Structural validity and reliability of the patient experience measure: A new approach to assessing psychosocial experience of upper limb prosthesis users.

Recent advances in upper limb prosthetics include sensory restoration techniques and osseointegration technology that introduce additional risks, higher costs, and longer periods of rehabilitation. To inform regulatory and clinical decision making, validated patient reported outcome measures are required to understand the relative benefits of these interventions. The Patient Experience Measure (PEM) was developed to quantify psychosocial outcomes for research studies on sensory-enabled upper limb prostheses. While the PEM was responsive to changes in prosthesis experience in prior studies, its psychometric properties had not been assessed. Here, the PEM was examined for structural validity and reliability across a large sample of people with upper limb loss (n = 677). The PEM was modified and tested in three phases: initial refinement and cognitive testing, pilot testing, and field testing. Exploratory factor analysis (EFA) was used to discover the underlying factor structure of the PEM items and confirmatory factor analysis (CFA) verified the structure. Rasch partial credit modeling evaluated monotonicity, fit, and magnitude of differential item functioning by age, sex, and prosthesis use for all scales. EFA resulted in a seven-factor solution that was reduced to the following six scales after CFA: social interaction, self-efficacy, embodiment, intuitiveness, wellbeing, and self-consciousness. After removal of two items during Rasch analyses, the overall model fit was acceptable (CFI = 0.973, TLI = 0.979, RMSEA = 0.038). The social interaction, self-efficacy and embodiment scales had strong person reliability (0.81, 0.80 and 0.77), Cronbach's alpha (0.90, 0.80 and 0.71), and intraclass correlation coefficients (0.82, 0.85 and 0.74), respectively. The large sample size and use of contemporary measurement methods enabled identification of unidimensional constructs, differential item functioning by participant characteristics, and the rank ordering of the difficulty of each item in the scales. The PEM enables quantification of critical psychosocial impacts of advanced prosthetic technologies and provides a rigorous foundation for future studies of clinical and prosthetic interventions.

Timed activity performance in persons with upper limb amputation: A preliminary study.

STUDY DESIGN: 55 subjects with upper limb amputation were administered the T-MAP twice within one week. PURPOSE: To develop a timed measure of activity performance for persons with upper limb amputation (T-MAP); examine the measure's internal consistency, test-retest reliability and validity; and compare scores by prosthesis use. INTRODUCTION: Measures of activity performance for persons with upper limb amputation are needed The time required to perform daily activities is a meaningful metric that implication for participation in life roles. METHODS: Internal consistency and test-retest reliability were evaluated. Construct validity was examined by comparing scores by amputation level. Exploratory analyses compared sub-group scores, and examined correlations with other measures. RESULTS: Scale alpha was 0.77, ICC was 0.93. Timed scores differed by amputation level. Subjects using a prosthesis took longer to perform all tasks. T-MAP was not correlated with other measures of dexterity or activity, but was correlated with pain for non-prosthesis users. DISCUSSION: The timed scale had adequate internal consistency and excellent test-retest reliability. CONCLUSIONS: Analyses support reliability and construct validity of the T-MAP. LEVEL OF EVIDENCE: 2c "outcomes" research.