Muse Direct  Available Data
Table of Contents
This is a list of all the data available from Muse Direct. For the data available from LibMuse, please see the API Reference for your platform.
EEG Data
Raw EEG
OSC Path  /eeg  
Units  uV  
Datatype  floats  
Resolution 


Range  0.0  1682.815 uV  
Sampling rate 


Channel configuration  [TP9, AF7, AF8, TP10] 
Notch Filtered EEG
OSC Path  /notch_filtered_eeg  
Units  uV  
Datatype  floats  
Resolution 


Range  0.0  1682.815 uV  
Sampling rate 


Channel configuration  [TP9, AF7, AF8, TP10] 
EEG Quantization Level
Datatype  float 
OSC path  /eeg/quantization 
OSC data format  f 
Range  1, 2, 4, 8, 16, 32, 64,128 
Accelerometer Data
Raw Accelerometer Data
 The gforce acting on a stationary object resting on the Earth’s surface is 1g (upwards) and results from the resisting reaction of the Earth’s surface bearing upwards equal to an acceleration of 1 g, and is equal and opposite to gravity. The number 1 is approximate, depending on location.
 The gforce acting on an object under acceleration can be much greater than 1g
For a visual representation of the axes, refer to the SDK API documentation
OSC Path  /acc  
Units  g  
Datatype  three floats  
Resolution 


Range  2  2g  
Sampling rate 

Gyroscope Data
Raw Gyroscope Data
For a visual representation of the axes, refer to the SDK API documentation
OSC Path  /gyro 
Units  degrees per second 
Datatype  three floats 
Resolution  16 bits 
Range  245, 245 degrees per second 
Sampling rate  52 Hz 
Muse Elements Data
FFT stands for Fast Fourier Transform. This computes the power spectral density of each frequency on each channel. Basically, it shows which frequencies make up a signal, and “how much” of each frequency is present.
Each FFT contains 129 decimal values with a range of roughly 40.0 to 20.0. Each array represents FFT coefficients (expressed as Power Spectral Density) for each channel, for a frequency range of 0110 Hz (Muse 2014) or 0128 Hz (Muse 2016) divided into 129 bins. We use a Hamming window of 1 second, then for the next FFT we slide the window 1/10th of a second over. This gives a 90% overlap from one window to the next. These values are used to compute the emitted algorithms.
Understanding Frequency Bins
The FFTs are calculated using a 256 sample window, which gives a transform that has 256 components and is symmetric (i.e. mirrored) around an additional component at 0Hz. In other words, you have 128 components, followed by one for 0Hz, and then the mirror image of the same components. This means you need only consider half of them (because the other half are the same, only reflected) plus the one for 0Hz at the centre, which gives you 129 in total.
To get the frequency resolution for the bins, you can divide the sampling rate by the FFT length, so in the case of Muse 2014: 220/256 ~ 0.86Hz/bin
So, the zeroth index of the FFT array represents 0Hz, the next index represents 00.86Hz, and so on up to 128*0.86 = 110Hz, which is the maximum frequency that our FFT with its 220Hz sampling rate can detect.
Absolute Band Powers
OSC Paths  /elements/delta_absolute /elements/theta_absolute /elements/alpha_absolute /elements/beta_absolute /elements/gamma_absolute 

Units  Bels (B)  
Datatype  floats  
Transmission frequency  10 Hz  
OSC Data Format  Four channels (electrode sites) for each band power: ffff  
Frequency Ranges* 

* The boundaries of the frequency ranges are inclusive of the end values. Where 2 ranges overlap, a frequency in the overlapping area counts in both ranges.
Relative Band Powers
The relative band powers are calculated by dividing the absolute linearscale power in one band over the sum of the absolute linearscale powers in all bands. The linearscale band power can be calculated from the logscale band power thusly: linearscale band power = 10^ (logscale band power).
Therefore, the relative band powers can be calculated as percentages of linearscale band powers in each band. For example:
alpha_relative = (10^alpha_absolute / (10^alpha_absolute + 10^beta_absolute + 10^delta_absolute + 10^gamma_absolute + 10^theta_absolute))
OSC Paths  /elements/delta_relative /elements/theta_relative /elements/alpha_relative /elements/beta_relative /elements/gamma_relative 

