Dual-tDCS and Anodal PMC tDCS Over the Contralesional Hemisphere on the Upper Limb Function in Stroke Patients

Summary

Background: Transcranial direct current stimulation (tDCS) has been gaining increasing interest as a potential therapeutic tool to improve upper extremity (UE) rehabilitation outcomes following stroke. Within the concept of interhemispheric inhibition (IHI), most tDCS studies have applied anodal ipsilesional and/or cathodal contralesional primary motor cortex (M1) tDCS to rebalance IHI and enhance motor recovery. However, compelling evidence suggests that an excitation/inhibition model is oversimplified, and the role of both hemispheres in the encoding of information during motor learning should be acknowledged. Moreover, multiple lines of evidence have demonstrated the potential relevance of contralesional premotor cortex (PMC) for recovery after M1 injury.

Objective: We are aiming to investigate and compare the effects of two tDCS montages at different cortical sites (Dual-M1 vs. a-tDCS over contralesional PMC) by measuring the clinical outcomes of the most affected UE in patients with chronic subcortical stroke.

Methods: 35 participants will be randomly assigned to 1 of 3 groups (Group A received dual- M1 tDCS, Group B received a-tDCS over contralesional PMC, and Group C received sham stimulation). tDCS will be applied using intensity of 2 mA for 20 min. (5 times/week) for 2 consecutive weeks. Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) and Action Research Arm Test (ARAT) will be used to quantify the UE functional motor ability. Box and Block Test (BBT) will be used for gross manual dexterity and Nine Hole Peg Test (NHPT) will be used to measure fine hand dexterity. All measurements will be taken pre-treatment (T0) and post-treatment (T1) immediately after the 10th session, then 4 weeks after the end of stimulation period (T2) to assess the long-term effects.

Expected results: This study would verify whether enhancing the motor cortical hyperexcitability in the contralesional hemisphere has a beneficial on recovery of the paretic hand, or regaining the balance of transcallosal inhibitory circuits between the motor areas in both hemispheres has more positive effects on the motor outcomes . This study would also provide a predictive approach to enable realistic rehabilitation goal-setting by identifying the proper tDCS montage for patients with stroke depending on their impairment level.

Conditions

• Stroke

Interventions

DEVICE

Dual M1-tDCS

In the M1- dual tDCS montage, the anodal electrode will be placed above ipsilesional M1 and the cathode will be positioned over contralesional M1.

DEVICE

a-tDCS over contralesional PMC

In the anodal-tDCS for PMC, the anodal electrode will be placed over the contralesional PMC. The PMC is defined as being 2.5 cm anterior to the M1. The cathodal electrode will be positioned over the contralateral suborbital region

DEVICE

Sham tDCS

For sham stimulation, there is no particular electrode configuration to be followed, thus, 6 participants will receive sham stimulation with the configuration will be used in group A, and 5 participants will receive sham stimulation with the configuration will be used in group B. By pressing the sham button, the current will automatically ramped up over 10 sec. till reaching 1 mA, then it will be decreased gradually over 30 seconds till turning off the apparatus. This is to ensure the typical initial itching sensation

Sponsors & Collaborators

• Turki Abualait

  lead OTHER_GOV

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2017-11-10

Primary Completion

2020-03-10

Completion

2020-03-14

FDA Device

Yes

Countries

• Saudi Arabia

Study Locations