著者

Isato FUKUSHI Yasumasa OKADA

出版者

Japanese Society for Brain Function and Rehabilitation

雑誌

Journal of Rehabilitation Neurosciences (ISSN:24342629)

巻号頁・発行日

vol.19, no.1, pp.22-32, 2019 (Released:2019-10-25)

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Dyspnea is defined as “a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity”. In patients especially with pulmonary diseases, dyspnea reduces daily activity, which worsens the physical condition, and thereby further increases dyspnea, forming a vicious cycle. In clinical practice, reduction of dyspnea in patients with diseases is crucial. One of the goals in pulmonary rehabilitation is reduction of dyspnea to break the above-mentioned vicious cycle. However, the mechanism of dyspnea perception has not been fully elucidated because it is complex and is not explained by a single factor such as changes in blood gas. Not all patients with chronic respiratory failure with hypercapnia are dyspneic, or not all patients with COPD with severe hypoxemia perceive dyspnea. To date, sufficiently effective methods to relieve dyspnea have not been established. We integrated the theories which explain the mechanisms of dyspnea perception with our considerations from the viewpoint of respiratory neurophysiology, and propose a model of dyspnea perception mechanism. In our model, dyspnea results from disassociation or mismatch between the neural respiratory motor output from the respiratory neural network in the lower brainstem and the actually accomplished ventilation. The projection modality of neural information on dyspnea to the higher sensory center of the brain, and the brain regions for comparison of the intended respiratory neural output from the brainstem respiratory center and the monitored actual ventilatory output remain unknown. Further clarification of these issues will enlighten understanding of the pathophysiology of dyspnea and contribute to more effective practice of pulmonary rehabilitation.