Motor Imagery in Aphantasia

NCT06140940 | Recruiting DMC

• 1 other identifier: 2023-A00887-38
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

The present study aims to characterize and modulate motor imagery abilities in individuals with aphantasia. The investigators will characterize the neurophysiological and physiological underpinnings of mental imagery abilities in participants with aphantasia by investigating several indices of motor imagery abilities and comparing them to participants with typical mental imagery abilities. The investigators will investigate whether non-invasive brain stimulation applied to the primary motor cortex improves mental imagery abilities in participants with aphantasia.

Conditions

Aphasia

Outcome Measures

Primary Outcomes (1)

• Gains in motor performance following mental training

  Gains in motor performance following mental training combined with tDCS will be measured using a sequential finger tapping-task. Gains following training will be expressed as a percentage of the baseline performance.

  2 times: immediately before tDCS (baseline) and immediately after tDCS

Secondary Outcomes (11)

• Motor corticospinal excitability at rest and during kinesthetic motor imagery

  1 time at baseline (Visit 1), in both groups

• Heart rate variability

  through study completion, an average of 1 month

• Skin conductance

  through study completion, an average of 1 month

• Mental imagery abilities

  1 time at baseline, in both groups

• Mental imagery abilities

  1 time at baseline, in both groups

Study Arms (2)

active stimulation group: 20 participants with aphantasia will receive a session of active HD-tDCS

EXPERIMENTAL

Participants will receive a session of active HD-tDCS at a current intensity of 4 mA for a duration of 15min. The placement of electrodes will be determined to specifically target the primary motor cortex (4 x 1 montage with the anode over C4). During the stimulation, participants will be engaged in a mental training task (sequential finger tapping-task).

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

placebo stimulation group: 20 participants with aphantasia will receive a session of sham HD-tDCS

PLACEBO COMPARATOR

High-definition transcranial direct current (HD-tDCS), sham condition. Participants will receive a session of sham HD-tDCS, which will be delivered following the same procedures as active HD-tDCS but the intensity of the current will be set at 4mA during the 30 first seconds at the beginning of the 15-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 primary motor cortex (4 x 1 montage with the anode over C4). During the stimulation, participants will be engaged in a mental training task (sequential finger tapping-task).

Procedure: High-definition transcranial direct current (HD-tDCS), sham condition

Interventions

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

Participants will receive a session of active HD-tDCS at a current intensity of 4 mA for a duration of 15min. The placement of electrodes will be determined to specifically target the primary motor cortex (4 x 1 montage with the anode over C4). During the stimulation, participants will be engaged in a mental training task (sequential finger tapping-task).

active stimulation group: 20 participants with aphantasia will receive a session of active HD-tDCS

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

Participants will receive a session of sham HD-tDCS, which will be delivered following the same procedures as active HD-tDCS but the intensity of the current will be set at 4mA during the 30 first seconds at the beginning of the 15-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 primary motor cortex (4 x 1 montage with the anode over C4). During the stimulation, participants will be engaged in a mental training task (sequential finger tapping-task).

placebo stimulation group: 20 participants with aphantasia will receive a session of sham HD-tDCS

Eligibility Criteria

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

You may qualify if:

• For the aphantasia group only: congenital aphantasia defined as a life-long inability to generate mental imagery (confirmed by a total score of 32 or less on the VVIQ, which is the gold standard questionnaire for aphantasia)
• For the no-aphantasia group only: typical mental imagery capacities (confirmed by a total score of more than 32 on the VVIQ)
• Covered by public health insurance
• Understanding the French language
• Signed written informed consent after being informed about the study

You may not qualify if:

• Presence or history of a somatic, neurologic, or mental illness
• Actual pain or musculoskeletal disorders at the upper limb
• Having a regular musical activity (more than once a week) because of high manual dexterity
• Contraindication for noninvasive brain stimulation including the presence of ferromagnetic or magnetic sensitive metal objects implanted in the head or in close proximity (e.g., brain stent, clip, cochlear implants, or stimulator)
• Pregnancy (controlled by urine pregnancy test in females without reported contraception)
• Active seizure disorder or history of seizures
• Participants under curatorship/guardianship

Sponsors & Collaborators

• Hôpital le Vinatier: lead

Study Sites (1)

Centre Hospitalier le Vinatier

Bron, 69678, France

RECRUITING

MeSH Terms

Conditions

Aphasia

Condition Hierarchy (Ancestors)

Speech Disorders; Language Disorders; Communication Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Marine MONDINO, PhD

  CH le Vinatier

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lydie SARTELET

CONTACT

0 437915531; lydie.sartelet@ch-le-vinatier.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Participants and experimenters (including tDCS operator) will not be informed about the nature (active or placebo) of the stimulation they will receive
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Single-center prospective randomized, double-blind, sham-controlled, crossover study with two conditions: active tDCS + mental training and sham tDCS + mental training. A control group (participants with typical mental imagery abilities) will also be included for comparison at baseline.

Study Record Dates

• First Submitted: November 13, 2023
• First Posted: November 21, 2023
• Study Start: March 28, 2024
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2028
• Last Updated: July 24, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

FR (1)