Clinical trials data

Symbol Coding in dementia and Alzheimer's trials: 117 registered studies

Every registered dementia and Alzheimer's disease study on ClinicalTrials.gov that names Symbol Coding in an outcome measure: how often it is a primary outcome, the tests named with it, how large the studies are and when they measure it.

Registered dementia and Alzheimer's disease studies name it in an outcome measure: 117
Name it in a primary outcome, 35%: 41 of 117
Of the condition's 1,673 studies name it, against 9% of all registered studies: 7%; Other conditions
Median participants per study: 114; By phase

Try the Symbol Key Game Try Symbol Coding

Tests named in the same studies

The library tests that dementia and Alzheimer's disease studies naming Symbol Coding name most often beside it.

1
Trail Making Test51 studies, 20 as a primary outcome
2
Category Fluency42 studies, 17 as a primary outcome
3
Verbal Fluency42 studies, 16 as a primary outcome
4
Verbal Learning37 studies, 20 as a primary outcome
5
Digit Span Test36 studies, 13 as a primary outcome
6
Short Story Recall26 studies, 13 as a primary outcome
7
Selective Reminding Task24 studies, 9 as a primary outcome
8
Stroop Color-Word Test23 studies, 13 as a primary outcome
9
Picture Naming Test14 studies, 8 as a primary outcome
10
Complex Figure Copy and Recall12 studies, 6 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

Studies by start year

Each study counted once. 2026 is partly planned starts.

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table

Registered studies by start year
Start year	Studies	A test as a primary outcome
2000	0	0
2001	2	0
2002	0	0
2003	0	0
2004	0	0
2005	1	1
2006	0	0
2007	3	0
2008	1	0
2009	2	1
2010	3	1
2011	2	2
2012	6	4
2013	4	1
2014	3	2
2015	2	0
2016	4	0
2017	5	3
2018	9	4
2019	11	5
2020	5	1
2021	14	6
2022	5	2
2023	12	4
2024	6	3
2025	9	1
2026	7	0

Phases and study sizes

By phase

Early phase 12 studies, 1 as a primary outcome
Phase 12 studies, 0 as a primary outcome
Phase 1/26 studies, 1 as a primary outcome
Phase 224 studies, 8 as a primary outcome
Phase 2/34 studies, 2 as a primary outcome
Phase 314 studies, 3 as a primary outcome
Phase 44 studies, 1 as a primary outcome
Not applicable42 studies, 13 as a primary outcome
Observational19 studies, 12 as a primary outcome

Participants per study

Phase 2116 median, 47 to 205
Phase 3802 median, 203 to 1,061
Not applicable83 median, 49 to 155
Observational400 median, 114 to 750

Participants per study. The bar spans the middle half of the studies in each phase, the mark is the median, and the axis is logarithmic. Phases with fewer than 10 studies that give a size are left out.

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Participants per dementia and Alzheimer's disease study that names Symbol Coding, by phase
Phase	Studies with a size	Median	Middle half
Phase 2	22	116	47 to 205
Phase 3	14	802	203 to 1,061
Not applicable	42	83	49 to 155
Observational	17	400	114 to 750

When dementia and Alzheimer's trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 14 weeks to 2 years. 38 primary outcomes give a duration.

Latest time point of each outcome

Within a day9 outcomes, 4 as a primary outcome
Up to 4 weeks13 outcomes, 1 as a primary outcome
1 to 3 months15 outcomes, 5 as a primary outcome
3 to 6 months23 outcomes, 9 as a primary outcome
6 to 12 months20 outcomes, 6 as a primary outcome
1 to 2 years13 outcomes, 4 as a primary outcome
Over 2 years19 outcomes, 9 as a primary outcome
No duration given5 outcomes, 3 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

