Data Subscription
Each data steam gives you real time access to data from the headset (EEG, motion...) or data calculated by Cortex (band powers, mental command...)
After you successfully subscribe to a data stream, Cortex will keep sending you data sample objects.
A subscription is linked to a session. All the subscriptions of a session are automatically cancelled when the session is closed. You can call unsubscribe to cancel a subscription.
Each data stream is identified by its name: "eeg", "mot", "dev", "eq", "pow", "met", "com", "fac", "sys".
Stream | Description |
eeg | The raw EEG data from the headset. |
mot | The motion data from the headset. |
dev | The device data from the headset. It includes the battery level, the wireless signal strength, and the contact quality of each EEG sensor. |
eq | The EEG quality of each EEG sensor. |
pow | The band power of each EEG sensor. It includes the alpha, low beta, high beta, gamma, and theta bands. |
met | The results of the performance metrics detection. |
com | |
fac | The results of the facial expressions detection. |
sys | The system events. These events are related to the training of the mental commands and facial expressions. See BCI for details. |
Depending on the license and the model of the headset, some streams may be available or not, and may send data samples objects at a different rate.
Stream | Supported headsets | Sample rate in hertz |
eeg | All, but requires a license | 128 or 256, depends on the headset and its settings. |
mot | All | Disabled, 32, 64, 128, depends on the headset and its settings. 6.4 hertz for MN8. |
dev | All | 2 |
eq | All | 2 |
pow | All | 8 |
met | All
EPOC Flex requires a special EEG sensor mapping | 2 if the license contains the scope "pm" and you activate the session before you subscribe.
0.1 otherwise (1 sample every 10 seconds) |
com | All
EPOC Flex requires a special EEG sensor mapping | 8 |
fac | All but MN8
EPOC Flex requires a special EEG sensor mapping | 32 |
sys | All |
By default, the streams "met", "com" and "fac" are not available for EPOC Flex. It is because Cortex doesn't implement the detections (performance metrics, mental command, facial expression) for EPOC Flex.
However, you can configure your EPOC Flex to simulate an EPOC X headset. In that case, Cortex runs the detections that are designed for EPOC X.
All you have to do is to use a sensor mapping that includes all the 14 EEG sensors of an EPOC X headset: AF3, F7, F3, FC5, T7, P7, O1, O2, P8, T8, FC6, F4, F8, AF4.
In addition, you should use P3 and P4 as references CMS and DRL. Please see the EPOC X user manual for the complete EPOC X configuration.
Your mapping can also include sensors that are not present on an EPOC X. Cortex will not use these additional sensors to run the detections, but you can use them to collect more EEG data.
This feature was added in Cortex 2.7.1
Last modified 2yr ago