Intraoperative electrostimulation for awake brain mapping: how many positive interference responses are required for...

Area of Science:

• Neuroscience
• Neurosurgery
• Clinical Neurology

Background:

• Accurate identification of language areas during brain surgery is crucial for minimizing deficits.
• Electrostimulation brain mapping is a common technique used in awake craniotomies.
• Understanding the reproducibility of language mapping trials is essential for reliable results.

Purpose of the Study:

• To characterize the reproducibility of language trials within and between brain mapping sessions.
• To evaluate the significance of different levels of positive electrostimulation trials.
• To investigate the impact of baseline error rates on trial interpretation.

Main Methods:

• Analysis of brain mapping and baseline testing data from 200 adult patients undergoing left-hemisphere tumor resection.
• Evaluation of data from 11 patients with repeat surgeries to assess long-term reproducibility.
• Application of a standardized electrostimulation protocol with a naming task and statistical comparison to baseline error rates.

Main Results:

• Full electrostimulation interferences (3/3 trials) were statistically significant in 92.7% of patients.
• Double interferences (2/3 trials) were significant in only 38.5% of patients, particularly those with lower baseline error rates.
• Repeat surgeries showed limited reproducibility, with only 26% of positive areas consistently identified.

Conclusions:

• Electrostimulation trials yield graded reproducibility levels influenced by baseline error rates.
• Caution is advised for interpreting double interferences; additional trials may be necessary.
• Reproducibility must be considered when interpreting awake brain mapping data for clinical decision-making.