EEG and P300 database to determine the signal to noise ratio during a variety of realistic tasks ================================================================================================ DOI: http://dx.doi.org/10.5525/gla.researchdata.1258 This work is licensed under a Creative Commons Attribution 4.0 International License. Bernd Porr , Lucía Muñoz Bohollo <2401478M@student.gla.ac.uk> and Ravinder Dahiya This database contains EEG and evoked potential recordings from 20 participants. This allows to assess the signal to noise ratio: - Signal: The P300 power and VEP power can be used to assess the signal power - Noise: The signal power consisting of EMG and baseline EEG during the different tasks allows to determine the noise level The data was acquired using an Attys device (www.attys.tech) and the data acquisition programs 'attys-ep' and 'attys-scope'. The Attys was connected to electrodes placed on the participants' heads. A compound electrode consisting of an inner electrode and a ring around it was placed at Cz, with the inner part connected to the positive input of Channel 1 and the ring to Channel 2. The A2 electrode was connected to the negative input of Channel 1, and the A1 electrode was connected to ground. Video recordings were taken of the participants to allow observation of artefacts. Every participant carried out 10 tasks where the electrodes were not moved or replaced between tasks to maintain maximum consistency: * VEP (visually evoked potential), 2min, chequer board inversion every second, rawvep.tsv * P300, 5min, chequer board inversion every second, oddballs randomly chosen every 8sec-13sec, rawp300.tsv * Lying down, eyes closed, 2min, lyingEC.tsv * Lying down, eyes open, 2min, lyingEO.tsv * Jaw clenching every 15 seconds, 2min, jawclench.tsv * Reading out loud, 2min, read.tsv * Colouring, 2min, colour.tsv * Solving a wordsearch, 2min, wordsearch.tsv * Solving a sudoku, 2min, sudoku.tsv * Playing 'subway surfers' on the phone, 2min, phoneApp.tsv The evoked potentials were acquired with attys-ep, the rest of the tasks with attys-scope. Data format ----------- The data is stored in .tsv (Tab Separated Values) files. The evoked potential raw data is stored in column 0, and the oddball/chequer board reversal in column 2. The sampling rate is 250Hz. The subject was asked to keep mental count of how many repetitions of the checker board were seen before the oddball stimulus. The oddball was triggered at random intervals between 7 ad 13 checker board changes. The 1000ms after the trigger were taken for averaging. For the tasks, Channel 1 data (inner electrode) is stored in column 7, and Channel 2 data (ring around the inner electrode) in column 8 (counting from 0). Column 0 is the timestamp and columns 1-3 contain accelerometer readings. The sampling rate is 500Hz. Example python scripts ---------------------- Example codes for plotting the EEGs and calculating the evoked potentials are provided: - `plot_ep.py` plots the filtered raw data for the evoked potentials (VEP & P300), as well as the averaged VEP and P300. You can specify the subject as a parameter, for example `python plot_ep.py 10` to plot subject 10. - `plot_tasks.py` plots the other 8 tasks for both Channels. You can specify the participant number and the task as a parameter, for example `python3 ./plot_tasks.py 2 read` plots the EEG data from participant 2 while reading.