Monitoring reaction time to digital device in the very-old to detect early cognitive decline.

Early detection of cognitive decline is essential for timely intervention and effective management of age-related impairments. We monitored repetitive reaction times to a simple task on senior-friendly tablet computers among 72 functionally independent older adults, with a mean age of 82, ranging up to 100 years, within natural settings over two years. Functional principal component analyses revealed a consistent decrease in reaction time in line with their task experience among those without subjective cognitive decline. Conversely, individuals reporting subjective cognitive decline showed no consistent trend and exhibited wide variability over time. These distinctive reaction time trajectories in very old adults suggest the potential for monitoring as a non-invasive, convenient method for early detection of cognitive impairment.