Diagnostic markers of axonal degeneration and demyelination in sensory nerve conduction.

Introduction: The aim of this study was to formulate diagnostic hallmarks of axonal degeneration and demyelination in sensory nerve conduction studies (NCS).
Methods: We compared nerve conduction data obtained with surface electrode (SE) NCS and on-nerve needle (ONN) NCS in 50 cases of demyelination and 22 cases of axonal degeneration as assessed by sural nerve biopsy.
Results: The overall diagnostic sensitivities of sensory nerve conduction were 26% by SE-NCS and 69% by ONN-NCS. The most helpful marker for demyelination was negative-peak nerve conduction velocity (NP-NCV), using a 36% decrease from the means in both techniques. Dispersion was also helpful in identifying demyelination. Low amplitude and absence of compound nerve action potential were indicative of general pathology in SE-NCS but of axonal degeneration in ONN-NCS.
Conclusion: Although diagnostic sensitivity is low, NP-NCV and dispersion can be used for diagnosis of demyelination in sensory NCS. Muscle Nerve 53: 866-871, 2016.
(© 2015 Wiley Periodicals, Inc.)