LPL and Parkinson disease: Only the PD-PS group had elevated oxyhemoglobin levels in the LPFC (p < 0.001), RPFC (p = 0.023), and LPL (p = 0.045) regions during the dual task, with a trend in the RPL (p = 0.086), while the PD-PF group had no significant differences in any of the four brain regions studied (p > 0.2).