Engagement Index

[MMEI]

Hi James,

Many thanks for a great App. I am trying to calculate the Engagement Index from data provided by Mind Monitor (Beta/Alpha+Theta) - I just wanted to clarify whether the below is correct when trying to work out the Relative Power of each Band.

The CSV provides absolute values for each Channel (e.g. Theta_TP9), but not the absolute values for each Band (e.g. Theta). These have undergone logarithmic transformation which is why some of the values are negative (as explained here https://web.archive.org/web/20181105231 ... and_Powers).

Method 1:

To calculate the Relative Power of each Band Channel e.g. for Theta TP9:

10^Theta_TP9/10^Delta_TP9+10^Theta_TP9+10^Alpha_TP9+10^Beta_TP9+10^Gamma_TP9) = Theta TP9 Relative Power

Then take the average of all Theta Band Relative Power values to obtain Theta Relative Power:

Average(Theta_TP9+Theta_TP10+Theta AF7+Theta AF8) = Theta Band Relative Power

Method 2

Alternatively, am I correct in saying that to calculate the Absolute Band Power you can simply:

Sum(Theta_TP9+Theta_TP10+Theta AF7+Theta AF8) = Theta Band Absolute Power

Followed by this calculation taken from the technical manual:

Theta_relative = (10^theta_absolute / (10^alpha_absolute + 10^beta_absolute + 10^delta_absolute + 10^gamma_absolute + 10^theta_absolute))

Many thanks for your help.

[James]

You are missing some braces in #1 and in #2 for the single value band power just average the channels with sum divided by count.

I would also recommend you also check the HSI and exclude any channels with poor data quality.

I'd go with #2, but they should work out the same. Just note that average is sum/count, not just adding up.