Study Protocol for CTS and Keyboard Controlled Randomized Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study Protocol for CTS and Keyboard Controlled Randomized Trial (NCT02101294), a na na study. The primary outcome is Length of Time Typing QWERTY Prior to Experiencing Symptoms of CTS (Carpal Tunnel Syndrome).

2. Clinical Question

The study's stated purpose was to evaluate two keyboard layouts in relation to carpal tunnel syndrome symptoms among typists, including whether the experimental keyboard might be used as an adjunct to other treatments or therapy. Its hypothesis concerned a relationship between keyboard layout and symptoms. The primary endpoint, however, is specifically the time to symptoms during QWERTY typing; the registry does not give a corresponding numerical result for that endpoint under the experimental device.

The narrative suggests repeated measurements within participants rather than a conventional parallel-group comparison: participants alternated keyboards over four sessions, with sessions separated by approximately one week. At the same time, the registry's formal design fields identify a single-group model and do not specify an allocation method. These features make it important not to read the record as reporting a standard randomized two-arm treatment effect.

3. Trial Design

The registry identifies this as a completed study of carpal tunnel syndrome and typing keyboards, sponsored by Finger Relief. It lists the phase as NA, allocation as NA, masking as none, and the model as single group. The record gives an enrollment of 31. The study began in 1997-01 and had primary completion in 2008-07.

The study summary describes people with a medical diagnosis of carpal tunnel syndrome participating in four typing sessions. Where not contraindicated, participants had also received confirmation of diagnosis by a nerve conduction velocity study. Two sessions used a traditional QWERTY keyboard and two used the experimental device. Sessions alternated between keyboards, and the keyboard used for the first session was determined by random assignment, according to the narrative. The sessions were separated by approximately one week to allow symptoms to subside. The summary says 20 participants completed all four sessions.

The narrative and formal design fields do not align neatly. The narrative describes randomized selection of the first keyboard and repeated exposure to both keyboards, while the registry records allocation as NA and the study model as single group. The record does not report a formal crossover design designation, a detailed sequence-generation method, or a description of how session order was handled beyond the narrative account. Masking is recorded as none.

The primary outcome concerns time typing on QWERTY before symptoms occurred. The record also lists measures of wrist swelling following typing on each keyboard. It lists four outcome measures overall, but does not provide numerical results for the primary endpoint or the named secondary outcomes. It lists zero analyses in the registry's analysis field. As a result, the design can be described from the narrative, but a numerical treatment contrast, its uncertainty, and the analysis procedure cannot be reconstructed from 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.

Overall Study

Reasons for not completing this period:

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: Study participants had a physician diagnosis of carpal tunnel syndrome, confirmed with an abnormal result from a nerve conduction velocity study, and completed all 4 testing sessions.

6. Primary Endpoint

The registry lists the primary outcome as Length of Time Typing QWERTY Prior to Experiencing Symptoms of CTS (Carpal Tunnel Syndrome), measured over Participants will be assessed at each study of 4 sessions, two typing with the traditional QWERTY keyboard and two typing with the experimental device, each typing session will be separated by approximately one week to allow CTS symptoms to subside.

The primary endpoint is the length of time, in minutes, that a participant typed on the QWERTY keyboard before experiencing a change in carpal tunnel syndrome symptoms. The description says participants were instructed to type until they experienced a change in symptoms, and the time was recorded. The outcome was defined by averaging the time from the two QWERTY sessions.

This endpoint measures symptom-onset time during a typing task. In general, time to a reported symptom can give a direct measure of how long a person performs a specified activity before noticing a change. It is not the same as a measure of symptom severity, a clinical examination, or long-term function. Interpretation depends on how symptoms were identified and reported, how comparable the typing tasks were, and how repeated-session measurements were summarized.

The record describes additional subjective pain assessments and clinical measures of swelling in its study summary, and it names wrist-swelling outcomes among the secondary outcomes. Those measures could address different aspects of symptoms or physical changes, but their results are not reported in the registry record. Nor does the record give the primary endpoint's mean or standard deviation, despite specifying that the endpoint was summarized as a mean with standard deviation.

Because the outcome is defined for QWERTY sessions, this endpoint description alone does not provide a direct estimate of the difference between QWERTY and the experimental device. The registry record does not report the corresponding numerical comparison or an analysis linking the endpoint to typing on the experimental device.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as continuous and specifies a mean with standard deviation. It describes the outcome as the average of the time from two QWERTY typing sessions. However, no numerical mean or standard deviation is reported in the registry record. The registry also lists zero analyses, so it does not document a primary-outcome analysis or its results.

What does a mean and standard deviation describe?

In general, a mean describes the center of measured values, while a standard deviation describes how dispersed participant measurements are around that center. For a clinical endpoint, these statistics help characterize both the typical measured value and variation across participants. They do not by themselves provide a comparison between study conditions. A comparison also requires a defined contrast and information about uncertainty, such as a standard error or confidence interval. Those comparative quantities are not reported for the primary endpoint in the registry record.

