Shannon criteria
In neural engineering, the Shannon criteria constitute an empirical rule that is used for evaluation of possibility of damage from electrical stimulation to nervous tissue. The Shannon criteria relate two parameters for pulsed electrical stimulation: charge density per phase, D (μCoulombs/(phase•cm²)) and charge per phase, Q (μCoulombs/phase) with a dimensionless parameter k: log D = k − log Q {\displaystyle \log D=k-\log Q} which can be written alternatively: 10 k = Q ∗ D {\displaystyle 10^{k}=Q*D} According to these criteria, stimulation parameters that yield k ≥ 1.85 (the lowest value where damage was observed in the two studies referenced in the original Shannon publication) could cause damage to the adjacent nervous tissue.