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 Atlas Predicted DBS Settings in Essential Tremor (NCT02678429), a randomized na study. The primary outcome is Fahn-Tolusa-Marsden Tremor Rating Scale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02678429 |
| Phase | NA |
| Condition | Essential Tremor |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Double |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Vanderbilt University |
| Results posted | Yes |
2. Clinical Question
Population
People with essential tremor receiving deep brain stimulation programming. The registry record lists enrollment of 4.
Intervention
Programming that begins with settings determined from a functional atlas, followed by settings determined through standard care.
Comparator
Programming that begins with the standard neurologist symptomatic response, followed by settings from the atlas.
Primary question
How did tremor quantification on the Fahn-Tolusa-Marsden Tremor Rating Scale compare at 1 month under the two programming sequences? The registry record says the primary-outcome data analysis was not completed.
The trial addressed whether using an atlas to guide the initial deep brain stimulation settings could be evaluated against a sequence beginning with standard neurologist-led programming. The registry summary describes the motivation as reducing the time-intensive nature of programming and potentially improving patients’ quality of life. Those aims are the rationale for the study, not results established by the posted data.
The comparison is about the order and basis of programming: atlas-derived settings first or standard-care settings first, with each sequence then moving to the other approach. The registry identifies the study as randomized, double masked, and crossover. It does not report the randomization procedure, the precise programming protocol, or how masking was maintained.
The primary measure was intended to quantify tremor at the stated 1-month timeframe. However, the record says data analysis was not completed because only one participant completed the DBS Programming from Atlas arm and disclosure could violate privacy interests. Consequently, the record does not establish an estimated difference between the programming sequences.
3. Trial Design
The registry describes a randomized, double-masked crossover study of deep brain stimulation programming for essential tremor. Enrollment is listed as 4, and the study status is terminated. The record lists the start as 2016-09 and primary completion as 2021-11-19. The phase is listed as NA.
In a crossover design, participants receive more than one treatment condition or approach in a sequence, so comparisons may be made within the same participant. In this study, the arm descriptions specify two orders. One starts with settings determined from the standard neurologist symptomatic response and then changes to atlas settings. The other starts with settings determined from a functional atlas and then changes to settings determined by standard care. The intervention is listed as “Change DBS programming.”
Randomization in a crossover study generally assigns participants to a sequence, rather than permanently assigning each participant to only one treatment. The registry does not report how sequence assignment was generated or concealed, or whether there were washout periods, stabilization periods, or safeguards against effects carrying from one programming period into another. These details matter because a crossover comparison can depend on both the treatment approach and its timing.
The record identifies double masking but does not state which people were masked or how masking was achieved. It also does not report a sample-size justification or a detailed statistical analysis plan. The study’s status and enrollment do not change the central interpretive point: the registry says the primary-outcome analysis was not completed. The available record therefore describes the intended design and endpoint, but does not provide a completed efficacy comparison.
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 | DBS Programming, Standard of Care | DBS Progamming From Atlas |
|---|---|---|
| STARTED | 3 | 1 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 3 | 1 |
Analysis population for the primary outcome, as defined in the registry: Data analysis was not completed because only one participant completed the DBS Programming from Atlas arm and disclosing data could violate privacy interests.
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 | DBS Programming, Standard of Care | DBS Progamming From Atlas | Total |
|---|---|---|---|---|
| Participants analysed | 3 | 1 | 4 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 3 | 1 | 4 |
| Sex: Female, Male: Female | Participants | 2 | 0 | 2 |
| Sex: Female, Male: Male | Participants | 1 | 1 | 2 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | participants | 3 | 1 | 4 |
6. Primary Endpoint
The registry lists the primary outcome as Fahn-Tolusa-Marsden Tremor Rating Scale, measured over 1 month.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the Fahn-Tolusa-Marsden Tremor Rating Scale, with the registry describing its purpose as “Tremor quantification.” The listed timeframe is 1 month. A tremor rating scale is used to represent tremor severity in a structured way, allowing investigators to assess an outcome beyond the programming settings themselves.
For an endpoint to support a treatment comparison, the recorded scores must be available and analyzed according to a defined approach. Here, the registry does not list a unit, a parameter type, or a measure of dispersion. It also does not specify which score or change from baseline was intended as the principal comparison, how the scale was administered, or the direction and clinical interpretation of score changes. Those details are not reported in the registry record.
