Validity and Psychometric Properties of the Severe Cognitive Rating Scale‐English Version, among Individuals with Dementia

Commonly used screening measures of cognitive function such as the Montreal Cognitive Assessment (MoCA) are not sensitive to assess cognitive function among individuals with severe cognitive impairment due to floor effect. The Severe Cognitive Impairment Rating Scale (SCIRS) was designed to assess cognitive function in those with severe cognitive impairment, however, psychometric properties of its English version have not been reported. Using the existing data from StaN and tTED studies, floor and ceiling effects (percentage of minimal or maximal scores) of SCIRS and MoCA were examined, and the association between SCIRS and MoCA was evaluated. Data from 141 participants (mean age = 78.7, 56% females) who completed either the SCIRS (n = 122) or MoCA (n = 80) were collected (n = 61 completed both). There was robust association between SCIRS and MoCA, supporting criterion validity of the SCIRS as a measure of cognitive function. SCIRS had a lower floor effect (13.1% minimal scores) as compared to the MoCA (27.5% minimal scores). Out of 22 participants with minimal scores on the MoCA, 16 participants completed the SCIRS with mean score of 9.8 (SD = 7.5). SCIRS appears to be a valid measure of cognitive function, showing better variance among individuals with severe cognitive impairment, as compared to MoCA.