The goal of this clinical trial is to evaluate whether dual-task inspiratory muscle training (IMT) is effective in improving cognitive and functional outcomes in adults with heart failure. It will also assess the effects of standard IMT and compare both approaches. The main questions it aims to answer are: * Does dual-task IMT improve cognitive function more than standard IMT or no intervention? * Does dual-task IMT improve respiratory function, inspiratory muscle strength, and exercise capacity? * What are the effects of dual-task IMT on symptoms such as dyspnea and fatigue, and on quality of life, anxiety, and depression? Dual-task IMT, standard IMT, and a control group (no additional intervention) will be compared to determine which approach is more effective in patients with heart failure (HF). Participants will: * Be randomly assigned to one of three groups: dual-task IMT, standard IMT, or control * Perform IMT training 5 days per week for 8 weeks (2 sessions per day, 15 minutes each) if assigned to an intervention group * Complete 1 supervised in-person session per week and 4 sessions via telerehabilitation if assigned to an intervention group * Undergo assessments before and after the 8-week intervention, including cognitive tests, respiratory function, exercise capacity, and symptom evaluations
HF is a complex clinical syndrome associated with reduced functional capacity and a high prevalence of cognitive impairment, which negatively affects prognosis and quality of life. Inspiratory muscle weakness is also common in HF and is associated with increased dyspnea and reduced exercise tolerance. The IMT has been shown to improve respiratory and functional outcomes; however, its effects on cognitive function remain unclear. Dual-task approaches, involving the simultaneous performance of motor and cognitive tasks, have been suggested to enhance neurocognitive integration and improve both cognitive and functional performance. Despite this, the effects of IMT applied within a motor-cognitive dual-task framework in HF patients have not been sufficiently investigated. This study is designed as a prospective, randomized controlled, single-blind trial. A total of 54 patients with heart failure will be included and randomly assigned to three groups: control, standard IMT, and dual-task IMT. Both intervention groups will receive IMT at 50% of maximal inspiratory pressure (MIP) for 8 weeks, 5 days per week, 2 sessions per day (15 minutes each). One session per week will be supervised, and the remaining sessions will be conducted via telerehabilitation (4 days/week, 2 sessions per day). Training intensity will be adjusted weekly. In the dual-task IMT group, cognitive tasks targeting attention, memory, and executive functions will be performed simultaneously with IMT. Assessments will be performed before and after the intervention. Primary outcomes will include cognitive function, while secondary outcomes will include respiratory function, inspiratory muscle strength and endurance, exercise capacity, dyspnea, fatigue, nitric oxide levels, frailty, physical performance, quality of life, and psychological status. This study aims to determine the effectiveness of dual-task IMT compared to standard IMT and control conditions, and to provide evidence for integrated rehabilitation approaches in patients with HF.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
54
IMT will be applied using a threshold loading device at 50% of MIP for 8 weeks (5 days/week, 2 sessions/day, 15 minutes each). One session per week will be supervised, and the remaining sessions will be performed via telerehabilitation. During IMT, participants will simultaneously perform cognitive tasks targeting attention, memory, and executive functions, which will be varied weekly to minimize learning effects.
IMT will be applied using a threshold loading device at 50% of MIP for 8 weeks (5 days/week, 2 sessions/day, 15 minutes each). One session per week will be supervised, and the remaining sessions will be performed via telerehabilitation. No additional cognitive task will be applied during training.
Istanbul University-Cerrahpaşa, Cardiology Institute
Istanbul, Fatih, Turkey (Türkiye)
RECRUITINGGlobal cognitive function
Global cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA), 0-30 point screening tool evaluating multiple cognitive domains including attention, memory, executive functions, visuospatial abilities, and language. Higher scores indicate better cognitive performance. The assessment will be administered by a certified physiotherapist.
Time frame: Baseline and 8 weeks (post-intervention)
Subjective cognitive function
Subjective cognitive function will be assessed using the Cognitive Failures Questionnaire (CFQ), which evaluates perceived cognitive performance over the past 6 months. The questionnaire consists of 25 items rated on a 5-point Likert scale (0-4), with total scores ranging from 0 to 100. Higher scores indicate greater perceived cognitive impairment.
