Sensory deprivation tanks can be used for a variety of reasons.
What is Sensory Deprivation?
Sensory deprivation is also known as perceptual isolation, and it involves removing or reducing stimuli from at least one of the senses. Beyond earmuffs or blindfolds for blocking hearing and vision, there are devices that can cut off touch, smells, taste, gravity, and heat-sense (thermoception). Chamber REST and flotation REST are two types of Restricted Environmental Stimulation Therapy. Subjects involved in chamber REST lie down on a bed in a dark and sound-reduced room for about 24 hours. Flotation REST involves a pool or tank filled with a “flotation medium…of a skin-temperature solution of water and Epsom salts” that allow the patient to float. Sessions last about an hour, and subjects may experience itchiness for the majority of that time (similar to early meditation stages). Subjects generally “transition from beta or alpha brainwaves to theta”, which are waves that occur before sleep and waking.1 The solution in the isolation tank of salt and water is designed to increase density so that the subject can float. Ear plugs are typically used. Users need to be freshly showered (to remove body oils) and often remain unclothed in the tank in order to reduce stress points. After use, subjects must bathe to remove the salts, and white vinegar is needed to rinse out the hair and ears. Disinfection issues have been raised, since the water in these tanks is “rarely changed” because of the “high salt content”. H2O2 (hydrogen peroxide) is considered a safe cleaning agent for the enclosed air space. Tanks are also treated with cartridge filtration, a surface skimmer and “ultraviolet sterilization and chemicals”2
Uses of Sensory Deprivation Chambers
Alternative medicine and psychology experiments have used sensory deprivation methods in order to promote meditation and relaxation. It is important to note that long term or forced deprivation can lead to depression, anxiety, bizarre thoughts, and hallucinations. Flotation therapy has been found to have positive results of relaxation, reduced stress, improved blood flow, and lower blood pressure. REST is used therapeutically to treat smoking, alcoholism, and drug use, as well as other conditions.3 Isolation tanks have a history of use back to John C. Lilly testing sensory deprivation in 1954. Modern tanks are used in alternative medicine, meditation, and relaxation. Users may perform self-hypnosis and mantras, or “utilize educational programs”. Flotation therapy also has a role in complementing other body work, such as massage, or in conjunction with talk therapy and hypnosis. Recent studies have shown that flotation therapy can help patients with fibromyalgia, depression, anxiety, and stress.4 Lilly believed that flotation tanks could allow him to contact “creatures from other dimensions” and other, more advanced civilizations. Comedian Joe Rogan has described his experiences as containing “hallucinations,…introspection, and the sensation that the mind has left the body”.5 The hallucinations seem to be a result of “faulty source monitoring”, which is when the brain mistakes the source of the experience. For some people, thoughts become misidentified as experiences coming from outside, leading to hallucination, according to Oliver Mason, a psychologist. Researchers are working on finding out how sensory deprivation affects patients who have schizophrenia.6
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