Clinical trials data
Cognitive tests in sleep trials: 749 registered studies
Every registered sleep and sleep disorders study on ClinicalTrials.gov that names a cognitive test in an outcome measure: the tests used most, how often as a primary outcome, which tests go together, how large the studies are and when they measure the outcome.
- Registered sleep and sleep disorders studies name a cognitive test in an outcome
- 749
- Led by industry
- 79
The tests sleep trials use most
The Psychomotor Vigilance Task leads: 237 of the 749 studies name it, 32%. Next comes the Stroop Color-Word Test (89). As a primary outcome, the Psychomotor Vigilance Task leads with 89 studies.
- 1
Psychomotor Vigilance Task237 studies, 89 as a primary outcome
- 2
Stroop Color-Word Test89 studies, 35 as a primary outcome
- 3
Symbol Coding89 studies, 29 as a primary outcome
- 4
Trail Making Test85 studies, 23 as a primary outcome
- 5
Verbal Learning66 studies, 18 as a primary outcome
- 6
Digit Span Test63 studies, 23 as a primary outcome
- 7
Verbal Fluency58 studies, 20 as a primary outcome
- 8
N-Back Task51 studies, 20 as a primary outcome
- 9
Go/No-Go Task44 studies, 14 as a primary outcome
- 10
Continuous Performance Test37 studies, 16 as a primary outcome
- 11
Balloon Risk22 studies, 8 as a primary outcome
- 12
Task Switching Test21 studies, 6 as a primary outcome
- 13
Card Sorting Test (Berg)21 studies, 3 as a primary outcome
- 14
Paced Visual Serial Addition Test20 studies, 15 as a primary outcome
- 15
Eriksen Flanker Task18 studies, 7 as a primary outcome
- 16
Paired Associate Learning18 studies, 3 as a primary outcome
- 17
Choice Reaction Time17 studies, 5 as a primary outcome
- 18
Delay Discounting16 studies, 7 as a primary outcome
- 19
Category Fluency15 studies, 4 as a primary outcome
- 20
Simple Reaction Time15 studies, 4 as a primary outcome
- 21
Sustained Attention to Response15 studies, 2 as a primary outcome
- 22
Stop-Signal Task14 studies, 6 as a primary outcome
- 23
Selective Reminding Task12 studies, 3 as a primary outcome
- 24
Matrix Reasoning11 studies, 5 as a primary outcome
- 25
Rapid Visual Information Processing11 studies, 4 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
17% of sleep and sleep disorders studies name only instruments outside the library, such as clinician-administered screening scales. They count in every figure on this page and are not listed. The explorer below holds all 116 tests.
Tests used together
- Psychomotor Vigilance Task and Symbol Coding35 studies name both
- Stroop Color-Word Test and Trail Making Test34 studies name both
- N-Back Task and Psychomotor Vigilance Task27 studies name both
- Digit Span Test and Trail Making Test24 studies name both
- Trail Making Test and Verbal Fluency24 studies name both
- Trail Making Test and Verbal Learning24 studies name both
- Digit Span Test and Stroop Color-Word Test23 studies name both
- Verbal Fluency and Verbal Learning19 studies name both
- Digit Span Test and Verbal Fluency18 studies name both
- Symbol Coding and Trail Making Test18 studies name both
Studies by start year
A test as a primary outcomeOnly in secondary or other outcomes
Show as a table
| Start year | Studies | A test as a primary outcome |
|---|---|---|
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 1 | 1 |
| 2003 | 3 | 0 |
| 2004 | 7 | 0 |
| 2005 | 6 | 3 |
| 2006 | 10 | 4 |
| 2007 | 8 | 0 |
| 2008 | 8 | 1 |
| 2009 | 11 | 1 |
| 2010 | 19 | 8 |
| 2011 | 9 | 4 |
| 2012 | 12 | 5 |
| 2013 | 13 | 4 |
| 2014 | 17 | 6 |
| 2015 | 18 | 8 |
| 2016 | 26 | 6 |
| 2017 | 39 | 12 |
| 2018 | 40 | 16 |
| 2019 | 46 | 16 |
| 2020 | 41 | 13 |
| 2021 | 47 | 28 |
| 2022 | 55 | 16 |
| 2023 | 60 | 19 |
| 2024 | 74 | 31 |
| 2025 | 92 | 32 |
| 2026 | 82 | 30 |
Phases and sponsors
By phase
- Early phase 16 studies, 3 as a primary outcome
- Phase 117 studies, 7 as a primary outcome
- Phase 1/210 studies, 3 as a primary outcome
- Phase 257 studies, 7 as a primary outcome
- Phase 2/35 studies, 0 as a primary outcome
- Phase 331 studies, 4 as a primary outcome
- Phase 435 studies, 7 as a primary outcome
- Not applicable468 studies, 176 as a primary outcome
- Observational120 studies, 57 as a primary outcome
Sponsors and study types
Lead sponsor: industry 79, NIH 1, universities, hospitals and others 669. Interventional 629, observational 120.
