TY - JOUR
T1 - Assessment of motor unit loss in patients with spinal muscular atrophy
AU - Sleutjes, Boudewijn T.H.M.
AU - Wijngaarde, Camiel A.
AU - Wadman, Renske I.
AU - Otto, Louise A.M.
AU - Asselman, Fay Lynn
AU - Cuppen, Inge
AU - van den Berg, Leonard H.
AU - Ludo van der Pol, W.
AU - Stephan Goedee, H.
N1 - Funding Information:
We thank all patients with SMA who have been participating in our ongoing study and the Stichting Spieren voor Spieren for their continuing support of our research. Our work was financially supported by the Prinses Beatrix Spierfonds (WAR 13-07 and WAR 14-26). B. Sleutjes, C. Wijngaarde, R. Wadman, L. Otto, F. Asselman, I. Cuppen, W.L. van der Pol, and H.S. Goedee have no potential conflicts of interest to be disclosed. L. van den Berg reports grants from ALS Foundation Netherlands, grants from The. Netherlands Organization for Health Research and Development (Vici scheme), grants. from The Netherlands Organization for Health Research and Development (SOPHIA, STRENGTH, ALS-CarE project), funded through the EU Joint Programme ?, Neurodegenerative Disease Research, JPND), and personal fees from Shire, Biogen, Cytokinetics, and Treeway.
Funding Information:
We thank all patients with SMA who have been participating in our ongoing study and the Stichting Spieren voor Spieren for their continuing support of our research. Our work was financially supported by the Prinses Beatrix Spierfonds ( WAR 13-07 and WAR 14-26 ).
Funding Information:
van den Berg reports grants from ALS Foundation Netherlands, grants from The.
Publisher Copyright:
© 2020 International Federation of Clinical Neurophysiology
PY - 2020/6
Y1 - 2020/6
N2 - Objective: To assess motor unit (MU) changes in patients with spinal muscular atrophy (SMA) using compound muscle action potential (CMAP) scans. Methods: We performed CMAP scan recordings in median nerves of 24 treatment-naïve patients (median age 39; range 12–75 years) with SMA types 2–4. From each scan, we determined maximum CMAP amplitude (CMAPmax), a motor unit number estimate (MUNE), and D50 which quantifies the largest discontinuities within CMAP scans. Results: Median CMAPmax was 8.1 mV (range 0.9–14.6 mV), MUNE was 29 (range 6–131), and D50 was 25 (range 2–57). We found a reduced D50 (<25) in patients with normal CMAPmax (n = 12), indicating MU loss and enlarged MUs due to reinnervation. Lower D50 values were associated with decreased MUNE (P < 0.001, r = 0.68, n = 43). CMAPmax, MUNE and D50 values differed between SMA types (P < 0.001). Lower motor function scores were related to patients with lower CMAPmax, MUNE and D50 values (P < 0.001). Conclusions: The CMAP scan is an easily applicable technique that is superior to routine assessment of CMAPmax in SMA. Significance: The detection of pathological MU changes across the spectrum of SMA may provide important biomarkers for evaluating disease course and monitoring treatment efficacy.
AB - Objective: To assess motor unit (MU) changes in patients with spinal muscular atrophy (SMA) using compound muscle action potential (CMAP) scans. Methods: We performed CMAP scan recordings in median nerves of 24 treatment-naïve patients (median age 39; range 12–75 years) with SMA types 2–4. From each scan, we determined maximum CMAP amplitude (CMAPmax), a motor unit number estimate (MUNE), and D50 which quantifies the largest discontinuities within CMAP scans. Results: Median CMAPmax was 8.1 mV (range 0.9–14.6 mV), MUNE was 29 (range 6–131), and D50 was 25 (range 2–57). We found a reduced D50 (<25) in patients with normal CMAPmax (n = 12), indicating MU loss and enlarged MUs due to reinnervation. Lower D50 values were associated with decreased MUNE (P < 0.001, r = 0.68, n = 43). CMAPmax, MUNE and D50 values differed between SMA types (P < 0.001). Lower motor function scores were related to patients with lower CMAPmax, MUNE and D50 values (P < 0.001). Conclusions: The CMAP scan is an easily applicable technique that is superior to routine assessment of CMAPmax in SMA. Significance: The detection of pathological MU changes across the spectrum of SMA may provide important biomarkers for evaluating disease course and monitoring treatment efficacy.
KW - CMAP scan
KW - Motor unit loss
KW - Spinal muscular atrophy
KW - Surface-EMG
UR - http://www.scopus.com/inward/record.url?scp=85083171993&partnerID=8YFLogxK
U2 - 10.1016/j.clinph.2020.01.018
DO - 10.1016/j.clinph.2020.01.018
M3 - Article
C2 - 32305855
SN - 1388-2457
VL - 131
SP - 1280
EP - 1286
JO - Clinical Neurophysiology
JF - Clinical Neurophysiology
IS - 6
ER -