Disease patterns · Core
Classify polyneuropathy patterns
Polyneuropathy patterns
Organize findings by distribution, fiber type, time course and physiology.
01Four useful axes
- Length-dependent or non-length-dependent; symmetric or asymmetric.
- Sensory, motor or mixed; acute, subacute or chronic; axonal or demyelinating features.
02Design the study
- Assess multiple sensory and motor nerves, adding upper-limb, contralateral and proximal sampling as needed.
- When distal responses are severely reduced or absent, a few surviving velocity values cannot establish the myelin pathology alone.
03Go beyond waveforms
- EDX describes a pattern. Etiology still requires clinical and laboratory assessment.
- Pain, asymmetry, rapid progression or marked motor predominance should direct a more specific differential.
Related nerves
Pause and explain
Explain in your own words: “Describe the pattern clearly before investigating its cause.” Then think of a situation in which it could be misinterpreted.
Show a review prompt
Normal routine NCS does not exclude small-fiber neuropathy.
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References and further reading
- Peripheral Polyneuropathy Part 1: Evaluation and Differential Diagnosis ↗AAPM&R KnowledgeNow · Society educational review · Link accessed 2026-09-08
- EAN/PNS guideline on diagnosis and treatment of CIDP, second revision (2021) ↗EAN / PNS · Clinical guideline · Link accessed 2026-09-08
Educational synthesis; independent neuromuscular specialist review is pending. Publication dates and compilation dates are distinct. This is an original teaching synthesis; consult the source for complete methods and criteria.