Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder characterized by recurrent upper airway obstruction during sleep, leading to intermittent hypoxia and sleep fragmentation. In addition to its well-known cardiometabolic consequences, OSA may negatively affect functional capacity and daily activity performance. However, upper extremity functional capacity in individuals with OSA has not been adequately evaluated.

The 6-Minute Pegboard and Ring Test (6PBRT) is a functional test designed to assess upper extremity functional capacity during unsupported arm activity. Although the test has been widely used in respiratory diseases, its measurement properties have not yet been evaluated in patients with OSA.

The aim of this study is to investigate the validity and reliability of the 6PBRT in adults diagnosed with obstructive sleep apnea using polysomnography. Participants with OSA will undergo polysomnographic evaluation and complete the 6PBRT. Test-retest reliability will be assessed by repeating the test under the same conditions. The relationship between 6PBRT performance and polysomnographic parameters (AHI, ODI, minimum SpO₂ and T90) will also be examined. In addition, associations between 6PBRT performance and clinical scales such as the Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire will be analyzed.

The findings of this study are expected to provide evidence regarding the measurement properties of the 6PBRT in individuals with OSA and contribute to the clinical assessment of upper extremity functional capacity in this population.

Obstructive sleep apnea (OSA) is characterized by repetitive episodes of upper airway obstruction during sleep resulting in intermittent hypoxia, sleep fragmentation, and increased sympathetic activity. These physiological disturbances may negatively affect physical performance, daily functioning, and exercise tolerance. Although previous studies have investigated balance, gait, and overall physical performance in individuals with OSA, upper extremity functional capacity has received limited attention.

The 6-Minute Pegboard and Ring Test (6PBRT) is a functional performance test that evaluates upper extremity endurance during unsupported arm activity. The test has been used primarily in patients with chronic respiratory diseases to assess functional limitation during activities involving arm elevation. However, the validity and reliability of the 6PBRT have not been investigated in individuals with OSA.

This observational methodological study aims to evaluate the validity and reliability of the 6PBRT in adults diagnosed with OSA using polysomnography. Participants diagnosed with OSA will be recruited from the sleep center of Mardin Training and Research Hospital. Demographic and clinical data including age, sex, body mass index, and comorbidities will be recorded. Polysomnographic parameters including apnea-hypopnea index (AHI), oxygen desaturation index (ODI), minimum oxygen saturation (SpO₂), and the percentage of sleep time with oxygen saturation below 90% (T90) will be collected from medical records.

Upper extremity functional capacity will be assessed using the 6PBRT. Participants will perform the test according to standardized procedures. Test-retest reliability will be evaluated by repeating the test under similar conditions. In addition, clinical scales including the Epworth Sleepiness Scale (ESS) and the Functional Outcomes of Sleep Questionnaire (FOSQ) will be administered.

The validity of the 6PBRT will be investigated by examining its relationship with polysomnographic parameters and clinical scales. Reliability will be evaluated using test-retest analysis and intraclass correlation coefficients. The results of this study will provide important information regarding the measurement properties of the 6PBRT in individuals with OSA and may support its use as a practical tool for assessing upper extremity functional capacity in clinical practice.

Inclusion Criteria:

• Being between 18 and 65 years of age

Having a diagnosis of obstructive sleep apnea (OSA) confirmed by polysomnography

Having sufficient cognitive ability to understand and follow the test instructions

Having adequate shoulder range of motion to elevate the upper extremities above head level for performing the 6PBRT

Voluntarily agreeing to participate in the study and providing written informed consent

Exclusion Criteria:

• Presence of neurological diseases that may significantly affect upper extremity function (e.g., stroke, multiple sclerosis, peripheral neuropathy)

Severe orthopedic conditions limiting upper extremity movement (e.g., advanced shoulder pathology, recent surgery, severe contracture)

Unstable cardiopulmonary conditions (e.g., recent myocardial infarction, decompensated heart failure, uncontrolled arrhythmia, acute COPD/asthma exacerbation)

Acute infection, febrile illness, or severe clinical exacerbation within the last 4 weeks

Pain severe enough to interfere with the test or any clinical condition preventing the safe administration of the test

Adults diagnosed with obstructive sleep apnea based on polysomnography who are followed in the Sleep Center of Mardin Training and Research Hospital will be included in the study. Participants will be classified into mild, moderate, and severe obstructive sleep apnea groups according to the apnea-hypopnea index (AHI). In addition, age- and sex-matched healthy individuals without obstructive sleep apnea will be recruited as a control group.

Individual participant data collected during the study will not be publicly shared to protect participant confidentiality. Only aggregated and anonymized results will be reported in scientific publications.