Construct validity, reliability, and sensitivity of proxy-reported pain interference in individuals with cerebral...

Area of Science:

• Pain Management
• Rehabilitation Medicine
• Psychometrics

Background:

• Chronic pain is common in individuals with cerebral palsy (CP).
• Assessing pain in CP is challenging due to communication and cognitive impairments.
• The Modified Brief Pain Inventory-Proxy (mBPI-P) is used for proxy pain assessment.

Purpose of the Study:

• To validate the 7-item mBPI-P for proxy reporting in individuals with CP.
• To examine the factor structure, reliability, and sensitivity of the mBPI-P.
• To support its use in clinical practice and research.

Main Methods:

• Confirmatory factor analysis (CFA) to assess construct validity of 7-, 10-, and 12-item mBPI-P versions.
• Multi-level modeling and linear mixed-effects analysis for test-retest reliability and sensitivity.
• Study 1: 250 individuals with CP and chronic pain. Study 2: Separate cohort for reliability and intervention sensitivity.

Main Results:

• The 7-item, two-factor mBPI-P model showed the best fit (CFI=.979, RMSEA=.083) with strong internal consistency (α=.900).
• Scores correlated moderately with pain severity/duration and negligibly with physical disability, supporting validity.
• Excellent test-retest reliability (RkF=.97) and significant pain reduction post-injection observed.

Conclusions:

• The 7-item mBPI-P is a reliable and valid measure of pain interference in individuals with CP.
• Its psychometric properties support its use in clinical settings and research for pain assessment and treatment efficacy.
• The reduced item count enhances measurement properties for proxy reporting.