Non-invasive brain stimulation to improve visual perception after stroke: a systematic review and meta-analysis

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Ophthalmology

Background:

• Stroke is a leading cause of long-term disability, often resulting in visual perception deficits.
• Impaired visual perception significantly impacts a stroke patient's functional independence and quality of life.
• Current rehabilitation strategies for visual deficits post-stroke have varying degrees of efficacy.

Purpose of the Study:

• To systematically review and meta-analyze the efficacy of non-invasive brain stimulation (NIBS) for improving visual perception in stroke survivors.
• To evaluate NIBS as a standalone therapy and in combination with other treatments.

Main Methods:

• A systematic review and meta-analysis adhering to PRISMA guidelines.
• Searched major databases (PubMed, Scopus, WoS, CINAHL, CENTRAL) for randomized controlled trials (RCTs) up to September 2025.
• Analyzed data using random effects meta-analyses, assessing effect sizes (SMD) and certainty of evidence (GRADE).

Main Results:

• Seven RCTs were included, with six contributing to meta-analysis.
• NIBS demonstrated a large effect size (SMD 0.83) in improving visual perception (MVPT) compared to sham stimulation (4 RCTs, n=124).
• NIBS combined with other therapies also showed a large effect size (SMD 1.20) compared to other therapies alone (2 RCTs, n=32).

Conclusions:

• There is low-certainty evidence supporting NIBS over sham stimulation for visual perception enhancement in stroke patients.
• Very low-certainty evidence suggests NIBS combined with other therapies may also improve visual perception.
• Further high-quality RCTs are warranted to confirm these findings.