The researchers assessed the frequency of breathing
disturbances, the time spent in each sleep state, the number of nighttime awakenings, and the duration of sleep.
In the study, the CPAP mask was attached to equipment that measured the frequency of breathing
and the depth of breathing.
Results: Five factors grouped different attributes of dyspnea: urge to breathe, depth and frequency of breathing
, difficulty breathing and phase of respiration, wheezing, and affective dyspnea.