DOES ANYBODY KNOW........

[limbo-lifer.73]

Is there any correlation between axonal nerve damage
in the white and gray matter of the brain, AND
evidence of relapsing/remitting axonal nerve damage
in the limbs, as shown on an EMG/NCS???

I've got no clue, so any enlightenment would be
most welcome. Perhaps some references that discuss
axonal brain damage in general?? Some of the
references mentioned in this board recently
paint a rather depressing picture, outcome-wise.

How is this type of damage even measured? Is there
any recovery from it? I'm new on this topic...ran
across it in Sawyer & Bachrach's book "The MS
Recovery Diet".

Anybody got any ideas?

Me

[Redwings]

Hi limbo-lifer:
I think one of the frustrations a lot of people have with MS is trying to understand how it works without having any background in anatomy and physiology. It's much more difficult to try to understand a function/dysfunction if learning the anatomy and physiology piecemeal and in isolation -- i.e., backwards. So my best recommendation for anyone who's wondering how MS works is to start by learning the basics and then see how things go wrong in MS.

Is there any correlation between axonal nerve damage in the white and gray matter of the brain

That's already a slippery slope when it comes to MS. Gray matter is composed overwhelmingly of neuronal cell bodies and dendrites with relatively few axons, and those axons generally aren't myelinated. MS changes in gray matter don't show up well on commercially used MRIs, so there isn't yet great understanding of what happens to unmyelinated axons in gray matter due to MS. In theory, the immune cells in MS go after myelin, so if there isn't any myelin to attract the immune cells, the axons in gray matter (or the cell bodies, for that matter) shouldn't be bothered. But research has shown that that's not exactly true, and not that simple.

To oversimplfy the explanation, I could say that axonal damage doesn't happen in gray matter because gray matter contains very few axons. And because there are so few axons in gray matter, their loss is not particularly significant.

The axons make up the white matter. The axons are the part of neurons covered in myelin, and it's the myelin that gives white matter its whitish appearance and visually distinguishes it from gray matter.

In MS, the immune cells attack myelin, which is in the white matter. About 95% of damage from MS occurs in white matter because that's where the myelin is. (Sort of like Willie Sutton saying he robbed banks because that's where the money is.) And subsequently, the axons can be/are damaged after they lose their myelin coating. Loss of axons IS significant because cells can't transmit electrical signals without them.

Is there any correlation between axonal nerve damage in ... the brain, AND evidence of relapsing/remitting axonal nerve damage
in the limbs, as shown on an EMG/NCS???

When it comes to MS, the answer is generally no, there is no correlation because MS is a disease of the central nervous system, not the peripheral nervous system. The ability to isolate nerve damage to the peripheral nervous system via EMG/NCS can be used to help rule out MS, because MS doesn't operate there.

There are diseases that can affect only peripheral nerves and some that can affect both central and peripheral, but those are all really outside the scope of a discussion of MS.

Perhaps some references that discuss axonal brain damage in general? Some of the references mentioned in this board recently paint a rather depressing picture, outcome-wise.

I'm not even going to attempt to provide references for a subject that broad. It can certainly be googled. Are there any references in the Sawyer & Bachrach book?

The short answer is that axonal damage in the brain from any cause can have a poor outcome because axons in the central nervous system regenerate extremely poorly to not at all. That's why spinal cord injuries are so devastating -- there's no redundancy and no rerouting. And axonal death in SPMS and PPMS is pretty much the end of the line. Once the axon is dead, it's gone, and the entire cell generally self-destructs.

Peripheral nerves, on the other hand, tend to regenerate quite efficiently.

How is this type of damage even measured? Is there any recovery from it?

The damage is measured by its effects: appearance on MRI, electrodiagnostic testing, functional testing, disability scales, etc.

Recovery depends on several factors. In the brain, there are redundancy and plasticity. Electrical signals can possibly be rerouted, and normal areas of the brain can sometimes be retrained to take on the functions of areas that are damaged. In that respect, functions can be recovered, even if they're being performed by different areas of the brain. Small areas of damage in the brain can sometimes go completely unnoticed ("silent" lesions in MS) because redundancy and plasticity work so well.

Also, early on in RRMS, lesions tend to remyelinate, sometimes within two or three weeks (protecting the axon), and the areas of brain surrounding the lesions are still healthy and functioning normally. Over time, the ability to remyelinate diminishes, leaving the axons vulnerable to attack and death. In addition, more areas of the brain are affected, leaving fewer healthy areas for signals to reroute through. The theory is that that's when RRMS converts to SPMS -- progressive because recovery diminishes.

And, as I said earlier, there is virtually no redundancy in the spinal cord, so axonal death even in small areas manifests swiftly and permanently. No fix, no recovery.

[limbo-lifer.73]

Whoa! Another perfectly good delusion shot to h***.
And, another inane false premise goes down in flames!

Sorry. I'm trapped between the un-DXedness of
idiopathic polyneuropathy, and possible MS. Oh,
and there's a little spinal stenosis thrown in, just
for good measure. My PCP and Chiro think it's both.
At least the stenosis was easy to rule in.

I'm always trying to find ways to prove/disprove
one or the other; or better still, ferret out a way
to bridge the gap between the two...or three.

Guess in the clutter of my un-DXed disease(s),
my cloudy thinking became muddled. I know better.
Note to self: SELF, don't ask any more stupid
questions! [check].

In any event, I greatly appreciate the time and effort
you took in the wee, wee hours of O'Dark:30am to
respond to my question. Your explanation helps
a lot. However, it does raise the question: When
do you sleep??

I'll just crawl back into my hovel now, down in Limboland
Village. If you need me, it's easy to find....
Mine is the one between a rock and a hard spot.

If you look closely, there's a carefully concealed,
circuitous pathway leading right to it.....just barely
wide enough for the approaching wheel chair.
Do mind all the rocks, craters, pitfalls, and gullys
along the way, won't you?

Have a great afternoon, or (in your case) early morning!

Me