Inspection time as a biological marker for functional age

"Tuesday 21 November 2006, Sydney Convention Centre, Darling Harbour, Sydney"--Cover.This paper presents a longitudinal investigation into the validity of Inspection Time (IT) as a biological marker of functional ageing. Within the field of cognitive ageing, speed of processing tasks show the largest decline with age, which makes them potentially informative as biomarkers. However, most speed tasks (e.g. reaction time and perceptual speed tasks) are problematic for use as biomarkers because they suffer from cohort effects and require a trade-off between speed and accuracy. IT is a psychophysical speed measure that does not suffer these problems. The use of IT allows the examination of speed of processing as a biomarker for functional age outcomes. This paper presents the first empirical research into this idea and the major goal was to determine whether the initial score and the change score for IT were important predictors of functional age outcome measures. One hundred and twenty seven elderly adults (70 – 91 years) completed a range of biomarkers (e.g. IT and grip strength), cognitive abilities tests (e.g. fluid and crystallised ability), everyday functioning and health questionnaires on three occasions over a period of 18-months. Results showed that the initial and the change score for IT were significant predictors of a number of outcomes including all three fluid ability tasks and independence of everyday living. Ultimately, it is hoped that IT could predict whether an individual is likely to experience decline in functioning in the subsequent two years but at this stage further research and replication is still required.Tess Gregor