This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Robotic Hand Orthosis Providing Grasp Assistance for Patients With Brachial Plexus Injuries (NCT04939233), a na na study. The primary outcome is Number of Successful Grasp Trials Per Participant Using Robotic Hand Orthosis.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04939233 |
| Phase | NA |
| Condition | Brachial Plexus Injury |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Carilion Clinic |
| Results posted | Yes |
2. Clinical Question
Population
Adults with paralysis due to a brachial plexus injury were the intended participants. The record lists an enrollment of 3. It does not report further eligibility details or describe participant characteristics.
Intervention
The intervention was an exoskeleton glove, described as a robotic hand orthosis intended to assist grasping. The study description frames its purpose as a feasibility evaluation in a small cohort, rather than a comparison of treatment strategies.
Comparator
No separate comparator group is listed. The study is recorded as single-group, with allocation listed as NA. Consequently, the record does not present a like-for-like control comparison or an estimate of the difference between the glove and another intervention.
Primary question
The primary measure is the number of successful grasp trials per participant using the robotic hand orthosis. It focuses on whether participants can successfully grasp objects during the described assessment. The registry record does not report the observed measure or an analysis comparing outcomes across groups.
In practical terms, the study asks whether use of the device can be assessed through grasping tasks among adults with brachial plexus injury-related paralysis. Its single-group feasibility structure can describe performance under the study conditions, but it cannot isolate a device effect from other explanations using a concurrent control group. The registry record also does not report a usual-care comparison, a device-free comparison, or a prespecified threshold for what would count as successful feasibility. Thus the question is narrower than whether the orthosis improves function in general: the registered endpoint counts successful object grasps during a defined task procedure. Neither the result for that endpoint nor a conclusion about feasibility is reported in the registry record.
3. Trial Design
The registry record identifies NCT04939233 as a completed study sponsored by Carilion Clinic. Its listed start date is 2021-07-01, and its primary completion date is 2022-05-20. The enrollment is 3. The condition is brachial plexus injury, and the study is listed as phase NA.
The design is recorded as single-group, with allocation listed as NA and masking listed as none. The intervention is the Exoskeleton Glove, described as a robotic orthosis for grasp assistance. The arm description characterizes the work as a feasibility trial in a small cohort of adult patients with paralysis due to brachial plexus injury. With no comparator arm, the design does not support a randomized between-group estimate. The absence of masking also means the record does not describe blinding of participants or investigators.
The primary outcome is the number of successful grasp trials per participant using the robotic hand orthosis. The stated expected study time is about 2 hours. The procedure description refers to the Southampton Hand Assessment Procedure (SHAP), prehensile and activities of daily living tasks, abstract object tasks, grasp types, and repeated attempts with objects. This is an assessment of task performance rather than a reported comparison with a control condition.
The registry record does not report a statistical analysis plan, a sample-size justification, or further design details such as eligibility criteria and participant flow. It records one outcome measure and zero analysis records. Those registry entries describe what is posted in the record; they do not establish whether additional analyses or procedures occurred outside the posted information. The completed status likewise indicates the recorded study status, not that the primary outcome was reported or that a particular feasibility conclusion was reached.
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.
Overall Study
| Stage | Exoskeleton Glove |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Exoskeleton Glove |
|---|---|---|
| Participants analysed | 3 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 30 (SD 0.82) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 2 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Successful Grasp Trials Per Participant Using Robotic Hand Orthosis, measured over The total expected time for the study is about 2 hours..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | Number of successful grabs of an object |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of successful grasp trials per participant using the robotic hand orthosis. The unit is stated as the number of successful grabs of an object. The outcome is described as a mean with full range as its dispersion. The registry record does not report the resulting mean, range, or participant-level values, so the recorded endpoint definition can be described but its observed performance cannot be characterized.
The measure is linked to the Southampton Hand Assessment Procedure (SHAP) and is intended to represent functional hand performance based on prehensile and activities of daily living tasks. The description says that six abstract object tasks were used and identifies cylinder, sphere, tip, tripod, and lateral grasp types. It also describes selecting ten objects from different grasp types and grasping each object five times per participant. The stated interpretation is successful grasps with ten different objects.