112 of the 117 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

Recruiting17 studies, 4 as a primary outcome
Not yet recruiting6 studies, 0 as a primary outcome
Active, not recruiting6 studies, 4 as a primary outcome
Completed58 studies, 21 as a primary outcome
Stopped early15 studies, 6 as a primary outcome
Status unknown15 studies, 6 as a primary outcome

What they test

Behavioral20 studies, 9 as a primary outcome
Drug48 studies, 12 as a primary outcome
Device15 studies, 4 as a primary outcome
Dietary supplement4 studies, 1 as a primary outcome
Procedure3 studies, 1 as a primary outcome
Diagnostic test3 studies, 1 as a primary outcome
Biological4 studies, 0 as a primary outcome
Radiation1 studies, 0 as a primary outcome
Combination product1 studies, 1 as a primary outcome
Genetic1 studies, 0 as a primary outcome
Other23 studies, 10 as a primary outcome
None given12 studies, 8 as a primary outcome

Intervention types as registered. A study can list several; observational studies often list none.

48 countries in all. A study with sites in several counts in each; 8 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 dementia and Alzheimer's disease studies that name Symbol Coding: 36 of 58, 62%

Every completed study with a cognitive outcome: 3,626 of 7,953, 46%

Completed dementia and Alzheimer's disease studies that name Symbol Coding and every completed study, by how they reported results
Results	Completed dementia and Alzheimer's disease studies that name Symbol Coding	Every completed study
Results on ClinicalTrials.gov and a paper	11, 19%	776, 10%
Results on ClinicalTrials.gov only	8, 14%	1,139, 14%
A results paper only	17, 29%	1,711, 22%
Neither	22, 38%	4,327, 54%

The 117 studies

Filter by phase, sponsor, status, country, intervention, outcome list, size and start year. Each study links to its record on ClinicalTrials.gov.

117 studies match. 41 name Symbol Coding in a primary outcome. Median size 114 participants. Median time to the primary outcome: 6 months.

Loading 117 studies; the filters turn on when they arrive.

By start year

2026 is partly planned starts. Not shown: 1 planned to start after 2026.

Show as a table

Matching studies by start year
Start year	Studies	As a primary outcome
2000	0	0
2001	2	0
2002	0	0
2003	0	0
2004	0	0
2005	1	1
2006	0	0
2007	3	0
2008	1	0
2009	2	1
2010	3	1
2011	2	2
2012	6	4
2013	4	1
2014	3	2
2015	2	0
2016	4	0
2017	5	3
2018	9	4
2019	11	5
2020	5	1
2021	14	6
2022	5	2
2023	12	4
2024	6	3
2025	9	1
2026	7	0

Library tests named most

Largest condition groups

Dementia and Alzheimer's117 studies, 41 as a primary outcome
Mild cognitive impairment25 studies, 6 as a primary outcome
Aging, frailty and exercise9 studies, 2 as a primary outcome
Obesity and diabetes4 studies, 2 as a primary outcome
Parkinson's disease3 studies, 1 as a primary outcome
Sleep and sleep disorders3 studies, 0 as a primary outcome
Hearing loss3 studies, 2 as a primary outcome
Depression and bipolar disorder2 studies, 1 as a primary outcome
Cancer2 studies, 0 as a primary outcome
Delirium, surgery and intensive care2 studies, 1 as a primary outcome
Cardiovascular disease2 studies, 0 as a primary outcome
Stroke1 study, 0 as a primary outcome

Phases

Participants

Lead sponsor: industry 36, NIH 1, other 80. Interventional 98, observational 19.

As a primary outcomeSecondary or other outcomeSymbol Coding

The studies, newest registration first

Each number opens the study's record on ClinicalTrials.gov.

