Abnormally fast nerve conduction

Question

Is there any neurological condition or disease where nerve conduction becomes abnormally fast?

We know that myelinated neurons conduct impulses much more rapidly than non-myelinated ones as the myelin ensures that the ions carrying the signals don't leak while flowing through the axons, acting as an insulating material. In demyelinating diseases, the myelin sheath gets lost, affecting the conduction velocity leading to abnormal nerve conduction, which can be rescued by certain therapies such as introducing NPCs that differentiate into oligodendrocytes promoting remyelination.

So I was wondering whether there is any form of disease or at least some theoretical possibility where the nodes of Ranvier are at abnormally long distances from each other leading to conduction velocities much greater than normal.

Answer 1

Action potential amplitude decays between nodes of Ranvier, which is why they exist and are spaced the way they are: to boost the signal at appropriate intervals.

Demyelinating disorders reduce the distance at which the propagated signal can extend without being 'boosted' at a node of Ranvier, leading to conduction failures. See another Q&A here:

Why does damage to myelin sheath in multiple sclerosis lead to a decrease in information reaching the brain from sensory receptors?

If you separated nodes of Ranvier too far apart, the same thing would happen: you might increase conduction velocity a bit, but you'd also cause propagation failures.

It's not really possible to prove a negative, so while it would be possible to provide a reference if there was a "neurological condition or disease where nerve conduction becomes abnormally fast?", it's not really possible to give a reference if the answer is "no", but at least it would not work the way you propose.

You might describe some forms of epilepsy as involving "too much neural activity" (as a simplification), but not "abnormally fast".

Speed of transmission is a function of the diameter of nerve fibers, so obtaining faster conduction would be at the expense of reducing space for the number of fibers in the PNS, or additionally the number of neurons in the CNS.