Sleep Quality and Cognitive Functions in Adults: A Cross-Sectional Study

April 27, 2026 updated by: Fatma Demir, Uskudar University

The Association Between Sleep Quality and Cognitive Functions in Healthy Young Adults

This observational cross-sectional study aims to examine the association between sleep quality and cognitive functions in healthy young adults. Subjective sleep quality will be assessed using the Pittsburgh Sleep Quality Index, and objective sleep parameters will be collected using a wearable device over five consecutive days. Cognitive functions will be evaluated at a single assessment session using standardized neuropsychological tests, including measures of attention, executive functions, and verbal memory. The study seeks to explore relationships between subjective and objective sleep measures and cognitive performance. Findings from this study may contribute to a better understanding of how sleep quality is associated with cognitive functioning in healthy young adults.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

This study is designed as an observational, cross-sectional investigation conducted in healthy young adults to examine the association between sleep quality and cognitive functions. Participants will be recruited from a non-clinical population and will undergo a single assessment period. Subjective sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI), a self-report questionnaire evaluating sleep quality and sleep-related disturbances over the previous month. In addition to subjective measures, objective sleep parameters will be collected using a wearable device worn continuously for five consecutive days. Wearable-derived sleep metrics will include total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset, as provided by the device's standard algorithms. Cognitive functions will be evaluated during a single in-person assessment session following completion of the sleep data collection period. Cognitive assessment will include standardized neuropsychological tests measuring attention, executive functions, and verbal memory. Attention and executive functions will be assessed using the Victoria Stroop Test, and verbal memory processes will be evaluated using the Öktem Verbal Memory Processes Test, administered according to standardized procedures. Demographic information and relevant background variables will be collected to characterize the study sample. Statistical analyses will primarily focus on examining associations between subjective and objective sleep parameters and cognitive test outcomes. Correlation analyses and multivariable statistical models may be used to explore relationships between sleep quality and cognitive performance while accounting for potential confounding variables. This study aims to contribute to the understanding of how variations in sleep quality are associated with cognitive functioning in healthy young adults, using both subjective and objective sleep measures.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
75

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

The study population consists of healthy young adults aged between 18 and 35 years. Participants are recruited from a non-clinical population and are required to be fluent in Turkish to ensure valid administration of cognitive assessments. Individuals with self-reported good general health and without active medical, neurological, or psychiatric conditions that may affect sleep or cognitive functioning are eligible. All participants are able and willing to comply with the study procedures, including wearing a wearable sleep monitoring device for five consecutive days and completing a single-session cognitive assessment.

Description

Inclusion Criteria:

  • Between 18 and 35 years.
  • Ability and willingness to provide written informed consent.
  • Sufficient ability to read, understand, and communicate in Turkish, the language in which the assessments are administered.
  • Self-reported good general health, with no active medical or psychiatric conditions that significantly affect daily functioning.
  • Willingness and ability to wear a wearable sleep monitoring device continuously for five consecutive days and to comply with device usage instructions.
  • Ability to attend and complete a single-session cognitive assessment

Exclusion Criteria:

  • Regular or frequent use of medications known to affect sleep or cognitive function, including sedative-hypnotics, benzodiazepines, antipsychotics, stimulants, opioids, or similar agents.
  • Initiation of, or dose changes in, psychotropic medications within the past four weeks.
  • Being under the influence of alcohol or illicit substances on the day of cognitive testing.
  • Engagement in night shift work or rotating shift schedules within the past one month.
  • Travel across time zones resulting in a time difference of two hours or more within the past two weeks.
  • Uncontrolled high daily intake of caffeine (e.g., >400 mg/day) and unwillingness to reduce consumption during the study period.
  • Color blindness or other color vision deficiencies, due to their potential impact on Stroop Test performance.
  • Dermatological conditions, allergies, or skin lesions at the wrist that prevent wearing the device, or refusal to wear the device as required.
  • Acute illness within the past two weeks, including febrile infections, severe pain, or other acute medical conditions that may temporarily affect sleep or cognitive performance.
  • Pregnancy or early postpartum period.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Healthy Young Adults
Healthy young adult participants without diagnosed neurological, psychiatric, or sleep disorders who undergo assessment of sleep quality and cognitive functions during a single observational assessment period.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Composite Objective Sleep Quality Index Derived From Wearable Device
Time Frame: During 5 consecutive days around baseline assessment
A composite objective sleep quality index will be derived from wearable device data collected continuously over five consecutive days. The composite score will be calculated by combining standardized values of total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset into a single summary measure representing overall objective sleep quality.
During 5 consecutive days around baseline assessment

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Sleep Quality (Pittsburgh Sleep Quality Index Scores)
Time Frame: Baseline (single assessment)
Subjective sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The total PSQI score ranges from 0 to 21, with higher scores indicating poorer sleep quality.
Baseline (single assessment)
Cognitive Performance (Victoria Stroop Test Scores)
Time Frame: Baseline (single assessment)
Attention and executive functions will be assessed using the Victoria Stroop Test. Outcome measures include completion time and error scores obtained during the test.
Baseline (single assessment)
Verbal Memory Performance (Öktem Verbal Memory Processes Test Scores)
Time Frame: Baseline (single assessment)
Verbal memory will be evaluated using the Öktem Verbal Memory Processes Test. Outcome measures include standardized scores reflecting learning and recall performance.
Baseline (single assessment)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Uskudar University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
The Scientific and Technological Research Council of Turkey

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Fatma Demir, MSc, Uskudar University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 26, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 21, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 29, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 61351342/020-1143
  • TUBITAK 2209A 1919B012466805 (Other Grant/Funding Number: The Scientific and Technological Research Council of Turkey (TUBITAK))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the study involves sensitive personal data related to sleep patterns and cognitive performance, and participant consent for data sharing was not obtained. Data will be used solely for the purposes defined in the approved study protocol.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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