Home-based tDCS in Major Depressive Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Home-based tDCS in Major Depressive Disorder (NCT04799405), a na na study. The primary outcome is Montgomery-Asberg Depression Rating Scale (MADRS).

2. Clinical Question

In statistical terms, the study asks how MADRS scores in this group are described across the stated assessment period during supervised home-based tDCS. A single-group study can describe change within participants, but it cannot by itself separate change associated with the intervention from change that might occur for other reasons. The registry record does not report the observed MADRS scores, the amount or direction of any change, or an estimate of uncertainty. It also does not report a separate control condition against which to interpret the observed course.

3. Trial Design

The registry identifies NCT04799405 as a completed study sponsored by Hebrew SeniorLife. The study title describes supervised home-based tDCS for major depressive disorder. Its model is single group, allocation is NA, and masking is none. The record lists enrollment of 5 participants and classifies the phase as NA. The study start is recorded as 2020-09-24 and primary completion as 2021-07-02.

The intervention is tDCS, classified as a device. The study summary describes telehealth-supervised, caregiver-delivered treatment at home for patients experiencing an acute depressive episode. The arm description identifies a tDCS MDD group of 5 participants. Since the registry design is single group, the arm description does not establish a separate control condition. The record also explicitly notes that this is not a randomized comparison and that the arms are not a like-for-like control comparison.

MADRS is the primary outcome, with a stated timeframe of 12 weeks. The record describes the measure as a clinical interview-based assessment of depressive symptom severity. Listed secondary outcomes include quality of life, depressive symptom questionnaires, cognitive assessment, and digit span measures. The registry record lists 9 outcome measures and 0 analyses. It does not report a statistical analysis plan, the results for the primary outcome, or estimates comparing outcomes over time.

The design supports a descriptive account of this group’s experience and measurements, subject to the outcomes actually reported. It does not support a randomized treatment-effect comparison. Enrollment and completion status describe the registered study, but they do not establish that every planned assessment was obtained or that a particular analysis was conducted; those details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: No significant events occurred between participant enrollment and start of the intervention.

Phase 1 - Acute Stimulation, Daily tDCS

Reasons for not completing this period:

Phase 2 - Tapered Stimulation Schedule

Phase 3 - Follow up Phase

Analysis population for the primary outcome, as defined in the registry: A group of participants with major depressive disorder (MDD).

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Montgomery-Asberg Depression Rating Scale (MADRS), measured over 12 weeks.

The primary endpoint is the total score on the Montgomery-Asberg Depression Rating Scale (MADRS), reported in units on a scale. The registry describes MADRS as a 10-item clinical rating scale based on an interview with a participant or patient. It covers areas including sadness, inner tension, sleep, appetite, concentration, lassitude, ability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 to 6, and the overall score ranges from 0 to 60. Higher scores indicate more severe depressive symptoms.

The record gives these score interpretations: 0 to 6 is normal or symptom absent, 7 to 19 is mild depression, 20 to 34 is moderate depression, and >34 is severe depression. It defines clinical remission as a MADRS score ≤ 10. These are scale interpretations, not results for the study participants.

The stated timeframe is 12 weeks. The outcome description says the primary outcome will be total MADRS score from baseline to one-month follow-up and also labels the assessment as pre- and post-intervention; the relationship between these timing descriptions is not reported in the registry record. MADRS is used to quantify symptom severity in a structured way, making a score-based description of change possible. No participant scores, group summary, change estimate, or uncertainty interval are reported in the registry record, so the endpoint’s observed course cannot be described from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a single-group study, not a randomized comparison. That distinction determines what statistical questions can be answered. A comparison between a treatment group and a concurrent control group can help distinguish intervention-associated differences from changes that might have occurred anyway. In a single-group design, measurements can describe participants over time, but there is no control-group contrast to provide that separation. This is a general limitation of the design, not a result about the participants.

What does a score change represent?

MADRS is a scale for depressive symptom severity. A change score is the difference between a participant’s score at a later assessment and a score at an earlier assessment. A group summary of such changes can describe the measured course among participants with usable assessments. It does not, on its own, establish why scores changed. The registry identifies baseline and follow-up language, but does not report the actual scores, a summary of changes, or how any missing assessments were handled.

The primary outcome is described as a mean, with full range as the dispersion measure. A mean summarizes the arithmetic center of observed scores, while a full range describes the lowest and highest observed values. These summaries answer different questions: a mean gives a compact description of the group’s scores, and a range conveys their spread across the observed values. Neither indicates how precisely the group summary estimates a broader population value. The record does not include the numerical mean or range for MADRS.

