title: Validation of an incremental motor unit number estimation technique in rabbits.
abstract: Motor unit number estimation (MUNE) allows for quantitative assessment of functional motor units in a nerve. Several techniques have been applied to human studies. Although MUNE has been performed in animals to study neurological disorders, reproducibility has not been addressed. We analyzed the test-retest reproducibility of an incremental MUNE technique in rabbits and performed histological correlation. A peroneal MUNE was performed in 9 rabbits on two occasions separated by 30 days. MUNE was then performed on 18 rabbits prior to euthanize. A count of total fibers and a second count of large myelinated fibers were performed on nerve cross-sections. Test-retest reproducibility revealed an intraclass correlation coefficient (ICC) of 0.75. The average test-retest relative difference was 26.6%. Comparison of MUNE and histomorphometrical counts revealed a correlation coefficient (r) of 0.21 (total fiber counts) and 0.27 (large fibers). Although incremental MUNE has a high degree of reproducibility in rabbits, there is poor correlation with histological fiber counts.
authors.affiliation: Neuromuscular Diagnostics Center, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge Street, Suite 820, Boston, Massachusetts 02114, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: David
authors.forename: Namita
authors.initials: N
authors.lastname: Goyal
authors.forename: Francis P
authors.initials: FP
authors.lastname: Henry
authors.forename: Laura E
authors.initials: LE
authors.lastname: Baldassari
authors.forename: Robert W
authors.initials: RW
authors.lastname: Redmond
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology / Q000294:innervation* / Q000502:physiology; D009412:Nerve Fibers / Q000502:physiology; D011817:Rabbits / Q000502:physiology*; D015203:Reproducibility of Results; D013223:Statistics as Topic