Effects of Transcranial Electrical Stimulation on Task Performance in Healthy Adults

NCT ID: NCT06995560

Last Updated: 2025-05-29

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 40 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2020-10-25
• Study Completion Date: 2024-10-31

Brief Summary

The objective of this randomized, double-blind, sham-controlled, crossover study is to evaluate the effects of transcranial electrical stimulation (tES) on complex cognitive task performance in healthy adult volunteers.

The primary questions this study aims to answer are:

1. Does tES improve task performance, including speed, accuracy, and overall success, during a computerized track-and-capture task?

2. Do different stimulation targets produce differential effects on performance?

3. Are there short-term post-stimulation effects on task performance (up to 48 hours)?

Participants will:

1. Complete two testing sessions under either active or sham stimulation conditions.

2. Perform a complex operational task involving dual-hand controllers while undergoing tES or sham stimulation, and immediately after.

3. Return for follow-up task performance assessments at 24 and 48 hours post-stimulation to evaluate after-effects.

Detailed Description

Transcranial electrical stimulation (tES) is a non-invasive neuromodulation technique that delivers low-intensity electrical currents (e.g., <2 mA) through scalp electrodes to modulate brain activity. Numerous studies have shown that tES can enhance cognitive functions such as learning, memory, attention, and decision-making in healthy individuals, as well as provide therapeutic benefits in psychiatric and neurological populations. Despite these findings, substantial knowledge gaps remain regarding the effects of tES, particularly in the context of complex, operationally relevant tasks.

Existing research has primarily focused on the effects of tES on simple cognitive tasks, with limited investigation into task that require multiple cognitive domain to operate simultaneously. Performance on complex tasks, such as those involving motor coordination, visual-spatial process, decision-making, and rapid response, may respond differently to tES than simple, isolated tasks. Understanding these effects could have broad applications in optimizing cognitive performance across various high-demand settings.

This study is designed to address several key uncertainties:

1. Inter-individual variability in behavioral and neurophysiological responses to tES.

2. the impact of stimulation parameters (location, type, intensity) on task performance.

3. The magnitude and duration of both immediate and post-stimulation effects on behavior.

To investigate these questions, healthy adults perform a computerized track-and-capture task requiring real-time motor control and decision-making using dual-hand controllers. Participants undergo both active and sham stimulation in a randomized, double-blind, crossover design. Stimulation will target either the left dorsolateral prefrontal cortex or the left anterior insula, guided by current flow modeling software. Performance is assessed during stimulation, immediately after, and at 24 and 48 hours post-stimulation to evaluate both immediate and short-term after-effects.

Outcome measures include task performance metrics (e.g., speed, accuracy, overall success) and neurophysiological data collected via non-invasive monitoring with functional near-infrared spectroscopy (fNIRS). The study is part of a broader research effort to characterize the functional impact of tES on complex behavior and to inform future applications in cognitive performance enhancement.

All stimulation procedures follow established safety guidelines for low-intensity tES, including continuous monitoring of electrode impedance and post-session adverse event questionnaires assessing discomfort, mood, and cognitive status. The Soterix Medical MXN-33 HD-tES system includes built-in safeguards to prevent excessive current delivery and to ensure safe electrode contact throughout the stimulation. Participants serve as their own controls in a within-subject crossover design, increasing statistical power for detecting within-subject differences between active and sham conditions.

Conditions

Healthy; Brain Stimulation; Transcranial Direct Current Stimulation (tDCS); Cognition; Psychomotor Performance; Neurophysiology

Study Design

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

Study Groups

DLPFC Stimulation Group

Participants receive transcranial electrical stimulation (tES) targeting the left dorsolateral prefrontal cortex (DLPFC) and perform a complex cognitive-motor task using the Robotic On-Board Trainer for Research (ROBoT-r) under both active and sham stimulation in a randomized, crossover design.

Group Type: EXPERIMENTAL

Active Transcranial Electrical Stimulation

Intervention Type: DEVICE

Active tES delivered using the Soterix Medical MXN-33 HD-tES stimulator. Stimulation is applied via high definition electrodes targeting either the left DLPFC or L-aINS at intensities up to 1.9 mA. Stimulation is performed for up to 45 minutes during task execution. Participants perform the ROBoT-r task during stimulation.

Sham Transcranial Electrical Stimulation

Intervention Type: DEVICE

Sham tES using the same Soterix Medical MXN-33 HD-tES stimulator and electrode placements. Stimulation ramps up and down over 20 seconds to mimic sensation but provides no continuous current. Participants perform the ROBoT-R task under sham conditions.

Anterior Insula Stimulation Group

Participants receive transcranial electrical stimulation (tES) targeting the left anterior insula and perform a complex cognitive-motor task using the Robotic On-Board Trainer for Research (ROBoT-r) under both active and sham stimulation in a randomized, crossover design.

Group Type: EXPERIMENTAL

Active Transcranial Electrical Stimulation

Intervention Type: DEVICE

Active tES delivered using the Soterix Medical MXN-33 HD-tES stimulator. Stimulation is applied via high definition electrodes targeting either the left DLPFC or L-aINS at intensities up to 1.9 mA. Stimulation is performed for up to 45 minutes during task execution. Participants perform the ROBoT-r task during stimulation.

Sham Transcranial Electrical Stimulation

Intervention Type: DEVICE

Sham tES using the same Soterix Medical MXN-33 HD-tES stimulator and electrode placements. Stimulation ramps up and down over 20 seconds to mimic sensation but provides no continuous current. Participants perform the ROBoT-R task under sham conditions.

Interventions

Active Transcranial Electrical Stimulation

Active tES delivered using the Soterix Medical MXN-33 HD-tES stimulator. Stimulation is applied via high definition electrodes targeting either the left DLPFC or L-aINS at intensities up to 1.9 mA. Stimulation is performed for up to 45 minutes during task execution. Participants perform the ROBoT-r task during stimulation.

Intervention Type: DEVICE

Sham Transcranial Electrical Stimulation

Sham tES using the same Soterix Medical MXN-33 HD-tES stimulator and electrode placements. Stimulation ramps up and down over 20 seconds to mimic sensation but provides no continuous current. Participants perform the ROBoT-R task under sham conditions.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• Age 25 to 55 years
• Master's or Doctorate degree, or equivalent relevant experience
• No history of head injury or neurological or psychiatric disorders
• No history of cardiac disease
• No metal implants in the head
• No implanted electronic devices
• Not taking medication affecting neural or cardiovascular function
• Able to provide written, dated informed consent

Exclusion Criteria

• Smoking within the past year
• Current illegal drug use
• Alcohol abuse
• Pregnancy (confirmed by urine test)
• Participation in another brain stimulation protocol withing the past month

• Minimum Eligible Age: 25 Years
• Maximum Eligible Age: 55 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Massachusetts General Hospital

OTHER

Sponsor Role: lead

Responsible Party

Gary E. Strangman

Principle Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Massachusetts General Hospital Research Institute

Charlestown, Massachusetts, United States

Countries

United States

Other Identifiers

NNX16AO30G

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

2020P002253

Identifier Type: -

Identifier Source: org_study_id