Time perception in people living with Alzheimer's disease

Abstract

AbstractBackgroundPeople may perceive time passed and the events happened in it from time to time. This is not only for the events happened outside the brains of the perceivers, but also for their thinking process. To sense the time lapsed as the time goes by is usually operated by a subconscious mechanism until confusion appears. The confusion may manifest as being not sure about something happened or not or something one has done or not, which occur very frequently in people living with Alzheimer's disease (AD). It may also play a role in spatial navigation, which relies on time and distance perceptions. The mechanism of time perception is complicated, and may involve several neural structures, including basal ganglia, insula, cerebellum, prefrontal lobes, and hippocampus. The aim of this study was to examine the perception of time in persons with mild AD, prodromal AD (prAD) and the cognitively unimpaired (CU).MethodWe invited people with mild AD, prAD and CU to participate in this study. We measured verbal time estimation in 10 seconds, 30 seconds, 60 seconds and time production in 10 seconds, 30 seconds, and 60 seconds. The participants were instructed to press a button on a device to measure time perception when they gauged each target of time had passed. The deviation from the correct response was recorded and compared among the three groups.ResultA total of 22 AD, 58 prAD and 142 CU persons completed the study. Their Mini‐Mental State Examination (MMSE) scores were on the average 22 (SD 4), 22 (5) and 28 (2). The time perception in terms of verbal estimation showed no difference among the three groups in 10 seconds, 30 seconds, or 60 seconds. Regarding time production, difference appeared between prAD and CU (10.8/7.9 [mean/S.D.] vs 7.7/5.4, p<0.01), and no difference was noted in any other group comparisons.ConclusionThe results provide an insightful information that short‐term time perception is of no difference among mild AD, prAD and CU. A study applying longer term time perception design is needed to show the difference and answer its role in spatial navigation or more complicated cognitive processes.