This review identifies cerebral haemodynamic fluctuations characteristic
of vigilance decrement, the tendency for lapses in sustained attention
to snowball with time on task. These characteristic fluctuations,
previously missed by existent literature, can be ascribed to a series of
methodological and analytic confounds associated with the use of
Functional Near Infrared Spectroscopy (FNIRS) to record regional tissue
oxygen saturation (rSO2) over the anterior frontal lobes during
sustained attention tasks. This review triangulates a sequence of
changes in rSO2 characteristic of vigilance decrement, that maps to
bio-cognitive models of the human attention system. Previous studies may
not have been able to identify this characteristic sequence, because
data was either not recorded for a sufficient amount of time or used
bucket averaging analysis methods that obfuscated changes in rSO2.
Lessons learned through this review may reinform FNIRS research methods
and ultimately lead future researchers to design experiments that better
leverage rSO2 as a measure of human attentional performance.