A virtual or augmented reality based system for assessment and measurement of reaction time is disclosed. In various embodiments the system, methods, and computer program products relate to assessing and measuring a reaction time of a patient/user in virtual reality (VR) or augmented reality (AR) environments. The VR/AR system may provide a sensory stimulus to the patient/user in the VR/AR environment, determine a plurality of motion parameters, and determine a reaction time based on the plurality of motion parameters by applying a time window selection model. In various embodiments, a time window shrinkage model may be applied after the time window selection model.
