Stepped Care for Aphasia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Stepped Care for Aphasia (NCT05851573), a na na study. The primary outcome is Change in the Depression Score on Hospital Anxiety and Depression Scale at Post-Intervention.

2. Clinical Question

3. Trial Design

The registry record describes a completed, single-group behavioral study titled “Stepped Care for Aphasia.” The intervention is named a psychosocial intervention and is focused on psychological well-being for people living with aphasia after stroke. The record lists Medical University of South Carolina as the sponsor. It gives a study start date of 2023-03-31, a primary completion date of 2023-12-31, and a status of completed.

The study summary describes baseline testing before treatment, a 5-week intervention, post-treatment testing and follow-up testing 1-month later. It also describes check-in phone calls during the period off treatment and interviews about participants’ experiences at the end of the study. The primary endpoint’s timeframe is described as through intervention completion, an average of 7 weeks. The record does not explain how that average timeframe relates to each participant’s schedule.

The study is not a randomized comparison: allocation is recorded as not applicable, masking as none, and the model as single group. There is no like-for-like control group. As a result, the primary endpoint is a within-participant change from baseline, not an estimate of a difference between treatment groups. The registry record does not report a protocol for a comparator or a planned randomized allocation.

Enrollment is listed as 11. The primary endpoint description says one participant was excluded because post-intervention HADS data were missing. The record does not report further details about the analysis population or the handling of missing data. It lists eight outcome measures and eight analyses, but does not give the numerical findings for the primary endpoint in the information recorded.

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: Interested participants provided informed consent and were then screened to determine if they meet all eligibility criteria. After enrollment, all participants were assigned to the same intervention arm.

Overall Study

Analysis population for the primary outcome, as defined in the registry: One participant was excluded due to missing HADS data at post-intervention.

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 Change in the Depression Score on Hospital Anxiety and Depression Scale at Post-Intervention, measured over through intervention completion, an average of 7 weeks.

The primary endpoint is change in the depression score on the Hospital Anxiety and Depression Scale (HADS) at post-intervention. The measure is the change in the total depression score between baseline and post-treatment, calculated in the direction baseline minus post-treatment. The scale runs from a minimum score of 0 to a maximum score of 21. In the registry’s definition, a positive change indicates improvement in symptoms, while a negative change indicates worsening.

The endpoint is a continuous measure, and the planned summary is a mean with a standard deviation. A mean describes the average change in the analyzed group; a standard deviation describes how much individual changes vary around that average. These statistics address different features of the data: the mean concerns the group’s average change, while the standard deviation describes spread across participants.

Measuring the same outcome at baseline and after treatment makes it possible to describe change over the intervention period. That change alone does not establish that the intervention caused it. In a single-group study, changes could also reflect factors such as the passage of time, other care or measurement variation. The registry record does not report the mean change, its standard deviation, a confidence interval or a significance test for this endpoint. Consequently, the actual size and precision of the observed change are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group change estimate?

A single-group before-and-after analysis compares measurements from the same participants at different times. In this study, the primary endpoint is defined as baseline HADS depression score minus post-treatment score. This direction matters: under the registry’s definition, a positive value means improvement and a negative value means worsening. The average change would describe the group’s mean change among the participants included in that analysis. It would not represent a comparison with what would have happened without the intervention, because no control group is recorded.

Repeated measurements can reduce some differences between people from influencing a within-person change: each person serves as their own reference over time. But that does not remove time-related influences or establish that the intervention caused the change. General examples include other care, changes in circumstances, natural fluctuation and measurement error. These are possible limitations of the design generally; the registry record does not say that any particular one occurred.

What do the mean and standard deviation describe?

The endpoint is continuous, and the registry identifies the mean and standard deviation as its summary statistics. The mean is the arithmetic average of the individual changes included in the analysis. It indicates the average direction and size of change, using the endpoint’s stated sign convention. The standard deviation describes the spread of individual changes around that mean. A larger spread indicates more variability in the observed changes, while a smaller spread indicates that changes are more closely clustered around the mean.

The standard deviation is not the same as the uncertainty in the estimated mean. A confidence interval is a general statistical way to express uncertainty around an estimate, taking account of the amount of information and variability in the data. It is not a range guaranteed to contain the true value. No confidence interval for the primary endpoint is reported in the registry record, so its precision cannot be assessed from the recorded outcome information.

What can a significance test establish?

In general, a statistical significance test evaluates how compatible observed data are with a specified null hypothesis under the assumptions of the test. A p-value does not measure the probability that the null hypothesis is true, the clinical importance of an effect, or the probability that a result will replicate. Interpretation should consider the estimated effect and its uncertainty, not a significance threshold alone. The registry record does not report a p-value or identify the primary endpoint’s test, so no test result can be interpreted for this outcome.

