Obstructive Sleep ApneaNCT07897474
EEG Markers From Polysomnography and Cognitive Performance in Obstructive Sleep Apnea
An observational study of Obstructive Sleep Apnea and Cognitive Impairment, run by University of Split, School of Medicine.
Trial summary
This cross-sectional study examines whether EEG markers derived from full-night polysomnography (sleep spindle density, K-complex density, and REM EEG slowing) are associated with cognitive performance in adults with obstructive sleep apnea, and whether they explain more variance in cognitive test scores than… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obstructive Sleep Apnea, Cognitive Impairment
- What is being tested?
- Full-night polysomnography with EEG marker analysis and cognitive testing
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- 1 Nov 2026to 31 Dec 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adult patients (18 years or older) with obstructive sleep apnea (apnea-hypopnea index ≥5 events/hour) referred for diagnostic full-night polysomnography at the Sleep Medicine Center Split, Croatia. Participants are recruited consecutively and complete a cognitive test battery before polysomnography. Patients with neurological disease, other sleep disorders, history of head trauma or head surgery, or chronic disease that may substantially affect cognition or sleep architecture are not included.
Who may be able to join
- Adults (18 years or older)
- Referred for diagnostic full-night polysomnography (PSG) at the Sleep Medicine Center Split
- Obstructive sleep apnea confirmed by PSG (apnea-hypopnea index ≥5 events/hour)
- Total sleep time greater than 4 hours on PSG
- Willing to complete the cognitive test battery
- Written informed consent
Who cannot join
- Active chronic disease that may substantially affect cognition or sleep architecture (e.g., uncompensated heart failure, malignancy)
- Neurological disease
- Other sleep disorders
- History of head trauma
- History of head surgery
- Inability to complete cognitive testing adequately
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: ASSOCIATION OF EEG METRICS FROM POLYSOMNOGRAPHY WITH COGNITIVE PERFORMANCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA: A CROSS-SECTIONAL STUDY
This cross-sectional study examines whether EEG markers derived from full-night polysomnography (sleep spindle density, K-complex density, and REM EEG slowing) are associated with cognitive performance in adults with obstructive sleep apnea, and whether they explain more variance in cognitive test scores than classical OSA metrics (AHI, T90, minimal SpO2).
Read the detailed description
BACKGROUND Obstructive sleep apnea (OSA) is a common chronic disorder and a risk factor for metabolic and cardiovascular disease. A subset of patients with OSA also exhibits cognitive impairment. Classical clinical metrics of OSA, such as the apnea-hypopnea index (AHI), time spent with oxygen saturation below 90% (T90) and minimal oxygen saturation (MinSpO2), show weak and inconsistent associations with cognitive outcomes. Sleep EEG markers derived from polysomnography (PSG), including sleep spindles, K-complexes and REM EEG slowing, have been proposed as more sensitive biomarkers of cognitive vulnerability. Sleep spindles have been linked to cognition in OSA, whereas the association of K-complexes and REM EEG slowing with cognitive performance in OSA remains understudied.
OBJECTIVES The primary objective is to examine whether sleep spindle density, K-complex density and REM EEG slowing are associated with cognitive test performance in adults with OSA, after adjustment for age, sex, body mass index, education and sleepiness. The secondary objective is to compare how strongly these EEG markers and the classical OSA metrics (AHI, T90, MinSpO2) are associated with performance on the same cognitive tests.
DESIGN This is a prospective, cross-sectional observational study conducted at the Sleep Medicine Center Split, Croatia. Consecutive adult patients referred for diagnostic full-night PSG will be invited to participate. After written informed consent, participants complete a standardized cognitive test battery before PSG, in a fixed order: Montreal Cognitive Assessment (MoCA), digit span test, Trail Making Test (TMT), Psychomotor Vigilance Test (PVT), Stroop test, Cognitive Flexibility Inventory (CFI) and Digit Symbol Substitution Test (DSST). Sleepiness is assessed with the Stanford Sleepiness Scale. Full-night PSG is recorded according to routine clinical procedures. Participants are included in the analysis if PSG confirms OSA (AHI ≥5 events/hour) and total sleep time exceeds 4 hours. Demographic, anthropometric and clinical data are obtained by direct measurement and from medical documentation. No intervention is applied.
