"ESSENCE INDEX"

Commonly confused with Essence, the Essence Index determines how many points 
of Bioware a runner's body can accept before it has adverse effects on the body.
Essence Index is determined by the current Essence rating + 3.  For example, 
someone with an Essence of 6 has an Essence Index of 9. Once Bioware exceeds the 
Essence Index, damage overflow ratings and healing rates are reduced with every 
point of Bioware that exceeds the EI.
For example, if the total bio index lost is 5 points, and your essence index is 4, 
then you lose 1 point of physical overflow damage and your healing rates are reduced.

^WSee also: ESSENCE, BIOWARE INDEX, ATTRIBUTES^n