The Effect of Inspiratory Muscle Training on Cognitive Functions, Cerebral Oxygenation, and Neurotrophic Factor Level in Patients With Obstructive Sleep Apnea Syndrome

Digit Span Test

时间窗: Baseline and 8 weeks

A subscale of the WAIS-R, this test aims to measure an individual's level of attention. It is administered in two parts using forward and backward sequencing of numbers. Numbers between 1 and 9 are presented to the individual in a random order, and the individual is asked to repeat them in the same sequence. The test is repeated until the individual correctly repeats the sequence twice in a row or until 12 repetitions are reached. In the evaluation of the test, 2 points are awarded for each correct sequence and 1 point for each sequence with one error. Since there are a total of 12 attempts, even if the individual correctly repeats the sequence twice, 2 points are added for each additional attempt required to reach 12 attempts. The maximum possible score on the test is 24. The test will be administered on the first and last days of treatment.

Montreal Cognitive Assessment Scale

时间窗: Baseline and 8 weeks

The Turkish version will be used to assess individuals' cognitive function. This scale, which takes approximately 10 minutes to administer, will be administered face-to-face with individuals. The maximum score that can be obtained on the scale is 30. One point is added for individuals with less than 12 years of education. The cutoff value for the scale has been set at \<23. The MBDÖ assesses 8 different cognitive function areas: memory, executive functions, visual construction skills, concentration, language, orientation, calculation, and attention. The first and last days of treatment will be evaluated.

Oktem Verbal Memory Processes Test

时间窗: Baseline and 8 weeks

The Turkish adaptation of the Verbal Memory Processes Test, developed by Rey in 1964, was created by Oget Oktem.It assesses verbal memory processes such as auditory-verbal learning, memory recording, recall, and recognition.There is a recognition list with 15 words on the front and 45 words on the back.The target word list on the front is repeated 10 times, and after each repetition, the individual is asked to say the words they have learned, which are recorded, and their score is tallied.This score is the Learning Score Dimension. After a 30-40 minute interval, the individual is asked to recall the target words.The score obtained here is the Spontaneous Recall Dimension score. For words that cannot be recalled, three recognition words consisting of one phonemic and one semantic distractor from the recognition list on the back side will be read, and then the individual will be asked whether the word is found in the target word list.The score obtained is the Recognit Dimension Score.

Stroop Test

时间窗: Baseline and 8 weeks

This test measures the ability to inhibit inappropriate responses in executive functions, provides information about selective attention under distracting conditions, and demonstrates frontal lobe functions in the brain.Before starting the test, the person is taught which buttons to press for 4 colors (1=yellow, 2=blue, 3=green, and 4=red).Then, the three-stage test begins: In the first stage, the person must identify the color of 24 colored circles appearing sequentially on the screen and press the correct key.In the second stage, the person must recognize only the color in which 24 neutral words of different colors appear sequentially on the screen and press the correct key.The third stage involves the most demanding task: words with color names written in different colors are displayed in sequence on the screen (for ex., the word "red" may be written in blue).The person is asked to focus on the color in which the word is written, not what the word says, and press the correct button

Functional near-infrared spectroscopy (fNIRS)

时间窗: Baseline and 8 weeks

Changes in blood flow in the prefrontal cortex related to executive functions will be assessed using functional near-infrared spectroscopy during a verbal fluency task. During the application, a total of 18 optodes will be placed on the dorsolateral prefrontal cortex (DLPFC). Each source/detector pair will be placed approximately 3 centimeters apart in accordance with the EEG 10-20 system. These optodes will be arranged into 24 channels using a soft neoprene cap. The phonemic verbal fluency test will be administered while the individual is wearing the cap, and data from the measurement during the test will be collected using the fNIRS control box and the connected computer. Thus, while the phonemic verbal fluency test is being administered, changes in the concentration of oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex will be recorded using the fNIRS device.

Verbal fluency test

时间窗: Baseline and 8 weeks

This test is used to evaluate various executive functions such as attention, semantic memory, information processing speed, task initiation, complex attention, and inhibition of inappropriate responses. The headset will be placed on the individual's head and the optode placement will be adjusted. Recording will then be performed using fNIRS, and a block design consisting of a total of three blocks for the letters 'K, A, S' will be used during the test. Each block covers a total of 140 seconds, consisting of a 10-second pre-rest period, a 60-second activation period, and a 70-second post-rest period. During the activation period, participants will be asked to generate as many words as possible beginning with a specific initial letter. Words should not be proper nouns, repetitions, or numbers. Digital recordings will be made, and the words spoken, their times of utterance, the number of incorrectly spoken words, and the number of repeated words will be recorded. The phonemic fluency sc

Brain-Derived Neurotrophic Factor

时间窗: Baseline and 8 weeks

Blood samples will be collected in biochemistry tubes before the first session and after the final session of the 8-week intervention. After 10 minutes of centrifugation, serum will be obtained and stored at -80°C until analysis. BDNF, a key neurotrophic factor for neuronal survival, differentiation, and synaptic plasticity, will be measured using the Human Free BDNF Quantikine ELISA Kit (R\&D Systems). The method is based on a sandwich ELISA principle to quantify serum BDNF levels. Venous blood is allowed to clot for 30-60 minutes, centrifuged at 1500-3000 rpm for 10-15 minutes, and stored at -80°C. Before analysis, samples are thawed and processed according to the kit protocol. After incubation, washing, and substrate steps, absorbance is read at 450 nm, and BDNF concentration is calculated from the standard curve. Duplicate measurements are recommended for reliability.