The development of a new computer adaptive test to evaluate chorea in Huntington disease: HDQLIFE Chorea.

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.

New measures to capture end of life concerns in Huntington disease: Meaning and Purpose and Concern with Death and Dying from HDQLIFE (a patient-reported outcomes measurement system).

PURPOSE: Huntington disease (HD) is an incurable terminal disease. Thus, end of life (EOL) concerns are common in these individuals. A quantitative measure of EOL concerns in HD would enable a better understanding of how these concerns impact health-related quality of life. Therefore, we developed new measures of EOL for use in HD. METHODS: An EOL item pool of 45 items was field tested in 507 individuals with prodromal or manifest HD. Exploratory and confirmatory factor analyses (EFA and CFA, respectively) were conducted to establish unidimensional item pools. Item response theory (IRT) and differential item functioning analyses were applied to the identified unidimensional item pools to select the final items. RESULTS: EFA and CFA supported two separate unidimensional sets of items: Concern with Death and Dying (16 items), and Meaning and Purpose (14 items). IRT and DIF supported the retention of 12 Concern with Death and Dying items and 4 Meaning and Purpose items. IRT data supported the development of both a computer adaptive test (CAT) and a 6-item, static short form for Concern with Death and Dying. CONCLUSION: The HDQLIFE Concern with Death and Dying CAT and corresponding 6-item short form, and the 4-item calibrated HDQLIFE Meaning and Purpose scale demonstrate excellent psychometric properties. These new measures have the potential to provide clinically meaningful information about end-of-life preferences and concerns to clinicians and researchers working with individuals with HD. In addition, these measures may also be relevant and useful for other terminal conditions.

HDQLIFE: the development of two new computer adaptive tests for use in Huntington disease, Speech Difficulties, and Swallowing Difficulties.

PURPOSE: Huntington disease (HD) is an autosomal dominant neurodegenerative disease which results in several progressive symptoms, including bulbar dysfunction (i.e., speech and swallowing difficulties). Although difficulties in speech and swallowing in HD have a negative impact on health-related quality of life, no patient-reported outcome measure exists to capture these difficulties that are specific to HD. Thus, we developed a new patient-reported outcome measure for use in the Huntington Disease Health-Related Quality of Life (HDQLIFE) Measurement System that focused on the impact that difficulties with speech and swallowing have on HRQOL in HD. METHODS: Five hundred and seven individuals with prodromal and/or manifest HD completed 47 newly developed items examining speech and swallowing difficulties. Unidimensional item pools were identified using exploratory factor analysis and confirmatory factor analysis (EFA and CFA, respectively). Item response theory (IRT) was used to calibrate the final measures. RESULTS: EFA and CFA identified two separate unidimensional sets of items: Speech Difficulties (27 items) and Swallowing Difficulties (16 items). Items were calibrated separately for these two measures and resulted in item banks that can be administered as computer adaptive tests (CATs) and/or 6-item, static short forms. Reliability of both of these measures was supported through high correlations between the simulated CAT scores and the full item bank. CONCLUSIONS: CATs and 6-item calibrated short forms were developed for HDQLIFE Speech Difficulties and HDQLIFE Swallowing Difficulties. These measures both demonstrate excellent psychometric properties and may have clinical utility in other populations where speech and swallowing difficulties are prevalent.

HDQLIFE: development and assessment of health-related quality of life in Huntington disease (HD).