Time frame: Baseline and 8 weeks (post-intervention)
Attention and executive function
Attention and executive function will be assessed using a Stroop Test (The Scientific and Technological Research Council of Türkiye, Basic Sciences Research Group version), a standardized tool evaluating selective attention, cognitive flexibility, and psychomotor speed. The test consists of five sections, and completion time, as well as the number of correct and incorrect responses, will be recorded for each section. Longer completion times and higher error rates indicate poorer performance.
Time frame: Baseline and 8 weeks (post-intervention)
Verbal memory
Verbal memory will be assessed using the Öktem Verbal Memory Processes Test, which evaluates different components of verbal memory including learning, delayed recall, and recognition. The test involves repeated presentation of a target word list, followed by delayed recall and recognition tasks. Performance will be quantified using learning, spontaneous recall, and recognition scores. The learning score reflects total words recalled across repeated trials (maximum 15). Spontaneous recall is assessed approximately 40 minutes after the learning phase, during which participants are asked to recall the words without cueing. Recognition performance is based on identifying previously presented words among distractors. Higher scores indicate better verbal memory performance.
Time frame: Baseline and 8 weeks (post-intervention)
Reaction time
Reaction time will be assessed using a BlazePod reaction kits. Participants, seated in front of a table, will respond to randomly illuminated light stimuli by tapping the lights as quickly as possible for 30 seconds using one hand. The system consists of four reaction pods positioned in a straight line at 20 cm intervals. Outcome measures will include total number of hits, total reaction time, and mean reaction time per stimulus. Missed responses will be recorded when the light deactivates before being tapped within 4 seconds. Lower reaction time indicates better performance.
Time frame: Baseline and 8 weeks (post-intervention)
Forced vital capacity
Forced vital capacity (FVC) will be assessed using spirometry according to American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. It will be recorded from three acceptable maneuvers performed in a seated position, and the highest value will be used for analysis.
Time frame: Baseline and 8 weeks (post-intervention)
Forced expiratory volume in 1 second (FEV1)
Forced expiratory volume in 1 second (FEV1) will be assessed using spirometry according to ATS/ERS guidelines. It will be recorded from three acceptable maneuvers performed in a seated position, and the highest value will be used for analysis.
Time frame: Baseline and 8 weeks (post-intervention)
FEV1/FVC
FEV1/FVC ratio will be assessed using spirometry according to ATS/ERS guidelines. It will be recorded from three acceptable maneuvers performed in a seated position, and the highest value will be used for analysis.
Time frame: Baseline and 8 weeks (post-intervention)
Peak expiratory flow
Peak expiratory flow (PEF) will be assessed using spirometry according to ATS/ERS guidelines. It will be recorded from three acceptable maneuvers performed in a seated position, and the highest value will be used for analysis.
Time frame: Baseline and 8 weeks (post-intervention)
Forced expiratory flow at 25-75% of FVC
Forced expiratory flow at 25-75% of FVC (FEF25-75) will be assessed using spirometry according to ATS/ERS guidelines. It will be recorded from three acceptable maneuvers performed in a seated position, and the highest value will be used for analysis.
Time frame: Baseline and 8 weeks (post-intervention)
Maximal inspiratory pressure
Maximal inspiratory pressure (MIP) will be assessed using a portable electronic mouth pressure device (MicroRPM; Micro Medical, UK), according to ATS/ERS guidelines. It will be measured in the seated position using a mouthpiece with nasal occlusion. Participants will perform maximal inspiratory effort for at least 2 seconds against an occluded airway. The highest value from three acceptable maneuvers with \<10% variability will be recorded in cmH₂O and as a percentage of predicted values using Black and Hyatt reference equations. Higher values indicate better inspiratory muscle strength.
