An EMG Study of the Lip Muscles During Covert Auditory Verbal Hallucinations in Schizophrenia

Abstract

Purpose: Auditory verbal hallucinations (AVHs) are speech perceptions in the absence of a external stimulation. An influential theoretical account of AVHs in schizophrenia claims that a deficit in inner speech monitoring would cause the verbal thoughts of the patient to be perceived as external voices. The account is based on a predictive control model, in which verbal self-monitoring is implemented. The aim of this study was to examine lip muscle activity during AVHs in schizophrenia patients, in order to check whether inner speech occurred.Methods: Lip muscle activity was recorded during covert AVHs (without articulation) and rest. Surface electromyography (EMG) was used on eleven schizophrenia patients. Results:Our results show an increase in EMG activity in the orbicularis oris inferior muscle, during covert AVHs relative to rest. This increase is not due to general muscular tension since there was no increase of muscular activity in the forearm muscle. Conclusion:This evidence that AVHs might be self-generated inner speech is discussed in the framework of a predictive control model. Further work is needed to better describe how the inner speech monitoring dysfunction occurs and how inner speech is controlled and monitored. This will help better understanding how AVHs occur.

Removing speech artifacts from electroencephalographic recordings during overt picture naming

“…Instead, it has been used to study, for instance, silent recitation (Livesay et al, 1996), speech in stutterers (Choo et al, 2010), covert verbal hallucinations in schizophrenia (Rapin et al, 2013), and articulation by aging participants (Rastatter et al, 1987b) and by articulatory disordered children (Rastatter et al, 1987a). The muscle complex that has typically been focused on is the orbicularis oris (OO), which is situated in the lips and controls lip posture during overt speech.…”

Modulation of articulation muscles during listening and reading: a matter of intention to speak out loud

“…Previous studies have shown subtle muscle activity in speech musculature using sEMG during verbal mental imagery, silent reading, and silent recitation (Jacobson, 1931;Livesay, Liebke, Samaras, & Stanley, 1996;McGuigan & Dollins, 1989). Also, activity in the OOI and the STH muscles was significantly higher when patients with schizophrenia reported hallucinations (Rapin, Dohen, Polosan, Perrier, and Loevenbruck, 2013). Lip muscles activation, as recorded in sEMG, was higher during covert speech, compared to activation in a silent visualization task (Livesay et al, 1996).…”

The Linguistic Determination of Conscious Thought Contents

“…We think that we can explain the sense of agency experienced when thinking if we move in that direction. Even though the application of the model to the cognitive domain may not be straightforward (see, e.g., Frith, 2012;Vicente, 2014), it is plausible that models such as those proposed by Rapin et al (2013), Swiney and Sousa (2014) and L{venbruck et al (forth. ), which explain agency in inner speech in terms of comparisons between goal states and predicted states, could also explain agency in UT.…”