ALS_EOG/README.md

ALS_EOG

A dataset of EEG and EOG recordings during a BCI task with a participant with ALS.

A substantial part of these data have been already published in Jaramillo-Gonzalez, Wu, Tonin, et al. (2021).

At the time of the first recording the patient was artificially fed, artificially ventilated and already in Locked-In State since he was not able to use eye-tracker-based AAC devices anymore.

Recordings have been performed at the patient's house during 13 visits. Each visit consists of one or more consecutive days during which BCI sessions have been conducted. Data belonging to the same visit are stored in the same subfolder.

For more information about the recordings, please refer to Tonin, Jaramillo-Gonzalez, et al. (2020) and Jaramillo-Gonzalez, Wu, Tonin, et al. (2021).

BCI Paradigm

During the BCI session the participant had to reply to known yes/no questions by moving the eyes in two different ways.

Each session consists of blocks of usually 20 trials. Each trial is formed by:

1. Baseline: the participant was asked to relax (~3-10s)
2. Stimulus: a known yes/no question was auditorily presented (~5s)
3. Response: The participant performed the eye movement (~3-10s)
4. Feedback: The classification of the response signal was auditorily presented (~2-3s)

Data

Data have been acquired with a 16 channel EEG amplifier (V-Amp DC, Brain Products, Germany) with Ag/AgCl active electrodes.

Data have been acquired at 500Hz, and are stored in the raw format directly provided by Brain Product software.

Each session consists in 3 files:

• Header file (*.vhdr), containing recording parameters and further meta-information, as the scaling factor necessary to convert the recorded raw amplitude to milivolts.
• Marker file (*.vmrk) describes the events and their onset during the data recording, in this case, the sequence of triggers.
• Raw EEG data file (*.eeg) is a binary file containing the EEG and EOG data and additional recorded signals.

Channel names use standard EEG 10-20 names, except for the following names:

Channel	10-20
L1	F3
L2	AF3
R1	F4
R2	AF4
EOGU	SO1
EOGD	IO1
EOGL	LO1
EOGR	LO2

Markers

Markers have been sent throw serial port and identify the type of the trial and the start time of each part of the trial. An exaustive explanation can be found in Jaramillo-Gonzalez, Wu, Tonin, et al. (2021), but for reference here is report a summary explanatory table:

Meaning	Yes trial	No trial	Open trial
Session start	S9	S9	S9
Baseline	S10	S11	S12
Stimulus	S5	S6	S7
Response	S4	S8	S13
Feedback	S1	S2	S3
Session end	S15	S15	S15