International Cooperative Ataxia Rating Scale

Original Editor - Ajay Upadhyay

Top Contributors - Ajay Upadhyay and George Prudden  


The International Cooperative Ataxia Rating Scale (ICARS) is an outcome measure that was created in 1997 by the Committee of the World Federation of Neurology with the goal of standardizing the quantification of impairment due to cerebellar ataxia. The scale is scored out of 100 with 19 items and 4 subscales of postural and gait disturbances, limb ataxia, dysarthria, and oculomotor disorders. Higher scores indicate higher levels of impairment.

Intended Population

Clients suffering from cerebellar ataxia. The ICARS has been validated for use in patients with focal cerebellar lesions [1] and hereditary spinocerebellar and Friedrich's ataxia. [2] [3]

Time taken to complete the test - 30 minutes

Method of Use

The International Cooperative Ataxia Rating Scale (ICARS) (Trouillas et al., 1997) is a 100-point semi-quantitative scale. It is divided into four parts, on the basis of the compartmentalization of cerebellar symptoms (Babinski & Tournay, 1913):

 Postural and stance disturbances (subscore: /34)
 Limb movement disturbances (subscore: /52)
 Speech disorders (subscore: /8)
 Oculomotor deficits (subscore: /6)

Posture and Gait Score (total of scores A to G)

A. Walking capacities: 10-m test including half-turn, near a wall

   0 Normal
 1 Almost normal naturally, unable to walk with feet in tandem
 2 Walking without support, but abnormal and irregular
 3 Walking without support but with considerable staggering; difficulties in half-turn
 4 Walking with autonomous support impossible; episodic support of the wall for a 10-m test
 5 Walking only possible with one stick
 6 Walking only possible with two special sticks or with a stroller
 7 Walking only with accompanying person
 8 Walking impossible, even with accompanying person (wheelchair)and so on.

PG: 34 Min.: 0 Max.: 100

Grading for ataxia. Balance assessed using posture and gait (PG) subcomponent


Cerebellar Disorders - A Practical Approach to Diagnosis and Management; Mario Ubaldo Manto, 4 - Clinical scales: 53-68


High inter-rater reliability (ICC50.95)

High test–re-test reliability (ICC50.97)

Adequate internal consistency(Cronbach’s a50.94)

Good internal structural validity



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  1. Schoch, B; et al. (Nov 2007). "Reliability and validity of ICARS in focal cerebellar lesions". Movement Disorders 22 (15): 2162–2169.
  2. Schmitz-Hubsch, T; et al. (May 2006). "Reliability and validity of the International Cooperative Ataxia Rating Scale: a study in 156 spinocerebellar ataxia patients". Movement Disorders 21 (5): 699–704
  3. Storey, E; Tuck, K.; Hester, R.; Hughes, A.; Churchyard, A. (Feb 2004). "Inter-rater reliability of the International Cooperative Ataxia Rating Scale (ICARS)". Movement Disorders 19 (2): 190–192.