Clairvoyant Psychic mediums have different ways of seeing things. This has been labelled as paranormal behaviour because it goes out of the scope of the five senses. Clair means clear.
Clairsentient psychic mediums which means to sense things. Be able to psychically pick things up whether it be physical items that have perhaps been lost or spirit that have passed over. This can be what they looked like, what food they liked, mannerisms etc. From this they can sense the messages the passed over loved one wants to give. Animals also come through because they are felt.
Clairaudient is being able to hear the voices of passed over loved ones. These messages can then be given to the person having a reading.
Clairvoyance Is being able to see spirit. The lost loved one and the clairvoyant are then able to communicate to give messages to the person having the reading.
Claircognizant is having feelings of just knowing spirit is there. They can know where they lived, how they died, their names and other factors that would be deemed paranormal.