Even if a within-group change were statistically distinguishable from zero, that would not resolve the lack of a control group. Statistical evidence of change over time is not equivalent to evidence that the intervention produced the change. This distinction is central to interpreting a single-group design.

Why can variability matter?

General statistical methods sometimes account for over-dispersion, meaning that observed variability is greater than assumed by a particular model. An analysis that does not account for extra variation can produce uncertainty estimates that are too narrow. Whether over-dispersion is relevant depends on the outcome and model. The primary endpoint is continuous and summarized by a mean and standard deviation; the registry record does not report an over-dispersion assessment or a model-based adjustment. It would therefore be inappropriate to claim that such an adjustment was or was not necessary.

How should planning illustrations be read?

The registry record describes sample-size illustrations as planning calculations based on the observed effect, not as part of the trial’s own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of the observed effect. For non-time-to-event outcomes, the illustrations are expressed as participants per arm; time-to-event calculations are described in terms of total events. These are general planning assumptions, not evidence that the study used two arms or enrolled participants according to such a calculation.

The record does not provide numerical values for the planning illustrations in the registry record for this interpretation. Such calculations would be prospective planning aids: they indicate sample sizes under stated assumptions for a future comparison. They are not observed power, and they do not establish that a result from this single-group study is reliable. Since the illustrations rely on an observed effect, their usefulness also depends on how well that estimate represents the effect a future study should plan to detect.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Psychosocial Intervention")
n   <- c(10)
m   <- c(2.2)
sp  <- c(2.82)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Psychosocial Intervention  10  2.200  2.820  0.183  4.217

11. Multiplicity, Missing Data and Analysis Populations

The record lists eight outcome measures and eight analyses. The primary endpoint is the change in HADS depression score at post-intervention, and the listed secondary outcomes cover mood, depression, anxiety, perceived stress, quality of life and communication confidence. The registry record does not report whether a particular outcome was designated as the sole confirmatory test, how the secondary outcomes were prioritized, or whether any adjustment for multiple testing was planned.

In general, testing multiple outcomes can increase the chance of at least one apparently unusual result when all tests are interpreted without regard to multiplicity. Adjustment methods or a prespecified hierarchy can address that issue, but the appropriate approach depends on the study’s aims and analysis plan. The registry record does not report such a plan. Because numerical results for the outcomes are not reported in the recorded information, the impact of multiplicity on any findings cannot be evaluated.

For the primary HADS endpoint, the record states that one participant was excluded because post-intervention data were missing. It does not report why the data were missing, whether baseline data were available for that participant, or how missingness was addressed beyond the stated exclusion. The record also does not report whether imputation, sensitivity analyses or alternative analysis populations were used. Missingness can matter when the people with observed outcomes differ in relevant ways from those without observed outcomes; whether that applies cannot be determined from the record.

The enrollment figure is 11, but the registry record does not give a detailed analysis-population definition or a full participant flow for this endpoint. The primary outcome result and its uncertainty are not reported in the registry record, which prevents assessment of how missing data and multiplicity relate to the estimated effect.

12. 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.

The serious adverse event record lists the psychosocial intervention group with 11 participants at risk and 0 serious adverse events. It lists 0 deaths. The record also lists 11 participants at risk for other adverse events and 0 such events. No serious adverse event terms are listed.

These figures describe what was recorded for this group in the registry. A count of 0 means that no event was recorded in that category; it does not establish that the intervention is free of risk. With a single group and no control group, the record cannot provide a comparative estimate of adverse event risk. The registry information does not describe event surveillance procedures, the severity criteria used beyond the serious-event classification, or the timing and duration of safety monitoring.

The figures should also be distinguished from the efficacy endpoint. They do not indicate whether depression scores changed, and the registry record does not report the primary outcome result. A safety count and a symptom-scale change answer different questions. The event counts are descriptive registry data and should not be interpreted as a comparative safety analysis or as evidence about unrecorded events.

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

The study record establishes that a psychosocial intervention for people with aphasia after stroke was evaluated in a completed, single-group study. It describes a 5-week treatment, baseline and post-treatment testing, further testing 1-month later, phone check-ins and end-of-study interviews. The primary outcome is a change in HADS depression score, with positive values defined as improvement and negative values as worsening. Those details explain what the study set out to measure and how the primary change was defined.

The record does not report the numerical primary outcome result. It therefore cannot show whether the average score changed, the size or direction of any change, how variable individual changes were, or how precise the estimate was. The listed secondary outcomes also lack numerical findings in the registry information available for this interpretation. The study’s completed status does not itself supply any of those results.

