Application of Cerebellar tDCS in Aphasia

NCT07353879 | Completed

• 1 other identifier: EAU23035
• Study Type: interventional
• Target: 6
• Locations: 1 country
• Sites: 2

Brief 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

Keywords

Aphasia; Non-Invasive Brain Stimulation; Transcranial Direct Current Stimulation; Cerebellum; Stroke Rehabilitation; Computerized intervention; Speech Perception training; Naming intervention; Noun naming; Verb naming

Outcome Measures

Primary Outcomes (2)

• Accuracy on a timed confrontation naming task

  The timed confrontation naming task comprises 120 picture stimuli from the Object and Action Naming Battery (OANB) and is set for data collection using DMDX . Participants are instructed to name displayed pictures as quickly and ac-curately as possible using a microphone. Each trial started with a central fixation point displayed for 500 ms, followed immediately by a single picture stimulus presented centrally on the screen. The stimulus remains visible until a response is detected or 5000 ms have elapsed. DMDX records an error if no response was produced within the 2000 ms time limit. The naming task consists of 60 trained and 60 untrained words, half of them nouns and the other half verbs.

  - The baseline assessment on 'Day 1' - Outcome measure on 'Day 5'. - Data will be reported "through study completion, an average of 1 year"

• Reaction Time on a timed confrontation naming task

  The timed confrontation naming task comprises 120 picture stimuli from the Object and Action Naming Battery (OANB) and is set for data collection using DMDX . Participants are instructed to name displayed pictures as quickly and ac-curately as possible using a microphone. Each trial started with a central fixation point displayed for 500 ms, followed immediately by a single picture stimulus presented centrally on the screen. The stimulus remains visible until a response is detected or 5000 ms have elapsed. DMDX records an error if no response was produced within the 2000 ms time limit. The naming task consists of 60 trained and 60 untrained words, half of them nouns and the other half verbs.

  - The baseline assessment on 'Day 1' - Outcome measure on 'Day 5'. - Data will be reported "through study completion, an average of 1 year"

Study Arms (2)

Active tDCS

EXPERIMENTAL

Cerebellar tDCS is delivered using a Soterix Medical MxN High Definition tDCS Stimulator. Real tDCS is 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. For real tDCS, participants receive five sessions, each consisting of 20 minutes of 2 mA anodal stimulation with 30-second ramp-up and ramp-down periods, with simultaneous behavioral treatment administered for 60 minutes (additional 40 minutes following active tDCS).

Device: anodal right posterolateral cerebellar high-definition tDCS; Behavioral: computerized visual speech perception naming intervention

Sham tDCS

SHAM COMPARATOR

For sham tDCS, electrodes were placed similarly, but the stimulator was turned off after a 30-second ramp-up and ramp-down period. Five session, similar procedures for the paired behavioral intervention.

Device: anodal right posterolateral cerebellar high-definition tDCS; Behavioral: computerized visual speech perception naming intervention

Interventions

computerized visual speech perception naming intervention BEHAVIORAL

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.

Active tDCS; Sham tDCS

anodal right posterolateral cerebellar high-definition tDCS DEVICE

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.

Active tDCS; Sham tDCS

Eligibility Criteria

• Age: 40 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Native Cantonese speakers
• Age: 40-80 years
• Diagnosed with aphasia
• Single left-hemispheric stroke ≥6 months prior
• Premorbid right-handedness
• Normal or corrected-to-normal vision
• Functional hearing (with or without hearing aids)

You may not qualify if:

• History of brain surgery
• Seizures within past 12 months
• Conditions contraindicated for tDCS (e.g., metallic implants, pacemakers)
• Prior neurological treatment (other than stroke-related)
• Severe cognitive impairment
• Naming accuracy \<10% or \>80% on noun/verb naming screening pretestt.

Sponsors & Collaborators

• The University of Hong Kong: lead

Study Sites (2)

The University of Hong Kong

Hong Kong, Hong Kong SAR, Hong Kong

Location

Speech and Neuromodulation Lab

Hong Kong, Hong Kong

Location

MeSH Terms

Conditions

Aphasia

Condition Hierarchy (Ancestors)

Speech Disorders; Language Disorders; Communication Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Mehdi Bakhtiar, PhD

  The University of Hong Kong

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 29, 2025
• First Posted: January 21, 2026
• Study Start: January 3, 2024
• Primary Completion: April 15, 2024
• Study Completion: June 1, 2025
• Last Updated: January 21, 2026

Record last verified: 2023-12

Data Sharing

• IPD Sharing: Will not share

Locations

HK (2)