Deafening Strike( Complete Scoundrel, p. 76)
Your stealthy attack leaves your foe's head ringing.
Sneak attack +4d6,
Your successful sneak attack causes the target to be deafened for 3 rounds. If you use this feat a second time on a target before 3 rounds have elapsed, the effect of the first use expires. Using this feat reduces your sneak attack damage by 3d6.