%0 Journal Article
%T Relationship between Respiratory Load Perception and Perception of Nonrespiratory Sensory Modalities in Subjects with Life-Threatening Asthma
%A Kathleen L. Davenport
%A Chien Hui Huang
%A Matthew P. Davenport
%A Paul W. Davenport
%J Pulmonary Medicine
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/310672
%X 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¨C20£¿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. 1. Introduction Asthma is a respiratory disease frequently diagnosed in childhood. To control and/or prevent an asthma attack, it is important for the patient to heed initial symptoms and to be compliant with their prescribed medication(s). Failure to recognize and self-manage of an asthma exacerbation is one cause of life-threatening asthma (LTA) [1¨C3]. Difficulty in perceiving asthma symptoms can be one of many factors causing the patient to fail to recognize the onset of an asthma attack [2, 4, 5]. A subpopulation of asthmatic patients with a history of LTA has been reported with reduced perception of both intrinsic and extrinsic respiratory loads [2, 4]. These LTA asthmatic patients have an increased threshold for detection of inspiratory resistive loads, a decreased ability to scale the magnitude of inspiratory loads and a decreased perception of intrinsic bronchoconstriction [2, 4]. It has also been reported that the somatosensory cortex is not activated by inspiratory loads in these LTA subjects suggesting a sensory neural deficit in respiratory information processing in this subpopulation of asthmatic patients [1]. While it is evident that these LTA subjects have
%U http://www.hindawi.com/journals/pm/2012/310672/