Content Validity of the Friedrich’s Ataxia Rating Scale – Activities of Daily Living (FARS-ADL) for use in Patients with Spinocerebellar Ataxia (SCA)

Topic:

Other

Poster Number: M277

Author(s):

Michele Potashman, M.S., PhD, Biohaven, Katja Rudell, PhD, Epidemiology and Real-World Sciences, Parexel International, London, UK, Naomi Suminski, MS, Epidemiology and Real-World Sciences, Parexel International, London, UK, Rinchen Doma, MPH, Epidemiology and Real-World Sciences, Parexel International, London, UK, Maggie Heinrich, PhD, Epidemiology and Real-World Sciences, Parexel International, London, UK, Linda Abetz-Webb, MS, Patient-Centered Outcomes Assessment, London, UK, Melissa Beiner, MD, Biohaven Pharmaceuticals, Inc., Liana S Rosenthal, MD, PhD, John Hopkins School of Medicine, Department of Neurology, Baltimore, MD, USA, Sheng-Han Kuo, MD, Columbia University, Department of Neurology, New York, NY, USA, Theresa Zesiewicz, MD, FAAN, University of South Florida, Terry Fife, MD, Barrow Neurological Institute, Pheonix, AZ, USA, Bart van de Warrenburg, MD, PhD, Radboud University Medical Center, Department of Neurology, Nijmegen, NL, Giovanni Ristori, MD, Sant’Andrea Hospital, Sapienza University of Rome and Fondazione Santa Lucia IRCCS, Matthis Synofzik, MD, Hertie-Institute for Clinical Brain Research, University Tübingen, Tuebingen, DE, S H Subramony, M.D., Univsersity of Florida, Fixel Center for Neurological Disorders, Susan Perlman, MD, University of California, Los Angeles, Jeremy D Schmahmann, MD, Ataxia Center, Laboratory for Neuroanatomy and Cerebellar Neurobiology, Department of Neurology, MGH, Gil L'italien, PhD, Biohaven

Introduction: The FARS-ADL is a valid and highly utilized 9-item measure for assessing patients with Friedrich’s Ataxia. While it has been used in several SCA studies, data supporting the content validity in SCA patients has not been established.

Methods: SCA patients (N=7) and clinicians treating SCA patients (N=8) participated in interviews to establish the patient-relevance, examine the clarity and ease of use of the FARS-ADL and to identify meaningful change scores. All interviews/analyses were conducted in accordance with standard procedures/methods.

Results: The FARS-ADL concepts most frequently reported by patients spontaneously were difficulties with walking (n=7/7), falls (n=6/7), speech difficulties (n=4/7) and swallowing (n=3/7). Clinicians described the use of assistive devices to walk and speech/communication impairments as impacts of key importance when describing disease severity/progression in clinical practice. Clinicians reported FARS-ADL as useful in clinical practice with SCA patients. The FARS-ADL was reported as clear to understand and easy to use by clinicians. Suggestions for improvements included methods to assess speech when patient has an accent; need to clarify response options for dressing, falling, walking and bladder items, as certain response options reflecting higher impairment levels were hard to distinguish; need to clarify sitting instructions and response options. Most clinicians interviewed found it possible to generate a correct and valid assessment in SCA patients, and reported rarely using the 0.5 scoring increment. Stability on any item and/or total score over 1-year was considered meaningful by n=5/8 clinicians, with others indicating a longer time period was needed, depending on the natural history of the respective SCA. A 1-3 point range for worsening/improvements on the total score was considered meaningful (median values: 2-points worsening and 1-point improvement).

Conclusions: Findings support the FARS-ADL as appropriately constructed for use in SCA patients, with suggestions offered to improve selected response options.