Immersive Virtual Reality in Stroke Pilot Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Immersive Virtual Reality in Stroke Pilot Study (NCT04429945), a na na study. The primary outcome is Action Research Arm Test.

2. Clinical Question

3. Trial Design

This completed pilot study is registered as NCT04429945 and is sponsored by the VA Office of Research and Development. Its listed condition is stroke, and the target population is Veterans receiving care for a stroke in a Comprehensive Interdisciplinary Inpatient Rehabilitation Program. The registry lists enrollment of 10. The study started on 2021-06-17 and has a primary completion date of 2022-12-14.

The intervention is a virtual reality device. Participants were to use an immersive headset for 30 minutes twice per day outside usual therapy times, while in bed with bedrails raised. The selected virtual reality games were intended to address relaxation, pain, and arm and hand recovery after stroke. The registry describes virtual environments that allow practice of movement in a safe setting.

The design is single-group and within-participants pre-post. Allocation is listed as NA, and masking is listed as NONE. This is not a randomized comparison and does not provide a like-for-like control group. Consequently, an observed change over time, if reported, would not by itself distinguish changes associated with the intervention from changes occurring during rehabilitation or from other influences.

The primary outcome is the Action Research Arm Test at 4 weeks. The registry lists Pain Outcomes Questionnaire-VA as a secondary outcome and reports three outcome measures in total. It lists no analyses. Primary outcome summary results, the analysis population, and details of any statistical analysis plan are not reported in the registry record. The record's completed status therefore describes study status, but does not establish that outcome results or an inferential analysis were posted.

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 participants were excluded from study participation. This was due to inclusion/exclusion criteria alignment with admission criteria for the inpatient stroke rehabilitation program. The post-treatment measurement period was reduced from week 4 to week 3 secondary to COVID-19 hospital policies which prioritized shorter inpatient stays when feasible. Specifically, the hospital triage approach prioritized inpatient beds for COVID-19 patients

Overall Study

Analysis population for the primary outcome, as defined in the registry: The target population was Veterans receiving care for a stroke in a Comprehensive Interdisciplinary Inpatient Rehabilitation Program.

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.

Population: The target population was Veterans receiving care for a stroke in a Comprehensive Interdisciplinary Inpatient Rehabilitation Program.

6. Primary Endpoint

The registry lists the primary outcome as Action Research Arm Test, measured over 4 weeks.

The primary endpoint is the Action Research Arm Test, assessed at 4 weeks and summarized as a mean with standard deviation. It is a clinician-administered measure of arm and hand function. The test covers Grasp, Grip, Pinch, and Gross Movement. Its 19 tests are scored from 0, meaning no movement is possible, to 3, meaning movement is performed normally. Scores are summed within domains and then combined into a total score ranging from 0 to 57. Higher total scores indicate better hand dexterity.

The test is relevant to the study's focus on arm and hand recovery after stroke because it measures task performance across several kinds of movement rather than relying on a single task. The endpoint can be used to describe participants' functional status and, in a pre-post design, to quantify change between assessments if both assessments and their results are reported.

The registry record gives the measure's scoring description and the 4-week timeframe, but it does not report the mean, standard deviation, baseline value, follow-up value, or change estimate. It also does not report an uncertainty interval or a statistical test for this endpoint. Without those results, the direction, magnitude, and precision of any change cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the outcome summary represent?

The primary measure is continuous: the Action Research Arm Test produces a total score, and the registry specifies a mean and standard deviation as the summary form. A mean describes the average score in the group. A standard deviation describes how spread out individual scores are around that average. These statistics answer different questions: the mean locates the group average, while the standard deviation describes participant-to-participant variation.

For a pre-post study, the central descriptive quantity of interest may be the change in score within participants. A paired analysis uses each participant's measurements together, rather than treating the baseline and follow-up groups as unrelated. This can account for the fact that measurements from the same person tend to be related. The registry record does not report whether a paired method was used, nor does it post the endpoint summaries or a change estimate.

How should an uncertainty interval be read?

General statistical explanation: a confidence interval gives a range of estimates compatible with the observed data under the assumptions of the statistical method. A narrower interval indicates greater precision, while a wider interval indicates greater uncertainty. An interval for a mean change would help readers judge both the plausible size and direction of that change. No confidence interval for the primary outcome is reported in the registry record, so its precision cannot be evaluated from this record.

A statistical test and a confidence interval are related but are not interchangeable. A test addresses compatibility with a specified null hypothesis under model assumptions. An interval conveys the range of estimates supported by the data and can show whether estimates of practical interest remain plausible. Neither provides a causal answer when the design lacks a concurrent control group. No primary-outcome test result or interval is reported in the registry record.

