Participant-Proxy Reliability in Traumatic Brain Injury Outcome Research

OBJECTIVE: To assess reliability between persons with Traumatic Brain Injury (TBI) and their self-selected proxies. DESIGN: Intraclass Correlation Coefficients were used to assess participant-proxy reliability on the Craig Handicap Assessment and Reporting Technique (CHART), the Community Integration Questionnaire (CIQ), and the Functional Independence Measure (FIM). SETTING: Participants had been discharged to the community from inpatient rehabilitation between six months and approximately five years prior to the study's beginning. PARTICIPANTS: 204 persons with moderate to severe TBI and their self-selected proxies. RESULTS: Eighty-seven percent of the items on the three instruments exhibited moderate to high intraclass correlation (ICC), with strongest participant-proxy agreement for questions assessing concrete, observable information. Participant-proxy agreement was poorest when assessing cognitive and money management capacity as well as out-of-home activities. CONCLUSIONS: For many types of items, participant-proxy reliability is sufficient to merit the use of proxies in TBI outcome research when the participants are allowed to select their own proxy.