Effectiveness of TDCS Over Broca's Area in Verb Naming: a Randomized, Double-Blind, Crossover Study

This clinical trial investigated whether transcranial direct current stimulation (tDCS) over Broca's area (F5) could improve verb naming abilities in adults with aphasia. Additionally, the study evaluated the stability of the treatment response to tDCS over time.

The main questions this study sought to answer were:

* Does tDCS improve verb naming abilities compared to inactive (sham) stimulation? * Are the observed effects stable over time?

Participants received 10 daily sessions of tDCS over two consecutive weeks (5 days per week). The study included two treatment conditions, separated by one-month washout period:

* Active tDCS: Stimulation over Broca's area at 2 mA; * Sham tDCS: Stimulation mimicking the active condition without delivering electrical current.

During the treatment, participants were asked to name aloud videos of actions displayed on a computer screen. One month after each treatment condition, follow-up testing was conducted to evaluate the stability of the treatment response.

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Key information

Conditions

Aphasia Non Fluent Aphasia Aphasia, Broca Brain Diseases Cardiovascular Diseases Central Nervous System Diseases Cerebrovascular Disorders Communication Disorders Language Disorders Mental Disorders Nervous System Diseases Neurobehavioral Manifestations Neurodevelopmental Disorders Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms Speech Disorders Stroke Vascular Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

I.R.C.C.S. Fondazione Santa Lucia

Roma, Italy, 00179

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

native Italian proficiency;
pre-morbid right-handedness;
a single left hemispheric stroke at least 6 months before the investigation.

Exclusion criteria

acute or chronic neurological symptoms requiring medication;
attention and/or memory deficits.

Treatment and study plan

Active Treatment

Device

Participants receive anodic tDCS using a battery-driven Eldith (neuroConn GmbH) Programmable Direct Current Stimulator with surface-soaked sponge electrodes (5×7 cm). A constant current of 2 mA is applied for 20 minutes per session. The stimulation targets the left frontal region (F5 of the extended International 10-20 EEG system), corresponding to Broca's area, while the reference electrode is placed over the contralateral frontopolar cortex. tDCS is performed for 10 daily sessions over two consecutive weeks (5 days per week).

Sham stimulation

Device

Participants receive sham tDCS using a battery-driven Eldith (neuroConn GmbH) Programmable Direct Current Stimulator with surface-soaked sponge electrodes (5×7 cm). No therapeutic current is applied during the 20-minute session. The electrode placement mimics the active condition, targeting the left frontal region (F5 of the extended International 10-20 EEG system), corresponding to Broca's area, while the reference electrode is placed over the contralateral frontopolar cortex. Sham tDCS is performed for 10 daily sessions over two consecutive weeks (5 days per week).

Primary outcomes

Action Naming Task

Time frame: Verb naming performance was assessed at baseline (pre-treatment), post-treatment (immediately after the 10-day intervention), and at follow-up (one month after each treatment condition) to evaluate both immediate effects and the stability of responses.

An action naming task was designed to evaluate verb naming performance. Video clips depicting various actions were presented on a 15-inch computer screen at a viewing distance of 1 meter, each preceded by an 800-millisecond fixation point. Participants were instructed to name the action depicted in each clip within a 15-second response window. The examiner manually recorded correct responses. For incorrect responses or failures to respond within the allotted time, the written name of the action was displayed beneath the video, and participants were required to read the name aloud. The video and the written name remained on the screen until the word was read correctly or 40 seconds had elapsed. The task was conducted during 20-minute tDCS sessions, wherein participants received either active stimulation targeting Broca's area or sham stimulation with identical electrode placement but no active current.

Sponsors and collaborators

Lead sponsor

I.R.C.C.S. Fondazione Santa Lucia

Other

Registry information

Official study title

La Stimolazione Transcranica (tDCS) E Transpinale a Corrente Diretta (tsDCS) Per Il Recupero Delle Funzioni Cognitive in Soggetti Affetti Da Patologia Cerebrovascolare O Neurodegenerativa

Important dates

Study start: 2023
Primary completion: 2024
Study completion: 2024
First posted: Jan 15, 2025
Registry last updated: Jan 15, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed