title: Validation of the German version of the extended ALS functional rating scale as a patient-reported outcome measure.
abstract: The revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) is a well-established rating instrument to assess the functional status of ALS patients. A recent innovation was the addition of three further items designed to improve its sensitivity at lower levels of physical function (ALSFRS-Extension, ALSFRS-EX). Neither the ALSFRS-R nor the ALSFRS-EX has been validated in German yet. The aim of the present study was the validation of the German version of a self-administered form of the ALSFRS-EX. Seventy-six patients participated in the study. Psychometric analysis included reliability assessment and factorial analysis. To evaluate convergent validity, correlations between ALSFRS-EX items and the MRC score, spasticity, tongue movement, pulmonary function, ALSAQ-40 and Borg dyspnoea scales (upright and supine) were performed. Internal consistency as measured by Cronbach's alpha (total scale 0.868, subscales 0.690-0.938) and corrected item to total correlations (all above 0.50) was high. Test-retest reliability assessed by Spearman's rho (0.882-0.972) and Cohen's Kappa (0.63-0.92) was also high. Principal component analysis with varimax rotation yielded a four-factor solution accounting for approximately 79% of the variance. Clinical parameters were strongly correlated with respective items and subscores of the ALSFRS-EX (muscle strength 0.568-0.833 p < 0.01; spasticity -0.236 to -0.376 p < 0.05; tongue movement 0.437-0.818 p < 0.01; pulmonary function 0.485-0.577 p < 0.01). ALSAQ-40 and Borg score correlated highly with the corresponding ALSFRS-EX items. The German self-report version of the ALSFRS-EX possesses very good psychometric properties similar to the original scale including high internal consistency and test-retest reliability as well as excellent convergent validity.
authors.affiliation: Department of Neurology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany. Abdulla.Susanne@mh-hannover.de
authors.forename: Susanne
authors.initials: S
authors.lastname: Abdulla
authors.forename: Stefan
authors.initials: S
authors.lastname: Vielhaber
authors.forename: Sonja
authors.initials: S
authors.lastname: Körner
authors.forename: Judith
authors.initials: J
authors.lastname: Machts
authors.forename: Hans-Jochen
authors.initials: HJ
authors.lastname: Heinze
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dengler
authors.forename: Susanne
authors.initials: S
authors.lastname: Petri
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care / Q000379:methods*; D015203:Reproducibility of Results; D057566:Self Report; D012720:Severity of Illness Index; D055815:Young Adult