Tinnitus, Tinnitus Disorder, and Other Phantom Perceptions

Tinnitus is a phantom perception, analogous to hallucinations, visual snow, or some forms of chronic pain. These phantom perceptions can be associated with affective, cognitive, and behavioural symptoms, which are largely defining the related distress and the functional disability. Accordingly, it has recently been proposed that tinnitus without and with suffering (or distress) should be differentiated by distinct terms: “tinnitus” for the former and “tinnitus disorder” for the latter. “Tinnitus” was defined as ‘the conscious awareness of a tonal and/or noise sound for which there is no identifiable corresponding external acoustic source’. By contrast, “tinnitus disorder” was defined as ‘tinnitus plus tinnitus-associated suffering with or without functional disability.’ Tinnitus was further differentiated in objective and subjective, pulsatile and non-pulsatile, constant and intermittent, or acute and chronic. Whereas tinnitus is a simple or elementary form of auditory phantom perception, musical hallucinosis and verbal hallucinations are more complex auditory phantom phenomena not only limited to sound perception, but also containing semantic content. Whereas verbal hallucinations are a typical feature of a psychiatric condition (i.e. psychosis or schizophrenia), musical hallucinosis commonly results from severe auditory deprivation, deafferentation, or deafness without altered consciousness. Hallucinations can also occur in other sensory modalities—visual, olfactory, gustatory, tactile, proprioceptive, vestibular, nociceptive, thermoceptive, and chronoceptive. Hallucinations can be associated with sensory deprivation, drug use (particularly deliriants), sleep deprivation, psychosis, neurological disorders, and delirium tremens.