title: Inventory of Non-Ataxia Signs (INAS): validation of a new clinical assessment instrument.
abstract: Although ataxia is by definition the prominent symptom of ataxia disorders, there are various neurological signs that may accompany ataxia in affected patients. Reliable and quantitative assessment of these signs is important because they contribute to disability, but may also interfere with ataxia. Therefore we devised the Inventory of Non-Ataxia Signs (INAS), a list of neurological signs that allows determining the presence and severity of non-ataxia signs in a standardized way. INAS underwent a rigorous validation procedure that involved a trial of 140 patients with spinocerebellar ataxia (SCA) for testing of inter-rater reliability and another trial of 28 SCA patients to assess short-term intra-rater reliability. In addition, data of the ongoing EUROSCA natural history study were used to determine the reproducibility, responsiveness and validity of INAS. Inter-rater reliability and short-term test-retest reliability was high, both for the total count and for most of the items. However, measures of responsiveness, such as the smallest detectable change and the clinically important change were not satisfactory. In addition, INAS did not differentiate between subjects that were subjectively stable and those that worsened in the 2-year observation period. In summary, INAS and INAS count showed good reproducibility, but unsatisfactory responsiveness. The present analysis and published data from the EUROSCA natural history study suggest that INAS is a valid measure of extracerebellar involvement in progressive ataxia disorders. As such, it is useful as a supplement to the measures of ataxia, but not as a primary outcome measure in future interventional trials.
authors.affiliation: Department of Neurology, University Hospital of Bonn, Sigmund-Freud-Straße 25, Bonn, Germany. heike.jacobi@ukb.uni-bonn.de
authors.forename: H
authors.initials: H
authors.lastname: Jacobi
authors.forename: M
authors.initials: M
authors.lastname: Rakowicz
authors.forename: R
authors.initials: R
authors.lastname: Rola
authors.forename: R
authors.initials: R
authors.lastname: Fancellu
authors.forename: C
authors.initials: C
authors.lastname: Mariotti
authors.forename: P
authors.initials: P
authors.lastname: Charles
authors.forename: A
authors.initials: A
authors.lastname: Dürr
authors.forename: M
authors.initials: M
authors.lastname: Küper
authors.forename: D
authors.initials: D
authors.lastname: Timmann
authors.forename: C
authors.initials: C
authors.lastname: Linnemann
authors.forename: L
authors.initials: L
authors.lastname: Schöls
authors.forename: O
authors.initials: O
authors.lastname: Kaut
authors.forename: C
authors.initials: C
authors.lastname: Schaub
authors.forename: A
authors.initials: A
authors.lastname: Filla
authors.forename: L
authors.initials: L
authors.lastname: Baliko
authors.forename: B
authors.initials: B
authors.lastname: Melegh
authors.forename: J-S
authors.initials: JS
authors.lastname: Kang
authors.forename: P
authors.initials: P
authors.lastname: Giunti
authors.forename: B P C
authors.initials: BP
authors.lastname: van de Warrenburg
authors.forename: R
authors.initials: R
authors.lastname: Fimmers
authors.forename: T
authors.initials: T
authors.lastname: Klockgether
mesh_terms: D019540:Area Under Curve; D005060:Europe; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009460:Neurologic Examination; D011594:Psychometrics; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000145:classification / Q000175:diagnosis* / Q000235:genetics; D013223:Statistics as Topic