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Time frame: Baseline and 8 weeks (post-intervention)
Maximal expiratory pressure
Maximal expiratory pressure (MEP) will be assessed using a portable electronic mouth pressure device (MicroRPM; Micro Medical, UK), according to ATS/ERS guidelines. It will be measured in the seated position using a mouthpiece with nasal occlusion. Participants will perform maximal expiratory effort for at least 2 seconds against an occluded airway. The highest value from three acceptable maneuvers with \<10% variability will be recorded in cmH₂O and as a percentage of predicted values using Black and Hyatt reference equations. Higher values indicate better expiratory muscle strength.
Time frame: Baseline and 8 weeks (post-intervention)
Respiratory muscle endurance
Respiratory muscle endurance will be assessed using a constant-load threshold loading test with a pressure threshold device (POWERbreathe Classic Light Resistance, POWERbreathe International Ltd., UK). The test will be performed at 60% of MIP. Participants will breathe through the device for up to 10 minutes, and endurance will be recorded as the time sustained (seconds) and achieved pressure load (cmH₂O). Higher endurance time indicates better respiratory muscle endurance.
Time frame: Baseline and 8 weeks (post-intervention)
Exercise capacity
Exercise capacity will be assessed using the 6-minute walk test (6MWT) according to ATS guidelines. Participants will be instructed to walk as far as possible for 6 minutes along a 30-meter corridor at a self-paced speed. A standardized rest period will be provided prior to testing. Total walking distance will be recorded in meters. Higher walking distance indicates better exercise capacity.
Time frame: Baseline and 8 weeks (post-intervention)
Dyspnea
Dyspnea will be assessed using the Modified Medical Research Council (mMRC) Dyspnea Scale, a 0-4 point scale based on the level of physical activity that induces breathlessness. Higher scores indicate greater severity of dyspnea.
Time frame: Baseline and 8 weeks (post-intervention)
Fatigue
Fatigue will be assessed using the Fatigue Severity Scale (FSS), a 9-item scale evaluating fatigue severity over the past week. Each item is rated on a 7-point Likert scale (1-7), and the total score is calculated by averaging item scores. A score ≥4 indicates severe fatigue. Higher scores indicate greater fatigue severity.
Time frame: Baseline and 8 weeks (post-intervention)
Fractional exhaled nitric oxide
Fractional exhaled nitric oxide (FeNO) will be measured using a NObreath® device (Bedfont Scientific Ltd., UK) according to the ATS guidelines. Measurements will be performed with controlled expiratory flow, and mean values will be recorded. Participants will perform controlled exhalation at a constant flow rate (50 mL/s) following standardized pre-test conditions. The mean of two acceptable measurements will be recorded as FeNO (parts per billion, ppb).
Time frame: Baseline and 8 weeks (post-intervention)
Frailty
Frailty will be assessed using the Edmonton Frail Scale, a 17-point scale evaluating multiple domains including cognition, general health status, functional independence, and social support. Scores range from 0 to 17, with higher scores indicating greater frailty severity.
Time frame: Baseline and 8 weeks (post-intervention)
Physical performance
Physical performance will be assessed using the Short Physical Performance Battery (SPPB), including balance tests, 4-meter gait speed, and chair stand tests. Total scores range from 0 to 12, with higher scores indicating better performance.
Time frame: Baseline and 8 weeks (post-intervention)
Quality of life (QoL)
Quality of life will be assessed using the Minnesota Living with Heart Failure Questionnaire, a 21-item disease-specific scale evaluating the physical and emotional impact of the disease over the past 4 weeks. Each item is scored from 0 to 5, with total scores ranging from 0 to 105. Higher scores indicate worse quality of life.
Time frame: Baseline and 8 weeks (post-intervention)
Anxiety and depression
Anxiety and depression will be evaluated using the Hospital Anxiety and Depression Scale (HADS), a 14-item questionnaire with two subscales assessing anxiety and depression. Each subscale ranges from 0 to 21, with higher scores indicating greater symptom severity.
Time frame: Baseline and 8 weeks (post-intervention)