The impact of healthy ageing on dual task performance using a novel dual task paradigm: Implications for clinical use in Alzheimer’s disease.

Abstract Primary objective: To explore the impact of healthy ageing on dual tasking abilities using a novel dual task paradigm and to consider any clinical implications in aiding the diagnosis of Alzheimer’s disease (AD). Secondary objective: To contribute to the theoretical understanding of the central executive. Research design: A cross-sectional research design was implemented to determine the impact of age on dual task performance using healthy participants. A correlational research design to identify relationships between dual tasking and other executive functions was also used. Methods and Procedures: Fifty participants aged between 19-86 years were assessed on their ability to dual task under ‘speeded’ (flashing) and ‘non-speeded’ (disc) conditions. To assess dual task performance, digit recall and a novel visuo-spatial tracking task were both performed initially as single tasks and then concurrently as dual tasks. Calibration of the individual tasks was carried out first to ensure titration across groups. Other cognitive function tests were administered assessing memory, crystallized intelligence and three executive functions of switching, inhibition and updating. Main results: No age effect was detected in the ability to dual task whether under ‘speeded’ (flashing) or ‘non-speeded’ (disc) conditions. However, a significant group difference in single task performance for digit recall was observed. Dual tasking was not found to be correlated with either measures of switching and updating but a correlation between the ‘speeded’ dual task condition and Inhibition was revealed. No correlations between the executive measures of switching and updating were reported and an age effect was revealed for the inhibition and updating measures only. Conclusions: The calibration process for the digit recall task must be replicated before this promising dual task paradigm can be evaluated as a possible diagnostic aid for AD. Results of the correlational analysis support theories that have attempted to fractionate the central executive