Hi Everyone please chip in if I dont get this right, Sarah Mae I am going to try and explain this to you but if I simplify too much please dont be offended.
There are three different types of nerve cell

1. Autonomic Nerves - these are the ones you dont have any conscious control over - they makes sure your internal organs work eg heart beat, digestion etc

2. Motor Nerves - these respond to signals from your brain that are conscious - ie they do the work that you personally want and they make your muscles contract so you can move your body.

3. Sensory nerves - they sense what is happening in the outside world and send a signal to your Central Nervous System and Brain to let your body know how to respond eg it is getting colder so the sensory nerves send a signal to your brain which in turn sends a signal to your body to contract muscles so that your body moves to put the heating on.

Your condition is effecting the third type of nerves which is why you may feel a burning in your feet when it is cold or your feet could be icy cold when it is really hot. The pain comes as these nerves are sending mixed up messages to the brain which means your brain thinks there is a stimuli hurting your body even although there isnt.
There are long and short nerves which is where the length dependant comes in - and I think the #s refer to specific nerves which have been damaged.

Nerves have a nucleus( this controls the function of the cell) in the main body of the cell and they have a long arm reaching out from the main body(think of it as an exploratory arm which is looking for the external signal) - this arm is the axon and has a protective coat around this called a myelin sheath. - sounds to me as if you have a problem with the axon inside the cell where others have damage to the protective layer outside.

Hope this helps - basically your sensory nerve cells are damaged and sending the wrong signals to the brain so the brain is getting jumbled up messages which means you are getting pain/burning/ice cold - the numbness is coming from cells which have been damaged too much.

Again sorry if this is too basic for you - I am coming to this from a teachers angle rather than a medical background.
Ironically this was my favourite topic to teach - little did I know it was going to control my life so much

No, that does help a lot... thank you. The only thing I don't understand is this... that all makes sense.. but I was told at Mayo that I have large fiber PN and that explains why I have motor and balance issues along with the sensory issues. I do have a lot of issues with balance... and I also have problems with my feet 'disappearing' on me. I don't know what else to call it.. but I lay in bed and suddenly I don't know where my feet are if I'm not looking at them. I can't tell how far apart they are, if they are touching, if my legs are crossed, etc. It only happened in bed until recently, and now it happens when I am walking if I walk too much and my feet go numb--my feet feel like they melt into the carpet and suddenly I lose sense of where they are altogether. I was told that was a part of motor issues, not sensory. Is that incorrect?
I really appreciate how you broke it down for me--thank you very much!

I may be making this up but I would imagine that the sensory nerves again are sending mixed up messages to the brain and then a mixed up message is being sent to the motor neurons so they stimulate the muscles to do the wrong thing and you lose your feet for a while - also the numbness in the feet mean you are not as aware of your surroundings so you may not lift your feet as much as you need to to clear the ground so you end up stumbling.
i have the exact same problem with stumbling and not being able to sense where my feet are at times.
Anyway this is only my theory someone in the know may come along and correct me-it is a long time since I studied this at Uni and my brain fog is quite bad at the moment.-I am having Lidocaine Infusions to help me with pain and this has worn off - I am waiting on another treatment next week so it will be sleepless nights and lots of pain and brain fog until then boohoo!

Okay, thanks... I'm just so confused because they told me at Mayo and at my neurologist's office that it was large fiber neuropathy that I had, not small fiber... and I just concluded on my own that I had to have small fiber as well because I have ALL the symptoms, I just didn't have all the correct tests for it... but what I posted came directly from the report from Mayo--yet they told me I had large fiber, not small. I don't understand that... I'm going to call on Monday (both places--Mayo and my neurologist's office) and see if they can send a report (in simpler terms, like large and small fiber neuropathy) of the diagnosis of what they believe I have as well as what they have suggested for treatment thus far for my records. I'll see what they end up sending me...

