Development of Item Pools
The HDQLIFE™ team utilized a rigorous, multi-phase process to develop the HDQLIFE item pools. First, to characterize HD-relevant health-related quality of life (HRQOL) domains (including the identification of relevant Neuro-QoL™/PROMIS® measures) and to develop items for domains that were not captured within these existing systems, literature reviews and focus group studies were conducted. Focus groups were conducted with different groups, including individuals at early and late stages of diagnosed, symptomatic HD, individuals at risk for HD (individuals that have not been tested but have a parent with HD), individuals with premanifest HD (individuals that have tested positive but have not yet been diagnosed with manifest HD), non-clinical HD caregivers (e.g. family members), and HD clinicians (physicians and nurses). Focus group discussions were analyzed to identify the most important issues affecting quality of life.
The next step of the development of the HDQLIFE measurement system was to create preliminary item pools examining chorea, speech and swallowing difficulties, and end of life issues. Each item pool went through several different iterations based on expert review, translatability review, literacy review, and cognitive debriefing interviews with individuals with HD.
Once the item pools were developed, all items were field tested in more than 500 individuals with HD from across the United States. The best items were included in the final HDQLIFE item banks (measures). A detailed explanation of this process can be found in the HDQLIFE overview paper.