ECoG high-gamma modulation versus electrical stimulation for presurgical language mapping

Ravindra Arya, Paul S. Horn, Nathan E. Crone

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Objective This meta-analysis compared diagnostic validity of electrocorticographic (ECoG) high-γ modulation (HGM) with electrical stimulation mapping (ESM) for presurgical language localization. Methods From a structured literature search, studies with electrode level data comparing ECoG HGM and ESM for language localization were included in the meta-analysis. Outcomes included global measures of diagnostic validity: area under the summary receiver operating characteristic (SROC) curve (AUC), and diagnostic odds ratio (DOR); as well as pooled estimates of sensitivity and specificity. Clinical and technical determinants of sensitivity/specificity were explored. Results Fifteen studies were included in qualitative synthesis, and 10 studies included in the meta-analysis (number of patients 1–17, mean age 10.3–53.6 years). Overt picture naming was the most commonly used task for language mapping with either method. Electrocorticographic high-γ modulation was analyzed at 50–400 Hz with different bandwidths in individual studies. For ESM, pulse duration, train duration, and maximum current varied greatly among studies. Sensitivity (0.23–0.99), specificity (0.48–0.96), and DOR (1.45–376.28) varied widely across studies. The pooled estimates are: sensitivity 0.61 (95% CI 0.44, 0.76), specificity 0.79 (95% CI 0.68, 0.88), and DOR 6.44 (95% CI 3.47, 11.94). Area under the SROC curve was 0.77. Results of bivariate meta-regression were limited by small samples for individual variables. Conclusion Electrocorticographic high-γ modulation is a specific but not sensitive method for language localization compared with gold-standard ESM. Given the pooled DOR of 6.44 and AUC of 0.77, ECoG HGM can fairly reliably ascertain electrodes overlying ESM cortical language sites.

Original languageEnglish (US)
Pages (from-to)26-33
Number of pages8
JournalEpilepsy and Behavior
StatePublished - Feb 2018


  • Epilepsy surgery
  • Functional brain mapping
  • Language localization

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Behavioral Neuroscience


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