The CMAP stimulus–response curve in patients with inflammatory demyelinating polyneuropathies and normal subjects. Issue 3 (March 2016)

• Record Type: Journal Article
• Authors: Paramanathan, S.; Tankisi, H.; Paramanathan, S.A.; Andersen, H.; Fuglsang-Frederiksen, A.
• Is Part Of: Clinical neurophysiology. Volume 127:Issue 3(2016:Mar.)
• Page Start: e46
• Page End: e47
• Publication Date: 2016-03
• Subjects: Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2015.11.151
• Languages: English
• ISSNs: 1388-2457

Abstract

Abstract : Objective: To examine the CMAP stimulus–response curve in patients with acute- and chronic-demyelinating polyneuropathies (AIDP, CIDP) and healthy subjects. Methods: Six AIDPs, five CIDPs and ten healthy subjects participated. The CMAP stimulus–response curve was obtained in abductor policis brevis by stimulating the median nerve. The CMAP response was plotted against the corresponding stimulation intensity and analyzed in MATLAB. Jumps (steps), are defined as clearly visible size difference between consecutive CMAP, were manually selected. Summative jump size percentage (SJS%) were determined by adding the size of all detected jumps divided by the maximum CMAP. Results: The number of jumps in CIDPs (6 (4–10)) (median (range min–max)) were higher compared to controls (4 (1–5)) ( p < 0.05). Furthermore SJS% in CIDPs (41.15 (19.61–64.6)) were increased compared to controls (10.46 (4.40–20.15)) ( p < 0.01). In AIDPs the number (5 (2–10)) and SJS% (20.34 (4.95–24.21)) were not different to controls ( p = 0.081, p = 0.19). Conclusions: The increased number of jumps indicates loss of motor units, the increased SJS% indicates reinnervation in CIDPs which was not seen in AIDPs probably due to short disease duration. Key message: The CMAP stimulus–response curve can be used to determine motor unit loss and reinnervation.