Most importantly, the registry states that data analysis was not completed because only one participant completed the DBS Programming from Atlas arm and disclosing data could violate privacy interests. Thus, the endpoint is identified, but no analyzed scale result or estimate of the difference between programming sequences is reported. The stated purpose of the scale explains why it was selected; it does not establish that either programming sequence improved tremor or differed from the other.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome is named, but the registry does not report an analyzed result for it. The stated reason is that only one participant completed the DBS Programming from Atlas arm and disclosure could violate privacy interests. Accordingly, there is no reported primary-outcome estimate, uncertainty interval, or statistical test result from which to judge the size or precision of a comparison between the programming sequences.
This is different from a finding that the approaches were equivalent, or that no difference was present. Without an analyzed outcome comparison, the record cannot show whether observed tremor scores were higher, lower, or similar under the two sequences. It also cannot show whether any observed difference would be large enough to matter clinically. The absence of an estimate is not evidence that the true difference is zero.
The enrollment of 4 and the report that only one participant completed the Atlas arm highlight the limited information available for the planned comparison. In a crossover trial, repeated measurements from the same participant can be informative because each participant may serve as their own comparison. But this design does not remove the need for enough usable observations, a suitable analysis, and attention to order, period, and carryover effects. The registry does not report such an analysis.
The adverse-event record lists zero serious adverse events and zero other adverse events in each group, with deaths listed as zero in each group. These are descriptive counts for the group denominators recorded in the registry. They do not replace the missing primary-outcome analysis or demonstrate that the approaches have the same safety profile. When the recorded groups are small, a lack of reported events provides limited information about events that might occur outside the observed participants.
In practical statistical terms, the registry record supports a description of the intended comparison, the endpoint, the enrollment, and the reason the primary analysis was not completed. It does not support a quantitative conclusion about tremor outcomes. The sponsor’s analysis is not present as a completed primary-outcome result in the record, and there are no listed analyses.
Any planning illustration based on an observed effect should be interpreted cautiously. A sample-size calculation can describe what a hypothetical future study might require under specified assumptions; it cannot restore information that was not analyzed in this trial. Such calculations are not observed power and should not be read as evidence that this study could reliably detect a treatment effect.
9. Statistical Methods Explained
Several statistical ideas help clarify what this registry record can and cannot establish. The first is the distinction between a design and a result. Randomization, masking, and crossover describe how a study was intended to compare approaches. They do not themselves provide an estimate of the effect. An estimate requires outcome data to be analyzed under a stated method. The record identifies the primary scale but says its analysis was not completed.
What does crossover mean for analysis?
In general, a crossover design compares approaches across periods within participants. A paired analysis can account for the fact that measurements from the same person tend to be related. This can be useful because stable differences between participants do not have to be treated as though they were treatment effects. However, the analysis must also consider the order in which approaches were used, changes over time, and whether the first programming approach continues to influence later observations.
The registry’s arm descriptions indicate opposite programming sequences: standard care followed by atlas settings, or atlas settings followed by standard care. They do not state whether periods were separated by a washout, whether outcome assessments were repeated at specified points beyond the listed 1-month timeframe, or how sequence and period would enter the analysis. These protocol and analysis details are not reported in the registry record. Without them, it is not possible to assess the planned handling of order or carryover effects.
What would an effect estimate communicate?
An effect estimate would express the observed contrast between the programming approaches on the chosen outcome scale. A confidence interval, in general, describes the range of values compatible with the data and the statistical model at a stated confidence level. A narrow interval indicates more precision than a wide one, while an interval spanning effects in different directions may leave substantial uncertainty about the comparison. No primary-outcome estimate or confidence interval is reported in this record, so neither the size nor the precision of a treatment contrast can be assessed.
A p-value, in general, measures how surprising the data would be under a specified null hypothesis and model. It does not measure the probability that the null hypothesis is true, nor does it describe the clinical importance of an effect. The registry lists no analyses, and it does not report a primary-outcome p-value. A significance threshold alone would not supply the missing estimate or resolve the lack of analyzed outcome data.
How should planning calculations be understood?