Status, results, interventions and countries
Status
- Recruiting178 studies, 64 as a primary outcome
- Not yet recruiting46 studies, 19 as a primary outcome
- Active, not recruiting30 studies, 10 as a primary outcome
- Completed380 studies, 130 as a primary outcome
- Stopped early33 studies, 11 as a primary outcome
- Status unknown82 studies, 30 as a primary outcome
What they test
- Behavioral230 studies, 71 as a primary outcome
- Drug160 studies, 29 as a primary outcome
- Device158 studies, 65 as a primary outcome
- Dietary supplement47 studies, 20 as a primary outcome
- Procedure18 studies, 7 as a primary outcome
- Diagnostic test17 studies, 8 as a primary outcome
- Biological5 studies, 3 as a primary outcome
- Radiation5 studies, 3 as a primary outcome
- Combination product4 studies, 2 as a primary outcome
- Genetic2 studies, 1 as a primary outcome
- Other160 studies, 69 as a primary outcome
- None given53 studies, 23 as a primary outcome
Intervention types as registered. A study can list several; observational studies often list none.
Where their sites are
- United States295 studies, 112 as a primary outcome
- France57 studies, 19 as a primary outcome
- China38 studies, 14 as a primary outcome
- Canada35 studies, 8 as a primary outcome
- Hong Kong35 studies, 9 as a primary outcome
- Switzerland30 studies, 5 as a primary outcome
- Taiwan27 studies, 4 as a primary outcome
- United Kingdom27 studies, 7 as a primary outcome
- Türkiye24 studies, 14 as a primary outcome
- Germany21 studies, 3 as a primary outcome
- Denmark19 studies, 3 as a primary outcome
- Italy19 studies, 6 as a primary outcome
52 countries in all. A study with sites in several counts in each; 38 list no site.
Reported results
Completed studies with results posted on ClinicalTrials.gov, a results paper the registry links to the study, or both.
Completed sleep and sleep disorders studies: 185 of 380, 49%
Every completed study with a cognitive outcome: 3,626 of 7,953, 46%
| Results | Completed sleep and sleep disorders studies | Every completed study |
|---|---|---|
| Results on ClinicalTrials.gov and a paper | 51, 13% | 776, 10% |
| Results on ClinicalTrials.gov only | 37, 10% | 1,139, 14% |
| A results paper only | 97, 26% | 1,711, 22% |
| Neither | 195, 51% | 4,327, 54% |
How many participants they enroll
- Phase 134 median, 20 to 60
- Phase 1/235 median, 16 to 61
- Phase 261 median, 38 to 131
- Phase 3158 median, 87 to 291
- Phase 448 median, 33 to 102
- Not applicable60 median, 33 to 115
- Observational100 median, 65 to 227
Show as a table
| Phase | Studies with a size | Median | Middle half |
|---|---|---|---|
| Phase 1 | 17 | 34 | 20 to 60 |
| Phase 1/2 | 10 | 35 | 16 to 61 |
| Phase 2 | 56 | 61 | 38 to 131 |
| Phase 3 | 30 | 158 | 87 to 291 |
| Phase 4 | 34 | 48 | 33 to 102 |
| Not applicable | 463 | 60 | 33 to 115 |
| Observational | 119 | 100 | 65 to 227 |
When the cognitive outcome is measured
Latest time point of each outcome
- Within a day173 outcomes, 72 as a primary outcome
- Up to 4 weeks334 outcomes, 133 as a primary outcome
- 1 to 3 months306 outcomes, 95 as a primary outcome
- 3 to 6 months189 outcomes, 34 as a primary outcome
- 6 to 12 months103 outcomes, 30 as a primary outcome
- 1 to 2 years38 outcomes, 16 as a primary outcome
- Over 2 years25 outcomes, 19 as a primary outcome
- No duration given141 outcomes, 54 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
1,168 of the 1,309 outcome measures give a duration. A single visit counts as within a day.
