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

Recruiting

Conditions

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

Observational

Enrollment (Estimated)

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 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

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
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

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

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

Uskudar University

Collaborators

The Scientific and Technological Research Council of Turkey

Investigators

  • 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)

January 26, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

August 1, 2026

Study Registration Dates

First Submitted

January 21, 2026

First Submitted That Met QC Criteria

January 29, 2026

First Posted (Actual)

February 4, 2026

Study Record Updates

Last Update Posted (Actual)

April 29, 2026

Last Update Submitted That Met QC Criteria

April 27, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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