Health Adult SubjectsCURRENT-FlowNCT07831525
Effect of Different Currents for Transcranial Modulation of the Sensorimotor Corticospinal Pathway in Healthy Subjects
A study testing Transcranial Alternating Current Stimulation, Transcranial Direct Current Stimulation and Transcranial Random Noise Stimulation (tRNS) in people with Health Adult Subjects, run by Hospital de Clinicas de Porto Alegre at 1 site in Brazil.
Trial summary
Transcranial modulation of the corticospinal sensorimotor pathway is a promising approach in neuroscientic functions. Among the techniques used, transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS) and the application of random noise current stand out. Read more about this study
- Who is it for?
- Ages 18 to 45 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Health Adult Subjects
- What is being tested?
- Transcranial Alternating Current Stimulation, Transcranial Direct Current Stimulation and Transcranial Random Noise Stimulation (tRNS)
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 14 participants
- Where
- 1 siteBrazil
- Study dates
- 15 Jul 2026to 26 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy male subjects aged 18-45 years, with at least a high school diploma, and not engaged in night-shift work.
Who cannot join
- Contraindications to transcranial stimulation include implanted medical devices in the brain, cardiac pacemakers, and cochlear implants.
- Current use of psychotropic medications.
- History of alcohol or substance abuse within the past 6 months.
- Neurological disorders, history of traumatic brain injury, or prior neurosurgery.
- Beck Depression Inventory-II (BDI-II) score >13.
- Self-Reporting Questionnaire (SRQ) score >7.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Brazil1 site
Hospital de Clinicas de Porto Alegre
Porto Alegre, Rio Grande do Sul
About this study
Official title: Effect of Different Currents for Transcranial Modulation of the Sensorimotor Corticospinal Pathway in Healthy Subjects: A Randomized Clinical Trial
Transcranial modulation of the corticospinal sensorimotor pathway is a promising approach in neuroscientic functions. Among the techniques used, transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS) and the application of random noise current stand out. Objective: To compare the e stimulus, in the EEG frequency bands, on Motor Evoked Potentials (MEP) and on the functional activation of the motor cortex, assessed by Functional Near Infrared Spectroscopy (fNIRS) and pain measurements in healthy subjects subjected to a standardized algogenic stimulus. Subjects and Method: This is a randomized, double-blind, controlled and crossover clinical trial, involving the inclusion of 14 healthy male subjects, with complete secondary education, aged between 18 and 40. years. Participants will be randomized to receive Transcranial Direct Current Stimulation (tDCS), (2) Transcranial Alternating Current Stimulation (tACs), (3) Random Noise Current, (4) Simulated Stimulation Session and (5) Rest Session. Experimental conditions will take place in a standard, quiet and bright room. Assessments will include Motor Evoked Potential, Heat Pain Threshold, Motor Area Activation through metabolic activation measured by fNIRS and analysis of EEG frequency waves. After the baseline assessment, participants will undergo a session of transcranial stimulation, followed by an algogenic stimulus with water at zero degrees, immersion of the dominant hand for 1 minute, with rest intervals of 3 minutes between each of the four serial stimuli. After this stimulus session, outcome measurements will be carried out. Expected results: This clinical trial is expected to provide insights into how tDCS, tACs and random stimulation in to an algogenic stimulus. The results may contribute to the development of therapeutic or neuromodulation strategies in clinical conditions where the regulation of the cortico-spinal sensorimotor pathway is relevant.
- Conditions
- Health Adult Subjects
- Being tested
- Transcranial Alternating Current Stimulation, Transcranial Direct Current Stimulation, Transcranial Random Noise Stimulation (tRNS), Sham Stimulation
- Keywords
- tDCS, tACS, RNS, QST, CPM-test
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Transcranial Alternating Current StimulationDevice
Also called tACS
Single session of active gamma transcranial alternating current stimulation delivered for 30 minutes using a battery-powered external stimulator. Stimulation is applied through two sponge electrodes (5 × 7 cm) mounted on a neoprene cap. The stimulation frequency is 40 Hz, based on previous gamma-band transcranial alternating current stimulation (tACS) studies. The anode is positioned at C3 (left primary motor cortex, M1), and the cathode over the ipsilateral clavicular region.