What does the single-group design allow?

In a single-group pre-post design, participants serve as their own reference over time. This can be useful for describing feasibility and patterns of change in a pilot. However, the comparison is between measurements taken at different times, not between randomized groups observed over the same period. Stroke rehabilitation and other events can coincide with the intervention. Thus, even a measured change would not by itself identify which factors produced it.

The listed allocation is NA, masking is NONE, and the model is SINGLE GROUP. These features mean that the registry record does not describe randomized assignment or a masked comparison. They also do not establish whether assessors knew the timing of measurements or whether other procedures were used to reduce measurement bias; those details are not reported in the registry record. The interpretation should be limited to the design actually recorded.

What do the planning assumptions mean?

General statistical explanation: a sample-size calculation uses assumptions about the effect to detect, the variability of the outcome, the error rate, and the design. The registry describes a planning illustration based on the observed effect and a stated fraction of that effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For time-to-event outcomes, its stated convention is a total event count; for other outcomes, it is participants per arm.

Those assumptions describe a hypothetical planning exercise, not the actual single-group design. In particular, equal allocation between two arms does not match the listed within-participants pre-post model. The planning outputs and the effect estimate used for the illustration are not reported in the registry record available for this analysis. A planning calculation is not evidence that a study had a particular probability of detecting an effect, and it must not be read as observed power.

Why does outcome distribution matter?

General statistical explanation: a mean and standard deviation are most informative when the distribution and measurement process make those summaries meaningful. If scores cluster near a scale boundary, or if a small group contains unusually high or low values, the mean may not fully describe the observed pattern. The Action Research Arm Test has a defined range and higher scores indicate better hand dexterity. The registry record does not provide participant-level scores or a distribution plot, so the shape of the observed scores cannot be assessed.

General statistical explanation: over-dispersion occurs when data vary more than a statistical model assumes. If a method assumes less variability than the data contain, standard errors and uncertainty intervals can be too small. That concern is relevant when selecting methods for outcomes with greater-than-expected variation, but the registry record does not report a model or diagnostics that would permit an assessment of over-dispersion for this endpoint.

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("Single Arm Within-participants Pre-post")
n   <- c(10)
m   <- c(38.8)
sp  <- c(22.03)
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  Single Arm Within-participants Pre-post  10  38.800  22.030  23.041  54.559

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, identifies the Action Research Arm Test as the primary outcome, and names Pain Outcomes Questionnaire-VA as a secondary outcome. It does not provide a full accounting of the remaining measures in the registry record for this record, or report results for any outcome. The registry lists no analyses. The statistical plan, including whether or how the investigators addressed multiple outcomes or multiple analyses, is not reported in the registry record.

General statistical explanation: when several outcomes or hypotheses are examined, the chance of at least one apparently unusual result can increase if each is tested without regard to the others. A prespecified hierarchy or an adjustment can be used to address that concern, depending on the study question. No such procedure should be assumed. With no posted outcome analyses, it is not possible to evaluate how multiplicity affected reported inference.

The registry does not report the analysis population, the number with outcome data at each assessment, exclusions, or a missing-data method. It is therefore unclear whether all enrolled participants contributed to the primary endpoint summary or whether any measurements were unavailable. General statistical explanation: missing measurements can affect a mean change estimate when participants without follow-up data differ from those with observed data. Appropriate handling depends on why measurements are missing and on the analysis assumptions. Neither the pattern nor the handling of missing data is reported in the registry record.

There is also no reported account of protocol deviations or a distinction between planned and completed analyses. Those omissions limit assessment of whether the analysis followed a prespecified plan. They should be treated as unreported information, not as evidence that a particular problem occurred.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists a single group titled “Single Arm Within-participants Pre-post.” Serious adverse events affected 0 participants among 10 at risk. Other adverse events affected 2 participants among 10 at risk, and deaths are listed as 0. No serious adverse-event terms are listed.

These are participant counts, not estimates of comparative risk. Because the study has no control group, the counts cannot show whether events were more or less frequent than they would have been without virtual reality. The registry record also does not establish whether any event was related to the intervention. The absence of listed serious events is a description of the posted record for this group, not proof that serious events are impossible or that the intervention is risk-free.

General statistical explanation: a small study has limited ability to characterize uncommon events. A count of 0 in a small group can coexist with uncertainty about the frequency of an event in a broader population. The record's enrollment of 10 is therefore important context when reading the safety counts. Details such as event timing, severity beyond the serious-versus-other grouping, and attribution are not reported in the registry record available for this analysis.

