Electrophysiologic correlations with clinical outcomes in CIDP

Abstract

Data are lacking on correlations between changes in nerve conduction (NC) studies and treatment response in chronic inflammatory demyelinating polyneuropathy (CIDP). This report examined data from a randomized, double-blind trial of immune globulin intravenous, 10% caprylate/chromatography purified (IGIV-C [Gamunex]; n = 59) versus placebo (n = 58) every 3 weeks for up to 24 weeks in CIDP. Motor NC results and clinical measures were assessed at baseline and endpoint/week 24. Improvement from baseline in adjusted inflammatory neuropathy cause and treatment score correlated with improvement in proximally evoked compound muscle action potential (CMAP) amplitudes (r = -0.53; P < 0.001) of all nerves tested and with improvement in CMAP amplitude of the most severely affected motor nerve (r = -0.36; P < 0.001). Correlations were observed between improvement in averaged CMAP amplitudes and dominant-hand grip strength (r = 0.44; P < 0.001) and Medical Research Council sum score (r = 0.38; P < 0.001). Overall, the change in electrophysiologic measures of NC in CIDP correlated with clinical response to treatment.

Intravenous immunoglobulin response in treatment-nai ve chronic inflammatory demyelinating polyradiculoneuropathy

“…Axonal dysfunction of peripheral nerves has been reported to be associated with a failure of IVIg response 9. Whether nerve conduction studies are useful in the prediction of treatment response in CIDP remains unclear 27 34 35…”

New Insights Into the Management of Chronic Inflammatory Demyelinating Polyradiculoneuropathy

“…A subanalysis of the ICE study found significantly greater improvement from baseline in favor of IVIG over placebo for averaged motor amplitudes from all motor nerves (treatment difference 0.62 mV; 95% CI: 0.05-1.20; p = 0.035) and conduction block (treatment difference -5.54%; 95% CI: -10.43 to -0.64; p = 0.027) [27]. These investigators also examined correlations between the changes observed in nerve conduction studies and response to treatment [28]. Motor nerve conduction results and clinical measures were assessed at baseline and at end point/week 24 of the ICE study.…”

Chronic Inflammatory Demyelinating Polyneuropathy

“…Fifty-four percent of patients treated with IVIg had an improvement in the adjusted INCAT disability score through week 24 compared with 21 % of subjects who received placebo ( P =0.0002). Improvements were also recorded for grip strength and in CMAP amplitudes of proximal and most severely affected nerves [89]. During the 24-week extension phase, participants who continued to receive IVIg had a longer time to relapse than did patients treated with placebo ( P =0.011).…”