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NCT Number: NCT06140940

Motor Imagery in Aphantasia

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.

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Key information

Conditions

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

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Centre Hospitalier le Vinatier

Bron, 69678, France

Location status: Recruiting

About this study

The investigators will recruit 20 participants with aphantasia and 20 participants with typical mental imagery capacities (no-aphantasia groups). Participants in both groups will complete a 3-hour visit for inclusion and baseline measurements (Visit 1) which will include neurophysiological, autonomic nervous system, cognitive and behavioral measures.

Participants in the aphantasia group will complete 2 additional visits to receive active and sham tDCS sessions (Visit 2 and 3), according to a randomized, double-blind, sham-controlled, crossover design. Mental training will be done concurrently with tDCS using a sequential finger tapping-task (Truong et al., 2022). Participants will receive the instructions of trying to imagine themselves performing the motor task, by feeling their fingers moving as if they were actually moving it (kinesthetic modality of motor imagery).

Visits will be separated by at least 7 days.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Treatment and study plan

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).

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).

Primary outcomes

  1. Gains in motor performance following mental training

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

    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.

Secondary outcomes

  1. Motor corticospinal excitability at rest and during kinesthetic motor imagery

    Time frame: 1 time at baseline (Visit 1), in both groups

    Motor corticospinal excitability will be assessed with single-pulse transcranial magnetic stimulation (TMS) applied over the primary motor cortex representation of the non-dominant hand. Using electromyography, we will measure the peak-to-peak mean amplitude of motor evoked potentials (MEPs, measured in mV) in the contralateral first dorsal interosseous muscle both at rest and during kinesthetic motor imagery.

  2. Heart rate variability

    Time frame: through study completion, an average of 1 month

    Heart rate variability, including respiratory sinus arrhythmia measures, expressed in milliseconds (ms), will be assessed at rest and during kinesthetic motor imagery by recording the heart rate using three electrodes placed in the left chest area. These electrodes will be connected to the Biopac MP150 system and monitored with the Acqknowledge software

  3. Skin conductance

    Time frame: through study completion, an average of 1 month

    Amplitude of electrodermal response will be measured at rest, during actual movements and during kinesthetic motor imagery using the Biopac MP150 system with the Acqknowledge software. The ratio between amplitudes during imagined/actual movements will be computed (expressed in percent).

  4. Mental imagery abilities

    Time frame: 1 time at baseline, in both groups

    Mental imagery abilities in different sensory modalities will be measured as scores at the following questionnaires: Vividness of Visual Imagery Questionnaire (VVIQ; range 16-80)

  5. Mental imagery abilities

    Time frame: 1 time at baseline, in both groups

    Mental imagery abilities in different sensory modalities will be measured as scores at the following questionnaires: the Kinesthetic and Visual Imagery Questionnaire (KVIQ; range 20-100).

  6. Mental imagery abilities

    Time frame: 1 time at baseline, in both groups

    Mental imagery abilities in different sensory modalities will be measured as scores at the following questionnaires: the Movement Imagery Questionnaire-Revised (MIQ-R; range 14-98)

  7. Mental imagery abilities

    Time frame: 1 time at baseline, in both groups

    Mental imagery abilities in different sensory modalities will be measured as scores at the following questionnaires: the Test of Ability in Movement Imagery (TAMI; range 0-24)

  8. Mental imagery abilities

    Time frame: 1 time at baseline, in both groups

    Mental imagery abilities in different sensory modalities will be measured as scores at the following questionnaires: Plymouth Sensory Imagery Questionnaire (Psi-Q; range 0-70)

  9. Source monitoring performance

    Time frame: 1 time at baseline, in both groups

    Source monitoring performance will be evaluated using a specific source monitoring task . Source-monitoring accuracy scores (range 0-100) will be calculated as proportions of accurate source attributions for each source

  10. Implicit motor imagery capacities

    Time frame: 1 time at baseline, in both groups

    Implicit motor imagery capacities will be measured using a hand laterality judgment task . The percentage of correct response at the task will be calculated (range 0-100%).

  11. Performance of time-to-contact estimation

    Time frame: 1 time at baseline, in both groups

    Performance will be measured using a specific time-to-contact (TTC) task. A TTC task involves temporal prediction in that the task requires a participant to predict the moment at which an event will occur given past sensory information (e.g., an auditory stimuli). The estimation of TTC requires determining the moment of contact (TTCa). The analysis of performance is based on BIAS quantification, which measures the average difference between individual estimation and TTCa

Interested in participating?

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Sponsors and collaborators

Lead sponsor

Hôpital le Vinatier

Other

Registry information

Official study title

Probing and Modulating Motor Imagery Capacities in Aphantasia

Acronym: OLIPHANT

Important dates

Study start
2024
Primary completion
2027
Study completion
2028
First posted
Nov 21, 2023
Registry last updated
Jul 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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