Continued from page 1
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