- Email: [email protected]
Voiced images, imagined voices
BIOL PSYCHIATRY 1990;27:811-812
811
EDITORIAL
Voiced Images, Imagined Voices The correspondence by Lauterbach in this issue has evoked some thoughts on tile problem of auditory hallucinations. The voices that so continually and insistently plague many schizophrenics have long tantalized students of the disordered mind. That they are generated in the patient's own mind (brain) one can hardly doubt, but what is generatedm the percept of the speech, or the speech that is perceived? i shall argue that this facevalid antithesis is ill conceived. Both propositions are correct, and both designate the same central events. We can use three data sets as basis for our conclusions: information about motor concomitants of hallucinations, maneuvers that suppress them, and how the voices sound and what they say. A sparse and spotty literature spanning many decades has documented what is taken to be articulatory activity accompanying auditory hallucinations (AH). One reported case even whispered the statements that he said he heard (Gould 1949). This work is inadequately controlled, both for the precise timing of the subvocal activity attributed to the auditory hallucinations, and for whether it is specifc or reflects the general level of somatic and muscle activity (Green and Kinsbourne, submitted). When such controls are attempted (Junginger and Rauscher 1987, Green and Kinsbourne 1989), the results have not been unequivocal. Nonetheless, the burden of evidence favors subvocalization as a tenable correlate of auditory hallucinations. Do patients hear the voices, or think in words and hear what they thought? In the former view the subvocalizations are causally irrelevant sequelae (repeating, or shadowing, what is heard). In the latter view subvocal speech is the source of the hallucinated experience. If so, then immobilizing (Bick and Kinsbourne 1987) or otherwise engaging the muscles of articulation (Green and Kinsbourne 1q89) should temporarily suppress auditory hallucinations, and this appears to be the case. Nor is this a nonspecific consequence of exerted effort, as this artefact was controlled. In contrast, reports that speech input reduces auditory hallucinations (e.g., Collins et al. 1989) could represent nonspecific diversion of attention to the novel input. It seems likely therefore that patients do generate (verbally encode) the speech that they hear. Hoffman (1986) has argued that hallucinating schizophrenics are deficient in intentionality when they formulate internal verbal discourse. If unintended, a verbal image might be referred to an outside agency. However, the hypothesized lack of intention is somewhat posthoc and it remains unclear why the utterances are so stereotyped, often pejorative, in the second rather than first person, and even in the voice of someone of different age and the opposite gender. They do not appear like a random selection of the patient's thoughts. A deficiency shared by otherwise diverse neurological theories of auditory hallucinations is their failure to relate this phenomenon to the central abnormality in schizophrenia: the thought disorder, specifically the delusions and deluded expectations. Do the voices simply say what the patient expects to hear, in the voice of the person from whom he expects it? Can intense expectation engender the percept, even without corresponding © 1990 Society of Biological Psychiatry
0006.3223/90/$03.50
812
BIOL PSYCHIATRY 1990;27:811-812
Editorial
physical stimulation, and would such anticipated speech be coded in terms of subvocal articulatory gestures? It is commonplace that one can image experiences in diverse modalities. Why might this capability have evolved? .Arbitrary out-of-context imaging may have entertainment value only, but if the image were an essential ingredient of voluntary selective attention, then its adaptive potential is readily understood. Neisser (1976) described images as perceptual anticipations and Farah (1989) has experimentally demonstrated that visual images lower detection criteria for corresponding physical stimuli. The image encodes the experience in anticipation. If the expectation is sufficiently intense (criterion sufficiently low), could it be mistaken for the expected event (as colorful accounts of the fallibility of eyewitness testimony imply)? In the absence of auditory input, imaged speech could be encnded in articulatory gestures--the same that, intentionally disinhibited, would realize corresponding speech. Basal ganglia overactivity could contribute (Lauterbach 1990, this issue). Engaging speech musculature in alternative activity would then impede the formation of the anticipatory percepts and reduce the incidence of auditory hallucinations. This selective attention hypothesis has the advantage that it explains the content and quality of the voices, as the patient's inner speech simulating another's voice and the message that he expects of the other. Is this an input or an output model? Both, in one. The patient generates what he hears and hears what he generated. If correct, this sequence of events illustrates the spurious nature of the supposed antithesis between the dynamic and the neurologic. The disordered thought generates the deviant physiology. No doubt, also, disordered physiology generates the disordered thought. But that is another story. Marcel £insbourne
References Bick PA and Kinsboume Id ( 1987): Auditory hallucinations and subvocalizations in schizophrenics. Am J Psychiatry 14:222-225. Collins MN, Cull CA, and Sireling L (1989): Pilot study of treatment of persistent auditory hallucinations by modified auditory input. Br Med Y 299:431--432. Farah MJ (1989): Mechanism of imagery-perception interaction. Y Exp Psychol [Hum Percept] 15:203-211. Green MF and Kinsbourne M (submitted): Subvocal activity and auditory hallucinations: Clues for behavioral treatment? Green MF, Kinsbourne M (1989): Auditory hallucinations in schizophrenia: Does humming help? Biol Psychiatry 25:630-633. Hoffman RE (1986): Verbal hallucinations and language production processes in schizophrenia. Behavioral Brain Science 9:503-548. Lauterbach, EC (1990): Humming, auditory hallucinations, and dystonia [Correspondence] Biol Psychiatry 27:934-935. Ncisser, U (1976): Cognition and Reality. San Francisco: Freeman.
