Central
Nervous System Processing in Idiopathic Scoliosis
By Jerry Larson,
M.A.
Diplomate,
American Board of Neurophysiological Monitoring
There are two kinds of scoliosis:
neuromuscular (associated with a known neuromuscular disease like cerebral
palsy or muscular dystrophy), and idiopathic. Idiopathic is a two-dollar word
meaning, "we don't know why", and probably more than half of the
cases are idiopathic. There are thousands of teenagers, and sometimes older
adults, having major spinal surgery for correction of idiopathic scoliosis
every year. I've been involved in a few of those surgeries myself.
There is an article in the journal Spine, "Intraoperative
Long-Latency Reflex Activity in Idiopathic Scoliosis Demonstrates Abnormal
Central Processing, a possible cause of idiopathic scoliosis" by Maguire
and others, Spine vol. 18 #12, 1993, pp 1621-26. I'm going to quote most of the
first paragraph, and then I'll translate. At the end I'll speculate about what
this means for Feldenkrais workers and other bodyworkers.
"The clinical manifestations of idiopathic scoliosis are well
known, yet its causes remain unclear. Several factors have been proposed,
including abnormal structural elements of the spine, dysfunctional spinal
musculature, genetic factors, alterations of collagen metabolism, and
abnormalities of the central nervous system. The most promising investigations
appear to implicate the central nervous system, especially those areas involved
with postural equilibrium. Spinal cord reflexes play an integral role in the
maintenance of posture. These complex polysynaptic segmental reflexes are
regulated by a variety of descending suprasegmental systems, by peripheral afferent
impulses and within the spinal cord by a network of interneurons and
propriospinal neurons."
So, in other words, there is a great deal of complex interaction between
different parts of the spinal cord involved in maintaining posture, including
information from the peripheral nerves, from the brain, and interactions within
the spinal cord. Messages from the brain fine-tune the process of postural
regulation that goes on within the spinal cord ("efferent control
system"). If you've ever studied the anatomy of the spinal musculature,
you know that there are several short muscles attached to each vertebra that
can rotate it in different directions, which maintain the functional coupling
of the vertebrae and determine how forces travel through the spine. Presumably
this is how Feldenkrais and other bodymind modalities can have an effect on
posture, walking, and spinal column function: through central mediation of the
spinal reflexes, the central mediation being (somewhat at least) accessible to
conscious control.
The article goes on to say that the abovementioned reflex activity can
be measured electrically by recording EMG. They studied 37 cases of idiopathic
scoliosis and 8 cases of neuromuscular scoliosis (three CP, three muscular
dystrophy, and two other neuromuscular disorders) by recording late reflex
activity during spinal surgery for correction of scoliosis. What they found was
that "long-latency complex polysynaptic activity" was present in
all 37 patients with idiopathic scoliosis, and absent in all 8 patients
with nonidiopathic scoliosis. (These late reflexes are also unknown in normal
subjects).
In other words, when you stimulate a nerve in the leg, you can record
electrical responses from a muscle in the leg. You get an early response, say 5
milliseconds, by direct stimulation, and around 35 ms you get some later
responses called H-reflexes and F-waves, which involve an impulse first going
to the spinal cord and then bouncing back down the same nerve, or being relayed
through a reflex arc in the spinal cord. In these idiopathic scoliosis patients
ONLY, there are late responses ranging from 20 -243 ms in latency and lasting
up to 4 seconds. It sounds to me like a ringing effect, a failure of damping.
It's like a car with bad shocks, bouncing up and down long after you hit the
bump, when the bouncing should have damped out quickly.
That means that there is some complex processing, involving lots of
neurological connections and hence taking a relatively long time, in the
idiopathic scoliosis patients. The best, and simplest, way to think of this is
that something abnormal—something not seen in normal subjects--showed up in the
central nervous system processing of the idiopathic patients ONLY.
Now, I'd like to know more about that; I can think of criticisms, I'd
like to see more of the waveforms, etc. If you're interested, you can look up
the article in Spine, and they have lots of references. But assume
they're correct. The conclusion is that "abnormal reflex processing may play
a role in the development of the spinal deformity in patients with idiopathic
scoliosis". This sounds somewhat like what Feldenkrais people have been
saying all along, doesn't it?
Now, the abnormalities we're talking about are in the spinal cord, and we
don't usually think of much learning going on in the spine, or even in the
brainstem; we usually think of learning as happening in the cerebral cortex. So
how can Feldenkrais work, or other bodyways, help with this kind of problem?
Well, remember that there are "descending" impulses involved in the
postural control mechanism of the spinal cord; in other words, higher centers
can exert some degree of control over it. You can't operate your postural
reflexes by conscious thought, but by practice, particularly by methods like
tai chi, yoga, Feldenkrais, etc., you can possibly have a very beneficial
influence on them.
It would be a little late to have a beneficial effect on this process
when the person has already developed a life-threatening structural abnormality,
maybe even had it corrected with multiple spinal fusions and instrumentation.
However, by catching scoliosis early, and using bodymind methods like tai chi,
Feldenkrais, etc., it might be possible to keep idiopathic scoliosis from
developing into a serious problem. By the way, theoretically you could also use
EMG biofeedback for this, but I don't know if it would be practical, since it
might involve either inserting needles into muscles, or delivering electrical
shocks while the person tries to modify the results of stimulation. Still, I
refuse to say it's impossible.
Published in print: Rolf Lines, Vol. 28, No.4 (Fall 2000)
Copyright 1997, 2000 Jerry Larson jerry@neuromon.com www.neuromon.com
May be reproduced in its entirety, as long as this copyright notice is
included and there is no cost to the reader.
Jerry Larson did graduate work in Linguistics and Communicative
Disorders. He has worked for many years in the field of neurodiagnostics,
performing EEG's, nerve conduction and evoked potential studies,
electronystagmography, quantitative EEG ("brain mapping") and
intraoperative neurophysiology monitoring. He is a board certified
intraoperative neurophysiologist. He is also a certified practitioner
of Bodymind Integration and of the Feldenkrais Method, and does Chinese
internal martial arts. He has lived in Los Angeles since what he
likes to refer to as "the McGovern Administration".
Jerry Larson, MA , Diplomate, American Board of
Neurophysiological Monitoring