Psychic nullifier (Fallout)

A psychic nullifier is a device placed on the head of a psyker to disable or prevent him or her from using his or her powers. A psychic nullifier also blocks incoming telepathic attacks when worn by a non-psyker, such as those frequently experienced in the Corridor of Revulsion. The Vault Dweller can obtain one to aid in passing through the Corridor of Revulsion on the way to the Master.

Fallout: New Vegas
Beneath the 188 Trading Post is a Psyker known as The Forecaster. He wears one of these as "headache medicine".