Sample-size planning uses assumptions about the outcome, expected effect, variability, allocation, and chosen error rates to estimate how much information a future study may need. The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It also says the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence about the study’s original design or its actual ability to detect an effect.
The record does not report the sample-size justification used when the trial was designed. Nor does a planning illustration demonstrate observed power. Observed power is not a substitute for an effect estimate and its uncertainty; when outcome results are unavailable, a hypothetical calculation cannot provide an empirical answer about the comparison. Any planning values should be read as conditional illustrations, not as trial findings.
Why can over-dispersion matter?
As a general statistical concept, over-dispersion occurs when outcome variability is greater than a model assumes. If ignored, standard errors can be too small and confidence intervals too narrow, making results appear more precise than they are. The appropriate approach depends on the outcome type and study design. The registry does not identify an outcome distribution, report variability, or describe model checks, so there is no basis for assessing over-dispersion in this trial.
More broadly, the analysis method should match the endpoint and the crossover structure. For a continuous score, an analysis might model within-participant measurements and relevant period or sequence terms. That is a general illustration, not a claim about the method planned or used. The record does not state the score’s parameterization, the analysis population, the handling of incomplete observations, or the covariance assumptions. Because the primary analysis was not completed, readers should distinguish general methods that might be considered from methods actually documented for this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and says there are no analyses. It identifies the Fahn-Tolusa-Marsden Tremor Rating Scale as the primary measure, but does not report the detailed analysis plan, the selection of a primary score or contrast, or a strategy for controlling multiplicity. It is therefore not possible to determine whether multiple time points, scale components, or other comparisons were planned beyond what appears in the registry.
Multiplicity is a general concern when many outcomes, time points, or comparisons are tested. Conducting multiple tests can increase the chance of finding a nominally unusual result by chance. A prespecified hierarchy or adjustment can address that issue, but neither a multiplicity strategy nor a completed set of analyses is reported. The record’s statement that the outcome has several categories or time points and is not reduced to one comparison further means that a single summary contrast cannot be inferred from the registry description.
Missing-data handling is also not reported. The record says analysis was not completed because only one participant completed the DBS Programming from Atlas arm and disclosure could violate privacy interests. This describes why results were not analyzed or disclosed; it does not specify how incomplete outcome observations would have been handled in an analysis. The analysis population—such as whether all randomized participants or only participants with completed measurements were to be included—is not reported in the registry record.
These omissions prevent assessment of whether the intended analysis protected against selective reporting, addressed incomplete observations, or followed a prespecified plan. They do not imply that a particular method was or was not used outside the registry record.
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 |
|---|---|---|---|
| DBS Programming, Standard of Care | 0 | 3 | 0.0% |
| DBS Progamming From Atlas | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| DBS Programming, Standard of Care | 0 of 3 |
| DBS Progamming From Atlas | 0 of 1 |
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 |
|---|---|
| DBS Programming, Standard of Care | 0 of 3 |
| DBS Progamming From Atlas | 0 of 1 |
The registry reports safety counts separately for the two programming groups. For DBS Programming, Standard of Care, serious adverse events affected 0 of 3 participants at risk, and other adverse events affected 0 of 3 participants at risk; deaths were 0. For DBS Programming From Atlas, serious adverse events affected 0 of 1 participant at risk, and other adverse events affected 0 of 1 participant at risk; deaths were 0.
These are counts recorded for the groups, not estimates of the probability of an event in a broader population. The registry does not list serious adverse-event terms. The small recorded denominators and the absence of reported events mean these figures give limited information about uncommon harms. In general, observing no events does not establish that the risk is absent.
The group counts should also be read in light of the crossover design. The record does not clarify whether the safety groups correspond to sequence assignment, exposure periods, or another reporting convention. It does not provide event timing or a detailed method for attributing events to a programming approach. The safety figures are therefore descriptive and should not be used as a stand-alone comparison of safety between the approaches.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized, double-masked crossover comparison of two programming sequences for deep brain stimulation in essential tremor. Its primary outcome was tremor quantification on the Fahn-Tolusa-Marsden Tremor Rating Scale at 1 month. Those details show what the study set out to examine.
The central result is that the primary-outcome analysis was not completed. The registry gives the reason: only one participant completed the DBS Programming from Atlas arm, and disclosure could violate privacy interests. No numerical comparison of tremor outcomes, uncertainty interval, or primary-outcome test is reported. Therefore, the posted record cannot establish whether one sequence produced different scores from the other.