In general, task-based endpoints can make a functional construct observable by recording performance on specified activities. A count of successful attempts is also straightforward to interpret at the task level: it distinguishes successful from unsuccessful grasps under the assessment conditions. It does not, by itself, establish how performance would generalize beyond the tested tasks or how it compares with performance without the device. Those broader interpretations require results and supporting design information that are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record defines a primary grasp-performance measure but does not report an observed result for it. No mean, full range, participant-level values, effect estimate, confidence interval, or hypothesis-test result for the primary endpoint is reported in the registry record. Therefore, the posted information does not allow the magnitude or precision of grasp performance to be described. It also does not support a conclusion about whether a prespecified feasibility target was met, because such a target is not reported.
The design matters when interpreting what a result could mean. This is a single-group study with no listed comparator. If outcomes were reported, they would describe performance among participants assessed with the exoskeleton glove under the study conditions. Without a control group or another comparison, a change in performance could not be attributed to the device on the basis of this design alone. The record does not report a baseline-versus-device analysis, so even that within-participant contrast should not be assumed to have been conducted.
The enrollment of 3 means the evidence base described by the registry is very limited in size. In general, results from a small group can be strongly influenced by individual observations, and estimates of variation are difficult to characterize precisely. The registry record does not report enough endpoint data to assess the actual distribution or determine how much individual participants differed. It is therefore not possible to judge whether the reported mean, if one had been posted, would represent a consistent pattern across participants.
The outcome procedure involves repeated grasps and multiple objects for each participant. In general, repeated attempts from the same person are not equivalent to observations from unrelated people: outcomes from one participant may be related because they share that participant's abilities and testing conditions. A statistical analysis that treats such observations as independent could misstate uncertainty. The registry record does not report how the repeated observations were summarized or modeled, so no particular approach should be attributed to the investigators.
The posted safety counts are also limited in what they establish. The record lists zero serious adverse events among 3 at risk, zero other adverse events among 3 at risk, and zero deaths. These are descriptive counts for the recorded group. They do not establish that the device has no risks, particularly given the limited enrollment and the absence of additional safety details in the registry record. The record does not report adverse-event definitions, event collection procedures, or duration of safety follow-up.
Overall, the available registry information describes a feasibility-oriented study and its primary task-based measure, but not the primary outcome findings. No efficacy conclusion, estimate of effect, or statistical-significance interpretation can be drawn from the posted outcome information. The absence of a reported result should not be recast as evidence that grasp performance was poor, unchanged, or successful.
9. Statistical Methods Explained
The outcome is specified as a mean with full range. A mean is a measure of the average across the observations included in its calculation. A range describes the span from the lowest to highest observed value. In general, reporting both can give readers a sense of central performance and the extent of observed variation, although a range is sensitive to the most extreme observations. The registry record does not report the actual mean or range for this endpoint, and it does not explain which level of data was used to calculate them.
The level of observation is important for this study. The description includes repeated grasp attempts for objects by each participant. In general, data from repeated attempts by one person are clustered: attempts from the same person may be more alike than attempts from different people. Treating every attempt as independent can make the amount of information appear greater than it is and can lead to uncertainty estimates that are too narrow. A participant-level summary, or a model that accounts for clustering, may be appropriate in some settings, but the registry record does not report which method was used. It would be inappropriate to assume a specific method from the endpoint description alone.
There is also a distinction between summarizing successful attempts and evaluating differences. A descriptive summary can report performance in the assessed group without making a causal comparison. An inferential analysis uses a statistical model or test to quantify uncertainty or evaluate a specified contrast. Because no comparator group is registered and no analysis record is posted, the registry does not provide a between-group estimate or a test of a treatment contrast. The record also does not report a within-person comparison or a statistical hypothesis for the primary endpoint.
In general, a confidence interval expresses a range of values compatible with the data under the assumptions of the statistical method. Its width reflects both the amount and variability of information, as well as the method used. A confidence interval is not a guarantee that the true value lies within its endpoints, and it does not remedy limitations in study design or measurement. No confidence interval for the primary outcome is reported in the registry record, so the precision of an endpoint estimate cannot be evaluated.
In general, a p-value assesses how compatible data are with a specified null model under the assumptions of a test. It is not the probability that the null hypothesis is true, nor does it measure clinical importance. A p-value also cannot establish causation where the design does not support a causal comparison. No primary-endpoint p-value or hypothesis-test result is reported in the registry record. Accordingly, there is no basis for labeling the primary result statistically significant or not statistically significant.
The study is described as a feasibility trial, but the registry record does not report a formal feasibility criterion or decision rule. Feasibility can refer to practical questions such as whether an assessment can be completed, whether a device can be used as intended, or whether a study procedure is acceptable. Those are distinct from a test of efficacy. The registered primary endpoint counts successful grasps, but that count alone does not establish all dimensions of feasibility, and the registry does not post enough results to assess even the endpoint dimension.