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

The registry record establishes that this was a completed pilot involving immersive virtual reality in Veterans receiving inpatient stroke rehabilitation, with an enrollment of 10 and a single-group pre-post design. It identifies the Action Research Arm Test at 4 weeks as the primary endpoint and explains how its total score represents arm and hand function. These details clarify the question the study was designed to explore.

The record does not report the primary endpoint results. It therefore does not show whether scores changed, how large any change was, how variable the scores were, or how precisely change could be estimated. Results for the listed secondary outcome are also not reported in the registry record for this record. Without outcome summaries and analyses, no conclusion about the observed pattern of benefit or harm can be drawn from the registry record.

Even if change estimates were available, this single-group design would describe change over time rather than provide a randomized estimate of the effect of virtual reality. Concurrent rehabilitation, natural recovery, other care, and measurement variation could contribute to a pre-post difference. The design does not separate those influences from the intervention.

The adverse-event counts provide a limited descriptive account: 0 serious events among 10 at risk, 2 other events among 10 at risk, and 0 deaths. They are not a controlled safety comparison and do not establish causation. The pilot's size and missing analysis details further limit inference.

Accordingly, the registry record is informative about the target population, intervention schedule, endpoint, and broad design, but it does not supply the outcome evidence needed to estimate a treatment effect. The sample-size planning assumptions are not a substitute for observed results and do not establish the precision or power of the completed study.

14. Why This Trial Matters Statistically

This study matters statistically because it illustrates the difference between a registered clinical question and an interpretable outcome analysis. The registry gives a focused primary measure, a defined follow-up timeframe, and a target population. It also identifies the study as a single-group pre-post pilot. Those features let readers understand the intended measurement and the limits of the design, even though the primary result is not reported.

A pilot can help describe procedures and generate information for later study planning. However, a small single-group study cannot provide the same causal comparison as a randomized controlled design. In particular, changes during inpatient rehabilitation may reflect more than one influence. Recognizing this prevents a before-and-after observation from being interpreted as a clean estimate of an intervention effect.

The record also highlights why outcome estimates need measures of uncertainty and transparent analysis details. A mean and standard deviation can describe a continuous outcome, but without posted values, change estimates, confidence intervals, and an account of missing data, readers cannot judge the observed effect or its precision. Listing a primary measure is not the same as reporting its result.

The adverse-event counts are useful as a record of what was posted for this group, but their interpretation depends on the small enrollment and lack of a control group. Likewise, a sample-size planning illustration based on an observed effect is not evidence of observed power or proof that a trial was adequately sized. Keeping design, estimation, uncertainty, and planning distinct is essential for reading pilot studies 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 the primary outcome results are not reported in the registry record. Without baseline and follow-up summaries or a change estimate, the observed direction and magnitude of change cannot be described. The registry also lists no analyses, so the method used to estimate change and its uncertainty is not available.

The design is single-group and within-participants pre-post, with allocation listed as NA and masking listed as NONE. There is no randomized control group for a like-for-like comparison. Any change over time, if measured, could reflect usual rehabilitation, natural recovery, other care, or measurement variation as well as the intervention. The design does not isolate these explanations.

Enrollment was 10, limiting the amount of information available about variation among participants and uncommon adverse events. The registry record does not report how many participants completed each assessment, whether data were missing, or how missing measurements were handled. It also does not report the analysis population, protocol deviations, assessor procedures, or a detailed statistical plan.

The registry identifies the Action Research Arm Test at 4 weeks as primary and lists a secondary pain outcome, but the full results for the three outcome measures are not available in the registry record for this record. The record does not report whether multiplicity was addressed. The planning assumptions describe a two-arm illustration rather than the listed single-group design, and the planning outputs are not reported. These limitations mean the record supports description of the study's design and aims, but not an estimate of treatment effect or a comprehensive assessment of efficacy and safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Immersive Virtual Reality in Stroke Pilot Study — NCT04429945.
• Registry record last updated 2024-02-28; status last verified 2024-01.
• Results first posted 2024-02-28.
• 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

NCT04429945 is a completed, single-group pilot study of immersive virtual reality for Veterans receiving inpatient stroke rehabilitation. The registry lists enrollment of 10 and describes headset use for 30 minutes twice per day outside usual therapy times. The primary outcome is the Action Research Arm Test at 4 weeks, a clinician-administered measure of arm and hand function on which higher total scores indicate better hand dexterity. Pain Outcomes Questionnaire-VA is listed as a secondary outcome.

The registry record does not report the primary outcome results, secondary outcome results, or statistical analyses. It lists 0 serious adverse events among 10 at risk, 2 other adverse events among 10 at risk, and 0 deaths. Given the single-group design and the unreported results and analysis details, the record does not establish a comparative treatment effect.