A Narrative Review of Hemodynamic Measures of Sustained Attention

Raul Ramirez

Advisor: Tyler H. Shaw, PhD, Department of Psychology

Committee Members: William Helton, Patrick McKnight

Online Location, Online
May 04, 2023, 02:00 PM to 04:00 PM


Many tasks, from industrial monitoring to airport security, require sustained attention over long periods of time. This phenomenon, referred to as vigilance, has been the subject of investigation since the 1940s. A consistently replicated feature of vigilance tasks is a marked degradation of performance over time, which is referred to as the vigilance decrement. Measuring vigilance solely through behavioral measures is inadequate for capturing an individual’s fatigue or availability of mental resources. Physiological measurements are able to capture live data of mental workload during vigilance tasks. There are a multitude of techniques for measuring mental workload. A central method for examining mental resource utilization is through cerebral hemodynamics. When mental effort is required in tasks, the brain requires an expenditure of oxygen and glucose to fuel brain activity.This metabolic activity is reflected in increases in regional cerebral blood flow (rCBF). Measures, such as positron emission topography (PET), transcranial Doppler sonography (TCD), functional near infrared spectroscopy (fNIRS), and functional magnetic resonance imaging (fMRI) are all able to measure indices of mental workload by measuring blood flow changes associated with metabolic activity. The purpose of this dissertation will be to provide an up to date review on physiological monitoring of vigilance using hemodynamic measures. There are currently a diversity of measures used to measure hemodynamic changes in vigilance performance. The lack of intercorrelation between hemodynamic measures in addition to variance in sensitivity, resolution, and applicability in applied scenarios indicate a need to analyze what features are appropriate for any given vigilance tasks. Making an appropriate decision on what hemodynamic measure to use can be aided by understanding the features of the measures as well as the ROIs implicated in particular vigilance tasks. Research showing differential activity during vigilance performance indicates that different vigilance tasks may activate different locations in the brain. Therefore, different hemodynamic measures may be more suitable depending on the nature of the task being measured. This review will discuss the results of vigilance research using these hemodynamic measures in order to understand the optimal application of these methods.