Medical devices for use in treating or diagnosing neurological conditions; Medical devices, namely, neurophysiology instruments used for recording and processing signals from human and animal nervous systems and electrophysiology equipment used for recording and processing electrical signals from human and animal subjects and neuroprosthetic devices designed to interface to human and animal nervous systems to restore lost function; medical devices, namely, sensor systems comprised of a wearable modular sensing units which are comprised of biofeedback sensors, optical sensors, magnetic sensors, and computer hardware for use in screening and diagnosing neurological conditions; medical devices, namely, sensor systems comprised of a wearable modular sensing units which are comprised of biofeedback sensors, optical sensors, magnetic sensors, and computer hardware for recording and processing brain activity and mental states from human and animal subjects