Does combining tDCS with therapy improve verb naming in chronic aphasia?
For people with chronic aphasia after a stroke, finding effective treatments for verb naming difficulties is a common challenge. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that applies a weak electrical current to specific brain areas. Research shows that pairing tDCS with speech therapy can boost verb naming more than therapy alone, and the improvements can last for weeks.
What the research says
A 2025 double-blind, randomized, sham-controlled crossover study tested anodal tDCS over the left inferior frontal gyrus combined with verb naming therapy in 32 people with chronic post-stroke aphasia 2. Participants received 10 daily sessions of real tDCS and 10 sessions of sham (placebo) stimulation. Verb naming improved significantly more with real tDCS, with large effect sizes, and the gains were still present at a one-month follow-up 2. Every participant showed greater improvement during the real tDCS condition compared to sham 2.
Earlier studies support these findings. A 2015 case study reported that a patient with chronic non-fluent aphasia who received 20 sessions of verb naming training combined with bihemispheric tDCS (anodal over left DLPFC, cathodal over right DLPFC) showed significant verb naming improvements that lasted for 48 weeks 8. Another 2015 study using voxel-based lesion-symptom mapping in 20 non-fluent aphasia patients found that anodal tDCS over the left IFG improved language performance, including verb naming, but the degree of benefit depended on which brain areas were damaged 9.
A 2023 literature review on noninvasive brain stimulation in primary progressive aphasia also noted that tDCS combined with speech therapy may improve verb production and action naming 7. While this review focused on a different condition (progressive aphasia), it adds to the broader evidence that tDCS can enhance language outcomes when paired with therapy.
Importantly, the 2025 study found that preserved frontal brain regions, especially the frontal pole, were linked to better responses to tDCS, while damage to posterior areas predicted poorer outcomes 2. This suggests that individual brain structure may influence how well someone responds to tDCS-enhanced therapy.
What to ask your doctor
- Could tDCS combined with speech therapy be an option for my verb naming difficulties?
- What is the typical number and duration of tDCS sessions used in studies?
- Are there any known risks or side effects of tDCS for someone with my brain lesion location?
- How long do the benefits of tDCS-enhanced therapy typically last, and are booster sessions needed?
- Do you know of any clinics or research centers near me that offer tDCS for aphasia?
This question is drawn from common patient questions about Neurology and answered using cited medical research. We do not provide individualized advice.