Units  Bels (B)  
Datatype  floats  
Transmission frequency  10 Hz  
OSC Data Format  Four channels (electrode sites) for each band power: ffff  
Frequency Ranges* 

* The boundaries of the frequency ranges are inclusive of the end values. Where 2 ranges overlap, a frequency in the overlapping area counts in both ranges.
Band Power Session Scores
The band session score is computed by comparing the current value of a band power to its history. This current value is mapped to a score between 0 and 1 using a linear function that returns 0 if the current value is equal to or below the 10th percentile of the distribution of band powers, and returns 1 if it’s equal to or above the 90th percentile. Linear scoring between 0 and 1 is done for any value between these two percentiles.
Be advised that these scores are based on recent history and it will take a few seconds before having a stable distribution to score the power against. The estimated distribution is continuously updated as long as the headband is on the head. However, every time it’s updated, the newest values are weighted to have more importance than the historical values. This means that eventually old values will not be present anymore in the estimated distribution. The halflife of the estimated distribution at any given point is around 10 s.
The score will start being calculated as soon as the headband has established a good connection with the skin. Whenever the headset loses connection with the head (as determined by the DRL/REF contact quality) the estimated distributions are reset. This means that when the headband is removed, the session data from any previous user will be cleared.
OSC Paths  /elements/delta_session_score /elements/theta_session_score /elements/alpha_session_score /elements/beta_session_score /elements/gamma_session_score 

Units  Unitless  
Datatype  floats  
Transmission frequency  10 Hz  
OSC Data Format  Four channels (electrode sites) for each band power: ffff  
Frequency Ranges* 

* The boundaries of the frequency ranges are inclusive of the end values. Where 2 ranges overlap, a frequency in the overlapping area counts in both ranges.
Headband Status
Headband On / Touching Forehead
OSC Path  /elements/touching_forehead 
Datatype  int 
Transmission frequency  10Hz 
Headband Status Indicator / Horseshoe
Status indicator for each channel.
1 = good, 2 = mediocre, 4 = bad
OSC Path  /elements/horseshoe 
Datatype  4 floats, 1 per channel 
Transmission frequency  10Hz 
Range  1 = Good 2 = Mediocre 4 = Bad 
Real Time EEG Quality
Strict data quality indicator for each channel, 0= bad, 1 = good.
OSC Path  /elements/is_good 
Datatype  4 ints, 1 per channel 
Transmission frequency  10Hz 
Range  0 = Bad 1 = Good 
Artifacts
Blinks
A boolean value, 1 represents a blink was detected.
OSC Path  /elements/blink 
Datatype  int 
Transmission Frequency  10Hz 
OSC Data Format  i 
Jaw Clenches
OSC Path  /elements/jaw_clench 
Datatype  int 
Transmission Frequency  10Hz 
Battery Data
OSC Path  /batt  
Datatype  3 floats  
Data format  [State of charge, Fuel gauge battery voltage, Temperature]  
Units 


Range 


Transmission frequency  0.1Hz 
DRL/Ref Data
The DrivenRightLeg (DRL) circuit has been used for about 50 years to reduce commonmode noise in biopotential amplifiers in applications that range from stationary equipment powered from the wall to batterypowered ambulatory monitors, and for systems that use gelled, dry, textile, and capacitive electrodes. The Driven Right Leg circuit is used to eliminate commonmode noise by actively cancelling it.
OSC Path  /drlref 
Datatype  2 floats 
Data format  [DRL voltage, REF voltage] 
Units  uV 
Range  0 to 3300000 
Sampling frequency  Same as EEG, depending on preset 