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I'll single out one item on cranial nerve exam as deserving special mention, and that is visual field exam. The visual fields are evaluated one eye at a time. While patient stares at an unmoving object, doctor asks if patient can see objects (like doctor's fingers) appearing in different locations of patient's peripheral vision. In order to detect objects in four corners of each eye's vision, patient must have proper functioning of each of six lobes of brain—both parietal lobes, both temporal lobes and both occipital lobes. In fact, this is only portion of entire neurological exam that checks right temporal lobe. Despite its importance, visual field exam sometimes gets skipped by medical students (in which case ones under this author's supervision must endure hearing an earful).
The motor exam includes some pretty obvious things like checking strength of different muscles in arms and legs, but also includes less obvious components like muscle tone, coordination, and presence of involuntary movements. It also includes an inspection of muscles for loss of size or presence of spontaneous twitches. Additionally, this is part of exam in which doctor pulls out his or her rubber hammer and checks reflexes in arms and legs. The motor exam also includes a briefly painful maneuver—called Babinski test—in which bottom of foot is scraped with a metal object while doctor observes for a reflexive response in certain foot-muscles.
The sensory exam focuses on processing of inputs from sensory nerve-endings in patient's skin and joints. It can include awareness of light touch, pain, warmth, coldness and vibration. In addition, doctor examines position-sense by moving patient's toes and fingers up or down and asking patient to say, without looking, which way they moved.
Finally, we have those portions of exam related to stance and walking, but also including patients' ability to transfer in and out of their chair. While on their feet, patients are asked to walk in their usual fashion, as well as on tiptoes. They are also observed while doing a "tandem gait," known more commonly as "state trooper test," in which they walk flat-footed in a straight line with heel of leading foot touching toes of trailing foot. Last, doctor checks patients' ability to remain standing after closing their eyes. This is called Romberg test.
That's about it. In hands of experienced clinicians neurological exam doesn't take much longer to perform than to describe, and yet provides a wealth of information about functioning of patient's nervous system. In this age of high-tech imaging devices neurological exam might seem archaic or old-fashioned, but it is still indispensable, and provides diagnostic information that even a battery of CT or MRI scans might miss.
(C) 2005 by Gary Cordingley
Gary Cordingley, MD, PhD, is a clinical neurologist, teacher and researcher who works in Athens, Ohio. For more health-related articles, see his website at: http://www.cordingleyneurology.com