My CIDP Record and Analysis 2002 through 2026 of Nerve Conduction Studies (NCS) record for Chronic Inflammatory Demyelinating Polyneuropathy
CIDP nerve conduction studies (NCS) + CIDP electro-diagnostic electromyography (EMG)

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My first nerve conduction study (NCS) October 8, 2002 (aged 56-years) was "pristine" albeit I reportedly had "very high amplitude sensory responses". I underwent this fist NCS because I felt something was wrong including a left leg and foot that very occasionally would suddenly begin to drag. April 18, 2008 (aged 62-years), nerve conduction studies by my principal doctor were "suggestive of axonal neuropathy" and CIDP was mentioned but it was reported by the doctor that he did "not have great electrodiagnostic evidence of a primary demyelinating lesion". A second NCS opinion four months later, August 5, 2008, was suggestive of "sensory more than motor polyneuropathy of most likely a demyelinating nature" (but no conduction block was reported). Then almost two years later on May 05, 2010 my condition was revised by my principal doctor to "exceedingly mild CIDP". Now in March 2026 I am finally doing my own analysis of NCS results with the assistance of an excellent team - an EMG Technologist with 30-years experience and her daughter a whizz-kid data analyst. I will shortly be posting the results here.

 

In 2015 when I was first transferred to the CIDP Clinic at Toronto General Hospital the Nerve Conduction Studies conclude my "nerve conduction study and needle examination show evidence of demyelinating polyneuropathy affecting the lower limbs (legs)". Motor and sensory studies of median nerve (arms) are normal. Motor studies of left peroneal and tibial nerves (both lower leg) show low CMAP, prolonged distal latencies, and slow conduction velocity. Since a study of left sural nerve (a purely sensory nerve of the lower leg and foot) shows slow conduction velocity. F waves of left median nerve (arm) are normal but prolonged and left peroneal and tibial nerves (both lower leg). Vibration perception thresholds are prolonged in the lower limbs. Needle EMG examination show evidence of denervation potentials in left tibialis anterior and gastrocnemius muscles, normal and vastus lateralis." Your can view the 2015 NCS report at this link: NCS-Clinic-Report-CIDPlog-2015-03-09.pdf.

 

Key Diagnostic Parameters in CIDP

Which is the most important parameter to diagnose CIDP: DML, CV, CMAP, or F latency

 

  • DML (Distal Motor Latency) prolongation in ms: Crucial for identifying distal demyelination, where a DML >50% above the upper limit of normal is a major criterion. Distal Motor Latency (DML) increases (becomes prolonged) in patients with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)..
  • CV (Conduction Velocity) decrease in m per s: Essential for identifying segmental demyelination, requiring a reduction ≥30% below the lower limit of normal. Conduction velocity (CV) decreases (slows down) in patients with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP).
  • F-Latency (F-wave) prolongation in ms: Highly sensitive, particularly in early cases or where other studies are normal, as it tests proximal segments and root involvement. F-Latency (F-wave latency) increases (prolongs) in patients with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP).
  • CMAP (Compound Muscle Action Potential) in mV: While reduced amplitudes (CMAP) are found in CIDP due to axonal loss, the diagnosis of demyelination is based on conduction velocity slowing, DML, F-wave latency, or abnormal temporal dispersion. The Compound Muscle Action Potential (CMAP) amplitude typically decreases for patients with CIDP. 

v Motor Nerve Parameter Charts:

 

For diagnosing Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), no single parameter is considered "most important" because the diagnosis relies on demonstrating demyelination across a combination of these values. However, Distal Motor Latency (DML) is statistically noted as the parameter least likely to contribute to false positives in some cohorts. So below are my results for Distal Motor Latency between 2002 and 2025:.

 

 

 

Also my results for motor nerve velocity between 2008 and 2025:

 

 

 

My results for F-Latency (F-wave study) prolongation in ms between 2008 and 2025:

 

 

 

My results for CMAP (Compound Muscle Action Potential) in mV between 2002 and 2025:

 

 

 

 

 

v Sensory Nerve Parameter Charts:

 

My CIDP doctors tell me that I am 70-80% sensory versus motor nerve involvement with my MADSUM classified CIDP. So below are my results for Sensory Latency between 2002 and 2025:

 

 

Also my results for sensory nerve velocity between 2008 and 2025:

 

 

My results for sensory CMAP (Compound Muscle Action Potential) in mV between 2008 and 2025::

 

 

 

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