Often the physiological and emotional state of a person can be associated with certain cortical activity that can cause certain thermal patterns on the persons forehead. Thus, thermal measurements of the forehead may be used to differentiate between user states. In one embodiment, a system includes at least one inward-facing head-mounted thermal camera (CAM) that takes thermal measurements of at least first and second regions on the right side of a users forehead (THR1 and THR2, respectively), and thermal measurements of at least third and fourth regions on the left side of the forehead (THL1 and THL2, respectively). The middles of the first and third regions are at least 1 cm above the middles of the second and fourth regions, respectively. The system also includes a computer that determines, based on THR1, THR2, THL1, and THL2, whether the user is in a normal state or an abnormal state.