Registered studies that match the filters, newest registration first, with the library tests each one names and the outcome list that names them.
Study	Start	Phase	Conditions	Participants	Lead sponsor	Status	Library tests named, with the latest time point
NCT07856043	Start2026	PhasePhase 1	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Cardiovascular disease	Participants18	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 weeks Symbol CodingSecondary12 weeks Selective Reminding TaskSecondary12 weeks
NCT07842146	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Verbal FluencySecondary11 months Symbol CodingSecondary11 months Category FluencySecondary11 months Delayed Recall ModuleSecondary11 months
NCT07717411	Start2026	PhasePhase 3	ConditionsDementia and Alzheimer's	Participants1,600	Lead sponsorIndustry	StatusRecruiting	Library tests named Trail Making TestSecondary4 years Symbol CodingSecondary4 years Category FluencySecondary4 years Short Story RecallSecondary4 years Selective Reminding TaskSecondary4 years
NCT07700615	Start2025	PhasePhase 4	ConditionsDementia and Alzheimer's	Participants120	Lead sponsorIndustry	StatusCompleted	Library tests named Trail Making TestSecondary9 weeks Symbol CodingSecondary9 weeks
NCT07664865	Start2024	PhaseObservational	ConditionsDementia and Alzheimer's	Participants250	Lead sponsorOther	StatusCompleted	Library tests named Stroop Color-Word TestPrimarysame day Verbal FluencyPrimarysame day Symbol CodingPrimarysame day Picture Naming TestPrimarysame day Clock Drawing TaskPrimarysame day Complex Figure Copy and RecallPrimarysame day Emoji Emotion RecognitionPrimarysame day Selective Reminding TaskPrimarysame day
NCT07651787	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome12 weeks N-Back TaskPrimary12 weeks Dimensional Change Card SortOther outcome12 weeks Size Order Memory TestOther outcome12 weeks Pattern and Letter ComparisonOther outcome12 weeks Picture Order Memory TestOther outcome12 weeks
NCT07452939	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Delirium, surgery and intensive care	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Verbal LearningSecondary4 weeks Verbal FluencySecondary4 weeks Symbol CodingSecondary4 weeks Psychomotor Vigilance TaskSecondary4 weeks Short Story RecallSecondary4 weeks
NCT07392944	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Aging, frailty and exercise	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary4 months Symbol CodingSecondary4 months
NCT07376135	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants300	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestOther outcome18 months Stroop Color-Word TestOther outcome18 months Verbal LearningOther outcome18 months Digit Span TestOther outcome18 months Symbol CodingOther outcome18 months Short Story RecallOther outcome18 months Complex Figure Copy and RecallOther outcome18 months
NCT07241598	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants70	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 months Verbal FluencySecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Go/No-Go TaskSecondary12 months Category FluencySecondary12 months
NCT07240805	Start2027	PhaseObservational	ConditionsDementia and Alzheimer's	Participants60	Lead sponsorIndustry	StatusNot yet recruiting	Library tests named Symbol CodingSecondarysame day
NCT07233512	Start2023	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants26	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary2 years Short Story RecallPrimary2 years Selective Reminding TaskPrimary2 years
NCT07163039	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants60	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestPrimary8 weeks Stroop Color-Word TestPrimary8 weeks Symbol CodingSecondary8 weeks Cancellation TestPrimary8 weeks
NCT07135245	Start2026	PhasePhase 2	ConditionsDementia and Alzheimer's	Participants180	Lead sponsorOther	StatusNot yet recruiting	Library tests named Symbol CodingSecondary18 months Complex Figure Copy and RecallSecondary18 months
NCT07089303	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants750	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months Clock Drawing TaskSecondary12 months Complex Figure Copy and RecallSecondary12 months
NCT06953167	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's	Participants600	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary8.5 years Category FluencyPrimary8.5 years Short Story RecallPrimary8.5 years Selective Reminding TaskPrimary8.5 years
NCT06832761	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants300	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Category FluencySecondary12 months
NCT06647498	Start2024	PhasePhase 2/3	ConditionsDementia and Alzheimer's	Participants280	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingSecondary3.5 years Category FluencySecondary3.5 years Selective Reminding TaskSecondary3.5 years
NCT06587763	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Brain injury and concussion, Cardiovascular disease	ParticipantsNot given	Lead sponsorOther	StatusStopped early	Library tests named Symbol CodingSecondary6 months
NCT06538116	Start2024	PhasePhase 2	ConditionsDementia and Alzheimer's	Participants304	Lead sponsorIndustry	StatusCompleted	Library tests named Verbal FluencySecondary6 months Symbol CodingSecondary6 months Category FluencySecondary6 months Cancellation TestSecondary6 months Delayed Recall ModuleSecondary6 months
NCT06492967	Start2021	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants1,065	Lead sponsorOther	StatusCompleted Paper	Library tests named Stroop Color-Word TestSecondary2 years Digit Span TestSecondary2 years Symbol CodingSecondary2 years Short Story RecallSecondary2 years Selective Reminding TaskSecondary2 years
NCT06424236	Start2020	PhasePhase 2/3	ConditionsDementia and Alzheimer's	Participants73	Lead sponsorOther	StatusStopped early Results Paper 1 Paper 2	Library tests named Digit Span TestSecondary3 years Symbol CodingSecondary3 years Category FluencySecondary3 years
NCT06416072	Start2023	PhaseObservational	ConditionsDementia and Alzheimer's	Participants3,000	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingSecondary6 years Category FluencySecondary6 years Selective Reminding TaskSecondary6 years
NCT06235840	Start2018	PhaseNot applicable	ConditionsDementia and Alzheimer's, Aging, frailty and exercise	Participants117	Lead sponsorOther	StatusCompleted Paper	Library tests named Stroop Color-Word TestPrimary4 weeks Digit Span TestSecondary4 weeks Symbol CodingSecondary4 weeks N-Back TaskPrimary4 weeks Matrix ReasoningSecondary4 weeks Operation SpanPrimary4 weeks
NCT06174038	Start2024	PhaseNot applicable	ConditionsDementia and Alzheimer's, Hearing loss	Participants150	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary12 months Symbol CodingPrimary12 months Selective Reminding TaskPrimary12 months

