In some practices for crossing the hedge, or travelling between the worlds, disorientation often plays a part in such. For anyone who has experienced sleep deprivation, he or she knows that disorientation often accompanies the inability (or perhaps choosing not to sleep and for other various reasons) to sleep.
Sleep deprivation is a technique some shamans or crossers use to aid in walking between the worlds. Sleep deprivation provides such a sense of detachment from one's physical body. This sense of detachment provides the ease of walking between the worlds as one may not necessarily feel as they are grounded, or "in the moment", being that they do not feel like they are currently within their own world (Midgard).
Personally, sleep deprivation is one of my preferred techniques to walk between the worlds for reasons as I stated above. Sleep deprivation gives me such a feeling of detachment that if I start to dance or listen to drumming, my disorientation and sense of detachment from my physical body increases threefold, resulting in the ultimate goal of travelling down into the Underworld.