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

Overview

The aim of this clinical study is to examine the effect of an 8-week training program applied to the respiratory muscles that enable breathing in individuals with obstructive sleep apnea syndrome on cognitive functions, oxygenation of brain tissue, and the brain's healing and adaptation processes. The main questions it aims to answer are: Does respiratory muscle training applied to individuals with obstructive sleep apnea syndrome have a beneficial effect on cognitive functions? Does respiratory muscle training applied to individuals with obstructive sleep apnea syndrome have a beneficial effect on brain oxygenation? Does respiratory muscle training applied to individuals with obstructive sleep apnea syndrome have a beneficial effect on the brain's healing and adaptation processes? A total of 42 individuals with obstructive sleep apnea syndrome will be included in the study. Researchers will compare the effectiveness of respiratory muscle training on individuals with obstructive sleep apnea syndrome by comparing the respiratory muscle training intervention with placebo (low-intensity respiratory muscle training) and usual care. At the beginning of the study, participants' demographic data will be recorded, they will be assessed, their blood will be drawn, and they will be asked to complete a questionnaire. Participants will be given an information brochure and a weekly follow-up form in addition to the necessary medical treatment. Participants will receive the necessary medical treatment for 8 weeks, fill out the follow-up form provided every day and send it to the researcher once a week, perform inspiratory muscle training exercises for 8 weeks, and meet face-to-face with the researcher once a week. The follow-up form will be checked every week. All assessments will be repeated at the end of the study.

Interventions

• Device inspiratory muscle training
  In addition to the control group, IMT will be applied for 8 weeks, 7 days a week, twice a day for 15 minutes (30 breaths/3 sets/1-minute break between sets).The intensity of the training provided in IMT will be gradually increased over the 8 weeks.Before starting the training, patients' mouth pressure (MIP) will be measured and the training workload will be determined. During the first 2 weeks of training, 50% of MIP will be applied as the workload, 60% of MIP during weeks 3 and 4, and 75% of MI
• Device Placebo inspiratory muscle training
  In addition to the control group, inspiratory muscle training at 15% of MIP will be administered twice daily for 15 minutes (30 breaths/3 sets/1-minute rest between sets) for 7 days a week over an 8-week period. Patients will be given treatment diaries and asked to mark their sessions and send these diaries to the physical therapist once a week.
• Other Usual Care
  Individuals will receive standard medical treatment. They will be informed about their illnesses, what they need to do, and what they need to be mindful of. A disease-specific informational brochure and a follow-up form will be provided.

Primary outcome measures

• Digit Span Test [Time frame: Baseline and 8 weeks]
• Montreal Cognitive Assessment Scale [Time frame: Baseline and 8 weeks]
• Oktem Verbal Memory Processes Test [Time frame: Baseline and 8 weeks]
• Stroop Test [Time frame: Baseline and 8 weeks]
• Functional near-infrared spectroscopy (fNIRS) [Time frame: Baseline and 8 weeks]
• Verbal fluency test [Time frame: Baseline and 8 weeks]
• Brain-Derived Neurotrophic Factor [Time frame: Baseline and 8 weeks]

Secondary outcome measures (11)

• Respiratory muscle strength [Time frame: Baseline and 8 weeks]
• Respiratory muscle endurance [Time frame: Baseline and 8 weeks]
• Respiratory function test [Time frame: Baseline and 8 weeks]
• Increasing Speed Shuttle Walk Test [Time frame: Baseline and 8 weeks]
• Biochemical analyses: Oxidative Stress [Time frame: Baseline and 8 weeks]
• Daytime Sleepiness Assessment: Epworth Sleepiness Scale (ESS) [Time frame: Baseline and 8 weeks]
• Sleep quality: Actigraphy [Time frame: Baseline and 8 weeks]
• Pittsburgh Sleep Quality Index (PSQI) [Time frame: Baseline and 8 weeks]
• Anxiety and depression: Hospital Anxiety and Depression Scale (HADS): [Time frame: Baseline and 8 weeks]
• Fatigue Severity Scale [Time frame: Baseline and 8 weeks]
• Quality of life assessment: Functional Outcomes of Sleep Questionnaire (FOSQ) [Time frame: Baseline and 8 weeks]

Eligibility criteria

Inclusion criteria

• Patients diagnosed with moderate OSA using polysomnography
• Aged 18-60
• Not using non-invasive mechanical ventilation (NIMV)
• General health status is stable (The participant does not have an acute -cardiovascular, respiratory, metabolic, or neurological disease; has not experienced a condition requiring hospitalization in the last three months)
• No mental problems that would interfere with cooperation

Exclusion criteria

• History of oropharyngeal surgery
• Presence of any neurological, psychological, or cardiac disease
• BMI ≥40 kg/m²
• Presence of hypothyroidism, uncontrolled hypertension, and diabetes
• Having severe obstructive nasal disease
• Being pregnant
• Having cognitive problems
• Having overlap syndrome
• Using drugs, alcohol, sedatives, and hypnotic medications

Exclusion criteria after the study began:

• Exercise group participants with <75% attendance at training sessions
• Failure to attend sessions for 2 consecutive weeks during the treatment period

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Cheng YY, Lin SY, Hsu CY, Fu PK. Respiratory Muscle Training Can Improve Cognition, Lung Function, and Diaphragmatic Thickness Fraction in Male and Non-Obese Patients with Chronic Obstructive Pulmonary Disease: A Prospective Study. J Pers Med. 2022 Mar 16;12(3):475. doi: 10.3390/jpm12030475. PMID 35330474
• Ferreira L, Tanaka K, Santos-Galduroz RF, Galduroz JC. Respiratory training as strategy to prevent cognitive decline in aging: a randomized controlled trial. Clin Interv Aging. 2015 Mar 20;10:593-603. doi: 10.2147/CIA.S79560. eCollection 2015. PMID 25848235
• Souza AKF, Dornelas de Andrade A, de Medeiros AIC, de Aguiar MIR, Rocha TDS, Pedrosa RP, de Lima AMJ. Effectiveness of inspiratory muscle training on sleep and functional capacity to exercise in obstructive sleep apnea: a randomized controlled trial. Sleep Breath. 2018 Sep;22(3):631-639. doi: 10.1007/s11325-017-1591-5. Epub 2017 Nov 9. PMID 29124630
• Nobrega-Junior JCN, Dornelas de Andrade A, de Andrade EAM, Andrade MDA, Ribeiro ASV, Pedrosa RP, Ferreira APL, de Lima AMJ. Inspiratory Muscle Training in the Severity of Obstructive Sleep Apnea, Sleep Quality and Excessive Daytime Sleepiness: A Placebo-Controlled, Randomized Trial. Nat Sci Sleep. 2020 Dec 2;12:1105-1113. doi: 10.2147/NSS.S269360. eCollection 2020. PMID 33293881

Identifiers

NCT: NCT07329049 · 2025/1362

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