Psychometric evaluation of self-report outcome measures for prosthetic applications

Abstract

Documentation of clinical outcomes is increasingly expected in delivery of prosthetic services and devices. However, many outcome measures suitable for use in clinical care and research have not been psychometrically tested with prosthesis users. The aim of this study was to determine test-retest reliability, mode-of-administration (MoA) equivalence, standard error of measurement (SEM), and minimal detectable change (MDC) of standardized, self-report instruments that assess constructs of importance to people with lower limb loss. Prosthesis users (n = 201) were randomly assigned to groups based on MoA (i.e., paper, electronic, or mixed-mode). Participants completed two surveys 2 to 3 d apart. Instruments included the Prosthetic Limb Users Survey of Mobility, Prosthesis Evaluation Questionnaire-Mobility Subscale, Activities-Specific Balance Confidence Scale, Quality of Life in Neurological Conditions-Applied Cognition/General Concerns, Patient-Reported Outcomes Measurement Information System Profile, and Socket Comfort Score. Intraclass correlation coefficients indicated all instruments are appropriate for group-level comparisons and select instruments are suitable for individual-level applications. Several instruments showed evidence of possible floor and ceiling effects. All were equivalent across MoAs. SEM and MDC were quantified to facilitate interpretation of outcomes and change scores. These results can enhance clinicians' and researchers' ability to select, apply, and interpret scores from instruments administered to prosthesis users.

Keywords: amputees; artificial limbs; health surveys; outcome assessment (health care); outcome measures; outcomes research; prosthesis; questionnaires; rehabilitation; reproducibility of results.

Figures

Figure 1. Study design overview. Participants were assigned to arms based on survey MOA and completed surveys twice within 2-3 days

Figure 2. Study flow diagram