Questions, answered from the data

How many dementia and Alzheimer's trials use Symbol Coding?

117 registered dementia and Alzheimer's disease studies on ClinicalTrials.gov name it in an outcome measure, 41 of them in a primary outcome: 7% of the condition's 1,673 studies with a cognitive outcome, against 9% of all of them. It is the 6th most named test in dementia and Alzheimer's trials.

Which tests do dementia and Alzheimer's trials use with Symbol Coding?

The Trail Making Test (51 studies), Category Fluency (42 studies) and Verbal Fluency (42 studies).

How many participants do phase 2 dementia and Alzheimer's trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 116 participants or fewer, and the middle half enroll 47 to 205. 22 of them give a size.

When do dementia and Alzheimer's trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 14 weeks to 2 years. 38 primary outcomes give a duration.

How many completed dementia and Alzheimer's trials that use Symbol Coding have reported results?

36 of the 58 completed studies that name it, 62%, have reported results: 19 posted them on ClinicalTrials.gov, 28 have a results paper linked to the registry record, and 11 did both. The other 22 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.

The census counts Symbol Key Game and Symbol Coding as one test family, so this page counts their studies together.

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Clinical trials data

Symbol Coding in dementia and Alzheimer's trials: 117 registered studies

Registered dementia and Alzheimer's disease studies name it in an outcome measure: 117
Name it in a primary outcome, 35%: 41 of 117
Of the condition's 1,673 studies name it, against 9% of all registered studies: 7%; Other conditions
Median participants per study: 114; By phase

Try the Symbol Key Game Try Symbol Coding

Tests named in the same studies

The library tests that dementia and Alzheimer's disease studies naming Symbol Coding name most often beside it.

