Orofacial muscle activity during inner speech and auditory verbal hallucinations: implications for a speech control model

Lucile Rapin (1) , Marion Dohen (1) , Lionel Granjon (1) , Mircea Polosan (2) , Pascal Perrier (3) , Hélène Loevenbruck (1)

1 GIPSA-PCMD - GIPSA - Perception, Contrôle, Multimodalité et Dynamiques de la parole
2 Service de Psychiatrie
3 GIPSA-MAGIC - GIPSA - Machines parlantes, Gestes oro-faciaux, Interaction Face-à-face, Communication augmentée

Auditory verbal hallucinations (AVHs) are a stressful symptom of schizophrenia, affecting 50% to 80% of the patients. AVHs are defined as speech perceptions in the absence of an external auditory stimulus. Some theories explain AVHs as a distortion in the production of inner speech (IS) in a way that the verbal thoughts of the patient are perceived as external voices. These theories can be implemented in the context of a speech motor control model in which the sense of agency derives from the comparison between the predicted and the actual outputs. According to these theories, during IS production in schizophrenia, deficits could arise in the prediction system, disrupting the feeling of agency and leading to hallucinations. The aim of this study was to examine orofacial activity during inner speech in healthy control subjects and during the occurrence of AVHs in schizophrenia patients. 11 French schizophrenia patients and 12 French healthy controls subjects participated in the study. Surface electromyography recordings were obtained in several conditions from 2 orofacial speech muscles: orbicularis oris superior (OOS) and orbicularis oris inferior (OOI) as well as from the nondominant forearm flexor (FF) muscle. The increase in OOI activation from rest to the AVH condition in schizophrenia patients suggests that there could be a speech related muscular activity during AVHs. Our results support the theories according to which AVHs are the consequence of a misattributed IS production: there would be a correct IS production (revealed by muscular activity increase) and a conflict would then take place in the prediction system.

Mots clés: schizophrenia; auditory verbal hallucinations; speech monitoring; electromyography; speech motor control model; inner speech

Domaines: Linguistique; Neurosciences; Linguistique

Lucile Rapin, Marion Dohen, Lionel Granjon, Mircea Polosan, Pascal Perrier, et al.. Orofacial muscle activity during inner speech and auditory verbal hallucinations: implications for a speech control model. ISSP 2011 - 9th International Seminar on Speech Production, Jun 2011, Montréal, Québec, Canada. pp.Abstract #20. ⟨hal-00613902⟩