title: Reliability of maximal voluntary isometric contraction testing in a multicenter study of patients with amyotrophic lateral sclerosis. Syntex/Synergen Neuroscience Joint Venture rhCNTF ALS Study Group.
abstract: Maximal voluntary isometric contraction (MVIC) is becoming widely used for monitoring disease progression in amyotrophic lateral sclerosis (ALS). We evaluated the variability of MVIC in a large multicenter (29 sites) drug trial in ALS. Intra- and interrater variability were assessed twice during the 19-month study. Intrarater reliability increased from the first to the second test, approaching the reliability reported for a single experienced clinical evaluator, but interrater reliability did not. Multiple clinical evaluators in a single site increased the variability of MVIC measurements. Rigorous quality assurance standards and monitoring of clinical evaluators should be incorporated into the design of multicenter studies using MVIC, since low variability is necessary to detect a modest treatment effect.
authors.affiliation: Amgen, Inc., Boulder, Colorado, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Hoagland
authors.forename: M
authors.initials: M
authors.lastname: Mendoza
authors.forename: C
authors.initials: C
authors.lastname: Armon
authors.forename: R J
authors.initials: RJ
authors.lastname: Barohn
authors.forename: W W
authors.initials: WW
authors.lastname: Bryan
authors.forename: J C
authors.initials: JC
authors.lastname: Goodpasture
authors.forename: R G
authors.initials: RG
authors.lastname: Miller
authors.forename: G J
authors.initials: GJ
authors.lastname: Parry
authors.forename: J H
authors.initials: JH
authors.lastname: Petajan
authors.forename: M A
authors.initials: MA
authors.lastname: Ross
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D012129:Respiratory Function Tests