I just wanted to say you have done a great job explaining what you wanted to say simple, clear, fully understandable, and yet to the point. I need you at my Drs. office when they are explaining what is wrong with me and how they are going to treat the problem. I look like a deer in headlights when my Dr. is explaining things to me as if I am a Dr. myself with all these medical terms.

--the division into sensory, motor, and autonomic is one, based on function.

The other division neurologists tend to use is that between large and small-fiber; that division tends to overlap with the functionality distinction, but not quite.

Large fiber nerves (which can be further broken down by types of fibers) generally involve any nerve that has a myelin sheath--a fatty covering designed to improve signal conduction. Large fiber nerves in the body include motor nerves that send signals to muscle (all motor nerve are "large fiber", as they are all myelin sheathed), and the sensory nerves that subsume the sensations of position, vibration, and mechanical touch. Both sensory and motor nerves can be found in the same nerve trunk, though--think of a thick telephone cable with many wires in it. Some large nerves, like the sciatic (the widest nerve in the body) can have thousands of seperate fibers coming to and from various areas. In general, in these nerves, the sensory tracts are located more to the surface and the motor tracts deeper. So, depedning on the actual location of damage, one can get sensory disruption, motor disruption, or both.

By the way, neuros often talk of "demyelinating" neuropathy if the main damage is to the fatty myelin sheath--this tends t cause fairly distinctive signal abnormalities on EMG/NVC studies, but not signal block. Damage to the axon, or nerve fiber itself, is termed axonopathy. This tends to be more difficult to recover from--the body can restore myelin sheathing more readily than it can repair fibers (which happens VERY slowly, and only if whatever is damaging the nerves is somehow arrrested). Most difficult to recove from is neuronopathy, which refers to damage death to the cell body, where the functions of the cell are controlled. If the cell itself, as opposed to its axon, dies, that cell is gone. Its function may be taken up by other nearby cells, but that tends to be hit or miss. And the number of cell deaths becomes important in determining function.

The small fiber nerves are sensory and autonomic, and are so-called as they do not have myelin coverings. Thus, by definition, damage to a small fiber nerve is axonal or cell body oriented. Small fiber sensory nerves subsume the sensation of pain and temperature. Small-fiber autonomic nerves control our blood pressure, sweat, and urologic/genital/sexual response.

It's certainly possible to have a predominantly large-fiber syndrome, a predominantly small-fiber syndrome, or a mixed syndrome. If large fibers are involved, one can have a predominantly demyelinating syndrome with secondary axonal damage, a predominantly axonal syndrome with secondary demyelination, a neuronopathy with secondary damage, etc.

Hi Hurting
I always go now to visit my doc with a list of preprepared questions so that i get the best out of my few minutes with them.
Also if you dont understand what they are telling you get them to write it down and you will get help with explanations on here - this was a trick I learned when my dad was ill, my sister lives far away and is a nurse and she always wanted a breakdown of what was going on and then made sense of it for my mum.
Just keep remembering these docs are getting paid a lot of money to treat you so they need to take time out to explain things.

Whew....that was a read for me. I went back on my neurontin and have temporarily lost control of my cognitive functioning....beats losing control of some other functions.....this too shall pass, I hope.

Now small fibers are 'thinly myelinated or unmyelinated'...and the C fibers are...I forgot, one of the two.

Sarah Mae, the small fiber nerves also are active in proprioception which is how we feel our bodies in space. If we don't get the proper feedback to the brain, we do not know where our 'parts' are in space. This also contributes to postural changes, and changes in our joints, which can cause injuries and arthritis.

I sometimes do not feel my legs below the knee, yet I can move them perfectly fine. Other times it feels like I am walking on a mattress, or huge bubble wrap. If I put my foot on something, like a chair support...I feel that feeling for 15 minutes after I take my foot off.

I have NO large fiber neuropathy and my EMGs are perfectly normal.

I have autonomic and sensory neuropathy....but it feels like my movement or motor is affected.

I think lots of posters explained things pretty well, given neuropathy is rather mysterious.

Foo, I lost my remote again.......