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Modified Friedreich's Ataxia Rating Scale (mFARS) NOC
Please visit this website for more information about the instrument: Modified Friedreich's Ataxia Rating Scale
The Modified Friedreich's Ataxia Rating Scale (mFARS) is a subset of the Friedreich's Ataxia Rating Scale (FARS). Please see the E4 - Appendix in the Additional Files section in Subramony et al., 2005
Core: Friedreich's Ataxia (FA)
Short Description of Instrument
The FARS is a series of physical examination assessments to measure disease progression in patients with FA. (Rummey et al., 2019) The FARS assesses the bulbar, upper limb, lower limb, peripheral nerve, and upright stability/gait functions and incorporates functional staging, activities of daily living and assessment, and performance measures into the score. (Ataxia Study Group, 2014)
The mFARS is a modified version of FARS that is used in clinical trials to assess the efficacy of investigational products for use in FA. (Rummey et al., 2019)
The mFARS has 4 subscales involving direct patient participation (bulbar, upper limb, lower limb, and upright stability). (Patel et al.,2016; Rummey et al., 2019; Subramony et al., 2005)
The bulbar function assesses areas including strength and volume of coughing and clarity of speech. These areas are assessed by asking patients to repeat specific sentences: "The President lives in the White House" and "The traffic is heavy today." Related daily activities: swallowing and speech.
The upper limb coordination subscale has a total of 5 different movements that are used to assess tremor (simple shaking) and coordination of the hands and arms. Related daily activities:  cutting food and handling utensils.
The lower limb coordination subscale assesses coordination of the legs and feet. Related daily activities: dressing.
Upright stability, the largest subscale in the mFARS, assesses ability to stand and walk. Sitting posture, upright stability with eyes opened or closed, and stance, among other activities, are measured. Related daily activities: standing and walking. (Subramony et al., 2005)
Comments/Special Instructions
The FARS comprises a measure of ataxia, an activity of daily living (ADL) subscale and a neurological subscale. Face and content validity and inter-rater reliability are good. (Subramony et al., 2005) The FARS is comprised of five components: bulbar, upper limb, lower limb, peripheral nervous system, and upright stability. (Patel et al., 2016; Subramony et al., 2005)
The mFARS is a subscale obtained from the FARS neurological domain that evaluates only the activities involving direct patient participation (bulbar, upper limb, lower limb, and upright stability) and excludes peripheral nerve testing. (Rummey et al., 2019)
The validity and structure of the mFARS have been confirmed and has an excellent test-retest reliability. (Rummey et al., 2019, 2020; Tai et al., 2021) It has been accepted by the US Food and Drug Administration as an appropriate primary outcome measure for clinical trials in Friedreich's Ataxia. (Freidreich's Ataxia Research Alliance, 2017; Tai et al., 2021)
Scoring and Psychometric Properties
The mFARS performs tests in the FARS subscales involving direct patient participation (bulbar, upper limb, lower limb, and upright stability). (Patel et al, 2016)
This scale scores up to a maximum total of 93 points (Rummey et al., 2019), where the higher the score the greater the disease severity. (Bürk et al. 2013; Patel et al. 2016; Saute et al. 2012; Subramony et al. 2005)
Maximum points per mFARS subscale:
Bulbar: 5
Upper limb coordination: 36
Lower limb coordination: 16
Upright stability: 36
Psychometric Properties:
Rummey et al., 2019 found that, "Cronbach alpha values were satisfactory for the upper limb (A, 0.87) and lower limb (B, 0.91), as well as for the upright stability scale (E, 0.87). The modified bulbar subscale (mA) in the mFARS showed an a of 0.65." For the complete examinations, both the FARS and the mFARS showed a Cronbach alpha of 0.92. All subscales correlated with disease duration. All items in the mFARS subscales correlated with coefficients of >0.3 with their subscores.
A correlation-based psychometric analysis of the neurologic FARS score justifies the validity of the scale. Omission of items in the mFARS strengthens the overall construct compared with the complete FARS. (Rummey et al., 2019)

The mFARS shows appropriate item-subscale groupings, inter subscale correlations and internal consistency (Cronbach's alpha >0.90). The omission of items of limited functional significance as created in the mFARS improved the features of the measures compared to the FARS. (Rummey et al., 2019)
The mFARS and FARS exams have excellent test-retest properties. The mFARS appears less prone to floor effects and shows a better dimensional structure than the FARS (Rummey et al., 2020).

