Multidimensional Study of Dyspnea at Rest, During Exertion, Self-induced Through a Virtual Reality Scenario, and Its Placebo Effect in Patients With COPD and Control Subjects.

Dyspnea is a complex and multidimensional symptom involving physiological, sensory, emotional, and cognitive components. In patients with chronic obstructive pulmonary disease (COPD), dyspnea is the most disabling symptom and is strongly associated with anxiety, reduced quality of life, and exercise intolerance. Current therapeutic approaches primarily target underlying physiological impairments; however, when these alterations are irreversible, central nervous system mechanisms become a relevant therapeutic target.

Emerging evidence suggests that dyspnea perception is modulated by higher cortical processes, particularly involving the prefrontal cortex, as well as by anticipatory mechanisms, emotional states, and prior experiences. Similar to pain, dyspnea is a subjective experience that can be influenced by cognitive and affective factors, including expectation and placebo effects. However, the neurophysiological mechanisms underlying these processes remain insufficiently understood.

This study aims to investigate dyspnea from a multidimensional and neuroscientific perspective by integrating physiological, neurophysiological, and psychological assessments. Specifically, the study evaluates prefrontal cortex activity using functional near-infrared spectroscopy (fNIRS), somatosensory profiles using quantitative sensory testing (QST), and sensorimotor responses during both rest and exertion.

Participants will undergo controlled dyspnea induction through inspiratory muscle loading, allowing standardized assessment of dyspnea perception. Additionally, the study incorporates immersive virtual reality (VR) scenarios designed to manipulate sensory input and expectations by dissociating visual and physical effort during cycling exercise. This approach enables the investigation of anticipatory neural mechanisms and their influence on dyspnea perception.

Furthermore, a placebo-controlled condition using high-flow nasal cannula (HFNC) will be implemented to explore expectation-driven modulation of dyspnea. Participants will be exposed to no support, simulated (placebo) HFNC, and active HFNC conditions, allowing the evaluation of placebo effects on respiratory perception and associated neurophysiological responses.

The study includes two groups: patients with moderate-to-severe COPD and age- and sex-matched healthy controls. This comparative design allows identification of differences in neural activation, somatosensory processing, and psychological modulation of dyspnea between populations.

By combining neuroimaging, sensory testing, and immersive technologies, this study seeks to advance understanding of the multidimensional mechanisms underlying dyspnea and to identify potential targets for innovative, non-pharmacological interventions aimed at improving symptom management and quality of life in patients with COPD.

Inclusion criteria

COPD:

• Diagnosed COPD (FEV1/FVC < 0.7 post-bronchodilator)
• GOLD stage 2-4
• Clinically stable
• Signed informed consent

Healthy subjects:

• Normal pulmonary function
• No chronic diseases
• Non-smoker or long-term ex-smoker

Exclusion criteria

COPD patients:

• Severe cardiac, neurological, or psychiatric disease
• Other respiratory diseases
• Recent exacerbation
• Use of ventilatory support (except CPAP)

Heatlhy subjects:

• Respiratory symptoms
• Recent infections
• Medication affecting respiratory function
• Substance abuse