Also referred to as motor hallucination, motor verbal hallucination, psychomotor verbal hallucination, and muscular verbal hallucination. The term subvocalization comes from the Latin words sub (beneath) and vox (voice). It refers to a process involving subtle instances of motor activity within the larynx and/or vocal cords that may or may not be accompanied by * verbal auditory hallucinations. The affected individual may even be convinced that he or she is speaking out loud, while this is not the case. As demonstrated by the American psychiatrist Louis N. Gould in 1949, the condition may be accompanied by faint whispers and recordable electromyographi-cal activity in the chin and the lip. In 1966, the American psychologist Frank Joseph McGuigan (1924-1998) succeeded in recording intelligible whispers in instances of subvocalization, using a pair of throat microphones attached to the skin over the larynx. A similar experiment was carried out during the 1980s. The male subject in this latter experiment asserted that the whispers he heard coincided with a hallucinated female voice. For a time, it was hoped that discoveries like these would be exemplary for all auditory hallucinations, but this has not proved to be the case. Experiments such as those by Gould and McGuigan may well have been inspired by the work of the Scottish paranormal researcher John B. M'Indoe (also spelled McIndoe), who used a sensitive telephone transmitter attached to the larynx of a medium in order to demonstrate subvocalization in cases of the * direct voice phenomenon. Subvocalization is sometimes classified as a variant of the group of *kinaesthetic hallucinations and sometimes as a variant of the group of * proprioceptive hallucinations. The French psychiatrist Louis Jules Ernest Séglas (1856-1939), who may well have been the first to describe a similar phenomenon in 1888 under the name *psychomotor hallucination, classified it as atypeof * verbal hallucination. It is often possible to interrupt voices concomitant to subvocaliza-tion by holding one's mouth wide open, holding a small amount of water in the oral cavity, humming a note or speaking out loud.
References
Gould, L.N. (1949). Auditory hallucinations and subvocal speech: Objective study in a case of schizophrenia. Journal of Nervous and Mental Disease, 109, 418-427.
Green, P., Preston, M. (1981). Reinforcement of vocal correlates of auditory hallucinations by auditory feedback: A case study. British Journal of Psychiatry, 139, 204-208.
McGuigan, F.J. (1966). Covert oral behaviour and auditory hallucinations. Psychophysiology, 3, 73-80.
Dictionary of Hallucinations. J.D. Blom. 2010.