[Polygraphic study during hyperpnea tests in elderly subjects (author's transl)].

The incidence of age on the frequency of post-hyperventilation apnea was studied in two randomly chosen distinct populations. The hyperpnea and ventilatory response were recorded during a standard E.E.G. tracing in 1 060 subjects by a thermistor and in 100 other subjects by pneumotachography and capnography. Post-hyperventilation frequency was determined for the two populations taken overall and then for subjects under and over 60 years of age. The results were compared with demographic data (sex, excess bodyweight coefficient, illness), and experimental conditions (alertness, recording technique). In the second population the mean ventilation per minute rate was calculated during a reference rest period and two successive hyperventilation tests. The frequency of post-hyperventilation apnea is higher before 60 years of age in the absence of variations in alertness and/or associated supramedullary lesions. Ventilatory response under 60 years of age is seen as a prolonged phase of hypoventilation. After 60 years of age, in the absence of apnea, ventilation returns immediately to its reference value, while in the presence of apnea the hypoventilatory phase observed is of brief duration and delayed. These results are discussed and compared to those in the published literature.