Development and refinement of outcome measures and users' satisfaction in physical medicine and rehabilitation

In recent years, the interest in outcome measures has grown in the effort to improve quality of care and customer satisfaction. This thesis provides an overview of topics related to development and refinement of outcome measures and users' satisfaction measurement in Physical and Rehabilitation Medicine. The eight chapters - represented by original articles - are examples of the application of contemporary measurement approaches to some instruments commonly used in rehabilitation. These studies illustrate advances in measurement theory and methods that allow outcome indicators to be measured more accurately, including Rasch analysis. Their utility for researchers and clinicians are discussed. Chapter I focuses on the interpretation of the change scores of two common outcome measures for the upper limb: the Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH) and its short version (QuickDASH). In this work the minimal clinically important difference (MCID) was calculated by a triangulation of distribution and anchor-based approaches for these two questionnaires. The MCID thresholds represents the smallest improvement considered worthwhile by a patient, and thus increase the interpretability of score changes at individual level observed in the clinical setting. Assessing patient progress is an integral part of clinical practice, and meaningful threshold change values of outcome tools are essential for decision making regarding a patient‟s status and to facilitate the communication of results in a concise and comprehensible fashion. Among the different tools used for the assessment of musculoskeletal disorders of the lower limb, the Foot and Ankle Ability Measure (FAAM) showed good psychometrics properties. However, it has not yet been made a translation into Italian. Chapter II shows how to conduct a translation and cross-cultural adaptation of a questionnaire according to the international guidelines for the forward/backward translation. The activities od daily living (ADL) module of the Italian FAAM (FAAM-I/ADL) was translated and then validated with the classical test theory, taking into consideration internal consistency, reproducibility, sensitivity to change and validity. Chapter III presents an example of the test-retest reliability analysis and normative data collection of the the Functional Dexterity Test (FDT). Among the available tests for fine finger dexterity, it has been indicated as a valid instrument to measure outcome in different conditions. FDT scores were collected on a large sample of subjects (N=698) stratified by sex and age. These data could be used, for example, to improve the diagnostic capacity of this test. Chapters IV, V and VI report the complex process of validation through the Rasch analysis. In particular, the aim of Chapter IV and V was to perform the translation and cross-cultural adaptation into Italian and Arabic of the recently revised version of the Client Satisfaction with Device (CSD) module of the Orthotics and Prosthetics Users' Survey (OPUS), and then analyze its psychometric properties using factor and Rasch analyses. The need for validated versions of this instrument into Italian and Arabic is documented by the fact that information on patient satisfaction with orthosis (PSwO) is crucial for verifying and enhancing orthotic quality, for clinical decision making, and for improving patient's quality of life. The aim of the study included in Chapter VI was to perform a comprehensive analysis of the psychometric properties and dimensionality of the Italian version of the Upper Limb Functional Index (ULFI) using both Classical Test Theory and Rasch analysis. The last two chapters - VII and VIII - are systematic reviews of the literature. Chapter VII reports a literature search aimed at identifying which validated questionnaires are used to investigate PSwO in limb orthotics, and analyse their main fields of clinical application, the orthosis-related features analysed by the questionnaires, and the strength of their psychometric properties. Chapter VIII covers the topic of post-surgical scar assessment in rehabilitation. The study is a systematic review that provides a critical appraisal of the most used and clinimetrically sound outcome measures currently available for this topic.