How should uncertainty be understood?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, while an interval that includes values in different directions can leave the direction of an effect uncertain. This is a general explanation; the registry record does not report a confidence interval for MADRS or another study outcome. Without the estimate and its uncertainty, the precision of any change cannot be assessed.

A p-value, when reported, describes how compatible the observed data are with a specified statistical model and null hypothesis. It is not a measure of the size or clinical importance of an effect. The registry record lists 0 analyses and does not report a p-value or a test for the primary endpoint. No inferential conclusion should therefore be attributed to the posted record.

What are the planning illustrations?

The sample-size assumptions describe a planning illustration computed from the observed effect, not the trial’s own design. The assumptions use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. These are hypothetical planning assumptions, not the design actually described for this single-group study. The registry record does not report the effect estimate on which the illustration is based, and no sample-size justification for the trial is reported in the registry record. The planning outputs should not be interpreted as observed power or as evidence about the study’s findings.

More generally, a sample-size calculation estimates the amount of information a proposed design may need to detect a specified effect under stated assumptions. It does not tell readers whether an effect was observed, whether the assumptions were appropriate, or whether the trial achieved its intended precision. In this case, the planning assumptions refer to a two-arm setup, whereas the registered model is single group. That distinction should remain clear when interpreting any planning illustration associated with the study.

Why does the design affect the analysis?

Repeated measurements on the same participant are related, rather than independent observations. A suitable analysis would need to account for that relationship if it used multiple measurements per participant. The registry record does not identify a model, a test, or a method for handling repeated measures. It also does not clarify which assessment timing description governed the analysis. No specific method should be imputed to the investigators.

For a small group, individual observations can have a substantial influence on a group summary. This is a general statistical point; it does not establish how the scores were distributed in this study. Reporting individual-level patterns or robust summaries can sometimes help readers understand that influence, but such results are not reported in the registry record. No distributional information or participant-level MADRS results are recorded in the registry record for this analysis.

The registry says the study is completed, but completion status is not an analysis result. To assess the endpoint statistically, readers would need the observed scores and a clear account of the analysis population, assessment timing, missing-data handling, and estimation method. These details are not reported in the registry record. In their absence, the defensible statistical interpretation is limited to the registered design and endpoint description, not an estimate of treatment effect.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 9 outcome measures, including MADRS as the primary outcome and secondary measures of quality of life, depressive symptoms, and cognition. Testing or estimating many outcomes can raise multiplicity concerns: the more questions examined, the greater the chance that some apparently notable result may arise by chance. This is a general statistical issue, not a finding about this study. The registry record does not report a multiplicity adjustment, a hierarchy for interpreting secondary outcomes, or a statistical analysis plan that explains how multiple outcomes would be handled.

The record lists 0 analyses and does not provide outcome results, so there is no reported inferential result for which an adjustment can be assessed. The registry record also does not report whether any interim analyses were planned or conducted. Their presence or absence should not be inferred.

Missing-data handling is not reported in the registry record. The listed enrollment does not reveal whether every participant completed every assessment, whether any scores were unavailable, or how incomplete records were treated. Different approaches to missing data can lead to different estimates, depending on why observations are missing and on the assumptions used. No particular missingness pattern or method can be attributed to this study.

The analysis population is also not reported in the registry record. The record does not say which participants or assessments would be included in an endpoint analysis, or whether an intention-to-treat, per-protocol, or other population was defined. These omissions limit reproducibility and make it impossible to determine precisely what population an unreported estimate would represent. Because outcome estimates are not posted, the appropriate conclusion is that multiplicity, missing-data procedures, and analysis populations cannot be evaluated from the registry entry.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

For the tDCS MDD group, the registry records 0 serious adverse events among 5 participants at risk and 0 other adverse events among 5 participants at risk. It records 0 deaths. No serious-event terms are listed. These are the recorded counts for the group, not estimates of risk that can be generalized from this small study.

A count of 0 means no event in that category is recorded for the listed group in the registry entry. It does not prove that the intervention has no risks, that every possible event was detected, or that events could not occur in another setting or population. The registry record does not report the methods for collecting adverse events, the observation period for these counts, or details that would allow completeness of ascertainment to be evaluated.

Serious and other adverse events are separate registry categories. They should not be combined into a broader safety claim without more information. The entries describe the posted safety counts only; they do not establish a causal assessment of events or compare safety with a control group. No control group is described in this single-group design.

12. What the Result Does, and Does Not, Mean

The record establishes that a completed single-group study of supervised home-based tDCS for major depressive disorder was registered, with enrollment of 5 participants and MADRS designated as the primary outcome. It also records a 12-week timeframe and lists several secondary measures. These registry entries describe the study’s registration and planned measurements; they do not show what happened to participants’ scores.

