In Screening for Dementia, Time Can Tell A Lot: A Conversation with Researcher David Libon, PhD

Contemporary digital cognitive assessment tools differentiate response accuracy from response latency, revealing cognitive struggles that may not be evident when using standard testing, according to neurocognitive researchers David Libon, PhD, and Rodney Swenson, PhD. In a recent interview with Patient Care, the research duo explained that the approach leverages time‑based measures to separate performance correctness from the underlying cognitive process.

More and more, latency measures are being considered as neurocognitive biomarkers for early detection of dementia, monitoring disease trajectories, and enhancing diagnostic precision. In the short video above, Libon underscores how latency‑based assessment augments traditional screening.

The following transcript has been lightly edited for clarity and flow.

Patient Care: Your recent paper focuses on the importance of latency and time based measures during digital assessment. How are the timing parameters critical in detecting subtle neurocognitive changes associated with very early dementia.

David J Libon, PhD: One thing we can do very easily now with digital technology is dissociate the correctness of a response from how long it takes to generate that response. For example, I might say, "I'm going to say three words, and after I say them, repeat them back to me." If someone responds quickly, "Toothbrush, cigarette, pen," that’s a perfectly fine, 100% correct answer. But someone else might say, "Um, let’s see... what was the first word? Uh, tooth... toothpaste... cigar, wait, no, no, no—toothbrush, cigarette, pen." That’s also scored as 100% correct.

But as you can hear in that second example, the amount of time it takes, and the amount of non-productive speech, are very different. These factors may indicate that the patient is struggling. With time-based, or latency, measures, we’re able to separate the accuracy of a response from the cognitive process required to generate it.

So even if someone is giving fully correct answers, if their timing parameters fall outside defined thresholds, current research suggests they may fall into a different category—one that indicates they are potentially at risk, or that there may be other evidence consistent with a diagnosable mild cognitive impairment, for example.

Rodney A Swenson, PhD is Clinical Professor of Psychiatry and Behavioral Sciences, at the University of North Dakota School of Medicine and Health Sciences in Grand Forks, ND.

David J Libon, PhD, is a Professor at the New Jersey Institute for Successful Aging, at at Rowan University, in  Glassboro, NJ.