Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming in Aphasic Patients.

Stroke Clinical Trial

Official title:

Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05570578
• Other study ID #: 2022-D0058
• Status: Recruiting
• Phase: N/A
• Start date: October 24, 2022
• Est. completion date: October 31, 2024

Study information

• Verified date: November 2023
• Source: University Hospital, Geneva
• Contact: Adrian G Guggisberg, MD
• Phone: +41316323081
• Email: Adrian.Guggisberg[@]insel.ch
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

High-Definition Transcranial Direct Current Stimulation (HD-tDCS) allows to induce, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of a given cerebral region and to obtain a very focused cortical effect. Previous studies using HD-tDCS have shown the effectiveness of this stimulation technique for enhancing language recovery in patients with aphasia.

However, language processes are not determined solely by local neural activity at a single site, but rather by the interaction between neural networks. This is because a large cortical network is involved in language processes and, therefore, the same language disorder may result from lesions at different locations in this network.

The investigators hypothesize that anodal HD-tDCS will enhance neural interactions between language areas and, thereby, improve language processing and word learning.

The investigators propose to carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.

Description:

Functional connectivity (FC) represents a means of analyzing functional interactions in the brain network by assessing the statistical dependence of neural activity between brain areas. The brain maintains a high level of interactions between brain areas even in the resting state, when it is not explicitly involved in a specific task. Resting-state interactions occur mainly in the so-called alpha frequency band (8-13 Hz) . Moreover, these resting-state interactions are crucial for correct task performance and learning. Indeed, healthy subjects with high resting-state alpha-band FC levels are better able to perform tasks and learn. For example, subjects with high levels of FC between Broca's area and the rest of the brain perform better on language production tasks and show greater training gains when learning new words. In addition, patients with brain damage due to stroke show a reduction in resting-state alpha-band FC, which correlates with the severity of neurological deficits. In particular, a loss of FC of structurally preserved inferior frontal areas was associated with more severe aphasia. Conversely, high-levels of FC between the inferior frontal brain areas and the rest of the brain during the first weeks after stroke was associated with better recovery from aphasia, probably reflecting a reorganization of neural connections as a neural mechanism involved in plasticity. Resting-state FC is therefore an interesting neural target for therapy, which could help improve recovery from aphasia.

In a previous study on healthy subjects, the investigators have indeed observed that HD-tDCS applied to Broca's area improves the ability for new-verb learning, i.e., the correct naming of action pictures. This improvement in learning correlated with greater increase in FC between Broca's and Wernicke's area.

The investigators now carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 14
• Est. completion date: October 31, 2024
• Est. primary completion date: September 30, 2024
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Ischemic or hemorrhagic stroke

• Presence of aphasia with difficulty finding words and/or naming objects/pictures

• =12 months post-stroke

• = 18 years of age

• French-speaking

• Able to participate in 30-60 min therapeutic sessions (good concentration and understanding of the task and ability to follow instructions

Exclusion Criteria:

• Patients unable to understand the given information on the study and its objectives, or instructions for tasks performed.

• Impaired alertness or delirium

• Severe co-morbidity affecting speech

• Contraindication to tDCS: pregnant women, patients with active implants such as pacemakers or cochlear implants, patients with one or more seizures, metal objects in the brain

• Occurrence of a new stroke during the study protocol.

Related Conditions & MeSH terms

• Aphasia
• Stroke

Intervention

Device:
• HD-tDCS
The anode electrode will be placed over Broca's area, 4 cathode electrodes will be placed at about 2 cm distance each from the anode in 4 directions.

Locations

Country	Name	City	State
Switzerland	Division of Neurorehabilitation, University Hospital of Geneva	Geneva	GE

Sponsors (1)

Lead Sponsor	Collaborator
Adrian Guggisberg

Country where clinical trial is conducted

Switzerland, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Action picture naming, long-term improvement	Change in number of correctly named action pictures	Change from day 1 (baseline) to week 4 (follow-up)
Other	Narrative speech, short-term improvement	Patient describes cookie-theft picture and action-picture, change in score	Change from day 1 (baseline) to day 5 (posttest)
Other	Narrative speech, long-term improvement	Patient describes cookie-theft picture and action-picture, change in score	Change from day 1 (baseline) to week 4 (follow-up)
Primary	Action picture naming, short-term improvement	Change in number of correctly named action pictures	Change from day 1 (baseline) to day 5 (posttest)
Secondary	Functional connectivity between Broca's and Wernicke's area	Change in the normalized imaginary component of coherence between Broca and Wernicke	Change from day 1 (baseline) to day 5 (posttest)