I was recently at the American Academy of Neurology conference, taking
a seminar on the history of named signs. One of the speakers asked
the audience (about 50 neurologists) a series of questions about how
they tested for Romberg's sign and what they thought it meant. There
was no consensus! It means different things to different
neurologists.
Dr. Romberg himself was originally interested in describing clinical
findings of late (tertiary) neuro-syphilis, specifically the syndrome
known as 'tabes dorsalis', where infection of the dorsal part of the
spinal cord causes a person to lose the sense of 'proprioception' -
the sense of knowing where body parts are, in space. Your brain is
constantly, subconsciously, processing data about muscle stretch and
joint angle and using that to form an inner map of your body posture.
Your body is equipped with three systems that help you maintain an
upright posture ('station'). These are the visual, the vestibular,
and the proprioceptive. (The vestibular is the balance organ in your
inner ear, which makes you feel dizzy after you spin in place.) You
need 2 of the 3 inputs operational to maintain an upright posture.
So, Dr. Romberg made his patients stand upright, feet together, and
then close their eyes (disabling the visual system.) At that time,
both the vestibular and the proprioceptive systems must be operational
to maintain station. If one is not operating properly, for any
reason, the patient will fall over. In the case of patients with
neuro-syphilis, the spinal cord tracts that carry proprioceptive
information are damaged, and so that system is not operational.
But there are many, many other reasons to show a positive Romberg's
sign. Some of them are treatable, but many - I dare say most - are
not. |