1
Trail Making Test51 studies, 20 as a primary outcome
2
Category Fluency42 studies, 17 as a primary outcome
3
Verbal Fluency42 studies, 16 as a primary outcome
4
Verbal Learning37 studies, 20 as a primary outcome
5
Digit Span Test36 studies, 13 as a primary outcome
6
Short Story Recall26 studies, 13 as a primary outcome
7
Selective Reminding Task24 studies, 9 as a primary outcome
8
Stroop Color-Word Test23 studies, 13 as a primary outcome
9
Picture Naming Test14 studies, 8 as a primary outcome
10
Complex Figure Copy and Recall12 studies, 6 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

Studies by start year

Each study counted once. 2026 is partly planned starts.

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table

Registered studies by start year
Start year	Studies	A test as a primary outcome
2000	0	0
2001	2	0
2002	0	0
2003	0	0
2004	0	0
2005	1	1
2006	0	0
2007	3	0
2008	1	0
2009	2	1
2010	3	1
2011	2	2
2012	6	4
2013	4	1
2014	3	2
2015	2	0
2016	4	0
2017	5	3
2018	9	4
2019	11	5
2020	5	1
2021	14	6
2022	5	2
2023	12	4
2024	6	3
2025	9	1
2026	7	0

Phases and study sizes

By phase

Early phase 12 studies, 1 as a primary outcome
Phase 12 studies, 0 as a primary outcome
Phase 1/26 studies, 1 as a primary outcome
Phase 224 studies, 8 as a primary outcome
Phase 2/34 studies, 2 as a primary outcome
Phase 314 studies, 3 as a primary outcome
Phase 44 studies, 1 as a primary outcome
Not applicable42 studies, 13 as a primary outcome
Observational19 studies, 12 as a primary outcome

Participants per study

Phase 2116 median, 47 to 205
Phase 3802 median, 203 to 1,061
Not applicable83 median, 49 to 155
Observational400 median, 114 to 750

Show as a table

Participants per dementia and Alzheimer's disease study that names Symbol Coding, by phase
Phase	Studies with a size	Median	Middle half
Phase 2	22	116	47 to 205
Phase 3	14	802	203 to 1,061
Not applicable	42	83	49 to 155
Observational	17	400	114 to 750

When dementia and Alzheimer's trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 14 weeks to 2 years. 38 primary outcomes give a duration.

Latest time point of each outcome

Within a day9 outcomes, 4 as a primary outcome
Up to 4 weeks13 outcomes, 1 as a primary outcome
1 to 3 months15 outcomes, 5 as a primary outcome
3 to 6 months23 outcomes, 9 as a primary outcome
6 to 12 months20 outcomes, 6 as a primary outcome
1 to 2 years13 outcomes, 4 as a primary outcome
Over 2 years19 outcomes, 9 as a primary outcome
No duration given5 outcomes, 3 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

112 of the 117 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

Recruiting17 studies, 4 as a primary outcome
Not yet recruiting6 studies, 0 as a primary outcome
Active, not recruiting6 studies, 4 as a primary outcome
Completed58 studies, 21 as a primary outcome
Stopped early15 studies, 6 as a primary outcome
Status unknown15 studies, 6 as a primary outcome

What they test

Behavioral20 studies, 9 as a primary outcome
Drug48 studies, 12 as a primary outcome
Device15 studies, 4 as a primary outcome
Dietary supplement4 studies, 1 as a primary outcome
Procedure3 studies, 1 as a primary outcome
Diagnostic test3 studies, 1 as a primary outcome
Biological4 studies, 0 as a primary outcome
Radiation1 studies, 0 as a primary outcome
Combination product1 studies, 1 as a primary outcome
Genetic1 studies, 0 as a primary outcome
Other23 studies, 10 as a primary outcome
None given12 studies, 8 as a primary outcome

Intervention types as registered. A study can list several; observational studies often list none.

