Sensory deprivation is the removal of external stimuli. It can range from the use of blindfolds and headphones to block out light and noise to immersion in a salt water tank to similarly prevent exposure to light, sound, touch, smell and taste.
Short term sensory deprivation is often used as anti-anxiety therapy, as the removal of stimuli can aid in relaxation and meditation. However, even after a few hours, prolonged sensory deprivation can lead to anxiety, hallucinations and even psychosis.
In House's Head, House puts himself in an isolation tank in an attempt to induce the hallucinations that have been providing him with clues about a person he saw before a bus crash he is sure whose life is threatened.