title: The development of a new computer adaptive test to evaluate chorea in Huntington disease: HDQLIFE Chorea.
abstract: Huntington's disease (HD) is an autosomal dominant neurodegenerative disease associated with motor, behavioral, and cognitive deficits. The hallmark symptom of HD, chorea, is often the focus of HD clinical trials. Unfortunately, there are no self-reported measures of chorea. To address this shortcoming, we developed a new measure of chorea for use in HD, HDQLIFE Chorea.
  
  
  
  Qualitative data and literature reviews were conducted to develop an initial item pool of 141 chorea items. An iterative process, including cognitive interviews, expert review, translatability review, and literacy review, was used to refine this item pool to 64 items. These 64 items were field tested in 507 individuals with prodromal and/or manifest HD. Exploratory and confirmatory factor analyses (EFA and CFA, respectively) were conducted to identify a unidimensional set of items. Then, an item response theory graded response model (GRM) and differential item functioning analyses were conducted to select the final items for inclusion in this measure.
  
  
  
  EFA and CFA supported the retention of 34 chorea items. GRM and DIF supported the retention of all of these items in the final measure. GRM calibration data were used to inform the selection of a 6-item, static short form and to program the HDQLIFE Chorea computer adaptive test (CAT). CAT simulation analyses indicated a 0.99 correlation between the CAT scores and the full item bank.
  
  
  
  The new HDQLIFE Chorea CAT and corresponding 6-item short form were developed using established rigorous measurement development standards; this is the first self-reported measure developed to evaluate the impact of chorea on HRQOL in HD. This development work indicates that these measures have strong psychometric properties; future work is needed to establish test-retest reliability and responsiveness to change.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Building NCRC B14, Room D037, Ann Arbor, MI, 48109-2800, USA. carlozzi@med.umich.edu.
authors.forename: N E
authors.initials: NE
authors.lastname: Carlozzi
authors.affiliation: College of Nursing, The University of Iowa, Iowa City, IA, USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Downing
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Building NCRC B14, Room D037, Ann Arbor, MI, 48109-2800, USA.|Institute for Social Research, University of Michigan, Ann Arbor, MI, USA.
authors.forename: S G
authors.initials: SG
authors.lastname: Schilling
authors.affiliation: Center on Outcomes, Research and Education, Evanston Northwestern Healthcare, Northwestern University, Evanston, IL, USA.|Institute for Health Services Research and Policy Studies, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: J-S
authors.initials: JS
authors.lastname: Lai
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Building NCRC B14, Room D037, Ann Arbor, MI, 48109-2800, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Goodnight
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Building NCRC B14, Room D037, Ann Arbor, MI, 48109-2800, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Miner
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: S
authors.initials: S
authors.lastname: A Frank
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002819:Chorea / Q000523:psychology*; D003201:Computers / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000150:complications / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Chorea; HDQLIFE; Health-related quality of life; Huntington’s disease; Motor function; Neuro-QoL; PROMIS; Patient-reported outcome (PRO)