EEG MEASURES From the PSG recordings, sleep spindle density (events/min of NREM sleep), K-complex density (events/min of NREM sleep) and REM EEG slowing (ratio of slow [delta, theta] to fast [alpha, beta, gamma] EEG bands) will be extracted and quantified with appropriate software. Classical OSA metrics (AHI, T90, MinSpO2) are taken from the same PSG.
OUTCOMES Primary outcomes are the scores of the individual cognitive tests (MoCA, digit span, PVT, TMT, Stroop, CFI, DSST), each tested for association with the three EEG markers. Secondary outcomes include the association of AHI, T90 and MinSpO2 with the same test scores, a comparison of the explanatory power of classical OSA metrics and EEG markers, and an exploratory analysis of the combination of all three EEG markers.
STATISTICAL ANALYSIS Data distribution will be assessed with the Shapiro-Wilk test and visual inspection of histograms and Q-Q plots. Associations will be examined with Pearson or Spearman correlation, as appropriate, and with multiple linear regression adjusted for age, sex, body mass index, education and sleepiness. Models based on classical OSA metrics and on EEG markers will be compared using regression coefficients, standardized beta coefficients, model fit indices and explained variance (R²). Results will be reported with 95% confidence intervals.
SAMPLE SIZE Sample size for the primary analysis was calculated for a correlation coefficient of 0.30 (alpha 0.05, power 80%), giving 85 participants. For the secondary analysis (multiple regression, 6 predictors, f2 = 0.15, alpha 0.05, power 80%), the minimum sample size is 97, which is the target sample size of the study.
The study will be reported according to the STROBE guidelines.
- Conditions
- Obstructive Sleep Apnea, Cognitive Impairment
- Being tested
- Full-night polysomnography with EEG marker analysis and cognitive testing
- Keywords
- polysomnography, sleep EEG, sleep spindles, K-complex, REM EEG slowing, cognition
- Medical subject headings
- Sleep Apnea, Obstructive, Cognitive Dysfunction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Full-night polysomnography with EEG marker analysis and cognitive testingDiagnostic test
Routine full-night diagnostic polysomnography (PSG) performed at the Sleep Medicine Center Split according to standard clinical procedures; no change to the clinical procedure is made for the study. From the recorded EEG, sleep spindle density (events/min of NREM sleep), K-complex density (events/min of NREM sleep) and REM EEG slowing (ratio of slow [delta, theta] to fast [alpha, beta, gamma] band power) are extracted and quantified with appropriate software. Classical OSA metrics (AHI, T90, minimal SpO2) are obtained from the same recording. This is an assessment applied to all participants, not a treatment.
Standardized cognitive assessment administered once, before PSG, by trained assessors using fixed instructions and a fixed test order: Montreal Cognitive Assessment (MoCA), digit span test, Trail Making Test (TMT), Psychomotor Vigilance Test (PVT), Stroop test, Cognitive Flexibility Inventory (CFI) and Digit Symbol Substitution Test (DSST).
What is being measured
The primary outcome is the main question the study is designed to answer.
