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International Cooperative Rating Scale (ICARS)

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Supplemental: Friedreich's Ataxia (FA)
Short Description of Instrument
The International Cooperative Ataxia Rating Scale (ICARS) is a commonly used evaluation and is composed of four clinical sub-scores involving the following: posture and gait, limb coordination, speech and oculomotor function. It was initially designed for longitudinal assessment of pharmacological therapies in patients with cerebellar ataxia.
Strengths: ICARS scores strongly correlate with the Ataxia Functional Composite Scale (AFCS).
Weaknesses: ICARS scores improve during normal development, until at least 13 years of age; thus, when used in pediatric studies, ICARS values could lead to misinterpretation of longitudinal outcomes, with "improved" scores being mistakenly representative of a therapeutic effect.
The ICARS score is the total sum of the sub scores and ranges from 0 to 100, with 100 indicative of the most severely affected outcome.
Key Reference:
Trouillas P, Takayanagi T, Hallett M, Currier RD, Subramony SH, Wessel K, Bryer A, Diener HC, Massaquoi S, Gomez CM, Coutinho P, Ben Hamida M, Campanella G, Filla A, Schut L, Timann D, Honnorat J, Nighoghossian N, Manyam B. International Cooperative Ataxia Rating Scale for pharmacological assessment of the cerebellar syndrome. The Ataxia Neuropharmacology Committee of the World Federation of Neurology. J Neurol Sci. 1997 Feb 12;145(2):205-11.
Other References:
Cano SJ, Hobart JC, Hart PE, Korlipara LV, Schapira AH, Cooper JM. International Cooperative Ataxia Rating Scale (ICARS): appropriate for studies of Friedreich's ataxia? Mov Disord. 2005 Dec;20(12):1585-91.
Sival DA, Brunt ER. The International Cooperative Ataxia Rating Scale shows strong age- dependency in children. Dev Med Child Neurol. 2009 July; 51(7):571-2.
Storey E, Tuck K, Hester R, Hughes A, Churchyard A. Inter-rater reliability of the International Cooperative Ataxia Rating Scale (ICARS). Mov Disord. 2004 Feb;19(2):190- 2.


Document last updated April 2020