Kral, who first wrote informatively on this type of memory disturbance 50 years ago, referred to it as benign senescent forgetfulness. He pointed out that such a memory disturbance, in distinction to that of Alzheimer disease, worsens very little or not at all over a period of many years and does not interfere significantly with the person’s work performance or activities of daily living. Crook and coworkers have refined the diagnostic criteria for senescent forgetfulness and proposed the term age-associated memory impairment (AAMI). The diagnostic criteria for AAMI include age of 50 years or older, a subjective sense of decline in memory, impaired performance on standard tests of memory function (at least one SD below the mean), and absence of any other signs of dementia. The current terminology is minimal cognitive impairment, but there has been increasing recognition that Kral’s original notion of a benign condition may have been incorrect and that cognitive decline in later years may be a premonitory symptom of Alzheimer disease.
In judging the degree of cognitive decline, several abbreviated tests of mental status have been developed and are of practical value (Kokmen et al, 1991; Folstein et al) in that they can be administered in the office or at the bedside in 5 to 10 min. Repetition of spoken items, such as a series of digits, orientation as to place and time, capacity to learn and to retain several items, tests of arithmetic and calculation (concentration), and specific tests for memory (particularly tests of delayed recall or forgetfulness) distinguish the performance of normal aging persons from that of patients with Alzheimer disease (Larrabee et al). With regard to performance on the Mini-Mental Status Examination (MMSE, range 0 to 30 with higher scores signifying better performance), a study by Crum and associates of a large urban population indicates a median score of 19 to 20 for individuals older than age 80 years who have a fourth grade education and 27 for those with a college education (out of maximum score of 30). A similar Montreal Cognitive Assessment has become popular in recent years (MOCA, range 0 to 30 with higher scores being better). Many other scales have been devised that detect cognitive decline with age, most conceived for the purpose of clinical trials, but they do not find much use in daily practice.
The foregoing effects of age on mental abilities are extremely variable. Some 70-year-olds perform better on psychologic testing than some “normal” 20-year-olds. And a few individuals retain exceptional mental power and perform creative work until late life. Verdi, for example, composed Otello at the age of 73 and Falstaff at 79.
Humboldt wrote the 5 volumes of his Kosmos between the ages of 76 and 89 years; Goethe produced the second part of Faust when he was more than 70 years old; Galileo, Laplace, and Sherrington continued to make scientific contributions in their eighth decades; and Picasso continued to paint in his nineties. It must be pointed out, however, that these accomplishments were essentially continuations of lines of endeavor that had been initiated in early adult life. Indeed, from general observation it can be concluded that little that is truly new and original to the individual is started after the 50th year. High intelligence, well-organized work habits, and sound judgment compensate for many of the progressive shortcomings of old age.
Personality Changes in the Aged