Cognitive assessment scale for stroke patients (CASP): A multicentric validation study

Background: The Mini Mental State Examination and Montreal Cognitive Assessment are commonly used as short screening batteries for assessing cognitive impairment after stroke. However, aphasia or hemispatial neglect may interfere with the results. For this reason, we developed the Cognitive Assessment scale for Stroke Patients (CASP), which takes these conditions into consideration and previously demonstrated its superiority over these scales in terms of feasibility.

Objectives: Our goal was to verify the psychometric properties of the (original) French version of the CASP.

Methods: We included 201 patients with a recent first hemispheric stroke and 50 controls. Stroke patients were examined 4 times (visit 1 [V1] to visit 4 [V4]) in the subacute post-stroke phase. The structural validity of the CASP was studied by principal factorial analysis, convergent validity by comparison with several variables including a comprehensive neuropsychological assessment, divergent validity by comparison with the total score between stroke patients and controls, and sub-scores between right and left stroke. Internal consistency, reproducibility and sensitivity to change were assessed. We propose the Minimal Clinically Important Difference (MCID) value and a pathological threshold as well as a threshold to predict cognitive change between V1 and V4.

Results: Of the 201 participants included (63% male; mean [SD] age 63 [13] years), CASP data were available for 199/150/133/93 at V1/V2/V3/V4, respectively. CASP has a one-dimensional structure. The hypotheses of convergent/divergent validities were confirmed. Internal consistency was good and reliability excellent. Responsiveness was small to moderate, but the MCID could still be estimated. We discuss the choice of a pathological threshold and a predictive threshold of V1 over V4.

Conclusions: CASP has good psychometric properties for screening cognitive impairment in the subacute post-stroke phase, which is consistent with its Italian and Korean versions. It can be used for patients with severe motor aphasia or left hemispatial neglect but not in case of severe oral comprehension or visual impairment.