The posted results do not include MADRS values, an estimated change, a measure of uncertainty, or a reported statistical test. Therefore, the record does not establish whether scores increased, decreased, or remained similar, nor how precisely any change was estimated. It cannot support a conclusion that tDCS did or did not improve depressive symptoms. The absence of an outcome result in the registry record is not evidence that there was no change.

The single-group design also limits causal interpretation. Even with complete pre- and post-intervention scores, a change over time would not show on its own that tDCS caused the change. The registry does not describe a randomized comparator, and it explicitly identifies the study as not being a randomized comparison. Alternative explanations for change cannot be separated using a control-group contrast that is not present in the registered design.

The recorded safety figures are limited to the reported categories and group: 0 serious adverse events, 0 other adverse events, and 0 deaths, with 5 at risk in each adverse-event category. Those counts should not be converted into a broad claim about safety or completeness of event reporting. The registry entry does not provide further information about event collection or follow-up for safety.

The most supportable reading is consequently narrow: the registry describes a feasibility-oriented home-based intervention study and its intended outcome framework, but does not report the clinical outcome estimates required to evaluate change. This distinction separates study completion and registration details from evidence about intervention effects.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of the difference between an intervention question and a design capable of answering a comparative causal question. Home-based, remotely supervised treatment is the setting described in the registry, and the outcome framework includes both symptom ratings and measures related to quality of life and cognition. Those features make clear what investigators aimed to measure. They do not, by themselves, supply evidence of an effect.

The single-group model makes the interpretation boundary especially important. Within-group observations can describe how measured scores change, but without a concurrent control condition, changes cannot be cleanly distinguished from time-related change, measurement variation, or other influences. The registry’s explicit note that the study is not a randomized comparison helps prevent readers from treating the registered groups as equivalent comparison arms.

The entry also illustrates why outcome reporting matters. A named primary endpoint and a stated assessment timeframe define what readers would expect to evaluate, but interpretation requires the observed values and an analysis that explains how they were summarized. Here, the registry lists 0 analyses and does not report MADRS results. The distinction between a completed study and a reported result is essential for evidence assessment.

Finally, the planning assumptions should be kept separate from the actual design and findings. Planning illustrations based on an observed effect can help explore hypothetical future designs, but they are not a substitute for estimates from the registered study and do not represent observed power. The record’s single-group design differs from the two-arm allocation assumed for the planning illustration. Recognizing that mismatch is part of reading statistical outputs in context, rather than treating every displayed number as a result from the trial itself.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation is that the registry record does not report the primary outcome values or an analysis of them. Without the MADRS scores, a change estimate, or an uncertainty measure, the magnitude and precision of any symptom change cannot be assessed. Secondary outcome results are also not reported in the registry record.

The study is single group, with allocation listed as NA and masking listed as none. There is no randomized comparator described, and the record explicitly cautions that this is not a randomized comparison or a like-for-like control comparison. This restricts causal interpretation even if within-group measurements were available. The listed enrollment of 5 also means the registered study is small; the record does not report a sample-size justification or a precision target.

Assessment timing is not fully clear. The primary outcome has a stated timeframe of 12 weeks, while its description refers to baseline to one-month follow-up and to pre- and post-intervention assessment. The registry record does not explain how these descriptions align or identify the timing of any reported analysis.

Important analysis details are not reported in the registry record. These include the statistical method, analysis population, handling of missing data, multiplicity procedures, and whether interim analyses were planned or conducted. The record does not provide enough information to assess adherence to a prespecified analysis plan or the completeness of endpoint and safety ascertainment.

Safety interpretation is also limited to the posted event counts. The record gives 0 serious events, 0 other events, and 0 deaths, but does not report event-collection methods or enough detail to assess completeness. These limitations do not establish that outcomes or events were absent; they describe what cannot be evaluated from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Home-based tDCS in Major Depressive Disorder — NCT04799405.
• Registry record last updated 2022-03-24; status last verified 2022-03.
• Results first posted 2022-03-24.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT04799405 is a completed, single-group study sponsored by Hebrew SeniorLife, titled Home-based tDCS in Major Depressive Disorder. The intervention is device-based tDCS, described as telehealth-supervised and caregiver-delivered at home. The registry lists enrollment of 5 participants, allocation as NA, and masking as none. The recorded study start is 2020-09-24, with primary completion on 2021-07-02.

MADRS is the primary outcome, with a stated timeframe of 12 weeks. The registry also lists secondary measures covering quality of life, depressive symptoms, and cognition. It records 9 outcome measures and 0 analyses. Primary and secondary outcome results are not reported in the registry record. The safety entries record 0 serious adverse events, 0 other adverse events, and 0 deaths in the listed group. The single-group design and absence of posted outcome analyses limit interpretation of treatment effects.