Precision HD-tACS for Enhancing Sensory Experience in Schizophrenia

NCT07632261 | Not Yet Recruiting

• 1 other identifier: 2025-A02370-49
• Study Type: interventional
• Target: 80
• Locations: 0 countries
• Sites: N/A

Brief Summary

To ensure unified sensory perception, the brain must link information from different senses across time and space. This unification of perception often referred to as a perceptual "binding constraint" is a prerequisite for any organized perception. Patients with schizophrenia exhibit deficits in the spatiotemporal binding of sensory information . Electroencephalography (EEG) studies highlight the role of delta-theta oscillatory dynamics (2-8 Hz) in neuronal entrainment processes underlying spatiotemporal binding, which enables the formation of a coherent and organized perceptual representation . These same dynamics are disrupted in schizophrenia . In tasks assessing perceptual binding, such alterations manifest as widened temporal binding windows, reflecting impaired temporal structuring of visual events. Physiologically, these disruptions may stem from impaired feedback mechanisms within the cortico-cerebello-thalamo-cortical (CCTC) loop. Schizophrenia patients also exhibit functional and structural deficits in the pulvinar and frontal cortex, key nodes of the CCTC loop . Recent technical advances in transcranial neurostimulation have reinforced its potential as a therapeutic tool. High-definition transcranial alternating current stimulation (HD-tACS) now enables individualized modulation of pre-identified neural networks , including targeted interventions for schizophrenia . Based on a personalized stimulation protocol, this research project proposes precision HD-tACS therapy, tailored for each patient according to their delta-theta peak frequency measured via EEG and the optimal functional stimulation site identified with functional MRI (fMRI). Stimulation will be applied functionally, i.e., while the patient performs a cognitive task. Structural connectivity alterations have been observed in fronto-thalamic, thalamo-cingulate, and cortico-cerebellar pathways in schizophrenia, potentially underpinning temporal and spatial binding deficits. Assessing the integrity of the CCTC loop with diffusion tensor imaging (DTI) will allow quantification of fiber coherence and white matter density connecting cortical and subcortical regions within this network.To evaluate both baseline perceptual deficits and the potential improvements induced by stimulation, a control group of healthy participants will be included.

Conditions

SCHIZOPHRENIA 1 (Disorder); Sensory Perceptual Characteristics

Keywords

perceptual binding; sensory perception; transcranial stimulation; tACS

Outcome Measures

Primary Outcomes (1)

• Point of subjective equality(PSE)

  This outcome measures perceptual bias by estimating the Point of Subjective Equality (PSE), defined as the stimulus intensity at which participants perceive two stimuli as equal with 50% probability. The PSE is extracted from a fitted psychometric function and compared between PRE and POST phases. Unit: same as stimulus dimension (e.g., ms, Hz, or intensity level). No fixed min/max value

  Day1: pre-intervention From 2 days to 20 days maximum: intervention and post-intervention

Secondary Outcomes (1)

• Functional connectivity, assessed via the phase-locking value (PLV).

  Day1: pre-intervention From 2 days to 20 days maximum: post-intervention

Study Arms (4)

Control Group Theta active

ACTIVE COMPARATOR

Device: Transcranial neurostimulation

Control Group Sham

SHAM COMPARATOR

Device: Sham Transcranial neurostimulation

Schizophrenic patients Group Theta active

ACTIVE COMPARATOR

Device: Transcranial neurostimulation

Schizophrenic patients Group Sham

SHAM COMPARATOR

Device: Sham Transcranial neurostimulation

Interventions

Transcranial neurostimulation DEVICE

Active HD-tACS

Control Group Theta active; Schizophrenic patients Group Theta active

Sham Transcranial neurostimulation DEVICE

Sham HD-tACS

Control Group Sham; Schizophrenic patients Group Sham

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Be aged 18 to 65 years inclusive.
• Have read and understood the study information sheet.
• Be affiliated with a social security system or be a beneficiary.
• Have normal or corrected-to-normal vision (glasses or contact lenses).

You may not qualify if:

• Any contraindication to tACS, e.g., cardiac pacemaker or other devices that could interfere with the electric field.
• Any contraindication to MRI, e.g., neurological stimulator, pacemaker, cardiac defibrillator, cardiac or vascular prosthesis, intracranial clips or clamps, cerebrospinal fluid shunt, metallic fragments in the eyes, cochlear implants, severe claustrophobia. (A standardized MRI screening questionnaire will be provided.)
• Pregnancy or breastfeeding. (Pregnancy status will be verified with a test on the day of the exam.)
• Legal incapacity (under guardianship, conservatorship, or judicial/administrative detention) or inability to provide informed consent.
• Major psychiatric disorders (excluding tobacco use disorder).
• Neurological disorders.
• Severe somatic disorders that could interfere with participation.
• Uncorrected visual impairments.
• Recent consumption of substances likely to alter brain activity (alcohol, drugs, etc.).
• Presence of any psychiatric disorder.
• Under legal protection (guardianship or conservatorship).
• A potential patient participant will be excluded if they have:
• Any contraindication to tACS, e.g., cardiac pacemaker or other devices that could interfere with the electric field.
• Any contraindication to MRI, e.g., neurological stimulator, pacemaker, cardiac defibrillator, cardiac or vascular prosthesis, intracranial clips or clamps, cerebrospinal fluid shunt, metallic fragments in the eyes, cochlear implants, severe claustrophobia. (A standardized MRI screening questionnaire will be provided.)
• Pregnancy or breastfeeding. (Pregnancy status will be verified with a test on the day of the exam.)

Sponsors & Collaborators

• Hôpital le Vinatier: lead

Study Officials

• William VALLET, PhD

  Le Vinatier Psychiatrie Universitaire Lyon Métropole

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lydie SARTELET

CONTACT

+334 37 91 55 31; lydie.sartelet@ch-le-vinatier.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: 40 patient participants and 40 healthy controls

Study Record Dates

• First Submitted: May 27, 2026
• First Posted: June 8, 2026
• Study Start: June 15, 2026
• Primary Completion: June 15, 2026
• Study Completion (Estimated): May 1, 2030
• Last Updated: June 8, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share