Abstract: An apparatus consistent with the present invention comprises a sensor for receiving a signal representing eye tremor and a processor for monitoring eye tremor while receiving the signal. A method consistent with the present invention includes receiving a signal representing eye tremor, comparing the received signal representing eye tremor to at least one reference value, and classifying a patient's brain stem function using the comparison of the received signal representing eye tremor to at least one reference value. An embodiment consistent with the present invention includes an ocular micro tremor (OMT) sensor and associated signal processing hardware and software for clinical analyses.