How does the repeated-session structure matter?

The narrative describes each participant typing on both keyboards over four sessions, with two sessions per keyboard and alternating exposure. In general, measurements from the same participant are related: some participants may tend to experience symptoms sooner than others under either condition. An analysis that recognizes this within-participant dependence can be more appropriate than treating every session as an independent observation. The registry record does not report which model or calculation was used, whether participant-level pairing was retained, or how session order was incorporated.

Repeated sessions can also make time and order relevant. In general, symptoms may vary across sessions, and the condition used first or later could be associated with changes unrelated to the keyboard itself. The summary says sessions were separated by approximately one week to allow symptoms to subside, and that the first keyboard was randomly selected. It does not report a detailed sequence-generation procedure, whether the intended alternation was followed for every participant, or an analysis of period, order, or carryover effects. These are questions the registry record leaves unanswered, not evidence that such effects occurred.

What does random assignment mean in this account?

The narrative says random assignment determined which keyboard was used for the first session. This description concerns session order, rather than an assignment of participants to separate keyboard groups, because the narrative says participants used both keyboards. The formal fields record allocation as NA and the model as single group. In general, randomizing order can help reduce systematic order differences, but it does not by itself establish that all other aspects of the comparison were controlled or that the analysis accounted for repeated observations. The registry record does not provide further details.

What can a confidence interval or p-value add?

In general, a confidence interval expresses the range of effect sizes reasonably compatible with the data and analysis assumptions, and conveys precision as well as direction. A p-value assesses how unusual the data would be under a specified null model; it does not measure the probability that a treatment works. Both require an analysis and reported results. The registry record gives no primary-outcome estimate, confidence interval, or p-value, so none can be interpreted for this comparison.

The sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe the effect to detect as a stated fraction of the observed effect. For time-to-event tables, the stated convention is a total number of events; for other outcomes, it is participants per arm. These are planning assumptions, not the study's observed power. The registry record does not report a sample-size justification as part of the trial's own design, and no numerical primary effect is reported for evaluating the basis of such an illustration.

In general, a planning calculation estimates the sample size needed under chosen assumptions; it does not reveal whether a completed study had adequate power or whether a result is true. The record does not report an inferential analysis plan, a model for the continuous endpoint, treatment of missing measurements, or any adjustment for multiple outcomes. Those methods cannot be inferred from the outcome definitions alone.

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("Length of Time Typing With QWERTY")
n   <- c(20)
m   <- c(71.063)
sp  <- c(69.32)
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  Length of Time Typing With QWERTY  20  71.063  69.320  38.620  103.506

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures, including the primary endpoint and named wrist-swelling outcomes. It does not report a multiplicity strategy, such as a prespecified hierarchy or an adjustment for testing several outcomes. In general, examining multiple outcomes can increase the chance of obtaining a nominally notable result by chance if results are selected or interpreted without accounting for the number of tests. No p-values or numerical outcome results are reported, so the impact of multiplicity cannot be evaluated for this record.

The study summary says 20 participants completed all four typing sessions, compared with an enrollment listing of 31. The registry record does not explain why some participants did not complete all sessions, whether they contributed partial measurements, or how missing outcome data were handled. It does not report an analysis population definition, such as whether the outcome analysis included all enrolled participants or only those with complete sessions. The number of participants with usable primary-outcome measurements is not reported in the registry record.

In general, missingness can affect both the precision and interpretation of an estimate, particularly when the likelihood of missing data is related to symptoms or study participation. The record does not provide enough information to assess the pattern or reasons for missing measurements, and no imputation or sensitivity analysis is reported. These absences limit the ability to judge how representative any complete-session results might be.

The registry lists zero analyses. It therefore does not describe a statistical analysis population or report how multiple outcomes and incomplete records were addressed. These details should be treated as unreported rather than assumed to follow a particular convention.

12. Safety Results

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

Other (non-serious) adverse events

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

For the listed Interossei Lumbricals Neuro Interface group, the record reports 31 participants at risk for serious adverse events and 0 affected. It also reports 31 at risk for other adverse events and 0 affected. These figures describe the adverse-event counts recorded for that group; they do not provide comparative safety estimates between keyboards.

The deaths field is null. A null entry is not a reported zero, so the record does not establish a death count from that field. The registry also provides no serious-event terms in its listed top terms. The absence of listed terms should not be taken to mean that a particular event was assessed and ruled out; the record does not give further detail on the scope or method of event collection.

In general, a zero reported count means no affected participants were recorded for that event category in the stated group and record. It does not prove that an event is impossible, nor does it describe the precision of a safety estimate. The registry does not report follow-up duration for safety outcomes or a comparison of event rates across the two keyboards. These figures should therefore be read narrowly, alongside the limitations of the reporting.

