For human beings across the world, trance dance has been the most prolific way by which we connect with the spiritual. They all danced. But trance is really nothing more than another word for meditation. When you meditate, you sit in silence for extended periods of time until the mind empties out and you become an empty vessel. Then your spirit can surface.
Trance is the same way, except the doorway is different.
It's done through catharsis. It's done through rhythm, sound and movement of the body. What occurs, either in that movement or at the end of that movement, is trance, a very deep meditational state. Traditionally, trance dance has always been accompanied by the rhythms of drumming. Instinctively, we know that sound.