Frequency-Dependent Effects of Transcranial Photobiomodulation With Same Peak Irradiance on Cortical Excitability and Fine Motor Performance

Starting soon · Phase 1 · Has a placebo group

Conditions studied: Healthy Volunteers (HV), Transcranial Photobiomodulation, Cortical Excitability

In brief

This study investigates the frequency-dependent neuromodulatory effects of transcranial photobiomodulation (tPBM) over the primary motor cortex (M1) on cortical excitability and fine motor performance in healthy young adults. Using a randomized, double-blind, sham-controlled, 5-arm crossover design, 20 healthy participants will undergo five experimental conditions separated by a mandatory 7-day washout period: Continuous Wave (CW), 10 Hz pulsed tPBM, 40 Hz pulsed tPBM, 100 Hz pulsed tPBM, and a Sham control. To isolate pulse frequency while holding peak intensity constant, all active interventions will utilize an identical peak irradiance, with pulsed modes operating at a 50% duty cycle (delivering 50% of the cumulative energy dose relative to CW). Primary outcomes include corticospinal excitability measured via single- and paired-pulse Transcranial Magnetic Stimulation (TMS), alongside fine motor speed and dexterity assessed via a computerized finger-tapping task.

Key facts

Study ID

NCT07752602

Run by

Hospital de Clinicas de Porto Alegre

People needed

20

Starts

2027-01-01

Expected to finish

2027-12-01

Last updated by the study team

2026-08-07

Who can join

Age: 18 and older, up to 35. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Voluntary Participation: Participants who are clear of their cognitive faculties, capable of understanding all experimental procedures, and who provide written informed consent prior to enrollment.
• Neurologically and Psychiatrically Healthy Status: Individuals with no current or prior history of neurological, neurodevelopmental, or psychiatric conditions;
• Age Range: Young adult volunteers aged between 18 and 35 years.

You may not qualify if…

• Use of any continuous psychotropic medication within the past 12 months.
• Any current psychiatric diagnosis based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).
• Diagnosis of any neurological disorder capable of altering cortical excitability (e.g., seizures/epilepsy, cerebrovascular accidents/stroke, brain tumors).
• Any clinical, psychological, or social condition that, in the investigator's opinion, places the participant at an increased risk, compromises participant safety, or precludes full compliance and successful completion of the study protocol.
• Presence of any intracranial devices or implants, including cochlear implants and aneurysm clips.
• Severe or uncompensated systemic medical illness that could interfere with study participation or confound physiological outcomes.
• Participation in any other interventional neuromodulation study within the preceding 6 months.

Where it is running

• Hospital de Clínicas de Porto Alegre — Porto Alegre, Rio Grande do Sul, Brazil

Full record on ClinicalTrials.gov

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