Clinical and Hemodynamic Correlates of Different Polarities of HD-tDCS in COPD

Federal University of Paraíba20 enrolled

Overview

The aim of this pilot randomized clinical trial is to identify the acute effects of HD-tDCS in the diaphragm cortex on cerebral hemodynamics in individuals with COPD. The main questions to answer are: Is there a change in cortical metabolism (HbO and OXYHb consumption) during and immediately after the application of HD-tDCS? Are there any particularities in cortical hemodynamics between the different HD-tDCS polarities? Participants will perform three HD-tDCS sessions, each one with a different type of stimulation (anodal, cathodal and sham) lasting for 20 minutes. Before, during and after stimulation, near-infrared spectrography will be used as assessment instruments.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Chronic Obstructive Pulmonary Disease

Interventions

Participants will receive stimulation through electrode positioning according to the International 10-20 System. The central electrode will be placed over the left diaphragm cortex, accompanied by four return electrodes. The current will be administered using a 3mA protocol for 20 minutes, with a 30-second ramp-up at the beginning and a 30-second ramp-down at the end of the stimulation for active groups. For the placebo group, the setup will remain identical; however, regarding the protocol, the device initially reaches a current of 3 mA and then drops to 0.1 mA within the first 30 seconds, remaining at this current for 20 minutes. A current of 3 mA will be reinstated only in the final 30 seconds, once again accompanied by ramp-up and ramp-down phases.

Sham High-definition Transcranial Direct Current StimulationOTHER

Participants received sham stimulation using the same electrode positioning as the active conditions (International 10-20 System), with a central electrode over the left diaphragm cortex and four return electrodes. The device initially reached a current of 3 mA and then dropped to 0.1 mA within the first 30 seconds, remaining at this current for 20 minutes. A current of 3 mA was reinstated only in the final 30 seconds, accompanied by ramp-up and ramp-down phases, replicating the initial and final sensations of active stimulation without delivering a sustained therapeutic current.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age over 18 years old; * Airflow limitation mild to severe (GOLD 1-3); * No contraindications for HD-tDCS, such as pregnancy, metal implants in the head, cochlear implants and pacemaker; * Absence of concomitant diseases of the central or peripheral nervous system. Exclusion Criteria: * Refusal to sign the TCLE; * Missing two consecutive or three alternate sessions during treatment; * Develop any disabling condition that prevents continued participation in the study.

Outcomes

Primary Outcomes

Change in cerebral hemodynamic response

Change in oxygenated (OxyHb) and deoxygenated (DeoxyHb) hemoglobin concentration measured by functional near-infrared spectroscopy (fNIRS)

Time frame: Before, during, and after each 20-minute HD-tDCS session

Secondary Outcomes

respiratory muscle strength

Maximum inspiratory and expiratory pressure values, recorded using manovacuometry.

Time frame: Immediately before and immediately after the intervention