Inhibitory control deficits in vascular cognitive impairment revealed using the Multi‐Item Localization (MILO) task

Abstract

AbstractBackgroundReaction time (RT) in Vascular Cognitive Impairment (VCI) is particularly slowed when assessed using tests of executive function, however, these tests do not reveal the integrity of specific functional subcomponents of information processing related to RT that are affected by VCI, thus limiting understanding of behavioural change, symptoms and disease progression. Pathological changes in white matter can be ‘silent’, on routine neuroimaging, and not all clinical tests may be sensitive to such effects, highlighting the importance of using of a wider range of tests than may be used at present. The Multi‐Item Localization (MILO) task is used to characterise the performance of mild/moderate VCI and is designed to explore the temporal context of visual search, in addition to measuring overall completion time, it provides a profile of serial reaction time (SRT) patterns across all items in a sequence. MILO assesses how well participants plan ahead during search, and whether items that have already been located can be effectively ignored (i.e., inhibited) identifying deficits in inhibitory control during search.MethodParticipant groups: VCI patients (n =26); cognitively healthy (CH) older adult control group (n=23); young adults (n=26). The MILO iPad app consisted of the digit sequence 1‐8, presented as red/white pool balls. Participants were required to tap each ball in consecutive order, quickly and accurately. In the Vanish condition, items were removed from the screen following the response. In the Remain condition, items were unaffected when touched and the set size were the same throughout a trial. Participants completed two blocks of 20 correct trials, one block of Vanish trials followed by one block of Remain trials.ResultsThe performance of VCI participants was characterised by overall slowing, increased error rates, and crucially, a compromised ability to use inhibitory tagging. Performance was compromised when items remained visible and have already been responded to, resulting in detrimental slowing of processing.ConclusionThe MILO task could be a useful tool for identifying non‐age‐related changes in behaviour with patient populations, and clearly hints at a specific inhibitory deficit in VCI.