Pilot study of objective cough monitoring in infants

Cough is common in childhood, resulting insignificant morbidity and frequent medical consultation. Despite this, little is known about the frequency or development of cough, particularly in infants and young children. Recent progress in monitoring has enabled cough to be measured objectively both day and night. However, to date, objective measurement has only been used in adults and older children. The aim of this study was to see whether such methods could be extended to allow objective cough monitoring in infants. Thirty infants were recruited: 13 with coughing illnesses (group 1), and 17 normal, healthy babies (group 2) born to nonatopic, nonsmoking parents. Group 2 infants were studied when well, several times in the first year of life. Coughs were recorded using an adapted commercial cough monitor (Logan Research LR100) and simultaneous infrared video and sound recording. Thirty-eight recordings with simultaneous cough monitor and video data were analyzed: 9 from group 1, and 29 from group 2. Overall, the sensitivity of the monitor when compared to video was 81%, with a positive predictive value of 0.8. There was good agreement between the two methods for infants with infrequent cough (<5 coughs per hour). Agreement in infants with more frequent cough was not as good, because more coughs were consistently identified by the cough monitor. The portability and small size of the cough monitor made it easy to use, although there were difficulties in keeping the leads attached in older, more mobile infants. In conclusion, objective assessment of cough is practical in infants, enabling the pattern of cough in illness and in health to be studied further.