1. Is the work clearly and accurately presented and does it cite the current literature?
Partly
The manuscript is generally understandable and addresses a clinically relevant topic. The rationale for bilateral anodal tDCS is clearly introduced and is linked to prior evidence suggesting bilateral sensorimotor involvement in children with cerebral palsy. The topic is relevant, and most of the cited literature is appropriate to the intervention and population.
However, several presentation and citation issues require correction. The abstract reports the effect size for left ankle dorsiflexion as g = 1.42, whereas Table 1 reports g = 1.49 for the same outcome. One of these values appears to be incorrect and should be reconciled. In addition, p-values are reported for some outcomes in the abstract but are not consistently presented in Table 1, making it difficult to cross-reference the significance claims against the tabulated results.
There is also an unresolved sentence fragment in the Discussion: “Hereby, there However, this study applied bilateral anodal tDCS...”, which requires editorial correction. Reference 9, concerning wet cupping therapy in adults with chronic medical conditions, has no clear relevance to tDCS, treadmill training, gait, or cerebral palsy and appears to be misplaced. The Introduction also refers to Nevalainen et al. as a 2015 study, whereas the reference list appears to cite Nevalainen et al. as 2012. This citation inconsistency should be checked and corrected.

2. Is the study design appropriate and is the work technically sound?
Partly
The single-group feasibility case series design is acceptable for an early-stage investigation of safety, feasibility, and preliminary signal detection. The bilateral tDCS montage is rationally justified by prior neurophysiological evidence suggesting bilateral sensorimotor disruption in cerebral palsy. This is a technically interesting and potentially novel aspect of the study.
However, the technical reporting is incomplete. The tDCS protocol states the current intensity and electrode locations, but electrode size in cm² is not provided; therefore, current density cannot be calculated. Impedance monitoring, impedance thresholds, and ramp-up/ramp-down procedures are also not reported. These details are important for safety interpretation and technical reproducibility.
There is also inconsistency between the reported gait assessment method and Figure 2. The Methods section describes tri-axial accelerometry, whereas Figure 2 depicts a Vicon/Nexus motion-capture setup. It is unclear whether Vicon data were collected, whether they contributed to the reported outcomes, or whether the figure is unrelated to the data presented. This should be clarified.
The GMFM version is also inconsistently identified. The abstract refers to GMFM-66, whereas the Methods section and Table 1 refer to GMFM-IS. These are not interchangeable labels and may involve different scoring approaches. The correct instrument and scoring method should be confirmed and reported consistently.

3. Are sufficient details of methods and analysis provided to allow replication by others?
Partly
The manuscript provides some useful intervention details, including the number of treatment sessions, treadmill familiarisation sessions, treadmill speed basis, current intensity, and approximate electrode locations. However, several key details needed for replication are missing.

The tDCS electrode size, current density, impedance values or thresholds, and ramp-up/ramp-down procedures are not reported. Without these details, another research group could not fully reproduce the stimulation protocol.

Protocol Reporting

• Electrode size (cm²) is not reported
• Impedance monitoring during sessions is not mentioned
• Ramp-up and ramp-down durations are not stated
• It is not explicitly confirmed whether tDCS stimulation ran concurrently for the full 10-minute treadmill period
• Recommendation: A dedicated tDCS parameter table following Peterchev et al. (2012) reporting standards should be added.

The statistical methods also require clarification. It is not clearly stated which outcomes were subjected to paired t-tests and which outcomes were interpreted using effect sizes only. This distinction should be explicitly stated in the Methods section or in a detailed table footnote.

Individual participant data are not presented in the manuscript. Given the very small sample size of five children, group means and standard deviations alone are insufficient to understand response variability, outliers, or consistency of response across participants.
Standard feasibility metrics are also incompletely reported. The number of children screened, number eligible, number declining participation, per-participant attendance, completion of all sessions, and treadmill speed progression are not clearly described. These details are especially important because the study is framed as a feasibility study and would inform the planning of a future trial.

4. If applicable, is the statistical analysis and its interpretation appropriate?
Partly
The statistical reporting requires substantial clarification before the preliminary efficacy claims can be interpreted reliably.

The Table 1 footnote reports t(9) = 3.97, p = 0.003 for medio-lateral alignment. However, the study included five participants in a single-group pre–post design. For a subject-level paired t-test with n = 5, the degrees of freedom should be n − 1 = 4, not 9. The reported df = 9 is therefore inconsistent with the stated sample size and paired design.

If df = 9 resulted from treating repeated walking trials as independent observations, this would raise a concern of pseudoreplication because repeated trials from the same child are not statistically independent. If trial-level data were analysed, the authors should use a method that accounts for clustering within participants, such as an appropriate repeated-measures or mixed-effects model.

Multiple outcomes appear to have been assessed for statistical significance, including walking tolerance, motor function, postural alignment, gait variability, and several passive range-of-motion outcomes. No correction for multiple comparisons is reported, and no clear primary efficacy outcome is identified. This increases the risk of Type I error, particularly in a sample of only five participants.

There are also internal reporting inconsistencies. The left ankle dorsiflexion effect size is reported as g = 1.42 in the abstract but g = 1.49 in Table 1. The abstract describes right ankle dorsiflexion as a moderate, non-significant improvement, whereas the Results section states that the treatment had a significant impact on both left and right ankle dorsiflexion. These inconsistencies should be corrected.

5. Are all the source data underlying the results available to ensure full reproducibility?
Partly
The manuscript provides a data availability statement and refers to a repository under a Creative Commons Attribution 4.0 license. Data is available on ZENODO. This is a positive aspect of the paper and supports transparency.
However, full reproducibility depends not only on the availability of the dataset but also on clarity of the analysis procedures. Because the manuscript does not clearly state which outcomes were analysed using paired t-tests, how repeated gait trials were handled, or how effect sizes were calculated, source data availability alone is not sufficient to ensure full reproducibility.

6. Are the conclusions drawn adequately supported by the results?
Partly
The conclusion that the intervention appears safe is supported by the reported absence of side effects or stimulation intolerance. However, the conclusion regarding feasibility should be more cautious because standard feasibility indicators, such as screening numbers, eligibility, recruitment flow, adherence, attendance, and protocol progression, are incompletely reported.

The conclusion that the intervention produced significant improvements in medio-lateral alignment and ankle dorsiflexion should also be interpreted cautiously. The reported degrees-of-freedom error, unclear handling of repeated gait trials, absence of correction for multiple outcome testing,  and p-value reporting weaken confidence in the statistical significance claims.

The Discussion also appears to attribute observed changes to specific mechanisms, such as tDCS-related reduction in spasticity or treadmill-related lateral force effects. Because this was a combined-intervention, single-group case series without a control group, the study cannot separate the effects of tDCS, treadmill training, maturation, practice effects, or measurement variability. These mechanistic explanations should therefore be framed as speculative and hypothesis-generating rather than demonstrated findings.

The recommendation for future larger randomized controlled trials is appropriate and well aligned with the feasibility nature of the study. However, the manuscript should avoid overstating preliminary efficacy until the statistical and reporting issues are corrected.