Sensory deprivation is the lack of sensory stimulus perception (sight, hearing, etc.) by experimentally taking away one or more of the senses. Sensory deprivation can be experienced in a simple manner by being blindfolded (that would eliminate the sense of sight) or by using earplugs (that would eliminate the ability to hear sound).
More complex sensory deprivation can be experienced in isolation tanks which cut off most or all of the senses. While short term sensory deprivation can be pleasant and meditative and is sometimes used for therapeutic reasons, prolonged sensory deprivation can lead to cognitive, behavioral, or perceptual alterations including hallucinations, depression, or anxiety. A clinical behavioral usage of sensory deprivation can be used with children with Down Syndrome and Autism Spectrum Disorders. Both of these conditions cause children to experience sensory stimuli in different and unpleasant ways. They can either be too responsive to sensual stimuli (causing the child to be overwhelmed) or not responsive enough. By using sensory deprivation the caregiver can reduce the overwhelming stimuli and slowly reintroduce it back to the child in order for them to grow accustomed and not be hyper-stimulated by their senses being overloaded.