Fragile X-associated tremor ataxia syndrome rating scale: Revision and content validity using a mixed method approach

Michelle H S Tosin; Glenn T Stebbins; Christopher G Goetz; Randi J Hagerman; David Hessl; Melissa A Zolecki; Peter K Todd; Maureen A Leehey; Deborah A Hall

doi:10.3389/fneur.2022.977380

Fragile X-associated tremor ataxia syndrome rating scale: Revision and content validity using a mixed method approach

Front Neurol. 2022 Sep 14:13:977380. doi: 10.3389/fneur.2022.977380. eCollection 2022.

Authors

Michelle H S Tosin¹, Glenn T Stebbins¹, Christopher G Goetz¹, Randi J Hagerman², David Hessl³, Melissa A Zolecki⁴, Peter K Todd^{5

6}, Maureen A Leehey⁷, Deborah A Hall¹

Affiliations

¹ Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States.
² Department of Pediatrics and the MIND Institute, University of California, Davis School of Medicine, Sacramento, CA, United States.
³ Department of Psychiatry and Behavioral Sciences and the MIND Institute, University of California Davis School of Medicine, Sacramento, CA, United States.
⁴ National Fragile X Foundation, McLean, VA, United States.
⁵ University of Michigan, Ann Harbor, MI, United States.
⁶ Ann Arbor Veterans Administration Healthcare System, Ann Arbor, MI, United States.
⁷ University of Colorado School of Medicine, Aurora, CO, United States.

Abstract

Background: The original Fragile X-associated Tremor Ataxia Syndrome Rating Scale (FXTAS-RS) contained 61 items, some requiring modifications to better meet recommendations for patient-focused rating scale development.

Purpose: Provide initial validation of a revised version of the FXTAS-RS for motor signs.

Method: We conducted a two-phase mixed-method approach. In Phase 1, revision, we implemented a Delphi technique identifying pertinent domains/subdomains and developing items through expert consensus. In Phase 2, content validation, we conducted cognitive pretesting assessing comprehensibility, comprehensiveness, and relevance of items to FXTAS motor signs.

Results: After five rounds of Delphi panel and two rounds of cognitive pretesting, the revised version of the FXTAS-RS was established with 18 items covering five domains and 13 subdomains of motor signs. Cognitive pretesting revealed adequate content validity for the assessment of FXTAS motor signs.

Conclusion: The revised FXTAS-RS has been successfully validated for content and it is now ready for large-scale field validation.

Keywords: FXTAS; fragile X syndrome; fragile X tremor ataxia syndrome; outcome measures; severity of illness index.

Abstract

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