title: MUNIX and incremental stimulation MUNE in ALS patients and control subjects.
abstract: OBJECTIVE
  This study compares the new Motor Unit Number Estimation (MUNE) technique, MUNIX, with the more common incremental stimulation MUNE (IS-MUNE) with respect to reproducibility in healthy subjects and as potential biomarker of disease progression in patients with ALS.
  
  
  METHODS
  Thirteen ALS patients and 48 control subjects were prospectively investigated - both groups were studied with MUNIX and IS-MUNE applied on the abductor digiti minimi (ADM) muscle. Additional retest was performed on 14 control subjects. Follow-up tests were carried out on 6 patients. The analysis included measures of reproducibility (Intraclass Correlation Coefficient (ICC)) and diagnostic performance (Receiver Operating Characteristic (ROC) analysis).
  
  
  RESULTS
  Test-retest reproducibility was low to moderate for MUNIX and IS-MUNE (ICC=0.38 and 0.56, respectively). Repeated MUNIX and IS-MUNE measurements on the same subject had a mean percentage difference (MPD) of 20% and 46%, respectively (p=0.039). In the control group, the coefficient of variation was markedly lower for MUNIX than for IS-MUNE (26% and 44%, respectively, p<0.0005). In ALS patients MUNIX had a notably better responsiveness in follow-up than IS-MUNE (percent change per month, 9.4 versus 5.6, p=0.046). ROC analysis suggested similar diagnostic accuracy of both tests.
  
  
  CONCLUSIONS
  MUNIX is a useful MUNE indicator when assessing progression of lower motor neuron affection in ALS. Furthermore, MUNIX displayed lower intrasubject variability, but no evident better diagnostic yield compared with IS-MUNE.
  
  
  CONCLUSIONS
  This study has established comparative assessment of MUNIX and IS-MUNE performance in test-retest setting and as diagnostic tests on a distal muscle in ALS patients.
authors.affiliation: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jasna
authors.initials: J
authors.lastname: Furtula
authors.forename: Birger
authors.initials: B
authors.lastname: Johnsen
authors.forename: Peter Broegger
authors.initials: PB
authors.lastname: Christensen
authors.forename: Kirsten
authors.initials: K
authors.lastname: Pugdahl
authors.forename: Carsten
authors.initials: C
authors.lastname: Bisgaard
authors.forename: Mette-Kirstine
authors.initials: MK
authors.lastname: Christensen
authors.forename: Jens
authors.initials: J
authors.lastname: Arentsen
authors.forename: Morten
authors.initials: M
authors.lastname: Frydenberg
authors.forename: Anders
authors.initials: A
authors.lastname: Fuglsang-Frederiksen
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015203:Reproducibility of Results