Therefore, its known narrative elements are not a part of the Doctor Who universe as we, on this Wiki, choose to define it. It may have been the basis for a similar story in another medium, however — and that story may indeed be valid.
The Brain-Dead was an unproduced story written by Brian Hayles for Season 9. The idea was submitted in the spring of 1971 but was rejected by script editor Terrance Dicks. Its inclusion of the Ice Warriors led to the development of The Curse of Peladon, however.
In particular, the Ice Warriors can use it to freeze a human brain, turning the afflicted individual into a subservient Brain-Dead. The Ice Warriors hijack a communications satellite and use it to take over the crew of its receiving station, whom they set to work constructing a giant "Z" beam transmitter. They plan to use the satellite network to broadcast the "Z" beam around the world, enslaving mankind and adjusting the Earth's climate to something suitable for Martian habitation. Realising that metals are extremely conductive at absolute zero, the Third Doctor overloads the "Z" beam transmitter just at the point of broadcast, destroying the Ice Warriors and the Brain-Dead. (REF: The Seventies)