Minor traumatic brain injury is detected by operating (a) an image generatorforpresenting a visual stimulus having a predetermined movement across a visualfield of a subjectand (b) a sensor device for monitoring fast eye movement of the subject whilethe subject viewsthe stimulus. The sensor device generates a signal encoding the subject's eyeposition. Acomputer or microprocessor operatively connected to the sensor device isconfigured fordetermining a parametric value for the fast eye velocity component.