PURPOSE: Huntington disease (HD) is a chronic, debilitating genetic disease that affects physical, emotional, cognitive, and social health. Existing patient-reported outcomes (PROs) of health-related quality of life (HRQOL) used in HD are neither comprehensive, nor do they adequately account for clinically meaningful changes in function. While new PROs examining HRQOL (i.e., Neuro-QoL-Quality of Life in Neurological Disorders and PROMIS-Patient-Reported Outcomes Measurement Information System) offer solutions to many of these shortcomings, they do not include HD-specific content, nor have they been validated in HD. HDQLIFE addresses this by validating 12 PROMIS/Neuro-QoL domains in individuals with HD and by using established PROMIS methodology to develop new, HD-specific content. METHODS: New item pools were developed using cognitive debriefing with individuals with HD, and expert, literacy, and translatability reviews. Existing item banks and new item pools were field tested in 536 individuals with prodromal, early-, or late-stage HD. RESULTS: Moderate to strong relationships between Neuro-QoL/PROMIS measures and generic self-report measures of HRQOL, and moderate relationships between Neuro-QoL/PROMIS and clinician-rated measures of similar constructs supported the validity of Neuro-QoL/PROMIS in individuals with HD. Exploratory and confirmatory factor analysis, item response theory, and differential item functioning analyses were utilized to develop new item banks for Chorea, Speech Difficulties, Swallowing Difficulties, and Concern with Death and Dying, with corresponding six-item short forms. A four-item short form was developed for Meaning and Purpose. CONCLUSIONS: HDQLIFE encompasses both validated Neuro-QoL/PROMIS measures, as well as five new scales in order to provide a comprehensive assessment of HRQOL in HD.

A new measure for end of life planning, preparation, and preferences in Huntington disease: HDQLIFE end of life planning.

BACKGROUND: Huntington disease is a fatal inherited neurodegenerative disease. Because the end result of Huntington disease is death due to Huntington disease-related causes, there is a need for better understanding and caring for individuals at their end of life. AIM: The purpose of this study was to develop a new measure to evaluate end of life planning. DESIGN: We conducted qualitative focus groups, solicited expert input, and completed a literature review to develop a 16-item measure to evaluate important aspects of end of life planning for Huntington disease. Item response theory and differential item functioning analyses were utilized to examine the psychometric properties of items; exploratory factor analysis was used to establish meaningful subscales. PARTICIPANTS: Participants included 508 individuals with pre-manifest or manifest Huntington disease. RESULTS: Item response theory supported the retention of all 16 items on the huntington disease quality of life ("HDQLIFE") end of life planning measure. Exploratory factor analysis supported a four-factor structure: legal planning, financial planning, preferences for hospice care, and preferences for conditions (locations, surroundings, etc.) at the time of death. Although a handful of items exhibited some evidence of differential item functioning, these items were retained due to their relevant clinical content. The final 16-item scale includes an overall total score and four subscale scores that reflect the different end of life planning constructs. CONCLUSIONS: The 16-item HDQLIFE end of life planning measure demonstrates adequate psychometric properties; it may be a useful tool for clinicians to clarify patients' preferences about end of life care.

Interpretation of a full-information item-level factor analysis of the MMPI-2: normative sampling and nonpathognomonic descriptors.

An exploratory item-level full-information factor analysis was performed on the normative sample for the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). This method of factor analysis, developed by Schilling and Bock (Bock & Schilling, 1997) and based on item response theory, works directly with the response patterns and avoids the artifacts associated with phi coefficients and tetrachoric coefficients. Promax rotation of the factor solution organizes the clinical scale items into 10 factors that we labeled Distrust, Self-Doubt, Fitness, Serenity, Rebelliousness, Instrumentality, Irritability, Artistry, Sociability, and Self-Reliance. A comparison was made to the results of Johnson, Butcher, Null, and Johnson (1984), who performed a principal-component analysis on an item set of 550 items from the previous version of the MMPI (Hathaway & McKinley, 1943). Along with version changes and sampling differences, the essential differences between Johnson et al.'s results and ours may be attributed to differences between the Schilling and Bock method, which uses all information in the item responses, and the principal-component analysis, which uses the partial information contained in pairwise correlation coefficients. This study included 518 of the complete 567 items of the MMPI-2, versus Johnson et al.'s retention of 309 of the initially included 550 items of the previous MMPI. The full-information analysis retained all 518 initially included items and more evenly distributed the items over the 10 resulting factors, all sharply defined by their highest loading items and easy to interpret. Sampling effects and factor label considerations are discussed, along with recommendations for research that would validate the clinical utility of the implied scales for describing normal personality profiles. The full-information procedure provides for Bayes estimation of scores on these scales.