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Published on: February 11, 2019
The development of a new computer adaptive test to evaluate chorea in Huntington disease: HDQLIFE Chorea
N E Carlozzi1, N R Downing2, S G Schilling3,4
1Department 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.
Insights
A new self-reported measure, HDQLIFE Chorea, was developed to assess chorea symptoms in Huntington's disease (HD). This tool aims to improve clinical trials by capturing the impact of chorea on quality of life for HD patients.
Area of Science:
- Neuroscience
- Clinical Psychology
- Psychometrics
Background:
- Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by motor, cognitive, and behavioral deficits.
- Chorea, a hallmark motor symptom of HD, significantly impacts patient quality of life (HRQOL).
- Existing clinical trials for HD often lack validated self-reported measures to quantify chorea severity and its impact.
Purpose of the Study:
- To develop and validate a novel, self-reported measure for assessing chorea in individuals with Huntington's disease.
- To create a reliable tool that captures the impact of chorea on HRQOL, addressing a critical gap in HD assessment.
Main Methods:
- A comprehensive item pool was generated through qualitative data and literature reviews, followed by iterative refinement including cognitive interviews and expert reviews.
- A large sample of 507 individuals with prodromal or manifest HD participated in field testing.
- Statistical analyses, including Exploratory and Confirmatory Factor Analyses (EFA/CFA) and Item Response Theory (IRT) models (GRM, DIF), were employed for item selection and measure development.
Main Results:
- The study successfully refined the item pool to a 34-item measure, supported by EFA and CFA.
- Item Response Theory analyses confirmed the suitability of all items for the final measure.
- A 6-item short form and a computer adaptive test (CAT) version (HDQLIFE Chorea) were developed, demonstrating high correlation (0.99) with the full item bank in simulations.
Conclusions:
- The HDQLIFE Chorea CAT and 6-item short form represent the first self-reported measures designed to evaluate chorea's impact on HRQOL in HD.
- These newly developed measures exhibit strong psychometric properties, based on rigorous development standards.
- Future research should focus on establishing the test-retest reliability and responsiveness to change of these instruments.
Purpose:
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.
Methods:
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.
Results:
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.
Conclusions:
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.
