How does a mind contemplate itself? That's a philosophical question I'll leave to minds smarter than mine, but what I can tell you is how to examine brain and other parts of nervous system.Most people are familiar with how doctors examine a heart or set of lungs. The physical exam of these organs consists mainly of using a stethoscope to listen to them in action. But when it comes to examining components of nervous system—consisting of brain, spinal cord, peripheral nerves and muscles—a stethoscope is pretty useless. The nervous system doesn't make sounds that doctor can listen to (though arteries in neck that deliver blood to brain can be usefully listened to). But because people can have medical disorders that damage nervous system, it is every bit as important to have a method for evaluating this organ as for any other.
The method is called neurological exam. Because different parts of nervous system do different things, basic idea of neurological exam is to put patient through a number of mini-exams, each evaluating function of a different component. And what a variety of functions there are! In fact, apart from exposure to an inspiring teacher, this is what drew me into study of neurology in first place—the sheer diversity of neurological exam.
This is an organ responsible for jobs as diverse as thinking, remembering, smelling, tasting, seeing, hearing, speaking, moving, walking, balancing, feeling and, yes, even contemplating itself—though I confess that my neurological exam doesn't include an assessment of self-contemplation. Moreover, nervous system handles many infrastructure tasks like controlling body-temperature, pulse, blood-pressure, breathing and enabling a person to urinate at a time and place of their choosing. What's not to admire about an organ system that can do so many things!
The many mini-tests of neurological exam are bundled together in following sub-groupings: mental status exam, cranial nerve exam, motor exam, sensory exam and evaluation of stance and walking. I'll provide a brief overview of each.
The mental status exam focuses on cerebrum which has a wrinkly, gray, outer surface usually shown in pictures of brain. The cerebrum is divided into eight lobes which includes pairs of frontal lobes, parietal lobes, temporal lobes and—bringing up rear—the occipital lobes. Each handles different mental tasks. In fact, even within a lobe, many different jobs are handled. So usual mental status exam consists of observing patient's behavior in exam room and using a variety of standard tests to check patient's orientation to time and place, attention, memory, speech, comprehension of language, memory, calculation and ability to track relative positions of objects in space.
The next grouping of mini-tests, cranial nerve exam, also assesses functioning of parts of cerebrum, but additionally focuses on brainstem. The brainstem is located at base of brain and connects cerebrum above to spinal cord below. The cranial nerve exam includes tests of smelling, vision, constriction of pupils, eye-movement, facial sensation, facial movement, hearing, and action of certain muscles in throat, tongue, neck and shoulders.