This record does not show that atlas-predicted programming was faster, improved quality of life, reduced tremor, or had an effect equivalent to standard care. These possibilities appear as motivation or questions for research, not as demonstrated outcomes. Nor does the lack of a reported analysis prove there was no effect. The available information is insufficient to estimate the direction, magnitude, or precision of an outcome difference.
The listed adverse-event counts report no events in the recorded groups, but the denominators are limited and the registry does not provide event terms or attribution details. Those counts should not be interpreted as proof of no risk or as a definitive safety comparison.
The most defensible conclusion is therefore about the evidence available in the registry: the study’s design and intended endpoint are documented, while its primary comparison remains unresolved in the posted results. A planning calculation, if considered, is a conditional illustration for study planning and not a replacement for an analyzed clinical outcome.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the difference between a well-defined research question and an answer supported by analyzable results. The registry records a randomized, double-masked crossover design and names a primary tremor measure, but also states that the primary analysis was not completed. The design features cannot substitute for the missing estimate.
The crossover structure raises questions that are important in many clinical studies: whether sequence, period, and carryover effects are addressed; whether measurements are paired within participants; and whether the analysis matches the way treatment was assigned and outcomes were collected. The registry record does not report the corresponding analysis details. This limits readers’ ability to assess how the design would have been translated into a statistical comparison.
The privacy rationale also illustrates a tension between reporting results and protecting participants. The record explains that data analysis was not completed because only one participant completed the Atlas arm and disclosure could violate privacy interests. That explanation is relevant to why a result is unavailable; it does not make a statistical estimate possible or allow readers to infer what the result would have been.
Finally, the study highlights why planning calculations and observed findings must be kept distinct. A planning illustration can help frame assumptions for future research, but it does not create evidence about the effect in this trial. Interpreting the record carefully means recognizing both what it documents—the design, endpoint, and reason for the absent analysis—and what it cannot establish: a quantitative comparison of tremor outcomes.
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 most important limitation is the absence of a completed primary-outcome analysis. The registry specifically states that only one participant completed the DBS Programming from Atlas arm and that disclosing data could violate privacy interests. No primary-outcome estimate or analysis result is reported, so the intended comparison cannot be quantified.
Enrollment is listed as 4, and the record indicates that the study was terminated. It does not state why the study was terminated. The record also does not give a sample-size justification, so it is not possible to assess the intended precision or the rationale for the planned enrollment from the registry information.
Important protocol and statistical details are not reported in the registry record. These include how randomization and masking were implemented, the timing and handling of crossover periods, whether carryover was considered, the precise scale score or contrast intended for analysis, the analysis population, missing-data methods, and any multiplicity strategy. The record does not report an estimate of variability or a detailed statistical model.
Safety reporting is limited to group counts. Serious adverse-event terms are not listed, and the record does not explain event timing or attribution in relation to the crossover sequences. With the recorded denominators, zero reported events cannot establish the absence of risk.
These limitations are specific to the information recorded and should not be taken as evidence that unreported procedures were absent. They do mean that the registry record cannot support a detailed appraisal of the planned analysis or a quantitative conclusion about efficacy or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Atlas Predicted DBS Settings in Essential Tremor — NCT02678429.
- Registry record last updated 2023-03-27; status last verified 2023-03.
- Results first posted 2023-03-27.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02678429, “Atlas Predicted DBS Settings in Essential Tremor,” is listed as a randomized, double-masked crossover study sponsored by Vanderbilt University. The condition is essential tremor, the intervention is change in DBS programming, and enrollment is listed as 4. The record gives the start as 2016-09, primary completion as 2021-11-19, and status as terminated.
The two sequences begin with either standard-care programming or atlas-based programming and then change to the other approach. The primary measure is the Fahn-Tolusa-Marsden Tremor Rating Scale for tremor quantification at 1 month. The record states that primary-outcome data analysis was not completed because only one participant completed the Atlas arm and disclosure could violate privacy interests.
No analyses are listed. Safety counts report zero serious adverse events, zero other adverse events, and zero deaths in each recorded group. These counts do not provide a completed comparison of the primary outcome or establish a broader safety conclusion.