The Burden of Stroke Scale (BOSS): Validating patient-reported communication difficulty and associated psychological distress in stroke survivors

Background: The Burden of Stroke Scale (BOSS) (Doyle et al., 2002) is a health-status assessment instrument designed to measure patient-reported difficulty in multiple domains of functioning, psychological distress associated with specific functional limitations, and general well-being in stroke survivors. Aims: This study was designed to examine the discriminative and concurrent validity of the BOSS Communication Difficulty (CD) and Communication-Associated Psychological Distress (CAPD) scales. A secondary purpose was to provide a preliminary examination of the relationships between the BOSS CD and CAPD scales and aspects of subjective well-being, including the frequency with which participants reported experiencing general positive and negative emotional states. Methods & Procedures: The BOSS was administered as a face-to-face interviewer-assisted survey to 281 medically stable, community-dwelling stroke survivors selected from five collaborating centres in the USA. Prior to administration of the BOSS, all subjects were rated for severity of communication impairment using the Boston Diagnostic Aphasia Examination (BDAE) Severity Rating Scale (Goodglass, Kaplan, & Baressi, 2001) and were administered Subtest 8 of the Revised Token Test (RTT), (McNeil & Prescott, 1978). The discriminant validity of the BOSS CD and CAPD scales was examined by comparing scores in stroke survivors with (N = 135) and without (N = 146) communication impairment, and within the communicatively impaired sample when classified according to BDAE ratings and RTT performance. Concurrent validity of the BOSS CD and CAPD scales was examined by correlating BOSS scores with BDAE ratings and RTT performance. Finally, correlations between the BOSS CAPD, BOSS CD, Positive Mood, and Negative Mood scales were calculated. Outcomes & Results: Statistical analyses revealed significant differences between communicatively impaired and non-communicatively impaired subjects on the BOSS CD and CAPD scales, as well as significant differences between communicatively impaired subjects of differing severity levels classified both by BDAE severity ratings and RTT performance. Correlational analyses revealed moderately strong relationships among the BOSS CD scale, BDAE severity ratings, and RTT performance. Finally, correlations among the BOSS CAPD, CD, Positive Mood, and Negative Mood scales revealed true covarying relationships of moderate strength between the BOSS CAPD and CD scales, and also between the CAPD and Negative Mood Scales. Conclusions: These findings provide preliminary support for the discriminant and construct validity of the BOSS Communication Difficulty (CD) and Communication Associated Distress (CAPD) Scales, and provide an empirical rationale for further research into the relationships between functional status, patient-reported health perceptions, and subjective well-being in stroke survivors with communication disorders.