Correlation between sleep spindle density and Montreal Cognitive Assessment (MoCA) total score
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and global cognitive performance assessed using the Montreal Cognitive Assessment (MoCA; total score, 0-30 points, with higher scores indicating better cognitive performance). The correlation will be assessed using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient (r) and its 95% confidence interval will be reported. An adjusted multiple linear regression analysis will additionally assess the relationship between sleep spindle density and MoCA total score, controlling for age, sex, body mass index, education, and daytime sleepiness.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Correlation between sleep spindle density and Digit Span Test forward score
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and Digit Span Test forward performance, measured as the maximum span length (number of digits correctly recalled). Higher scores indicate better performance. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Correlation between sleep spindle density and Psychomotor Vigilance Test (PVT) mean reaction time
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and mean reaction time on the Psychomotor Vigilance Test (PVT), measured in milliseconds (ms). Shorter reaction times indicate better sustained attention. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Correlation between sleep spindle density and Trail Making Test Part A (TMT-A) completion time
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and TMT-A completion time, measured in seconds. Shorter completion times indicate better processing speed. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Correlation between sleep spindle density and Stroop Test interference-condition completion time
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and completion time for the interference condition of the Stroop Test, measured in seconds. Shorter completion times indicate better performance. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Correlation between sleep spindle density and Digit Symbol Substitution Test (DSST) score
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and the Digit Symbol Substitution Test (DSST) score, measured as the number of correctly completed symbol substitutions according to the test scoring rules. Higher scores indicate better processing speed. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Secondary outcomes (1)
Variance in cognitive test scores explained by a multivariable model including all three EEG markers
Exploratory multiple linear regression models will assess the combined contribution of sleep spindle density, K-complex density, and REM EEG slowing to cognitive test performance. Separate models will be fitted for each prespecified cognitive outcome: MoCA total score, Digit Span forward and backward scores, PVT mean reaction time, TMT-A and TMT-B completion times, TMT B-A difference score, prespecified Stroop Test measures, and DSST score. Models will be adjusted for age, sex, body mass index, education, and daytime sleepiness. The combined contribution of the EEG markers will be summarized using the coefficient of determination (R²), adjusted R², regression coefficients, and their 95% confidence intervals, as appropriate.
Measured: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Oct 2026
- Study start1 Nov 2026 (estimated)
- Primary completion30 Jun 2028 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Split, School of Medicine
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ivana Pavlinac Dodig, University of Split, School of Medicine
- Investigators
- Renata Pecotic, Prof, Study chair, Department for Neuroscience, University of Split School of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07897474
- Sponsor's protocol ID
- 029-01/26-04/0002
- Status last verified
- Oct 2026
- First submitted
- 9 Oct 2026
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is no plan to make individual participant data available to other researchers. Participant-level data will be kept at the study site to protect participant privacy; aggregate results will be published.
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ASSOCIATION OF EEG METRICS FROM POLYSOMNOGRAPHY WITH COGNITIVE PERFORMANCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA: A CROSS-SECTIONAL STUDY
- ClinicalTrials.gov ID
- NCT07897474
- Acronym / sponsor ID
- 029-01/26-04/0002
- Conditions
- Obstructive Sleep Apnea, Cognitive Impairment
- Keywords
- polysomnography, sleep EEG, sleep spindles, K-complex, REM EEG slowing, cognition
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University of Split, School of MedicineUniversity, hospital or other
- Study start
- 1 Nov 2026 (estimated)
- Primary completion
- 30 Jun 2028 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 27 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This cross-sectional study examines whether EEG markers derived from full-night polysomnography (sleep spindle density, K-complex density, and REM EEG slowing) are associated with cognitive performance in adults with obstructive sleep apnea, and whether they explain more variance in cognitive test scores than classical OSA metrics (AHI, T90, minimal SpO2).
Detailed description
BACKGROUND Obstructive sleep apnea (OSA) is a common chronic disorder and a risk factor for metabolic and cardiovascular disease. A subset of patients with OSA also exhibits cognitive impairment. Classical clinical metrics of OSA, such as the apnea-hypopnea index (AHI), time spent with oxygen saturation below 90% (T90) and minimal oxygen saturation (MinSpO2), show weak and inconsistent associations with cognitive outcomes. Sleep EEG markers derived from polysomnography (PSG), including sleep spindles, K-complexes and REM EEG slowing, have been proposed as more sensitive biomarkers of cognitive vulnerability. Sleep spindles have been linked to cognition in OSA, whereas the association of K-complexes and REM EEG slowing with cognitive performance in OSA remains understudied.