48 countries in all. A study with sites in several counts in each; 8 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 dementia and Alzheimer's disease studies that name Symbol Coding: 36 of 58, 62%

Every completed study with a cognitive outcome: 3,626 of 7,953, 46%

Completed dementia and Alzheimer's disease studies that name Symbol Coding and every completed study, by how they reported results
Results	Completed dementia and Alzheimer's disease studies that name Symbol Coding	Every completed study
Results on ClinicalTrials.gov and a paper	11, 19%	776, 10%
Results on ClinicalTrials.gov only	8, 14%	1,139, 14%
A results paper only	17, 29%	1,711, 22%
Neither	22, 38%	4,327, 54%

The 117 studies

Filter by phase, sponsor, status, country, intervention, outcome list, size and start year. Each study links to its record on ClinicalTrials.gov.

117 studies match. 41 name Symbol Coding in a primary outcome. Median size 114 participants. Median time to the primary outcome: 6 months.

Loading 117 studies; the filters turn on when they arrive.

By start year

2026 is partly planned starts. Not shown: 1 planned to start after 2026.

Show as a table

Matching studies by start year
Start year	Studies	As a primary outcome
2000	0	0
2001	2	0
2002	0	0
2003	0	0
2004	0	0
2005	1	1
2006	0	0
2007	3	0
2008	1	0
2009	2	1
2010	3	1
2011	2	2
2012	6	4
2013	4	1
2014	3	2
2015	2	0
2016	4	0
2017	5	3
2018	9	4
2019	11	5
2020	5	1
2021	14	6
2022	5	2
2023	12	4
2024	6	3
2025	9	1
2026	7	0

Library tests named most

Largest condition groups

Dementia and Alzheimer's117 studies, 41 as a primary outcome
Mild cognitive impairment25 studies, 6 as a primary outcome
Aging, frailty and exercise9 studies, 2 as a primary outcome
Obesity and diabetes4 studies, 2 as a primary outcome
Parkinson's disease3 studies, 1 as a primary outcome
Sleep and sleep disorders3 studies, 0 as a primary outcome
Hearing loss3 studies, 2 as a primary outcome
Depression and bipolar disorder2 studies, 1 as a primary outcome
Cancer2 studies, 0 as a primary outcome
Delirium, surgery and intensive care2 studies, 1 as a primary outcome
Cardiovascular disease2 studies, 0 as a primary outcome
Stroke1 study, 0 as a primary outcome

Phases

Participants

Lead sponsor: industry 36, NIH 1, other 80. Interventional 98, observational 19.

As a primary outcomeSecondary or other outcomeSymbol Coding

The studies, newest registration first

Each number opens the study's record on ClinicalTrials.gov.