In general, over-dispersion occurs when observed variability is greater than a statistical model assumes. For count outcomes, it can matter because a model with overly restrictive variance assumptions may understate uncertainty. The endpoint is count-like, but no statistical model or distributional assumption is reported in the registry record. There is therefore no basis to say whether over-dispersion was assessed or whether it affected an analysis.
Planning calculations are distinct from observed evidence. Any sample-size illustration based on an observed effect is a planning exercise, not observed power and not a substitute for the missing endpoint results. The registry record does not report a sample-size justification or the assumptions used for the original study design. In general, power calculations depend on design and assumptions about the effect, variability, allocation, and analysis. They cannot demonstrate that an effect exists, and a planning illustration cannot recover an unreported result.
Finally, statistical methods cannot compensate for the limitations of a single-group design. Random allocation, when used, helps balance measured and unmeasured factors between groups on average; it is not listed for this study. A concurrent comparator can help distinguish the intervention from changes due to time, testing, or other influences, but none is registered. The posted information therefore supports a description of the study's intended measurement, not a causal estimate.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and zero analysis records. The primary measure is the number of successful grasp trials per participant using the robotic hand orthosis. The presence of one registered outcome measure does not establish that no additional outcomes were collected or examined; it describes what is recorded in the registry entry. Likewise, zero posted analysis records does not establish that no analyses were conducted outside the registry record.
A multiplicity plan addresses the risk of misleading findings when several outcomes, comparisons, time points, or statistical tests are examined. In general, testing many hypotheses can increase the chance of a nominally unusual result arising by chance. Approaches to address multiplicity depend on the analysis objectives and the relationships among the tests. The registry record does not report a multiplicity strategy, nor does it report the statistical analysis plan needed to determine whether adjustment was intended or appropriate.
The record does not report how missing or incomplete grasp attempts were handled, whether any endpoint observations were unavailable, or what rules defined an evaluable participant. It also does not report analysis populations, such as whether the primary analysis included all enrolled participants or only participants with completed assessments. These details matter because exclusions and missing observations can affect both the estimate and its interpretation. No assumptions about missingness or imputation can be inferred from the endpoint description.
For a small feasibility study, participant-level reporting and transparent accounting of incomplete assessments can be particularly informative. The registry record does not provide participant flow or individual endpoint data. As a result, readers cannot assess whether the endpoint summary includes all enrolled participants, whether the repeated tasks were completed as planned, or whether missing data could have influenced the result.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Exoskeleton Glove | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Exoskeleton Glove | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Exoskeleton Glove | 0 of 3 |
The registry record lists the Exoskeleton Glove group with 3 participants at risk for serious adverse events and 0 affected. For other adverse events, it lists 3 at risk and 0 affected. It also lists 0 deaths. These are the posted event counts for the registered group; they are not comparative safety estimates because no control group is listed.
A zero count means no event in that category was recorded in the registry entry for the listed group. It does not prove that an event is impossible or that the intervention is free of risk. In general, safety counts depend on the size and follow-up of the group, how events are defined and collected, and what information is entered into the record. With enrollment of 3, the counts provide only limited information about uncommon or delayed events.
The registry record does not report detailed adverse-event definitions, individual event descriptions, severity grading beyond the serious-event category, relatedness assessments, or duration of safety monitoring. It also does not provide an explanation of how adverse events were solicited or adjudicated. The counts should therefore be read as a narrow registry summary, not as a comprehensive characterization of safety.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed single-group feasibility study was registered to assess an exoskeleton glove in adults with paralysis due to brachial plexus injury. It identifies a task-based primary measure: the number of successful grasp trials per participant using the robotic hand orthosis. It also describes the grasping tasks and lists the size of the enrolled group. These details clarify what the study intended to assess.
The record does not report the primary endpoint result. It provides no observed mean, range, participant-level grasp counts, effect estimate, or confidence interval. Therefore, the posted information does not show how often successful grasps occurred, how consistent performance was, or how precisely any estimate was measured. It cannot establish whether the intervention met a feasibility criterion, because such a criterion is not reported either.
The design also limits what could be concluded even if descriptive outcome values were available. With one group and no listed comparator, the study cannot distinguish device-associated performance from other influences through a randomized between-group comparison. The record does not report a comparison against baseline or an alternative condition. Any causal claim would require evidence and design features not present in the registry entry.
