Are all stops truly equal? Inhibitory control distinctions in older adults

Being able to resist temptations, ignore distractions, and stop actions is vital in everyday life. These stopping abilities have been considered a single cognitive process called ‘inhibitory control’, but distinct processes may occur depending on the demands of the situation. Twenty-six older adults (M_age = 73.2 years), including three diagnosed with amnestic mild cognitive impairment (aMCI) and one with Alzheimer’s Disease (AD), completed a series of four commonly used inhibitory control tasks. It was hypothesised the relationships between results from these tasks would not support a single latent factor of inhibitory control. Correlations between tasks were generally low and a one-factor model did not fit the data. It was also expected that there would be fatigue and sequence effects in the older adults due to the number of trials (680 in total). However, trial number and task sequence were not associated with increased response times for any of the tasks. Finally, it was expected that reduced inhibitory control would be seen for the participants with a cognitive impairment. This was not supported in this small pilot sample, as no difference in performance between groups on any task was found. The results demonstrate that in older adults, different types of stopping behaviours are not controlled by a single latent inhibitory process. Furthermore, the paradigms developed for this research project were shown to be feasible to assess inhibitory function in older people with early-stage cognitive decline in future studies.