A nerve conduction velocity test measures how fast an electrical signal travels along a nerve, calculated from the time taken and the distance covered. Slowed velocity typically indicates damage to the myelin sheath insulating the nerve. Reduced amplitude points instead to loss of nerve fibres, and reports often describe a mixture of both patterns.
A nerve conduction velocity test measures how fast an electrical signal travels along a nerve, calculated from the time taken and the distance covered. Slowed velocity typically indicates damage to the myelin sheath insulating the nerve. Reduced amplitude points instead to loss of nerve fibres, and reports often describe a mixture of both patterns.
The nerve is stimulated at two points a measured distance apart, and the time taken for the response to appear is recorded at each. Subtracting one from the other gives the time taken to travel the segment between them, and dividing the distance by that time gives the conduction velocity. It is a genuine physical measurement rather than an estimate, which is why skin distance measurement and limb temperature both matter to accuracy.
Velocity and amplitude tell you different things and the distinction drives the diagnosis. Slowed conduction velocity points towards damage to myelin, the insulating layer that allows rapid signal transmission. Reduced amplitude, meaning a smaller response, points towards loss of nerve fibres themselves, described as axonal. Demyelinating and axonal patterns have different causes and different implications, so a report describing which predominates is doing real diagnostic work.
Conduction slows in cold tissue, so a cold limb can produce a velocity that looks abnormal when the nerve is healthy. That is why limbs are warmed before testing and why temperature is often recorded on the report. Normal ranges are also wide, so results are judged against your other side and against the pattern across several nerves rather than against a published number alone. Both CNS offices perform and interpret these studies.
Clinical Neurology Specialists has been physician-owned since 1998, when Leo Germin, M.D., FAANEM founded it. Five board-certified neurologists and four advanced practice providers see patients at the Las Vegas and Henderson offices, each with its own AANEM-accredited electrodiagnostic laboratory.
Clinical Neurology Specialists is an adult outpatient neurology practice for patients 18 and older. The practice performs no surgery and operates no imaging suite, infusion suite or interventional pain programme, and provides no emergency or inpatient care.
Physician-reviewed. Reviewed by the physicians of Clinical Neurology Specialists — board-certified neurologists, AANEM-accredited electrodiagnostic laboratories, physician-owned since 1998. Reviewed 1 August 2026. This article is general education for adults 18 and older and is not a substitute for a consultation.
Adults 18 and older, at the Las Vegas and Henderson offices. Call 702-804-1212 or request an appointment online.