Median time to the primary outcome, by test
| Test | Primary outcomes | Median |
|---|---|---|
| Psychomotor Vigilance Task | 74 | 2 weeks |
| Stroop Color-Word Test | 32 | 8 weeks |
| Symbol Coding | 24 | 2 weeks |
| Digit Span Test | 21 | 8 weeks |
| Trail Making Test | 21 | 13 weeks |
| Verbal Fluency | 19 | 12 weeks |
| Verbal Learning | 17 | 12 weeks |
| Continuous Performance Test | 16 | 9 weeks |
| N-Back Task | 16 | 2 weeks |
| Go/No-Go Task | 14 | 4 weeks |
Explore the sleep and sleep disorders studies
619 studies match. 232 name a library test in a primary outcome. Median size 62 participants. Median time to the primary outcome: 4 weeks.
Loading 619 studies; the filters turn on when they arrive.
2026 is partly planned starts. Not shown: 1 planned to start after 2026 and 1 with no start year.
Show as a table
| Start year | Studies | As a primary outcome |
|---|---|---|
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 1 | 1 |
| 2003 | 3 | 0 |
| 2004 | 7 | 0 |
| 2005 | 6 | 3 |
| 2006 | 10 | 4 |
| 2007 | 8 | 0 |
| 2008 | 7 | 1 |
| 2009 | 10 | 1 |
| 2010 | 19 | 8 |
| 2011 | 9 | 4 |
| 2012 | 11 | 5 |
| 2013 | 12 | 3 |
| 2014 | 12 | 6 |
| 2015 | 15 | 7 |
| 2016 | 25 | 6 |
| 2017 | 31 | 11 |
| 2018 | 33 | 15 |
| 2019 | 39 | 14 |
| 2020 | 27 | 9 |
| 2021 | 37 | 24 |
| 2022 | 49 | 16 |
| 2023 | 56 | 19 |
| 2024 | 54 | 24 |
| 2025 | 74 | 28 |
| 2026 | 62 | 23 |
Library tests named most
Largest condition groups
Phases
Participants
Lead sponsor: industry 77, NIH 1, other 541. Interventional 534, observational 85.
As a primary outcomeSecondary or other outcome
The studies, newest registration first
Each number opens the study's record on ClinicalTrials.gov.
| Study | Start | Phase | Conditions | Participants | Lead sponsor | Status | Library tests named, with the latest time point |
|---|---|---|---|---|---|---|---|
| NCT07903896 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCD | Participants75 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07897474 | Start2026 | PhaseObservational | ConditionsSleep and sleep disorders | Participants100 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07889466 | Start2025 | PhaseNot applicable | ConditionsSleep and sleep disorders, Pain and fatigue | Participants203 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07882433 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants50 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07882108 | Start2025 | PhaseNot applicable | ConditionsParkinson's disease, Sleep and sleep disorders | Participants72 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07871929 | Start2026 | PhaseNot applicable | ConditionsAging, frailty and exercise, Sleep and sleep disorders | Participants240 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07852052 | Start2026 | PhaseObservational | ConditionsSubstance use and addiction, Sleep and sleep disorders | Participants34 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07848659 | Start2026 | PhasePhase 1 | ConditionsSleep and sleep disorders | Participants12 | Lead sponsorIndustry | StatusRecruiting | Library tests named
|
| NCT07846865 | Start2026 | PhasePhase 2/3 | ConditionsObesity and diabetes, Sleep and sleep disorders | Participants256 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07841938 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants20 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07840924 | Start2024 | PhasePhase 2 | ConditionsMultiple sclerosis, Sleep and sleep disorders | Participants16 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07830056 | Start2025 | PhasePhase 4 | ConditionsSleep and sleep disorders | Participants33 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07827651 | Start2025 | PhaseNot applicable | ConditionsHealthy volunteers, Aging, frailty and exercise, Sleep and sleep disorders | Participants64 | Lead sponsorIndustry | StatusActive, not recruiting | Library tests named
|
| NCT07803068 | Start2025 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants40 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07799753 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants50 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07786116 | Start2025 | PhaseNot applicable | ConditionsDementia and Alzheimer's, Mild cognitive impairment, Parkinson's disease, Sleep and sleep disorders | Participants215 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07767617 | Start2026 | PhaseNot applicable | ConditionsADHD, Sleep and sleep disorders | Participants150 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07766343 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants760 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07744581 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders | Participants25 | Lead sponsorOther | StatusActive, not recruiting | Library tests named
