Psychomotor speed in a random sample of 7,979 subjects aged 30 years and over

Slowing of psychomotor speed among older individuals has been shown in numerous studies. However, in most cases these studies were based on small and selected groups of people and, in some cases, the test procedures did not allow separation of decision time and motor components of the overall performance. The purpose of the present study was to analyse in a large, randomly selected population sample the differences in decision and movement times in simple and multiple-choice test conditions. The association of educational background with psychomotor speed was also examined.

Data on psychomotor speed were collected from a representative nation- wide sample of the Finnish population aged 30 years and over (n=7979) with the help of a computerized device in simple and multiple-choice test conditions, with visual stimuli. Background information (education) was collected by a structured interview.

Results showed a systematic and significant decline in both decision time and movement time when proceeding from the youngest (30-39-year-olds) to the oldest (80+ yrs) age groups. This decline was more pronounced in the multiple-choice test than in the simple test. In both test conditions, movement times were shorter in men than in women. In the young and middle-aged groups, participants with longer formal education were faster than the less educated subjects.

On the basis of the large representative random sample of this study, it may be concluded that decline in psychomotor speed during aging can already be seen at a quite young age. Decline accelerates after the age of about 70. Differences in socio-economic background factors, such as education, may modify the differences observed between younger and older individuals. These results emphasize the need for the separation of decision time and movement time in psychomotor speed tests, when differences between age groups as well as between men and women are analysed.