Transcranial Direct Current StimulationDevice
Also called tDCS
Stimulation is delivered using two sponge electrodes (5 × 7 cm) mounted on a neoprene cap. The electrodes are positioned on the scalp according to the international 10-20 system. The anode is placed at position C3 (left primary motor cortex, M1) and the cathode over the ipsilateral clavicular region. The sinusoidal current intensity per channel ranges from ±2 mA. The session duration is 20 minutes.
Transcranial Random Noise Stimulation (tRNS)Device
Also called tRNS
Stimulation is delivered using two sponge electrodes mounted on a neoprene cap. The anode is positioned at C3 (left primary motor cortex, M1), and the cathode over the ipsilateral clavicular region. A random current level is generated for each sample at a sampling rate of 1280 samples per second. The random values are normally distributed, following a bell-shaped probability density function. The noise signal contains all frequencies up to half the sampling rate (maximum 640 Hz) and has no DC offset.
Sham StimulationDevice
Also called sham
During the sham stimulation session, the tDCS device ramps up the current to 2 mA over 30 seconds and then is immediately turned off. This procedure mimics the sensations of active stimulation without delivering therapeutic current for the remainder of the session.
| Study group | Role | What they receive |
|---|---|---|
| Transcranial Direct Current Stimulation (tDCS) over motor area (M1) | Active comparator | Participants receive active transcranial direct current stimulation over the primary motor cortex (M1) during the intervention sessions. Receives: Device: Transcranial Direct Current Stimulation |
| Transcranial Alternating Current Stimulation (tACS) over M1 | Active comparator | Participants receive active transcranial alternating current stimulation over the primary motor cortex (M1) during the intervention sessions. Receives: Device: Transcranial Alternating Current Stimulation |
| Transcranial Random Noise Stimulation (tRNS) over M1 | Active comparator | Participants receive active transcranial random noise stimulation over the primary motor cortex (M1) during the intervention sessions. Receives: Device: Transcranial Random Noise Stimulation (tRNS) |
| Sham Stimulation | Sham comparator | Participants undergo sham stimulation, experiencing the same setup as active stimulation without actual current delivery. Receives: Device: Sham Stimulation |
| Rest State | No intervention | Participants remain seated with their eyes open for 20 minutes during the rest session, without performing any other task. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Resting-State EEG Power Spectra Across Frequency Bands (Delta, Theta, Alpha, Beta 1, Beta 2, and Gamma)
Electroencephalography (EEG) will be used to quantify neuronal activity through quantitative EEG (qEEG) analysis. Resting-state EEG power spectra will be analyzed across delta, theta, alpha, beta, and gamma frequency bands, reflecting synchronized neuronal oscillations. EEG data will be recorded using a 20-electrode montage according to the international 10-20 system during an 8-minute resting-state paradigm with alternating eyes-open and eyes-closed conditions. Cortical source localization will be performed using standardized Low-Resolution Brain Electromagnetic Tomography (sLORETA).
Measured: Immediately before and immediately after the intervention.
Secondary outcomes (5)
Corticospinal Excitability
Corticospinal excitability will be assessed using single-pulse transcranial magnetic stimulation (TMS) applied over the left primary motor cortex. Motor evoked potentials (MEPs) will be recorded from the right first dorsal interosseous muscle, and measures will include resting motor threshold (RMT) and MEP amplitude, with MEPs obtained at 130% of the motor threshold.
Measured: Immediately before and immediately after the intervention.
Motor Cortex Functional Connectivity
Functional connectivity of the motor cortex will be assessed using functional near-infrared spectroscopy (fNIRS) with a continuous-wave NirScout® system. Optodes will be positioned according to the international 10-10 system to cover the bilateral motor cortex. Data will be acquired during resting-state conditions and during the cold pressor task. Functional connectivity will be analyzed within predefined motor cortex regions of interest.
Measured: Immediately before and immediately after the intervention.
Heat Pain Threshold
Heat pain threshold will be assessed via quantitative sensory testing (QST) on the left forearm using a thermode that increases temperature from 30°C to 52°C at a rate of 1°C per second. The pain threshold is calculated as the average temperature at which pain is first reported across three trials. Higher values indicate greater pain threshold.
Measured: Immediately before and immediately after the intervention.
Function of the Descending Pain Inhibitory System
The function of the descending pain inhibitory system will be assessed using the Conditioned Pain Modulation Test (CPM-test). Pain intensity is rated using a verbal numerical rating scale (0 = no pain to 10 = worst possible pain) before (T0) and during (T1) cold-water immersion. The CPM effect is calculated as the difference between pain ratings at T0 and T1, with greater reductions indicating more effective pain inhibition.
