EFNS/PNS electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP)1
| I: “Definite CIDP”: at least one of the following: |
| a. At least 50% prolongation of the motor distal latency above the upper limit of normal values in two nerves, or |
| B. At least 30% reduction in motor conduction velocity below the lower limit of normal values in two nerves, or |
| C. At least 20% prolongation of F-wave latency above the upper limit of normal values in two nerves (>50% if amplitude of negative peak compound muscle action potential (CMAP) <80% of lower limit of normal values), or |
| D. Absence of F waves in two nerves if these nerves have amplitudes of distal negative peak at least 20% of lower limit of normal values+at least one other demyelinating parameter in at least one other nerve, or |
| E. Partial motor conduction block: at least 50% amplitude reduction in the proximal negative peak CMAP relative to distal, if distal negative peak CMAP at least 20% of lower limit of normal values, in two nerves, or in one nerve+at least one other demyelinating parameter in at least one other nerve, or |
| F. Abnormal temporal dispersion (>30% duration increase between proximal and distal negative peak CMAP) in at least two nerves, or |
| G. Distal CMAP duration (interval between onset of the first negative peak and return to baseline of last negative peak) of at least 9 ms in at least one nerve nerve+at least one other demyelinating parameter in at least one other nerve |
| II. “Probable CIDP” |
| At least 30% amplitude reduction in the proximal negative peak CMAP relative to distal, excluding the posterior tibial nerve, if distal negative peak CMAP at least 20% of lower limit of normal values in two nerves, or in one nerve nerve+at least one other demyelinating parameter in at least one other nerve |
| III. “Possible CIDP” |
| As in “I” but in only one nerve |
EFNS/PNS, European Federation of Neurological Societies/Peripheral Nerve Society.