OBJECTIVES The primary objective is to examine whether sleep spindle density, K-complex density and REM EEG slowing are associated with cognitive test performance in adults with OSA, after adjustment for age, sex, body mass index, education and sleepiness. The secondary objective is to compare how strongly these EEG markers and the classical OSA metrics (AHI, T90, MinSpO2) are associated with performance on the same cognitive tests.
DESIGN This is a prospective, cross-sectional observational study conducted at the Sleep Medicine Center Split, Croatia. Consecutive adult patients referred for diagnostic full-night PSG will be invited to participate. After written informed consent, participants complete a standardized cognitive test battery before PSG, in a fixed order: Montreal Cognitive Assessment (MoCA), digit span test, Trail Making Test (TMT), Psychomotor Vigilance Test (PVT), Stroop test, Cognitive Flexibility Inventory (CFI) and Digit Symbol Substitution Test (DSST). Sleepiness is assessed with the Stanford Sleepiness Scale. Full-night PSG is recorded according to routine clinical procedures. Participants are included in the analysis if PSG confirms OSA (AHI ≥5 events/hour) and total sleep time exceeds 4 hours. Demographic, anthropometric and clinical data are obtained by direct measurement and from medical documentation. No intervention is applied.
EEG MEASURES From the PSG recordings, sleep spindle density (events/min of NREM sleep), K-complex density (events/min of NREM sleep) and REM EEG slowing (ratio of slow [delta, theta] to fast [alpha, beta, gamma] EEG bands) will be extracted and quantified with appropriate software. Classical OSA metrics (AHI, T90, MinSpO2) are taken from the same PSG.
OUTCOMES Primary outcomes are the scores of the individual cognitive tests (MoCA, digit span, PVT, TMT, Stroop, CFI, DSST), each tested for association with the three EEG markers. Secondary outcomes include the association of AHI, T90 and MinSpO2 with the same test scores, a comparison of the explanatory power of classical OSA metrics and EEG markers, and an exploratory analysis of the combination of all three EEG markers.
STATISTICAL ANALYSIS Data distribution will be assessed with the Shapiro-Wilk test and visual inspection of histograms and Q-Q plots. Associations will be examined with Pearson or Spearman correlation, as appropriate, and with multiple linear regression adjusted for age, sex, body mass index, education and sleepiness. Models based on classical OSA metrics and on EEG markers will be compared using regression coefficients, standardized beta coefficients, model fit indices and explained variance (R²). Results will be reported with 95% confidence intervals.
SAMPLE SIZE Sample size for the primary analysis was calculated for a correlation coefficient of 0.30 (alpha 0.05, power 80%), giving 85 participants. For the secondary analysis (multiple regression, 6 predictors, f2 = 0.15, alpha 0.05, power 80%), the minimum sample size is 97, which is the target sample size of the study.
The study will be reported according to the STROBE guidelines.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult patients (18 years or older) with obstructive sleep apnea (apnea-hypopnea index ≥5 events/hour) referred for diagnostic full-night polysomnography at the Sleep Medicine Center Split, Croatia. Participants are recruited consecutively and complete a cognitive test battery before polysomnography. Patients with neurological disease, other sleep disorders, history of head trauma or head surgery, or chronic disease that may substantially affect cognition or sleep architecture are not included.