Registered studies that match the filters, newest registration first, with the library tests each one names and the outcome list that names them.
Study	Start	Phase	Conditions	Participants	Lead sponsor	Status	Library tests named, with the latest time point
NCT07856043	Start2026	PhasePhase 1	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Cardiovascular disease	Participants18	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 weeks Symbol CodingSecondary12 weeks Selective Reminding TaskSecondary12 weeks
NCT07842146	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Verbal FluencySecondary11 months Symbol CodingSecondary11 months Category FluencySecondary11 months Delayed Recall ModuleSecondary11 months
NCT07717411	Start2026	PhasePhase 3	ConditionsDementia and Alzheimer's	Participants1,600	Lead sponsorIndustry	StatusRecruiting	Library tests named Trail Making TestSecondary4 years Symbol CodingSecondary4 years Category FluencySecondary4 years Short Story RecallSecondary4 years Selective Reminding TaskSecondary4 years
NCT07700615	Start2025	PhasePhase 4	ConditionsDementia and Alzheimer's	Participants120	Lead sponsorIndustry	StatusCompleted	Library tests named Trail Making TestSecondary9 weeks Symbol CodingSecondary9 weeks
NCT07664865	Start2024	PhaseObservational	ConditionsDementia and Alzheimer's	Participants250	Lead sponsorOther	StatusCompleted	Library tests named Stroop Color-Word TestPrimarysame day Verbal FluencyPrimarysame day Symbol CodingPrimarysame day Picture Naming TestPrimarysame day Clock Drawing TaskPrimarysame day Complex Figure Copy and RecallPrimarysame day Emoji Emotion RecognitionPrimarysame day Selective Reminding TaskPrimarysame day
NCT07651787	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome12 weeks N-Back TaskPrimary12 weeks Dimensional Change Card SortOther outcome12 weeks Size Order Memory TestOther outcome12 weeks Pattern and Letter ComparisonOther outcome12 weeks Picture Order Memory TestOther outcome12 weeks
NCT07452939	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Delirium, surgery and intensive care	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Verbal LearningSecondary4 weeks Verbal FluencySecondary4 weeks Symbol CodingSecondary4 weeks Psychomotor Vigilance TaskSecondary4 weeks Short Story RecallSecondary4 weeks
NCT07392944	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Aging, frailty and exercise	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary4 months Symbol CodingSecondary4 months
NCT07376135	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants300	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestOther outcome18 months Stroop Color-Word TestOther outcome18 months Verbal LearningOther outcome18 months Digit Span TestOther outcome18 months Symbol CodingOther outcome18 months Short Story RecallOther outcome18 months Complex Figure Copy and RecallOther outcome18 months
NCT07241598	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants70	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 months Verbal FluencySecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Go/No-Go TaskSecondary12 months Category FluencySecondary12 months
NCT07240805	Start2027	PhaseObservational	ConditionsDementia and Alzheimer's	Participants60	Lead sponsorIndustry	StatusNot yet recruiting	Library tests named Symbol CodingSecondarysame day
NCT07233512	Start2023	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants26	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary2 years Short Story RecallPrimary2 years Selective Reminding TaskPrimary2 years
NCT07163039	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants60	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestPrimary8 weeks Stroop Color-Word TestPrimary8 weeks Symbol CodingSecondary8 weeks Cancellation TestPrimary8 weeks
NCT07135245	Start2026	PhasePhase 2	ConditionsDementia and Alzheimer's	Participants180	Lead sponsorOther	StatusNot yet recruiting	Library tests named Symbol CodingSecondary18 months Complex Figure Copy and RecallSecondary18 months
NCT07089303	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants750	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months Clock Drawing TaskSecondary12 months Complex Figure Copy and RecallSecondary12 months
NCT06953167	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's	Participants600	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary8.5 years Category FluencyPrimary8.5 years Short Story RecallPrimary8.5 years Selective Reminding TaskPrimary8.5 years
NCT06832761	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants300	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Category FluencySecondary12 months
NCT06647498	Start2024	PhasePhase 2/3	ConditionsDementia and Alzheimer's	Participants280	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingSecondary3.5 years Category FluencySecondary3.5 years Selective Reminding TaskSecondary3.5 years
NCT06587763	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Brain injury and concussion, Cardiovascular disease	ParticipantsNot given	Lead sponsorOther	StatusStopped early	Library tests named Symbol CodingSecondary6 months
NCT06538116	Start2024	PhasePhase 2	ConditionsDementia and Alzheimer's	Participants304	Lead sponsorIndustry	StatusCompleted	Library tests named Verbal FluencySecondary6 months Symbol CodingSecondary6 months Category FluencySecondary6 months Cancellation TestSecondary6 months Delayed Recall ModuleSecondary6 months
NCT06492967	Start2021	PhaseNot applicable	ConditionsDementia and Alzheimer's	Participants1,065	Lead sponsorOther	StatusCompleted Paper	Library tests named Stroop Color-Word TestSecondary2 years Digit Span TestSecondary2 years Symbol CodingSecondary2 years Short Story RecallSecondary2 years Selective Reminding TaskSecondary2 years
NCT06424236	Start2020	PhasePhase 2/3	ConditionsDementia and Alzheimer's	Participants73	Lead sponsorOther	StatusStopped early Results Paper 1 Paper 2	Library tests named Digit Span TestSecondary3 years Symbol CodingSecondary3 years Category FluencySecondary3 years
NCT06416072	Start2023	PhaseObservational	ConditionsDementia and Alzheimer's	Participants3,000	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingSecondary6 years Category FluencySecondary6 years Selective Reminding TaskSecondary6 years
NCT06235840	Start2018	PhaseNot applicable	ConditionsDementia and Alzheimer's, Aging, frailty and exercise	Participants117	Lead sponsorOther	StatusCompleted Paper	Library tests named Stroop Color-Word TestPrimary4 weeks Digit Span TestSecondary4 weeks Symbol CodingSecondary4 weeks N-Back TaskPrimary4 weeks Matrix ReasoningSecondary4 weeks Operation SpanPrimary4 weeks
NCT06174038	Start2024	PhaseNot applicable	ConditionsDementia and Alzheimer's, Hearing loss	Participants150	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary12 months Symbol CodingPrimary12 months Selective Reminding TaskPrimary12 months

