SynthesisCoDAS2026
Effects of Transcranial Direct Current Stimulation on Speech and Voice Changes in Parkinson's Disease: a Systematic Review with Meta-Analysis.
Synthesis in CoDAS, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeThis meta-analysis aims to evaluate the existing evidence on the effects of tDCS on speech and voice alterations in patients with PD. SEARCH STRATEGIES: PubMed, LILACS, EMBASE, Cochrane Central Register of Controlled Trials, Science Direct, Web of Science, Scopus, and gray literature searches: Google Scholar and Open Grey. The search included the descriptors: "Parkinson Disease, Transcranial Direct Current Stimulation, Voice, Speech" combined with AND and OR. SELECTION CRITERIA: Patients with Parkinson's Disease, both sexes. Use of Transcranial Direct Current Stimulation (tDCS) to treat voice and speech parameters in patients with Parkinson's Disease. DATA ANALYSIS: A total of 1,345 articles were included, 14 articles in the systematic review and 6 articles in the meta-analysis. The risk of bias and level of evidence were assessed using REVIEW MANAGER 5.4.1 and GRADE software.
resultsThe results showed an overall effect size of tDCS of Z=0.89 (P=0.37). Studies targeting the prefrontal cortex (PFC) showed a larger effect size of 1.38 (P=0.17), thus demonstrating a greater impact on speech and voice outcomes with the use of tDCS for PD. Three studies presented a low risk of bias, and three studies presented an unclear risk.
conclusionDespite the small number of studies, the findings of this meta-analysis suggest the potential applicability of tDCS as an adjunctive tool in the treatment of voice and speech disorders in patients with PD.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.