EmotivPRO v3.0
  • EmotivPRO
  • Getting started
    • System requirements
    • Install EMOTIV Launcher
    • Installing EmotivPRO onto your PC or Mac
    • Updating EmotivPRO
    • Logging into EmotivPRO
    • Creating an EmotivID and password
    • Forgotten password
    • Viewing your account information
    • Logging out of EmotivPRO
  • EmotivPRO license options
    • Purchasing an EmotivPRO license
    • Changing the number of seats in your license
    • Organization License
    • Using EmotivPRO offline
    • Cancelling your EmotivPRO license
  • Connecting your headset to EmotivPRO and fitting your headset
    • Connecting your EEG headset to EmotivPRO via Bluetooth
      • Bluetooth connection troubleshooting
    • Pairing your EEG headset with a USB receiver dongle
    • Connecting your EEG headset to EmotivPRO
    • Disconnecting your EEG headset from EmotivPRO
    • Fitting your EEG headset
    • Contact quality map
      • Contact Quality (CQ) vs. EEG Quality (EQ)
  • Using EmotivPRO
    • EmotivPRO home screen and menu
    • EEG quality indicator
    • Battery indicator
    • EPOC+ and EPOC X configurations
  • Data Streams
    • Real time data streams, recording, and playback
    • Raw EEG
    • Frequency Bands
    • Performance Metrics
    • Motion
    • Data Packets
  • Recordings
    • About recordings
    • Starting and stopping a recording
    • Baseline recording
    • Adding a note to a recording
    • Timer
  • Event markers
    • About event markers
    • Baseline markers
    • Serial port markers
    • Keystroke markers
    • USB markers
    • EMOTIV Extender triggering
  • Managing your EEG data recordings
    • Recordings history list
    • Cloud synchronization
    • Playing an EEG data recording
    • Deleting an EEG recording
    • Exporting an EEG data recording
      • EDF files
      • EDF+ / BDF+
      • CSV files
      • JSON files
    • Editing an EEG data recording note
    • Closing a recording
    • Timestamp correction
  • Lab Streaming Layer (LSL)
    • About LSL
    • LSL Outlet
    • LSL Inlet
  • D-Lab Client
    • About D-Lab Client
    • Exporting D-Lab settings from EmotivPRO
    • Starting a Network Data Stream
    • Creating recordings on D-Lab
  • Exported data files
    • Opening a locally saved EDF file
    • Converting EDF files to CSV files
  • Notes on the data
    • DC Offset
    • Code Examples
  • EmotivPro Builder
    • Building experiments with EmotivPRO Builder
  • EmotivPRO Analyzer
    • Analyzing your EEG data with EmotivPRO Analyzer
  • Using Organization Licensing
    • Important notes on Organization Licensing
    • Licensing
    • User roles and permissions
    • Inviting users
    • Accepting an Organization invitation
    • Removing users
    • Organization Data Sharing
  • Release Notes
    • v3.0
    • v3.0.1
    • v3.2
    • v3.2.1
    • v3.3
    • v3.4.1
    • v3.5
    • v3.5.3
    • v3.7.0
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On this page
  • What is EEG Quality?
  • How is EEG Quality Different to Contact Quality?
  • Okay, but what actually is EQ?
  • How is Overall EQ Calculated?
  1. Connecting your headset to EmotivPRO and fitting your headset
  2. Contact quality map

Contact Quality (CQ) vs. EEG Quality (EQ)

What is EEG Quality?

EEG Quality (EQ) has been built to give you an easy way to assess whether you are recording high quality brain signals or not. Basically, it is a scoring system for the quality of the signal in each sensor. Each sensor is given a black, red, orange, light green or dark green colour to indicate the quality of the EEG signal for that specific sensor.

Overall EEG Quality as displayed in your EMOTIV application is presented as a score of 0-100. This number makes it easy to understand the quality of your signal at a glance. How do we calculate it? See below.

How is EEG Quality Different to Contact Quality?

Contact Quality is a simple measurement of impedence of the channel. While this measurement is used widely in neuroscience and medical settings, it is really only a useful reading to a trained EEG professional and does not give the full picture on the quality of the signal. Signals that have low impedance are not necessarily brain signals - and you might have found that sitting your headset on the table can produce a false positive - leading the user to falsely believe they are recording high quality brain data.

Okay, but what actually is EQ?

EEG Quality is a machine-learning trained algorithm that automatically determines the quality of the signal based on multiple metrics. Each of these metrics are important in assessing whether the recording data accurately captures the underlying brain signal. These metrics include

  • Contact Quality (CQ) (as above) - an impedance measurement that indicates the quality of the electrical signal passing through the sensors and the reference. It can be one of 4 values: 0 - very bad (black), 1 - bad (red), 2 - ok (orange) and 4 - good (green).

  • ML Signal Quality (SQ): A machine learning algorithm trained on high quality EEG recordings that were assessed and collected by the EMOTIV Research team. The Signal Quality algorithm assess data over 2 seconds and is scored 0 - very bad (black), 1 - bad (red), 3 (light green) and 4 -good (dark green)

  • Signal Magnitude Quality (SMQ): A measure of the signal amplitude. Sometimes, the above metrics i.e. CQ, SQ are good but the signal amplitude is very small and therefore small power fluctuations in the FFT would be undetectable. Often, this is due to poor sensor hydration or poor scalp contact. SMQ gives scores for the average signal magnitude within a 2 second epoch. The scores can be 0 - very low (black), 1 - low (red), 4 - ok (green).

Each of these metrics are important in determining the quality of the signal, therefore the sensor colour will not be dark green unless all of these metrics have a “good” score of 4. The “EQ Map” UI in your EMOTIV software displays the minimum score of any of these metrics. The resulting EQ Score for each channel can be 0,1,2,3,4 corresponding to the colours black, red, orange, light green and dark screen, respectively.

How is Overall EQ Calculated?

Overall EQ is calculated and displayed as a number out of 100 so you can see your EEG Quality for all channels at a glance. Overall EQ is calculated as the sum of the worst 3 channels divided by the sum of the maximum score of these 3 channels, as a percentage. The resulting mathematical formula is (min1 + min2 + min3 / 12) * 100.

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Last updated 3 years ago