Characterization of muscle strength using the strength domain of the stroke impact scale: An integrative review

Abstract

BACKGROUND AND OBJECTIVE: Muscle weakness is among the most common and obvious impairments in older adults and individuals with neurologic disorders. Although impairments in muscle strength are typically characterized using performance measures, the impairments have also been described using patient or observer-report. The objective of this review was to summarize literature describing use of a patient-report instrument, the Strength Domain (SD) of the Stroke Impact Scale (SIS), to grade strength impairments. METHODS: Peer-reviewed literature reporting SD scores for the SIS was identified using computerized searches of the CINAHL, PubMed, and Scopus databases followed by hand searches. Potentially relevant articles were then mined for data on the participants tested, the SIS version used, scores documented, and clinimetric properties reported. RESULTS: Sixty-five articles were judged appropriate based on inclusion and exclusion criteria. The articles involved more than 7000 residents of 22 countries. All articles focused on individuals with stroke (usually chronic), although one also included community-dwelling adults without stroke. The SIS version used was frequently unreported, but 3.0 was version most often specified. For articles reporting SD scale scores the mean ranged from 19.7 to 85.5. Construct (known groups, convergent, and discriminant) validity of the SD was supported by the literature as was its internal consistency and test-retest reliability. Responsiveness of the SD was evinced by numerous studies showing increases in SD scores with time or accompanying effective interventions. However, only one study indicated responsiveness using an anchor-based statistic. CONCLUSIONS: The SD of the SIS is a well-established and mostly clinimetrically sound patient-report measure of paretic limb strength among individuals with stroke. Its use with individuals with weakness accompanying aging or diagnoses other than stroke remains to be substantiated.