Non-invasive Stimulation on Central Nervous System Excitability

Summary

A crossover trial with healthy volunteers will be conducted. Six sessions will be performed once a week in a counterbalanced order and at least with seven days washout period to minimize carry-over effects. In each session, volunteers will be submitted to quantity and quality of sleep, type of eating, fatigue and motivation level, cortical brain activity measures through paired pulse transcranial magnetic stimulation (ppTMS), spinal cord activity measures through electrical stimulation, non-invasive spinal stimulation (tsDCS) or non-invasive brain stimulation (rTMS) and physical exercise (gait training).

Conditions

• Healthy

Interventions

DEVICE

anodal tsDCS

Transcutaneous spinal cord stimulation will be delivered through a direct current (DC) stimulator (NeuroConn Plus, Germany) using a pair of saline-soaked sponge electrodes (35cm²). The active electrode (anode) will be placed between the eleventh and the twelfth thoracic vertebra) and the reference electrode, over the right arm (deltoid muscle). Will be delivered a current intensity of 2.5 milliampere (mA), fade in and fade out of 10 seconds, during 20 minutes.

DEVICE

cathodal tsDCS

Transcutaneous spinal cord stimulation will be delivered through a DC stimulator (NeuroConn Plus, Germany) using a pair of saline-soaked sponge electrodes (35cm²). The active electrode (cathode) will be placed between the eleventh and the twelfth thoracic vertebra) and the reference electrode, over the right arm (deltoid muscle). Will be delivered a current intensity of 2.5 mA, fade in and fade out of 10 seconds, during 20 minutes.

DEVICE

sham tsDCS

sham transcutaneous spinal cord stimulation will be delivered through a DC stimulator (NeuroConn Plus, Germany) using a pair of saline-soaked sponge electrodes (35cm²). The electrode anode will be placed between the eleventh and the twelfth thoracic vertebra) and the reference electrode, over the right arm (deltoid muscle). Will be delivered a current intensity of 2.5 mA, fade in and fade out of 10 seconds, during only 30 seconds but the volunteers will continue with electrodes montage for 20 minutes.Thus, early sensations (eg. mild to moderate tingling or itch) on stimulation site will be experienced without inducing any modulatory effects.

DEVICE

Gait training

It consists of moderate gait training exercise for 20 minutes. To ensure that the exercise will be performed at moderate intensity will be used the 64% - 76% of maximum heart rate (HRmax = 220-age). Heart rate will be monitored every three minutes through a heart polar. In addition will be monitored perceived effort, gait speed and inclination of the treadmill. The Borg scale will be used to evaluate perceived effort. This is an analogue scale graded from 6 (light exercise) to 20 points (exhaustive exercise). Information about the exercise on the treadmill will be noted in the evolution record.

DEVICE

High frequency rTMS

Initially, the higher cortical representation area (hotspot) of first right dorsal interosseous (FDI) muscle will be determined through a figure-eight coil connected to the magnetic stimulator (Rapid2, Magstim, UK) held manually and positioned over the scalp (C3 - 10/20 System) at an angle of 45 degrees from the midline pointed to the target muscle (FDI). Thereafter, RMT will be measure. rTMS protocols was based on previous studies. High frequency protocol: 20 hertz (Hz), 90% RMT, 45 trains, 40 stimuli per train, inter interval of 28 seconds, 1800 stimuli. After each rTMS session, presence of adverse effects will be computed.

DEVICE

Low frequency rTMS

Initially, the higher cortical representation area (hotspot) of first right dorsal interosseous (FDI) muscle will be determined through a figure-eight coil connected to the magnetic stimulator (Rapid2, Magstim, UK) held manually and positioned over the scalp (C3 - 10/20 System) at an angle of 45 degrees from the midline pointed to the target muscle (FDI). Thereafter, RMT will be measure. Low frequency protocol: 1Hz, 90% RMT, 1500 stimuli (1 train). After each rTMS session, presence of adverse effects will be computed.

DEVICE

sham rTMS

The hotspot of first right dorsal interosseous (FDI) muscle will be determinate through a figure-eight coil connected to the magnetic stimulator positioned over the motor primary cortex (C3). Then, the motor threshold (RMT) of FDI will be measure. Sham rTMS will be performed with low frequency (1Hz, 90% RMT, 1500 stimuli) protocol using two coils. The first one - connected to the stimulator - will be positioned on a coil support close to the volunteer but not visible. Therefore, characteristic stimulation noises will be audible. The second - disconnected to the stimulator - will be placed over left primary motor area. After each rTMS session, presence of adverse effects will be computed.

Sponsors & Collaborators

• Universidade Federal de Pernambuco

  lead OTHER

Principal Investigators

• Kátia K Monte-Silva, PhD · Universidade Federal de Pernambuco

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

40 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2015-10-31

Primary Completion

2016-01-31

Completion

2016-03-31

Countries

• Brazil

Study Locations