F127. Abnormal axonal inward rectification revealed in ALS patients with a low number of functionally intact motor units

• Published in: Clinical neurophysiology 2018-05, Vol.129, p.e115-e115
• Main Authors: Larsen, Lotte H., Jacobsen, Anna B., Grafe, Peter, Fuglsang-Frederiksen, Anders, Tankisi, Hatice
• Format: Article
• Language: English
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2018.04.290

Amyotrophic Lateral Sclerosis (ALS) is characterized by progressive loss of motor units. Changes in axonal excitability parameters have already been shown in earlier studies differing between severely and moderately affected disease by staging the disease using compound muscle action potential (CMAP) amplitude. However, CMAP amplitude may be normal until 50% of motor units are lost due to collateral sprouting. We aimed in this study to examine the axonal excitability properties in ALS patients correlated to disease severity determined by the novel motor unit number estimation (MUNE) method MScanFit MUNE (MScan). Twenty-five patients with ALS (mean age: 64.7 ± 3.2) were prospectively evaluated by multiple motor excitability measurements (strength duration time constant (SDTC), threshold electrotonus (TE), recovery cycle (RC), current–threshold relationship (I/V)) and MScan using Qtrac software in abductor pollicis brevis muscle. The patients were divided into two groups according to the number of motor units in MScan MUNE (MSFNUnits): (1) patients with MSFNUnits ⩾40 and (2) patients with MSFNUnits