The Effect of Aging and of the Development of Disease on the Ballistocardiogram

Second ballistocardiograms were taken on 80 subjects who were part of the series from which the original normal standards were secured in 1937, 1938 and 1939. Sixty-five of these subjects had retained good health during the long interval; by a comparison between their old and new records, the effect of "normal" aging on the ballistocardiogram has been determined. Fifteen subjects lost their health during the interval and two of them have died since the second test. The evolution of their ballistocardiograms has been compared with the development of their disabilities.