Dr. Bä:ckman and Colleagues Reply

To the Editor: We accept the premise of Oliver French, M.D., that the definition of very old age is far from an exact science. Like many other classificatory labels, determining which individuals fit the category and which do not is a relativistic matter. Neugarten (1) was among the first to differentiate between specific segments of the aging population, making the distinction between the “young-old” (55–74 years) and the “old-old” (75-plus years). More recently, authors have referred to individuals above 85 years as the “oldest-old” (2), and centenarians, those who are 100 years and older, have received some empirical attention (3). Thus, terms such as “old” or “very old” are not static entities. Their meanings vary across time and cultures. As the life expectancy continues to increase because of changes in medical technology and lifestyle behaviors (4), and with the advent of possible means to extend the human life span by means of chromosomal modification (5), the definition of very old age is likely to be altered in the near future.

Even finding a clear-cut operational definition of very old age at a given point in time may be difficult, because this segment of the population is characterized by such large interindividual variability—biological, cognitive, and social (6). Although our use of the term “very old age” largely reflects conventions within our specific domain of research, we take some comfort in noting that the average life span for men varies between 69 and 77 years in the industrialized countries at present; the corresponding figures for women range between 77 and 82 years (7). The mean age in our study group was 83.2 years. Thus, the term we used would not seem to be completely out of bounds.

We finally note that Dr. French’s cousin carries a much more pessimistic view of late life than is scientifically justified. It is not “all downhill” after age 75! It is true that various biological and cognitive functions decline as part of the normal aging process and that several diseases known to be detrimental to psychological functioning (e.g., dementia) increase dramatically in advanced age (8). It is equally true, however, that many individuals who live into their 80s and above are not fundamentally different from what they were 30 years earlier. Studies of memory in individuals carefully screened for health indicate minimal losses from the 70s through the 90s (9); the prevalence of depression does not increase in late life (10); the majority of healthy elderly adults benefit greatly from cognitive interventions (11); and life satisfaction appears to remain stable or increase rather than decrease from midlife through old age (12), to mention a few among several possible examples. Thus, although the remarkable accomplishments in late life by Sophocles, Picasso, and Rubinstein may represent extreme points on a continuum, the relative maintenance of functioning in old age exhibited by these individuals is shared by a substantial proportion of the population at large.