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Pulmonary Medicine
Volume 2012, Article ID 310672, 7 pages
Clinical Study

Relationship between Respiratory Load Perception and Perception of Nonrespiratory Sensory Modalities in Subjects with Life-Threatening Asthma

1Department of Rehabilitation Medicine, University of Washington, 1959 Northeast Pacific Street, P.O. Box 356490, Seattle, WA 98195, USA
2Department of Physical Therapy, Tzu Chi University, 701 Zhongyang Road, Section 3, Hualien 97004, Taiwan
3Department of Chemistry and Food Science, Framingham State University, 100 State Street, Framingham, MA 01701, USA
4Department of Physiological Sciences, University of Florida, P.O. Box 100144 HSC, Gainesville, FL 32610, USA

Received 4 November 2011; Revised 12 April 2012; Accepted 18 April 2012

Academic Editor: Dimitris Georgopoulos

Copyright © 2012 Kathleen L. Davenport et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Subjects with life-threatening asthma (LTA) have reported decreased sensitivity to inspiratory resistive (R) loads. It is unknown if decreased sensitivity is specific for inspiratory R loads, other types of respiratory loads, or a general deficit affecting sensory modalities. This study hypothesized that impairment is specific to respiratory stimuli. This study tested perceptual sensitivity of LTA, asthmatic (A), and nonasthmatic (NA) subjects to 4 sensory modalities: respiratory, somatosensory, auditory, visual. Perceptual sensitivity was measured with magnitude estimation (ME): respiratory loads ME, determined using inspiratory R and pressure threshold (PT) loads; somatosensory ME, determined using weight ranges of 2–20 kg; auditory ME, determined using graded magnitudes of 1 kHz tones delivered for 3 seconds bilaterally; visual ME, determined using gray-to-white disk intensity gradations on black background. ME for inspiratory R loads lessened for LTA over A and NA subjects. There was no significant difference between the 3 groups in ME for PT inspiratory loads, weight, sound, and visual trials. These results demonstrate that LTA subjects are poor perceivers of inspiratory R loads. This deficit in respiratory perception is specific to inspiratory R loads and is not due to perceptual deficits in other types of inspiratory loads, somatosensory, auditory, or visual sensory modalities.