811
EDITORIAL
Voiced Images, Imagined Voices The correspondence by Lauterbach in this issue has evoked some thoughts on tile problem of auditory hallucinations. The voices that so continually and insistently plague many schizophrenics have long tantalized students of the disordered mind. That they are generated in the patient's own mind (brain) one can hardly doubt, but what is generatedm the percept of the speech, or the speech that is perceived? i shall argue that this facevalid antithesis is ill conceived. Both propositions are correct, and both designate the same central events. We can use three data sets as basis for our conclusions: information about motor concomitants of hallucinations, maneuvers that suppress them, and how the voices sound and what they say. A sparse and spotty literature spanning many decades has documented what is taken to be articulatory activity accompanying auditory hallucinations (AH). One reported case even whispered the statements that he said he heard (Gould 1949). This work is inadequately controlled, both for the precise timing of the subvocal activity attributed to the auditory hallucinations, and for whether it is specifc or reflects the general level of somatic and muscle activity (Green and Kinsbourne, submitted). When such controls are attempted (Junginger and Rauscher 1987, Green and Kinsbourne 1989), the results have not been unequivocal. Nonetheless, the burden of evidence favors subvocalization as a tenable correlate of auditory hallucinations. Do patients hear the voices, or think in words and hear what they thought? In the former view the subvocalizations are causally irrelevant sequelae (repeating, or shadowing, what is heard). In the latter view subvocal speech is the source of the hallucinated experience. If so, then immobilizing (Bick and Kinsbourne 1987) or otherwise engaging the muscles of articulation (Green and Kinsbourne 1q89) should temporarily suppress auditory hallucinations, and this appears to be the case. Nor is this a nonspecific consequence of exerted effort, as this artefact was controlled. In contrast, reports that speech input reduces auditory hallucinations (e.g., Collins et al. 1989) could represent nonspecific diversion of attention to the novel input. It seems likely therefore that patients do generate (verbally encode) the speech that they hear. Hoffman (1986) has argued that hallucinating schizophrenics are deficient in intentionality when they formulate internal verbal discourse. If unintended, a verbal image might be referred to an outside agency. However, the hypothesized lack of intention is somewhat posthoc and it remains unclear why the utterances are so stereotyped, often pejorative, in the second rather than first person, and even in the voice of someone of different age and the opposite gender. They do not appear like a random selection of the patient's thoughts. A deficiency shared by otherwise diverse neurological theories of auditory hallucinations is their failure to relate this phenomenon to the central abnormality in schizophrenia: the thought disorder, specifically the delusions and deluded expectations. Do the voices simply say what the patient expects to hear, in the voice of the person from whom he expects it? Can intense expectation engender the percept, even without corresponding © 1990 Society of Biological Psychiatry
0006.3223/90/$03.50
812
BIOL PSYCHIATRY 1990;27:811-812
Editorial
physical stimulation, and would such anticipated speech be coded in terms of subvocal articulatory gestures? It is commonplace that one can image experiences in diverse modalities. Why might this capability have evolved? .Arbitrary out-of-context imaging may have entertainment value only, but if the image were an essential ingredient of voluntary selective attention, then its adaptive potential is readily understood. Neisser (1976) described images as perceptual anticipations and Farah (1989) has experimentally demonstrated that visual images lower detection criteria for corresponding physical stimuli. The image encodes the experience in anticipation. If the expectation is sufficiently intense (criterion sufficiently low), could it be mistaken for the expected event (as colorful accounts of the fallibility of eyewitness testimony imply)? In the absence of auditory input, imaged speech could be encnded in articulatory gestures--the same that, intentionally disinhibited, would realize corresponding speech. Basal ganglia overactivity could contribute (Lauterbach 1990, this issue). Engaging speech musculature in alternative activity would then impede the formation of the anticipatory percepts and reduce the incidence of auditory hallucinations. This selective attention hypothesis has the advantage that it explains the content and quality of the voices, as the patient's inner speech simulating another's voice and the message that he expects of the other. Is this an input or an output model? Both, in one. The patient generates what he hears and hears what he generated. If correct, this sequence of events illustrates the spurious nature of the supposed antithesis between the dynamic and the neurologic. The disordered thought generates the deviant physiology. No doubt, also, disordered physiology generates the disordered thought. But that is another story. Marcel £insbourne
References Bick PA and Kinsboume Id ( 1987): Auditory hallucinations and subvocalizations in schizophrenics. Am J Psychiatry 14:222-225. Collins MN, Cull CA, and Sireling L (1989): Pilot study of treatment of persistent auditory hallucinations by modified auditory input. Br Med Y 299:431--432. Farah MJ (1989): Mechanism of imagery-perception interaction. Y Exp Psychol [Hum Percept] 15:203-211. Green MF and Kinsbourne M (submitted): Subvocal activity and auditory hallucinations: Clues for behavioral treatment? Green MF, Kinsbourne M (1989): Auditory hallucinations in schizophrenia: Does humming help? Biol Psychiatry 25:630-633. Hoffman RE (1986): Verbal hallucinations and language production processes in schizophrenia. Behavioral Brain Science 9:503-548. Lauterbach, EC (1990): Humming, auditory hallucinations, and dystonia [Correspondence] Biol Psychiatry 27:934-935. Ncisser, U (1976): Cognition and Reality. San Francisco: Freeman.