Key inclusion criteria (6 listed)
- Adults (18 years or older)
- Referred for diagnostic full-night polysomnography (PSG) at the Sleep Medicine Center Split
- Obstructive sleep apnea confirmed by PSG (apnea-hypopnea index ≥5 events/hour)
- Total sleep time greater than 4 hours on PSG
- Willing to complete the cognitive test battery
Key exclusion criteria (6 listed)
- Active chronic disease that may substantially affect cognition or sleep architecture (e.g., uncompensated heart failure, malignancy)
- Neurological disease
- Other sleep disorders
- History of head trauma
- History of head surgery
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Full-night polysomnography with EEG marker analysis and cognitive testingRoutine full-night diagnostic polysomnography (PSG) performed at the Sleep Medicine Center Split according to standard clinical procedures; no change to the clinical procedure is made for the study. From the recorded EEG, sleep spindle density (events/min of NREM sleep), K-complex density (events/min of NREM sleep) and REM EEG slowing (ratio of slow [delta, theta] to fast [alpha, beta, gamma] band power) are extracted and quantified with appropriate software. Classical OSA metrics (AHI, T90, minimal SpO2) are obtained from the same recording. This is an assessment applied to all participants, not a treatment. Standardized cognitive assessment administered once, before PSG, by trained assessors using fixed instructions and a fixed test order: Montreal Cognitive Assessment (MoCA), digit span test, Trail Making Test (TMT), Psychomotor Vigilance Test (PVT), Stroop test, Cognitive Flexibility Inventory (CFI) and Digit Symbol Substitution Test (DSST). | Diagnostic test | – |
Primary outcome
Correlation between sleep spindle density and Montreal Cognitive Assessment (MoCA) total score
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and global cognitive performance assessed using the Montreal Cognitive Assessment (MoCA; total score, 0-30 points, with higher scores indicating better cognitive performance). The correlation will be assessed using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient (r) and its 95% confidence interval will be reported. An adjusted multiple linear regression analysis will additionally assess the relationship between sleep spindle density and MoCA total score, controlling for age, sex, body mass index, education, and daytime sleepiness.
Correlation between sleep spindle density and Digit Span Test forward score
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and Digit Span Test forward performance, measured as the maximum span length (number of digits correctly recalled). Higher scores indicate better performance. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Correlation between sleep spindle density and Psychomotor Vigilance Test (PVT) mean reaction time
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and mean reaction time on the Psychomotor Vigilance Test (PVT), measured in milliseconds (ms). Shorter reaction times indicate better sustained attention. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Correlation between sleep spindle density and Trail Making Test Part A (TMT-A) completion time
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and TMT-A completion time, measured in seconds. Shorter completion times indicate better processing speed. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Correlation between sleep spindle density and Stroop Test interference-condition completion time
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and completion time for the interference condition of the Stroop Test, measured in seconds. Shorter completion times indicate better performance. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
Correlation between sleep spindle density and Digit Symbol Substitution Test (DSST) score
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
The correlation between sleep spindle density, quantified from full-night polysomnography (PSG), and the Digit Symbol Substitution Test (DSST) score, measured as the number of correctly completed symbol substitutions according to the test scoring rules. Higher scores indicate better processing speed. Pearson's or Spearman's correlation coefficient, as appropriate, and its 95% confidence interval will be reported. Multiple linear regression adjusted for age, sex, body mass index, education, and daytime sleepiness will additionally be performed.
1 secondary outcome
Variance in cognitive test scores explained by a multivariable model including all three EEG markers
Time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
- Individual participant dataSharing planned: No. There is no plan to make individual participant data available to other researchers. Participant-level data will be kept at the study site to protect participant privacy; aggregate results will be published.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Renata Pecotic, Prof study chair
Department for Neuroscience, University of Split School of Medicine
Questions about this trial
What is this clinical trial studying?
An observational study of Obstructive Sleep Apnea and Cognitive Impairment, run by University of Split, School of Medicine.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 27 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ivana Pavlinac Dodig, Assoc. Prof. (021557853, ivana.pavlinac@mefst.hr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Correlation between sleep spindle density and Montreal Cognitive Assessment (MoCA) total score (time frame: Single assessment at baseline (at study enrollment), on the day of the overnight PSG.). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Oct 2026; AzTrials last refreshed its copy on 29 Oct 2026.