Cerebral Hemodynamics and Vigilance Performance

Five studies are described using transcranial Doppler sonography (TCD) and near-infrared spectroscopy (NIRS) to examine brain systems in vigilance. The results indicate that the vigilance decrement, the temporal decline that typifies vigilance performance, is paralleled by a decline in cerebral blood flow velocity as indexed by TCD. In addition, both measures showed greater activity in the right than in the left cerebral hemisphere in response to a variety of psychophysical challenges, indicating a right hemispheric system in control of vigilance performance. The TCD measure was also found to be potentially useful in selecting observers for vigilance assignments.