Using the patient generated index to evaluate response shift post-stroke Sara Ahmed 1, *, Nancy E. Mayo 2,3 , Sharon Wood-Dauphinee 2,4 , James A. Hanley 2,5 & S. Robin Cohen 6,7 1 Clinical and Health Informatics, Faculty of Medicine, McGill University, Montreal, Quebec, Canada (E-mail: sara.ahmed@mail.mcgill.ca); 2 Division of Clinical Epidemiology, Royal Victoria Hospital, Montreal, Quebec, Canada; 3 Faculty of Medicine, School of Physical and Occupational Therapy, McGill University, Montreal, Quebec, Canada; 4 School of Physical and Occupational Therapy, Department of Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada; 5 Department of Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada; 6 Departments of Oncology and Medicine, McGill University Health Center and Lady Davis Institute Medical Scientist, Canada; 7 National Cancer Institute of Canada and Canadian Institutes of Health Research, Canada Accepted in revised form 27 May 2005 Abstract Background: Individualized measures allow for the assessment of health-related quality of life (HRQL) based on areas that are relevant to the person and may prove to be useful for evaluating response shift (reconceptualization of HRQL and change in values). Objective: The objective of this study was to assess reconceptualization of HRQL and change of individual values among persons with stroke during the first six months of recovery. Methods: The data collection for this study was incorporated into a randomized trial of acute post-stroke care. Individualized HRQL was evaluated at 6 and 24 weeks post-stroke using the Patient Generated Index (PGI). At 24 weeks a semi-structured interview was administered to assess whe- ther verbalizations given by subjects indicated that they had experienced a response shift. Results: Ninety two subjects (61%) had complete PGI information at the 6- and 24-week evaluations, and of these, 46 completed the semi-structured interview. Between the 6- and 24-week evaluations, the domains selected were: the same for 10 (11%) subjects, reduced for 27 (29%), expanded for 11 (12%), and completely different for 44 (48%) subjects. Twenty eight percent (n=13) of subjects recovering from stroke experienced a response shift as evidenced by the semi-structured interviews. Conclusion: The PGI provides valuable information regarding changes in person’s conceptualization of HRQL and values, but the feasibility of using an individualized measure during the first six months post-stroke is limited by the added complexity of completing and interpreting such a measure. Key words: Individualized Health-Related Quality of Life, Response Shift, Stroke, Change Introduction Health-related quality of life (HRQL) outcomes play a central role in clinical research. To evaluate the benefit of interventions, researchers are not only focusing on biological and physical indicators of health, but are also considering the broader implications on individuals’ perceived well-being. Although there has not been one clear definition of HRQL, there is general agreement that it refers to a person’s subjective physical, emotional, and social well being [1]. The challenge of using HRQL measures in lon- gitudinal studies or clinical trials is related to their self-report nature. Because measures of HRQL are completed from the perspective of the individual, Quality of Life Research (2005) 14: 2247–2257 Ó Springer 2005 DOI 10.1007/s11136-005-8118-4