Measured: Immediately before and immediately after the intervention.
Cold Pressor Test Pain Tolerance
Pain intensity and tolerance will be assessed using the Cold Pressor Test, in which participants immerse the non-dominant hand in ice-saturated water (~1°C) for up to 2 minutes. Pain intensity will be continuously rated using an electronic visual analog scale, allowing calculation of peak pain, mean pain, and area under the curve (AUC) over the test duration.
Measured: Immediately before and immediately after the intervention.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2026
- Study start15 Jul 2026
- Primary completion26 Oct 2026 (estimated)
- Study completion26 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Health Adult SubjectsStudies of the same condition, open and under way.
- More trials run by Hospital de Clinicas de Porto AlegreThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 14 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital de Clinicas de Porto Alegre
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07831525
- Sponsor's protocol ID
- 81182524.7.0000.5327
- Other IDs
- 20240121
- Acronym
- CURRENT-Flow
- Status last verified
- Sep 2026
- First submitted
- 13 Jan 2026
- Last updated
- 21 Sep 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data will be available upon request at wcaumo@hcpa.edu.br after 6 months of publication.
Study at a glance
From the registry record, last updated by the sponsor on 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Different Currents for Transcranial Modulation of the Sensorimotor Corticospinal Pathway in Healthy Subjects: A Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT07831525
- Acronym / sponsor ID
- CURRENT-Flow / 81182524.7.0000.5327
- Conditions
- Health Adult Subjects
- Keywords
- tDCS, tACS, RNS, QST, CPM-test
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 14 participants (estimated)
- Lead sponsor
- Hospital de Clinicas de Porto AlegreUniversity, hospital or other
- Study start
- 15 Jul 2026 (actual)
- Primary completion
- 26 Oct 2026 (estimated)
- Study completion
- 26 Dec 2026 (estimated)
- First posted
- 21 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Transcranial modulation of the corticospinal sensorimotor pathway is a promising approach in neuroscientic functions. Among the techniques used, transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS) and the application of random noise current stand out. Objective: To compare the e stimulus, in the EEG frequency bands, on Motor Evoked Potentials (MEP) and on the functional activation of the motor cortex, assessed by Functional Near Infrared Spectroscopy (fNIRS) and pain measurements in healthy subjects subjected to a standardized algogenic stimulus. Subjects and Method: This is a randomized, double-blind, controlled and crossover clinical trial, involving the inclusion of 14 healthy male subjects, with complete secondary education, aged between 18 and 40. years. Participants will be randomized to receive Transcranial Direct Current Stimulation (tDCS), (2) Transcranial Alternating Current Stimulation (tACs), (3) Random Noise Current, (4) Simulated Stimulation Session and (5) Rest Session. Experimental conditions will take place in a standard, quiet and bright room. Assessments will include Motor Evoked Potential, Heat Pain Threshold, Motor Area Activation through metabolic activation measured by fNIRS and analysis of EEG frequency waves. After the baseline assessment, participants will undergo a session of transcranial stimulation, followed by an algogenic stimulus with water at zero degrees, immersion of the dominant hand for 1 minute, with rest intervals of 3 minutes between each of the four serial stimuli. After this stimulus session, outcome measurements will be carried out. Expected results: This clinical trial is expected to provide insights into how tDCS, tACs and random stimulation in to an algogenic stimulus. The results may contribute to the development of therapeutic or neuromodulation strategies in clinical conditions where the regulation of the cortico-spinal sensorimotor pathway is relevant.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 5
| Arm | Type | Receives |
|---|---|---|
| Transcranial Direct Current Stimulation (tDCS) over motor area (M1) | Active comparator | Device: Transcranial Direct Current StimulationParticipants receive active transcranial direct current stimulation over the primary motor cortex (M1) during the intervention sessions. |
| Transcranial Alternating Current Stimulation (tACS) over M1 | Active comparator | Device: Transcranial Alternating Current StimulationParticipants receive active transcranial alternating current stimulation over the primary motor cortex (M1) during the intervention sessions. |
| Transcranial Random Noise Stimulation (tRNS) over M1 | Active comparator | Device: Transcranial Random Noise Stimulation (tRNS)Participants receive active transcranial random noise stimulation over the primary motor cortex (M1) during the intervention sessions. |
| Sham Stimulation | Sham comparator | Device: Sham StimulationParticipants undergo sham stimulation, experiencing the same setup as active stimulation without actual current delivery. |
| Rest State | No intervention | –Participants remain seated with their eyes open for 20 minutes during the rest session, without performing any other task. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Healthy male subjects aged 18-45 years, with at least a high school diploma, and not engaged in night-shift work.
