Construct Validity of the Stroke Upper-Limb Capacity Scale as a Measure of Upper Extremity Capacity

Research Objectives: The Stroke Upper-Limb Capacity Scale (SULCS) is a standardized assessment of 10 upper extremity (UE) functional tasks, but there are little data on construct validity in acute stroke. Using International Classification of Function definitions, we hypothesize: H1 – a stronger relationship between the SULCS and another activity measure (Functional Independence Measure Selfcare (FIM-SC)), as compared to the SULCS and an impairment measure Motricity Index-UE (MI-UE)); H2 – a stronger association between the SULCS and UE items on the FIM (eating, grooming and bathing (FIM-E, FIM-G, FIM-Ba, respectively)) compared to FIM items not dependent on UE function (walking, bowel and expression (FIM-W, FIM-Bo, FIM-Exp, respectively)).

Design: Cross-sectional.

Setting: Academic inpatient rehabilitation unit.

Participants: N=341/488 (70%) admissions with complete data, age=70±15 years, time post stroke=10±9 days, length of stay=14±8 days, female=47.2%, Admission Total FIM=60±20, Admission SULCS=5.5±3.6, Admission MI-UE=65±35.

Interventions: N/A

Main Outcome Measures: SULCS, FIM and MI-UE.

Results: H1: SULCS correlated significantly with FIM-SC and MI-UE (ρ=0.74 and ρ=0.85, respectively; (p < 0.001)). H2: SULCS correlated significantly with upper extremity selfcare items (FIM-E/ρ=0.61, FIM-G/ρ=0.56 and FIM-Ba/ρ=0.60), and significantly but more weakly with non-upper extremity items (FIM-Bo/ρ=0.47, FIM-W/ρ=0.57 and FIM-Exp/ρ=0.37). All p< 0.001.

Conclusions: Contrary to H1, SULCS was similarly and strongly correlated with MI-UE and FIM. The inability to compensate for hemiparesis with the intact extremity on both SULCS and MI-UE may explain this unexpected finding. H2 was generally supported, as SULCS demonstrated stronger correlations with UE selfcare items compared to non-UE items. The correlation between SULCS and FIM-W is likely due to hemiparesis in stroke commonly affecting upper and lower extremities. We conclude that SULCS is likely a valid measure of UE capacity early after stroke.

Author(s) Disclosures: The authors declare that they have no relevant conflicts that relate to the research described in this paper.