Biomedical Engineering (M.S.F.), and Neurosurgery (W.S.A.), Johns Hopkins University, Baltimore, MD; Fischell Department of Bioengineering (Y.W.), University of Maryland College Park; and Department of Psychology (A.F.), New York University, New York. ywang154@jhu.edu.
Objective:
To investigate the feasibility and clinical utility of using passive electrocorticography (ECoG) for online spatial-temporal functional mapping (STFM) of language cortex in patients being monitored for epilepsy surgery.
Methods:
We developed and tested an online system that exploits ECoG's temporal resolution to display the evolution of statistically significant high gamma (70-110 Hz) responses across all recording sites activated by a discrete cognitive task. We illustrate how this spatial-temporal evolution can be used to study the function of individual recording sites engaged during different language tasks, and how this approach can be particularly useful for mapping eloquent cortex.
Results:
Using electrocortical stimulation mapping (ESM) as the clinical gold standard for localizing language cortex, the average sensitivity and specificity of online STFM across 7 patients were 69.9% and 83.5%, respectively. Moreover, relative to regions of interest where discrete cortical lesions have most reliably caused language impairments in the literature, the sensitivity of STFM was significantly greater than that of ESM, while its specificity was also greater than that of ESM, though not significantly so.
Conclusions:
This study supports the feasibility and clinical utility of online STFM for mapping human language function, particularly under clinical circumstances in which time is limited and comprehensive ESM is impractical.

