Improving the Conceptual Coverage of the 15-item Penn Parkinson’s Daily Activity Questionnaire (PDAQ-15) for Use in the Mild-to-Moderate Lewy Body Dementia Population
Author(s)
Daniel Weintraub, MD1, JEssica Baldasaro, BS2, Andrew Siderowf, PhD1, Eugenia Mamikonyan, PhD1, Antoine Regnault, PhD3, Sara Strzok, MA4, Leanne Munsie, MD5, Julie Chandler, PhD5, Kevin Biglan, MD5, Laure Delbecque, PhD5.
1University of Pennsylvania School of Medicine, Pennsylvania, PA, USA, 2Modus Outcomes, Cary, NC, USA, 3Modus Outcomes, Lyon, France, 4Modus Outcomes, Minneapolis, MN, USA, 5Eli Lilly and Company, Indianapolis, IN, USA.
1University of Pennsylvania School of Medicine, Pennsylvania, PA, USA, 2Modus Outcomes, Cary, NC, USA, 3Modus Outcomes, Lyon, France, 4Modus Outcomes, Minneapolis, MN, USA, 5Eli Lilly and Company, Indianapolis, IN, USA.
OBJECTIVES: Improve the PDAQ-15 by adding new items to detect treatment benefit in mild-to-moderate Lewy body dementia (LBD; i.e., Parkinson’s disease dementia and dementia with Lewy bodies) patients, and evaluate the content validity of the updated questionnaire.
METHODS: This multi-phase study was approved by Copernicus Group Independent Review Board. Phase 1 involved reviewing the PDAQ’s original item pool and qualitative data from five focus groups with 35 knowledgeable informants (KI) of LBD patients to identify potential supplemental items. Phase 2 included concept elicitation and cognitive debriefing interviews of the PDAQ-15 and proposed supplemental items with 11 KIs of mild-to-moderate LBD patients in the United States. Interview transcripts were thematically analyzed using ATLAS.ti software and compiled in summary tables. Conceptual saturation was assessed.
RESULTS: In Phase 1, 12 supplemental items from the PDAQ’s original item pool were added to the PDAQ-15. In Phase 2, KIs identified 46 concepts related to activities impacted by cognitive impairment. Data trended towards conceptual saturation. Concepts related to 9/15 PDAQ-15 items and 11/12 supplemental items were elicited spontaneously, and all items were endorsed as relevant with probing. Interview findings and discussions with the instrument developer led to revisions of 4 PDAQ-15 items, 4 supplemental items and instructions for clarity, deletion of 2 supplemental items due to response issues and conceptual overlap with existing PDAQ-15 items, and creation of 2 items, resulting in a total of 12 supplemental items. Feedback on the items, recall period and response options was broadly positive.
CONCLUSIONS: This research supports the conceptual relevance and comprehensiveness of the PDAQ-15 plus 12 supplemental items in mild-to-moderate LBD. There were no major issues with item understanding, recall period, or response options. These results provide a foundation for future evaluation using Rasch analyses of the instrument’s ability to accurately measure cognition-related instrumental activities of daily living in this population.
METHODS: This multi-phase study was approved by Copernicus Group Independent Review Board. Phase 1 involved reviewing the PDAQ’s original item pool and qualitative data from five focus groups with 35 knowledgeable informants (KI) of LBD patients to identify potential supplemental items. Phase 2 included concept elicitation and cognitive debriefing interviews of the PDAQ-15 and proposed supplemental items with 11 KIs of mild-to-moderate LBD patients in the United States. Interview transcripts were thematically analyzed using ATLAS.ti software and compiled in summary tables. Conceptual saturation was assessed.
RESULTS: In Phase 1, 12 supplemental items from the PDAQ’s original item pool were added to the PDAQ-15. In Phase 2, KIs identified 46 concepts related to activities impacted by cognitive impairment. Data trended towards conceptual saturation. Concepts related to 9/15 PDAQ-15 items and 11/12 supplemental items were elicited spontaneously, and all items were endorsed as relevant with probing. Interview findings and discussions with the instrument developer led to revisions of 4 PDAQ-15 items, 4 supplemental items and instructions for clarity, deletion of 2 supplemental items due to response issues and conceptual overlap with existing PDAQ-15 items, and creation of 2 items, resulting in a total of 12 supplemental items. Feedback on the items, recall period and response options was broadly positive.
CONCLUSIONS: This research supports the conceptual relevance and comprehensiveness of the PDAQ-15 plus 12 supplemental items in mild-to-moderate LBD. There were no major issues with item understanding, recall period, or response options. These results provide a foundation for future evaluation using Rasch analyses of the instrument’s ability to accurately measure cognition-related instrumental activities of daily living in this population.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR136
Topic
Clinical Outcomes, Methodological & Statistical Research, Patient-Centered Research
Topic Subcategory
Instrument Development, Validation, & Translation, Patient-reported Outcomes & Quality of Life Outcomes
Disease
Neurological Disorders, No Additional Disease & Conditions/Specialized Treatment Areas