Objective measurement of frequency and pattern of nocturnal cough in children with asthma exacerbation

Abstract Background Although a number of patients with asthma report experiencing persistent cough during sleep, it has not yet been objectively investigated. Objective To classify cough severity and evaluate a characteristic pattern of cough frequency in children with asthma using an objective cough monitoring system. Methods An objective cough monitoring system that specialized in children was used to measure cough frequency and nocturnal cough patterns. Coughs were recorded with microphone and accelerometer and analyzed using a customized software program. The number of nocturnal coughs and the pattern of cough frequency in 30-minute intervals were measured along with the severity of each asthma exacerbation, and the results were compared with children without asthma. Results The total overnight cough count of 34 children with asthma was higher than that of 15 children without asthma ( P < .001). The total overnight cough count in children with severe asthma exacerbation was higher than that in children with moderate asthma exacerbation ( P < .05). The cough counts were significantly increased at the time of falling asleep and waking. This pattern was not observed in children without asthma. The total cough counts and cough patterns in children with asthma were not affected by sex, age, cause of asthma exacerbation, or therapy. Conclusion Our data indicate huge cough counts and characteristic nocturnal cough patterns in children with asthma. Objective and precise cough monitoring is useful for the management of childhood asthma.