|
| NCT07740967 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders, Pain and fatigue, Cardiovascular disease | Participants34 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07735910 | Start2026 | PhaseNot applicable | ConditionsMild cognitive impairment, Depression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCD | Participants60 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07729930 | Start2026 | PhaseNot applicable | ConditionsSleep and sleep disorders, Pain and fatigue, Cardiovascular disease | Participants38 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07714772 | Start2026 | PhaseObservational | ConditionsParkinson's disease, Sleep and sleep disorders | Participants50 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07706283 | Start2025 | PhaseNot applicable | ConditionsHealthy volunteers, Sleep and sleep disorders, Pain and fatigue | Participants81 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07697092 | Start2026 | PhaseObservational | ConditionsSleep and sleep disorders | Participants128 | Lead sponsorOther | StatusRecruiting | Library tests named
|
Questions, answered from the data
Which cognitive test do sleep trials use most?
The Psychomotor Vigilance Task: 237 of the 749 registered studies name it in an outcome measure, 32%. Next come the Stroop Color-Word Test (89) and Symbol Coding (89).
Which cognitive test do sleep trials use most as a primary outcome?
The Psychomotor Vigilance Task, named in a primary outcome by 89 studies. 264 of the 749 studies, 35%, name a cognitive test in a primary outcome.
How many participants does a phase 2 sleep trial enroll?
Half of the phase 2 sleep and sleep disorders studies enroll 61 participants or fewer, and the middle half enroll 38 to 131. 56 of them give a size.
How long after the start do sleep trials measure a cognitive outcome?
Half of the primary outcomes that name a library test are measured within 4 weeks of the start, and the middle half from 1 week to 13 weeks. 399 primary outcomes give a duration.
Which cognitive tests do sleep trials use together?
The Psychomotor Vigilance Task with Symbol Coding most often: 35 studies name both. Next, the Stroop Color-Word Test with the Trail Making Test (34).
How many completed sleep trials have reported results?
185 of the 380 completed sleep and sleep disorders studies, 49%, have reported results: 88 posted them on ClinicalTrials.gov, 148 have a results paper linked to the registry record, and 51 did both. The other 195 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.
How the studies are counted
For each test family, the census runs ClinicalTrials.gov's own outcome search for the family's names and reads every study first posted by the day the family was counted. These studies were read on 10 November 2026. A study counts once on a page, however many tests it names. Counts for a test cover every version of the task under any of its names, so a page can count studies that used a commercial version.
The census adds two things to each record and changes nothing in it: which outcome list names the test (primary, then secondary, then other), and the condition groups, matched on the study's condition names and MeSH terms. A study can fall in several groups; one whose only condition is cognitive impairment or decline falls in “Cognitive impairment and decline”. Studies that name only instruments outside the library count in every total and share but are not listed.
A second read on 10 November 2026 added each study's overall status, whether results are posted, its intervention types, the countries of its sites and the time frame of the outcome that names each test. A time frame counts by the latest time point it names: “Baseline, 12 and 24 weeks” is 24 weeks, a single visit is within a day, and one that names no duration, such as “end of treatment”, is left out of the timings.
A third read on 10 November 2026 added the papers the registry links to each study: those its sponsor lists as reporting results, and those PubMed links to it through the study's NCT number. A study has a results paper when one of them came out in or after the month of its primary completion and PubMed does not class it as a protocol, review or comment. A paper that never gives the NCT number is not linked, so some studies counted as reporting neither did publish.
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine, which does not endorse these pages. Every study line is in the data release 2.1.0, and the explorer's own file is clinical-trials-studies.json.
Plan the cognitive outcomes of a sleep and sleep disorders trial
Choose tests with a record in registered trials, and run them in a browser at every site, on the same version each visit.