Approximately 1% of the general population will be affected by schizophrenia over the course of their lives, with life expectancy being reduced by 20 years on average and quality of life being severely diminished in affected individuals. One third of patients suffering from schizophrenia will evolve towards a resistant form of the disease, amongst which many will suffer from auditory-verbal hallucinations (AVH) that current therapeutic approaches struggle to alleviate. Previous work from our team has demonstrated the possibility of robustly inferring the periods of occurrence of AVH from fMRI data, paving the way for the development of a closed-loop neuromodulation system comprised of an electrode array positioned in Broca's area, which would detect AVH in real time, and effector electrodes which would stimulate the temporo-parietal cortex to interrupt them. The aim of this project is to assess the feasibility of this system. To do so, we will first test the ability of transcranial magnetic stimulation of the "continuous theta burst" (cTBS) type, applied at the time of AVH onset, to reduce their duration and intensity, and assess whether this is associated with therapeutic response to the current gold standard rTMS protocol for AVH reduction through neuroplasticity induction. Demonstrating the feasibility of acute suppression of AVH by cortical neurostimulation is an essential element in the feasibility of a closed-loop reactive neuromodulation system.
The research project comprises two phases:
-Phase 1: randomized controlled clinical trial (1 weekly session per patient over 12 weeks: 6 active stimulation sessions and 6 sham sessions) evaluating the phasic effects of rTMS on AVHs as they appear during the sessions.
Phase 2: open-label study offering patients a routine rTMS protocol which has demonstrated its effects on AVH (10 TMS sessions over one workweek - twice daily with 1-hour intervals, MULTIMODHAL study, NCT01373866).
Age > 18 years old
Schizophrenic Disorder (Diagnostic and statistical manual of mental disorders, DSM-5-TR, American Psychiatric Association, 2013)
AVHs that have resisted to at least two properly conducted antipsychotic therapies at an effective dose for at least 8 weeks (criteria of Kinon et al., 1993)
Frequent AVHs (at least 10 times per hour) (Fovet et al., 2022)
Pregnancy (based on date of last menstrual period with possibility of urine test if in doubt)
Anticonvulsant therapy
Neurological disorder (e.g., multiple sclerosis, epilepsy)
Current addictive behavior (except tobacco and cannabis, widely used in this clinical population; Fovet et al., 2022)
Crossover
Active Transcranial Magnetic Stimulation (TMS)
DeviceActive rTMS (continuous theta burst, cTBS) applied to the temporo-parietal junction (TPJ) at the onset of the Auditory Verbal Hallucinations (AVH).
Sham Transcranial Magnetic Stimulation (TMS)
DeviceSham rTMS (continuous theta burst, cTBS) applied to the temporo-parietal junction (TPJ) during the onset of the Auditory Verbal Hallucinations (AVH). An electrical stimulator is synchronised with the magnetic stimulation to recreate the tactile sensation and the coils emits the same noise during sham stimulation as in the active configuration, making it impossible to distinguish between active and placebo magnetic stimulation.
Duration of auditory-verbal hallucinations
The primary endpoint is the reduction in the duration of AVH (in seconds) during active phasic stimulation sessions compared to sham sessions. Participants will press a button when an AVH occurs (starting the intervention) and press another when the AVH disappears. This allows for the recording of the duration of the AVHs.
Clinical scales scores
An evaluation of the following clinical measures will take place : AHRS, CGI, Visual analog scale for AVH intensity and frequency, GAF and PANSS.
Measure of the duration and/or intensity of HAV (in seconds) during active phasic stimulation sessions compared to sham sessions (phase 1) among TMS responders and non-responders in phase 2
Reduction in duration and/or intensity of HAV (in seconds) during active phasic stimulation sessions compared to sham sessions (phase 1) among TMS responders and non-responders in phase 2 (response: decrease in pre/post AHRS score \>25%).
Intensity of auditory-verbal hallucinations
Phase 1 At the end of each active or sham cTBS train, the computer screen will display an 5-point Likert Scale, through which the patient will have to report AVH-intensity before the session can continue.
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