In this study, we investigate the effect of pulse waves on the transmission of near-infrared radiation in the outer tissue layers of the human head. This effect is important in using optical radiation to monitor brain conditions based on measuring the transmission changes in the near-infrared radiation between the source and the detector, placed on the surface of the scalp. This is because the signal related to the changes in the width of the subarachnoid space (SAS) due to the pulse wave is modified. These latter changes can be used, for instance, in detecting cerebral edema and in evaluating cerebral oxygenation. The research was performed by modeling the propagation of near-infrared radiation in the tissue layers using a Monte-Carlo method. The main objective of this study was to assess the extent to which the changes in the transmission of near-infrared radiation correspond to the changes in the optical parameters of the tissues of the head and in the width of the subarachnoid layer.