The design also limits causal interpretation. Without a control group, a change from baseline to post-treatment cannot separate the intervention’s contribution from other changes over time. This is a general limitation of before-and-after evidence in a single group, not a claim that another factor caused a change in this study. The registry record does not report a randomized comparison or a comparator arm.

The record reports 0 serious adverse events and 0 deaths in the intervention group, with 11 listed at risk. These are descriptive counts, not proof that no risk exists and not a comparison against another treatment. One participant was excluded from the primary endpoint because post-intervention HADS data were missing; the record does not report further details about the missing data or analysis population.

Overall, the registry record describes the question, design and outcome definitions, but not the outcome estimates needed to judge the observed change or its uncertainty. It supports no conclusion that the intervention did or did not improve depression symptoms.

14. Why This Trial Matters Statistically

This study raises a useful statistical distinction between measuring change and attributing change. A baseline-to-post-treatment endpoint can characterize how scores differ over time among participants with measurements. A single-group design, however, does not supply the control-group contrast needed to estimate what would have occurred over the same period without the intervention. The distinction matters whenever an observed pre-post difference is discussed as if it were necessarily caused by treatment.

The outcome is a continuous depression score with an explicit direction for interpreting change. That definition helps prevent a common reading error: a positive baseline-minus-post-treatment value is defined as improvement, not worsening. The planned mean and standard deviation would describe average change and participant-to-participant variability, respectively. Yet neither the endpoint definition nor the choice of summary statistics reveals the actual result; the numerical findings are not reported in the registry record.

Missing outcome data also deserve attention even in a small single-group study. The record notes that one participant was excluded because post-intervention HADS data were missing, but does not explain the reason or report sensitivity analyses. Whether missingness could affect the estimate depends on the circumstances, which are not reported. This illustrates why participant flow and analysis-population details are important alongside an outcome estimate.

Finally, the registry lists multiple outcome measures and analyses. Without a reported multiplicity plan and numerical results, readers cannot determine how outcomes were prioritized or interpret any pattern of statistical findings. The record’s planning illustrations are explicitly described as calculations based on an observed effect and are not the study’s design or observed power. Taken together, these features make clear why study design, outcome reporting, missing-data handling and analysis plans are all needed to interpret clinical evidence responsibly.

15. 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 most important limitation for interpretation is that numerical findings for the primary endpoint are not reported in the registry record. Without the mean change, standard deviation, confidence interval or test result, the direction, size and precision of the observed change cannot be assessed. Numerical findings for the listed secondary outcomes are likewise not reported in the information recorded.

The design is single-group, with no randomized allocation or control group. A pre-post change can describe change over time but cannot isolate the contribution of the intervention from other possible influences. The record gives no comparative estimate against usual care or another condition. This limits causal interpretation regardless of whether a within-group change was observed.

For the primary endpoint, one participant was excluded because post-intervention HADS data were missing. The record does not report why the data were missing, whether any other data were missing, or whether sensitivity analyses were performed. It also does not provide a detailed analysis-population definition or participant flow for the endpoint. These omissions make it difficult to assess whether the analyzed participants represent the enrolled group.

The registry lists eight outcome measures and eight analyses, but does not report the approach to multiplicity or the statistical plan for those analyses. It also does not report the endpoint’s analysis model, the handling of potential deviations from assumptions, or whether interim analyses occurred. Those details are not reported in the registry record and should not be inferred.

The study summary describes follow-up testing 1-month after treatment and interviews, while the primary endpoint timeframe is described as through intervention completion, an average of 7 weeks. The record does not specify the findings at later testing or explain how follow-up results were analyzed. The adverse-event counts are descriptive and lack a control group for comparison.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Stepped Care for Aphasia — NCT05851573.
• Registry record last updated 2025-02-24; status last verified 2025-02.
• Results first posted 2025-02-24.
• 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.

19. Record Summary

The registry record describes a completed, single-group behavioral study of a psychosocial intervention for people with aphasia after stroke. It lists enrollment of 11 and identifies change in the HADS depression score from baseline to post-treatment as the primary endpoint. Positive baseline-minus-post-treatment scores are defined as improvement; negative scores are defined as worsening.

The study summary describes baseline testing, a 5-week treatment, post-treatment testing, further testing 1-month later, phone check-ins and interviews. The primary endpoint timeframe is through intervention completion, an average of 7 weeks. One participant was excluded from the primary endpoint because post-intervention HADS data were missing. The registry lists 0 serious adverse events and 0 deaths in the intervention group.

Numerical primary and secondary outcome findings, precision estimates and details of the statistical analysis plan are not reported in the registry record. The single-group design does not provide a control comparison, so a pre-post change alone would not establish a causal intervention effect.