Also referred to as acoasm, acousma, and akoasmic noise. All four terms stem from the Greek verb akouein, which means to hear. The term akoasm was introduced in or shortly before 1900 by the German neurologist Carl Wernicke (18481904) to denote relatively simple, *nonverbal (or *nonvocal) auditory hallucinations such as buzzing sounds, rappings, and rustling noises. Wernicke used the term akoasm in opposition to the term * phoneme (which is used as a synonym for * verbal auditory hallucination).
References
Wernicke, C. (1900). Grundriss der Psychiatrie. Leipzig: Verlag von Georg Thieme.
Critchley, M. (1939). Visual and auditory hallucinations. British Medical Journal, 2, 634-639.
Blom, J.D., Sommer, I.E.C. (2009). Auditory hallucinations. Cognitive and Behavioral Neurology (in press).
Dictionary of Hallucinations. J.D. Blom. 2010.