H. Folgering, ed. / Respirator)
FEEDBACK
J. GALLEGO, G. VARDON Laboratoire
psychophysioloa
AND PACING IN VENTILATORY
J. ANKAOUA, M. LETHIELLEUX, and C. JACQUEMIN
de Physiologic Respiratoire,
abstract, I985
1x7
LEARNING
B. CHAMBILLE,
lJniversit6 Plerre et Marie Curie, Paris cedex 06, France
Breathing retraining has been used for many years as a treatman in chronic obstructive pulmonary disease. In some cases, the aim of this training is to slow down the respiratory rate, while increasing the tidal volume, in order to increase alveolar ventilation. It has often been considered that long-term objective benefit was little, but this method could probably be improved if more was discovered about ventilatory learning per se, independently from clinical applications. The purpose of this study was to compare two procedures of ventilatory learning in 40 normal subjects. The first procedure (Feedback, denoted F) consisted in informing the subject of inspiratory duration (T,) after each inspiration and to instruct him to maintain this T,-value between two limits previously established by the experimenter, and visible by the subject. The second procedure (Synchronization, or pacing, denoted S) consisted in delivering the subject a periodic signal and instructing him to adjust his repiratory rate to this signal. The target value of T, was computed independantly for each subject, according to his particular breathing parameters; the same formula was used for all subjects. The 40 subjects were randomly assigned to five experimental groups. By combining each of the two learning sessions with the two procedures, four learning groups were determined: the fifth was a control group. A retention test, consisting in comparing performances between the two sessions, was performed. Learning was also estimated as the gain in capability in one of the task (for instance, F), as a result of practice in the other task (transfer test). The conclusions were the following: (a) Performances were more affected by the feedback procedure than by synchronization. (b) Feedback was the only procedure where retention was proved. (c) No transfer from one task to the other was observed. (d) When no instructions concerning tidal volume are given, increasing T, during voluntary controlled breathing produces an increase in V,, showing a correlation between these two variables. This correlation (already observed during spontaneous breathing) does not seem to be related to any homeostatic function.