Inspection time (IT) is a processing speed measure, recently investigated as a biomarker of ageing. This study examined whether earlier IT predicts subsequent problems in everyday functioning in community-dwelling elderly people.
Participants completed IT at baseline, 6 months and 18 months. At 42 months, two groups of 15 elderly people matched for education and age (74-88 years) and selected for slower or faster baseline IT, completed a fourth estimate of IT and a practical assessment of everyday functioning (Timed Instrumental Activities of Daily Living - Adelaide).
At 42 months, the group with slower baseline IT had significantly poorer performance (slower completion, higher errors) on more than half of the everyday functioning tasks.
Slower IT predicts difficulties up to 4 years later in everyday functioning of elderly adults, providing discriminant validation for IT as a biomarker for future changes.