Accuracy of high-density EEG electrode position measurement using an optical scanner compared with the photogrammetry method

•We measured EEG electrode positions in high-density array.•We compared an optical scanner with the conventional photogrammetry method.•The optical scanner was more accurate than photogrammetry.The real-time scanning was feasible – it took 5–10 min per patient. To determine the feasibility and accuracy of a handheld optical scanner to measure the three-dimensional (3D) EEG electrode coordinates in a high-density array of 256 electrodes. We compared the optical scanning with a previously validated method, based on photogrammetry. Electrode coordinates were co-registered with the MRI of the patients, and mean distance error relative to the three-dimensional MRI reconstruction was determined for each patient. We included 60 patients: 30 were measured using the photogrammetry method, and 30 age and gender matched patients were measured with the optical scanner. Using the optical scanner, the mean distance error was 1.78 mm (95% confidence interval: 1.59–1.98 mm) which was significantly lower (p