Electrocorticographic (ECoG) high-γ modulation (HGM) can serve as a specific way to localize language preoperatively, when compared with electrical stimulation mapping (ESM), which is considered the gold standard, according to a recent meta-analysis. But the same analysis concluded that it was not sensitive enough when compared with ESM.
- The meta-analysis reviewed several metrics for diagnostic validity, including area under the summary receiver operating characteristic (SROC) curve, diagnostic odds ratio, and pooled estimates of sensitivity and specificity.
- To determine language mapping, the most common task used was overt picture naming.
- ECoG was analyzed at 50 to 400 Hz, with different studies using different bandwidths.
- Among the studies that looked at ESM, there were wide variations in pulse duration, train duration, and maximum current.
- The pooled diagnostic odds ratio was 6.44 and the AUC was 0.77, making HGM a fairly reliable way to ascertain electrodes overlying ESM cortical language sites.
Aryaa R, Horn PS, Crone NE, et al. ECoG high-gamma modulation versus electrical stimulation for presurgical language mapping. Epilepsy Behav. 2018;79:26-33.