Ceiling effects are apparent in some of the subscales, i.e., subscale C, heel-shin tap and heel-shin slide and subscale E, upright stability. Additional analyses of longitudinal changes will be necessary specifically in non-ambulant patients. (Rummey et al., 2019)
Key References:

Subramony SH, May W, Lynch D, Gomez C, Fischbeck K et al. Measuring Friedreich ataxia: Interrater reliability of a neurologic rating scale. Neurology 2005;64:1261-1262.
Rummey C, Corben LA, Delatycki MB, Subramony SH, Bushara K, Gomez CM, Hoyle JC, Yoon G, Ravina B, Mathews KD, Wilmot G, Zesiewicz T, Perlman S, Farmer JM, Lynch DR. Psychometric properties of the Friedreich Ataxia Rating Scale. Neurol Genet. 2019 Oct 29;5(6):371.
Rummey C, Zesiewicz TA, Perez-Lloret S, Farmer JM, Pandolfo M, Lynch DR. Test-retest reliability of the Friedreich's ataxia rating scale. Ann Clin Transl Neurol. 2020 Sep;7(9):1708-1712.
Additional References:

Ataxia Study Group. (2014) The modified Friedreich's Ataxia Scale (mFARS). Available from: Accessed 14November2022.  
Bürk K, M?lzig U, Wolf S, Heck S, Dimitriadis K, Schmitz-Hübsch T, Hering S, Lindig TM, Haug V, Timmann D, Degen I, Kruse B, DÖrr JM, Ratzka S, Ivo A, SchÖls L, Boesch S, Klockgether T, Klopstock T, Schulz JB. Comparison of three clinical rating scales in Friedreich ataxia (FRDA). Mov Disord. 2009 Sep 15;24(12):1779-84.
Bürk K, Schulz SR, Schulz JB. Monitoring progression in Friedreich ataxia (FRDA): the use of clinical scales. J Neurochem. 2013 Aug;126 Suppl 1:118-24.
Corti M, Casamento-Moran A, Delmas S, Bracksieck S, Bowman J, Meyer B, Norman S, Subramony S, Christou EA. Temporal but not spatial dysmetria relates to disease severity in FA. J Neurophysiol. 2020 Feb 1;123(2):718-725.
Friedman LS, Farmer JM, Perlman S, Wilmot G, Gomez CM, Bushara KO, Mathews KD, Subramony SH, Ashizawa T, Balcer LJ, Wilson RB, Lynch DR. Measuring the rate of progression in Friedreich ataxia: implications for clinical trial design. Mov Disord. 2010 Mar 15;25(4):426-32.
Friedreich's Ataxia Research Alliance. Biomarkers and Endpoints for Friedreich's Ataxia. Available from: BiomarkersEndpointsForFA.pdf ( Accessed 07November2022.
Lynch DR, Farmer JM, Tsou AY, Perlman S, Subramony SH, Gomez CM, Ashizawa T, Wilmot GR, Wilson RB, Balcer LJ. Measuring Friedreich ataxia: complementary features of examination and performance measures. Neurology. 2006 Jun 13;66(11):1711-1716.
Patel M, Isaacs CJ, Seyer L, Brigatti K, Gelbard S, Strawser C, Foerster D, Shinnick J, Schadt K, Yiu EM, Delatycki MB, Perlman S, Wilmot GR, Zesiewicz T, Mathews K, Gomez CM, Yoon G, Subramony SH, Brocht A, Farmer J, Lynch DR. Progression of Friedreich ataxia: quantitative characterization over 5 years. Ann Clin Transl Neurol. 2016 Jul 25;3(9):684-94.
Reata Pharmaceuticals. (2019) Understanding the modified Friedreich's ataxia rating scale (mfars). Available from: Accessed 02November2022.
Saute JA, Donis KC, Serrano-Munuera C, Genis D, Ramirez LT, Mazzetti P, PÉrez LV, Latorre P, Sequeiros J, Matilla-Dueñas A, Jardim LB; Iberoamerican Multidisciplinary Network for the Study of Movement Disorders (RIBERMOV) Study Group. Ataxia rating scales--psychometric profiles, natural history and their application in clinical trials. Cerebellum. 2012 Jun;11(2):488-504.
Sudarsky LR. Validation of a neurological-exam-based rating scale (FARS) for Friedreich's ataxia. Nat Clin Pract Neurol. 2007 Mar;3(3):138-139.
Tai G, Corben LA, Woodcock IR, Yiu EM, Delatycki MB. Determining the Validity of Conducting Rating Scales in Friedreich Ataxia through Video. Mov Disord Clin Pract. 2021 Apr 6;8(5):688-693.
Document last updated June 2023