Application of Cerebellar tDCS in Aphasia

Summary

The goal of this clinical trial is to learn if adding brain stimulation (cerebellar anodal tDCS) helps a computer-based therapy improve word-finding in Cantonese-speaking adults with aphasia after stroke. It will also check if the stimulation is safe and comfortable.

The main questions it aims to answer are:

Does real brain stimulation during therapy help people name pictures (both objects and actions) better and faster than fake (sham) stimulation?

Are there different effects on naming nouns (objects) versus verbs (actions)? Do any participants feel side effects like tingling or discomfort from the stimulation?

Researchers will compare real brain stimulation to sham (fake) stimulation while everyone gets the same 5-day computer therapy.

Participants will:

Do 60 minutes of computer word-naming practice every day for 5 days, twice (once with real stimulation, once with sham), with at least 2 weeks break in between

Wear a cap with electrodes on the back of the head for the first 20 minutes of each session to receive either real or sham brain stimulation

Name pictures on a computer before and after each 5-day block to measure improvement

Report any feelings or side effects after each session

Conditions

• Aphasia Following Cerebral Infarction

Interventions

DEVICE

anodal right posterolateral cerebellar high-definition tDCS

Intervention delivered in two phases (active tDCS or sham tDCS first, order of treatment randomized across participants). Cerebellar tDCS: delivered using a Soterix Medical MxN High Definition tDCS Stimulator. Real tDCS applied to the right posterolateral cerebellum, with one anodal electrode (2 mA) placed at PO10 and two return electrodes (-1 mA each) at P10 and O10, using EEG-sized electrodes (external diameter of 1.2 cm) secured in an EEG cap. Participants received five sessions of tDCS combined with 60-min behavioral treatment. Real tDCS: delivered in the first 20 minutes of the behavioral intervention, 2 mA anodal stimulation with 30-second ramp-up and ramp-down periods. Sham tDCS - delivered using a Soterix Medical MxN High Definition tDCS Stimulator with similar montage as the active condition. Electrodes were placed similarly, but the stimulator was turned off after a 30-second ramp-up and ramp-down period.

BEHAVIORAL

computerized visual speech perception naming intervention

Computerized Naming Treatment: five consecutive 60-minute sessions. The computerized naming treatment adapted to Cantonese from Fridriksson et al. and delivered using DMDX. Lexical-semantic processing is engaged by providing auditory and visual articulatory cues. DMDX featured 100 Cantonese picture stimuli (50 objects and 50 actions), which have norms for timed-picture- naming in Cantonese. Participants viewed a black-and-white image of an item for 2 seconds, followed by a video showing the lower part of a speaker's face (nose and mouth) articulating the corresponding word. Participants then had up to 7 seconds to judge whether the picture stimulus matched the audio-visual presentation by pressing a "correct" or "incorrect" button.

Sponsors & Collaborators

• The University of Hong Kong

  lead OTHER

Principal Investigators

• Mehdi Bakhtiar, PhD · The University of Hong Kong

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

40 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-01-03

Primary Completion

2024-04-15

Completion

2025-06-01

Countries

• Hong Kong

Study Locations