Questions, answered from the data

How many dementia and Alzheimer's trials use Symbol Coding?

Which tests do dementia and Alzheimer's trials use with Symbol Coding?

The Trail Making Test (51 studies), Category Fluency (42 studies) and Verbal Fluency (42 studies).

How many participants do phase 2 dementia and Alzheimer's trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 116 participants or fewer, and the middle half enroll 47 to 205. 22 of them give a size.

When do dementia and Alzheimer's trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 14 weeks to 2 years. 38 primary outcomes give a duration.

How many completed dementia and Alzheimer's trials that use Symbol Coding have reported results?

How the studies are counted

The census counts Symbol Key Game and Symbol Coding as one test family, so this page counts their studies together.

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Symbol Coding in dementia and Alzheimer's trials: 117 registered studies

Tests named in the same studies

Studies by start year

Phases and study sizes

By phase

Participants per study

When dementia and Alzheimer's trials measure it

Latest time point of each outcome

Status, results, interventions and countries

Status

What they test

Where their sites are

Reported results

The 117 studies

Library tests named most

Largest condition groups

Phases

Participants

The studies, newest registration first

Questions, answered from the data

How many dementia and Alzheimer's trials use Symbol Coding?

Which tests do dementia and Alzheimer's trials use with Symbol Coding?

How many participants do phase 2 dementia and Alzheimer's trials that use Symbol Coding enroll?

When do dementia and Alzheimer's trials measure Symbol Coding?

How many completed dementia and Alzheimer's trials that use Symbol Coding have reported results?

More on Symbol Coding and dementia and Alzheimer's disease

Symbol Coding in other conditions

Other tests in dementia and Alzheimer's trials

How the studies are counted

Run Symbol Coding in your trial

Symbol Coding in dementia and Alzheimer's trials: 117 registered studies

Tests named in the same studies

Studies by start year

Phases and study sizes

By phase

Participants per study

When dementia and Alzheimer's trials measure it

Latest time point of each outcome

Status, results, interventions and countries

Status

What they test

Where their sites are

Reported results

The 117 studies

Library tests named most

Largest condition groups

Phases

Participants

The studies, newest registration first

Questions, answered from the data

How many dementia and Alzheimer's trials use Symbol Coding?

Which tests do dementia and Alzheimer's trials use with Symbol Coding?

How many participants do phase 2 dementia and Alzheimer's trials that use Symbol Coding enroll?

When do dementia and Alzheimer's trials measure Symbol Coding?

How many completed dementia and Alzheimer's trials that use Symbol Coding have reported results?

More on Symbol Coding and dementia and Alzheimer's disease

Symbol Coding in other conditions

Other tests in dementia and Alzheimer's trials

How the studies are counted

Run Symbol Coding in your trial