Externalization and Stimulation

NCT ID: NCT05936307

Last Updated: 2024-03-07

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-01-16
• Study Completion Date: 2025-09-30

Brief Summary

The distinction between self-generated and external information is impaired in patients with schizophrenia, who are assumed to confuse imagination with real perceptions. To better understand the underlying mechanisms of these abnormalities, the investigator will investigate the brain mechanisms supporting auditory externalization. Auditory externalization is the ability to perceive whether a sound comes from inside or outside oneself. Our study, in healthy participants, will use functional brain imaging to identify the brain areas involved in the externalization of sound sources and to test whether neuromodulation of this area can modify this ability and provide a therapeutic lead in pathological populations

Detailed Description

30 healthy participants will be included. The participants will undergo three separate visits. During the first one, the participants will listen to sounds coming from either internal or external sources while undergoing an fMRI session. This will allow us to identify the brain region involved in externalizing abilities with the highest activity. In the second and third visits, this specific region will be targeted by HD-tDCS (a non-invasive high-definition neuromodulation technique whose precision is enhanced by individual data) to modulate its activity and test its causal involvement in externalization processes. Each participant will receive both active and placebo stimulation, with the order counterbalanced. During the stimulation, participants will complete an externalization task, followed by a reality monitoring task and a self-agency task. Additionally, the investigator will gather socio-demographic and psychometric data.

Conditions

Healthy Participants

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: TRIPLE

Study Groups

15 healthy participants active then placebo

15 healthy participants will receive a session of active HD-tDCS and then a session of placebo HD-tDCS.

Group Type: ACTIVE_COMPARATOR

High-definition transcranial direct current (HD-tDCS), active condition

Intervention Type: PROCEDURE

Participants will receive a session of active HD-tDCS at a current intensity of 2 mA for a duration of 25min. The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task.

High-definition transcranial direct current (HD-tDCS), placebo condition

Intervention Type: PROCEDURE

Participants will receive a session of placebo HD-tDCS, which will be delivered following the same procedures as active HD-tDCS but the intensity of the current will be set at 2mA during the 30 first seconds at the beginning of the 25-min period of the stimulation, and equal to 0 mA for the reminding period of stimulation to simulate the tingling sensation often experienced by individuals during active stimulation.

The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task

15 healthy participants placebo then active

15 healthy participants will receive a session of placebo HD-tDCS and then a session of active HD-tDCS.

Group Type: PLACEBO_COMPARATOR

High-definition transcranial direct current (HD-tDCS), active condition

Intervention Type: PROCEDURE

Participants will receive a session of active HD-tDCS at a current intensity of 2 mA for a duration of 25min. The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task.

High-definition transcranial direct current (HD-tDCS), placebo condition

Intervention Type: PROCEDURE

Participants will receive a session of placebo HD-tDCS, which will be delivered following the same procedures as active HD-tDCS but the intensity of the current will be set at 2mA during the 30 first seconds at the beginning of the 25-min period of the stimulation, and equal to 0 mA for the reminding period of stimulation to simulate the tingling sensation often experienced by individuals during active stimulation.

The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task

Interventions

High-definition transcranial direct current (HD-tDCS), active condition

Participants will receive a session of active HD-tDCS at a current intensity of 2 mA for a duration of 25min. The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task.

Intervention Type: PROCEDURE

High-definition transcranial direct current (HD-tDCS), placebo condition

Participants will receive a session of placebo HD-tDCS, which will be delivered following the same procedures as active HD-tDCS but the intensity of the current will be set at 2mA during the 30 first seconds at the beginning of the 25-min period of the stimulation, and equal to 0 mA for the reminding period of stimulation to simulate the tingling sensation often experienced by individuals during active stimulation.

The placement of electrodes will be determined to specifically target the brain area that has been identified as being involved in the process of externalization, as evidenced by fMRI. During the stimulation, participants will be engaged in a computer-based externalization task

Intervention Type: PROCEDURE

Eligibility Criteria

Inclusion Criteria

• Having given their written informed consent
• Affiliated with a social security scheme
• French speakers and readers

Exclusion Criteria

• With contraindication to HD-tDCS stimulation or fMRI
• With a history of or current hearing problems, including tinnitus
• Taking medication (except contraceptives)
• With a history of or current psychiatric diagnosis (DSM-5 criteria)
• First-degree relatives with a diagnosis of schizophrenia spectrum disorder or bipolar disorder (DSM5)
• Have a personal history of neurological disorders or head trauma with loss of consciousness
• With an intellectual disability (Raven's Matrices)
• With developed musical abilities (i.e., regular practice of a musical instrument for at least 10 years with assiduity or at a music school or conservatory)
• Pregnant or nursing
• Being in a period of exclusion and/or having exceeded the annual indemnity ceiling (€4,500) for other clinical research.
• Under guardianship

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 30 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Hôpital le Vinatier

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Marine MONDINO, Phd

Role: PRINCIPAL_INVESTIGATOR

hospital le Vinatier

Locations

Centre Hospitalier le Vinatier

Bron, , France

Site Status: RECRUITING

Countries

France

Central Contacts

Marine MONDINO, PhD

Role: CONTACT

marine.mondino@ch-le-vinatier.fr

0437915565 ext. +33

Lydie SARTELET

Role: CONTACT

lydie.sartelet@ch-le-vinatier.fr

0437915531 ext. +33

Facility Contacts

Marine Mondino

Role: primary

marine.mondino@ch-le-vinatier.fr

0437915565 ext. +33

Jérôme Brunelin

Role: backup

jerome.brunelin@ch-le-vinatier.fr

0437915297 ext. +33

Other Identifiers

2023-A00452-43

Identifier Type: -

Identifier Source: org_study_id