The listed adverse-event counts are descriptive: zero serious adverse events, zero other adverse events, and zero deaths are recorded for the group. These counts are not evidence that risk is absent, especially in a small study with limited safety details. They also do not answer the primary grasp-performance question.
In general, feasibility studies can provide early information about whether a device and assessment procedures can be studied in a target population. Such information can help frame later research, but it is not the same as proof of effectiveness or broad generalizability. For this study, the registry record describes the rationale and measurement approach but does not post the outcome findings needed to judge the observed feasibility or grasp performance.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the difference between an endpoint description and an endpoint result. The registry specifies what it intended to count—successful grasps during a structured task—but does not report the resulting values. A clearly defined measure is necessary for interpretation, but it is not enough to establish what happened in the study. Without observed values, readers cannot assess central performance, variability, or precision.
The single-group feasibility design also illustrates how design determines the scope of inference. Descriptive data from a group using a device can characterize that group under the assessment conditions. A control comparison addresses a different question: whether outcomes differ from those under another condition. The registered design has no comparator, so a causal contrast is not available from the record. This distinction is important when reading claims about function or device benefit.
The repeated grasp procedure raises an important analysis issue. Multiple attempts can provide a richer account of task performance, but attempts from one participant are related observations rather than interchangeable independent observations. Statistical summaries and uncertainty estimates need to respect the way measurements are collected. Since the registry does not describe its analysis, it cannot show how that dependence was addressed.
Finally, the safety counts demonstrate why event totals must be read in context. Zero recorded events in a small enrolled group is a description of that registry entry, not a definitive safety conclusion. The study may be relevant as an early investigation of a device and a functional measurement approach, but the posted record leaves the primary outcome and analysis unreported. Its statistical value lies in clarifying the intended question and the limits on what the record can answer.
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 central limitation of the registry information is that it defines the primary endpoint without reporting its observed result. No mean, range, participant-level counts, or inferential analysis is available in the registry record. This prevents assessment of the direction, magnitude, variability, and precision of grasp performance, and prevents readers from evaluating whether the feasibility objective was achieved.
The enrollment is 3, and the study has a single group. This offers little basis for generalizing to a broader population and does not support a randomized comparison. No comparator is listed, allocation is NA, and masking is none. The record also does not report baseline performance or a pre-post analysis, so neither a between-group nor a within-person change can be evaluated from the posted data.
Further design details are not reported in the registry record, including fuller eligibility criteria, participant characteristics, participant flow, the handling of incomplete task attempts, and the analysis population. The statistical analysis plan, sample-size justification, and multiplicity approach are also not reported. Without these details, it is not possible to determine whether the endpoint analysis followed a prespecified plan or how much missing information could have affected results.
The endpoint procedure involves repeated attempts and multiple objects, but the registry does not explain how those observations were combined or analyzed. The description also refers to six abstract object tasks while listing five grasp types, without clarifying the relationship between those descriptions. The primary endpoint results are not posted, so the practical impact of these measurement details cannot be assessed.
Safety reporting is limited to the registry counts. Event definitions, monitoring duration, relatedness, and detailed event descriptions are not reported. The zero counts should therefore not be treated as proof of absence of risk. Taken together, the available entry supports an account of the intended feasibility assessment, but not a complete evaluation of its results or safety profile.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Robotic Hand Orthosis Providing Grasp Assistance for Patients With Brachial Plexus Injuries — NCT04939233.
- Registry record last updated 2025-10-20; status last verified 2025-10.
- Results first posted 2025-10-20.
- 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.
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18. Record Summary
NCT04939233 is listed as a completed, single-group feasibility study sponsored by Carilion Clinic. The record concerns adults with paralysis due to brachial plexus injury and lists an enrollment of 3. The intervention is an exoskeleton glove, described as a robotic hand orthosis intended to assist grasping. Allocation is listed as NA, and masking as none.
The primary endpoint is the number of successful grasp trials per participant using the device, summarized as a mean with full range. The task description references SHAP, prehensile and activities of daily living tasks, multiple object types, and repeated grasp attempts. The stated expected study time is about 2 hours.
The registry record does not report the primary endpoint result, an analysis plan, or a comparator-group result. It records zero serious adverse events, zero other adverse events, and zero deaths for the listed group. These figures are descriptive and should be interpreted in light of the small enrollment and limited safety details.