Key exclusion criteria (6 listed)
- Contraindications to transcranial stimulation include implanted medical devices in the brain, cardiac pacemakers, and cochlear implants.
- Current use of psychotropic medications.
- History of alcohol or substance abuse within the past 6 months.
- Neurological disorders, history of traumatic brain injury, or prior neurosurgery.
- Beck Depression Inventory-II (BDI-II) score >13.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Transcranial Alternating Current StimulationAlso: tACSSingle session of active gamma transcranial alternating current stimulation delivered for 30 minutes using a battery-powered external stimulator. Stimulation is applied through two sponge electrodes (5 × 7 cm) mounted on a neoprene cap. The stimulation frequency is 40 Hz, based on previous gamma-band transcranial alternating current stimulation (tACS) studies. The anode is positioned at C3 (left primary motor cortex, M1), and the cathode over the ipsilateral clavicular region. | Device | Transcranial Alternating Current Stimulation (tACS) over M1 |
| Transcranial Direct Current StimulationAlso: tDCSStimulation is delivered using two sponge electrodes (5 × 7 cm) mounted on a neoprene cap. The electrodes are positioned on the scalp according to the international 10-20 system. The anode is placed at position C3 (left primary motor cortex, M1) and the cathode over the ipsilateral clavicular region. The sinusoidal current intensity per channel ranges from ±2 mA. The session duration is 20 minutes. | Device | Transcranial Direct Current Stimulation (tDCS) over motor area (M1) |
| Transcranial Random Noise Stimulation (tRNS)Also: tRNSStimulation is delivered using two sponge electrodes mounted on a neoprene cap. The anode is positioned at C3 (left primary motor cortex, M1), and the cathode over the ipsilateral clavicular region. A random current level is generated for each sample at a sampling rate of 1280 samples per second. The random values are normally distributed, following a bell-shaped probability density function. The noise signal contains all frequencies up to half the sampling rate (maximum 640 Hz) and has no DC offset. | Device | Transcranial Random Noise Stimulation (tRNS) over M1 |
| Sham StimulationAlso: shamDuring the sham stimulation session, the tDCS device ramps up the current to 2 mA over 30 seconds and then is immediately turned off. This procedure mimics the sensations of active stimulation without delivering therapeutic current for the remainder of the session. | Device | Sham Stimulation |
Primary outcome
Resting-State EEG Power Spectra Across Frequency Bands (Delta, Theta, Alpha, Beta 1, Beta 2, and Gamma)
Time frame: Immediately before and immediately after the intervention.
Electroencephalography (EEG) will be used to quantify neuronal activity through quantitative EEG (qEEG) analysis. Resting-state EEG power spectra will be analyzed across delta, theta, alpha, beta, and gamma frequency bands, reflecting synchronized neuronal oscillations. EEG data will be recorded using a 20-electrode montage according to the international 10-20 system during an 8-minute resting-state paradigm with alternating eyes-open and eyes-closed conditions. Cortical source localization will be performed using standardized Low-Resolution Brain Electromagnetic Tomography (sLORETA).
5 secondary outcomes
Corticospinal Excitability
Time frame: Immediately before and immediately after the intervention.
Motor Cortex Functional Connectivity
Time frame: Immediately before and immediately after the intervention.
Heat Pain Threshold
Time frame: Immediately before and immediately after the intervention.
Function of the Descending Pain Inhibitory System
Time frame: Immediately before and immediately after the intervention.
Cold Pressor Test Pain Tolerance
Time frame: Immediately before and immediately after the intervention.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Sep 2026.
- Individual participant dataSharing planned: Yes. Data will be available upon request at wcaumo@hcpa.edu.br after 6 months of publication.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Transcranial Alternating Current Stimulation, Transcranial Direct Current Stimulation and Transcranial Random Noise Stimulation (tRNS) in people with Health Adult Subjects, run by Hospital de Clinicas de Porto Alegre at 1 site in Brazil.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 21 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Resting-State EEG Power Spectra Across Frequency Bands (Delta, Theta, Alpha, Beta 1, Beta 2, and Gamma) (time frame: Immediately before and immediately after the intervention.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Sep 2026.