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

The record documents a study intended to compare typing-related symptoms while participants used a standard QWERTY keyboard and an experimental keyboard device. It describes repeated typing sessions and defines the primary outcome as time typing on QWERTY before symptoms occurred. It also records that 20 participants completed all four sessions and lists an enrollment of 31.

What the record does not establish is the size, direction, or precision of a difference between the keyboards. Numerical primary-outcome results are not reported, and there is no reported confidence interval, test statistic, or p-value. The endpoint definition and study hypothesis cannot substitute for observed outcome data. Without those results, it is not possible to determine from this record whether symptom-onset time differed or how consistently measurements varied among participants.

The narrative describes random assignment of the first keyboard, but the formal registry fields list allocation as NA and model as single group. The account suggests repeated exposure to both keyboards rather than separate assigned arms. The record does not provide a detailed analysis of repeated observations, session order, or missing data. Therefore, it also does not support treating the study as a conventional parallel-group randomized comparison.

The adverse-event entries report zero affected participants for the listed serious and other adverse-event categories, with 31 at risk in each category. The deaths entry is null. These entries are limited safety reporting and do not answer the primary efficacy question or establish broader safety conclusions.

In general, a study's result is interpreted through its measured outcomes, analysis, and uncertainty, not only its stated aim or design. Here, the registry record gives useful information about the intended endpoint and study conduct but lacks the numerical results and analysis details needed for a reliable comparative interpretation. The unreported information should remain unreported rather than being filled in by assumptions.

14. Why This Trial Matters Statistically

This study illustrates why a registry description and a numerical result answer different questions. The record states a clinical hypothesis about keyboard layout and carpal tunnel syndrome, and it describes a structured sequence of typing sessions. Those details show what investigators intended to examine. They do not quantify what was observed.

Statistically, the repeated-session structure is important. When participants experience both keyboard conditions, their measurements are naturally linked within person. In general, accounting for that relationship can distinguish within-person variation from differences between participants. The record does not state how the repeated measurements were analyzed, so readers cannot tell whether the analysis used that structure appropriately.

The record also demonstrates the value of aligning design fields with the study narrative. The registry lists a single-group model and allocation as NA, while the summary describes random selection of the first keyboard and alternating use of both keyboards. These descriptions are not interchangeable with a fully specified randomized comparison. Clear reporting of allocation, sequence, analysis, and participant flow would make the design easier to evaluate.

Finally, an endpoint can be defined precisely while its results remain unavailable. The record specifies the unit, summary measure, and timing for the primary outcome, but does not report its mean, standard deviation, or comparative analysis. This distinction matters for clinical researchers: methodological detail helps readers understand what was measured, while outcome estimates and uncertainty are needed to judge the evidence. The registry record contains the former but not the latter.

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 primary limitation for interpretation is that numerical results for the primary endpoint are not reported in the registry record. The record names the mean and standard deviation as the summary statistics but gives neither, and it provides no comparative estimate or measure of uncertainty. The listed secondary outcomes also lack numerical results.

The design information is incomplete and partly discordant. The registry identifies a single-group model and allocation as NA, while the narrative describes random assignment of the first keyboard and repeated, alternating use of both keyboards. The record does not explain this difference or fully describe the session sequence. It also does not report whether an analysis accounted for repeated measurements or session order.

Participant flow is not fully described. Enrollment is listed as 31, while the summary says 20 completed all four sessions. Reasons for noncompletion, partial data, analysis-population definitions, and missing-data methods are not reported in the registry record. These omissions prevent assessment of how incomplete sessions may have affected the results.

The registry lists four outcomes but does not report a multiplicity plan, a statistical analysis plan, or inferential analyses. It does not provide a sample-size justification for the trial's own design. The planning assumptions described for illustrations do not resolve those omissions or establish observed power.

Safety reporting is also limited: the record lists zero affected participants in the serious and other adverse-event categories, but the deaths field is null and the record gives no further details on collection or follow-up. These limitations constrain interpretation of both comparative outcomes and safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study Protocol for CTS and Keyboard Controlled Randomized Trial — NCT02101294.
• Registry record last updated 2014-09-29; status last verified 2014-09.
• Results first posted 2014-09-29.
• 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 describes a completed study of typing sessions using a standard QWERTY keyboard and an experimental keyboard device among people diagnosed with carpal tunnel syndrome. It lists an enrollment of 31 and says 20 participants completed all four sessions. The narrative describes two sessions on each keyboard, alternating exposure, with the first keyboard determined by random assignment.

The primary endpoint was time typing on QWERTY before symptoms, summarized as a mean with standard deviation. Numerical primary and secondary outcome results, comparative estimates, and inferential analyses are not reported in the registry record. The formal design fields list allocation as NA and the model as single group, making the design description less definitive than the narrative alone may suggest.

The record lists zero serious and other adverse events among 31 at risk in the named group; deaths are recorded as null. Overall, it documents the study question and endpoint but does not provide the outcome data needed to assess the comparative effect.