Three dementia screening tools validated in a multi-ethnic Asian setting

The Community Screening Instrument for Dementia (CSI-D), Chinese Mini Mental State Examination (CMMSE), and Elderly Cognitive Assessment Questionnaire (ECAQ) have been confirmed to be valid instruments for dementia screening in a multiethnic, multilingual Singaporean population comprising ethnic Chinese, Malays, and Indians.

In a study, locally adapted versions of the CSI-D, CMMSE, and ECAQ had acceptable and comparable diagnostic accuracies, with the area under receiver operating characteristic curve values ranging from 0.85 to 0.98. [Healthcare 2024;12:410]

“The instruments correlated highly with one another, indicating good convergent reliabilities between the instruments,” the investigators said.

Already, the CMMSE and ECAQ are widely used for dementia screening in Singapore. The CMMSE, which is a modified version of the MMSE, consists of 22 test items that cover various domains such as orientation, naming, arithmetic, recall, comprehension, and copying. Meanwhile, the ECAQ comprises 10 test items culled from the MMSE and Geriatric Mental State Schedule (GMSS) to assess orientation/information and memory. [Int J Geriatr Psychiatry 2000;15:234-241; Acta Psychiatr Scand 1992;85:119-122]

The CSI-D, on the other hand, leverages the combined inputs from patients and informants. This tool is tailored for populations with diverse educational, cultural, and linguistic backgrounds and has demonstrated good adaptability and utility in many heterogenous populations. Three summary scores are generated for the CSI-D, as follows: (1) Cognitive Score (COGSCORE), an item-weighted score based on the participant’s performance on the cognitive component; (2) Informant Score (RELSCORE), an unweighted total score from the caregiver interview; and (3) Discriminate Function Score (DFSCORE), an item-weighted discriminant score combining COGSCORE and RELSCORE. [BMC Neurol. 2009;26:48; Int J Geriatr Psychiatry 2000;15:521–531]

The CMMSE has only been validated among the Chinese, while the ECAQ extends to both Chinese and Malay populations. The CSI-D has been validated in Chinese, Taiwanese, and Indian populations. [Int J Geriatr Psychiatry 2000;15:234-241; Acta Psychiatr Scand 1992;85:119-122; Dement Geriatr Cogn Disord 2003;15:10-18; Am J Geriatr Psychiatry 2005;13:581-588; Int J Geriatr Psychiatry 2016;31:879-891]

Ethnic difference in Informant Score

In the present study, the CMMSE, ECAQ, and CSI-D were administered in random order to 85 Chinese, 85 Malays, and 89 Indians. Their mean age of the entire population was 70.15 years, and most of the participants were women (65.4 percent) and had no/minimal formal education (58.8 percent). There was no significant difference in age, gender distribution, educational level, and cognitive status across the three ethnic groups. In total, 22.8 percent of participants had dementia.

When performance of the screening instruments was evaluated by ethnicity, the RELSCORE had a lower diagnostic accuracy for the Malays, which, according to the investigators, partially accounted for the lower overall diagnostic accuracy for the RELSCORE. Aside from this, the discriminative ability of the screening instruments generally did not differ across the different ethnic groups.

The respective sensitivities and specificities were as follows: 100.0 percent and 83.5 percent for the COGSCORE (cutoff point ≤27.80), 79.3 percent and 87.1 percent for the RELSCORE (cutoff point ≥4.83), 82.8 percent and 90.0 percent for the DFSCORE (cutoff point ≥0.1502), 89.9 percent and 90.5 percent for the CMMSE (cutoff point ≤19.00), and 89.8 percent and 91.5 percent for the ECAQ (cutoff point ≤7.00).

ECAQ a simpler tool

The investigators noted that performance on the dementia screening instruments varied according to the participants’ level of education. As expected, education played a lesser role in ECAQ performance than in the COGSCORE and CMMSE due to the minimal cognitive demands of the ECAQ, they pointed out.

“Given the reduced cognitive requirements and smaller education bias, the ECAQ may be more appropriate for use with elderly who have none to minimal education, while the CMMSE and the CSI-D may be more appropriate for those who have at least completed primary schooling. However, cognitive measures that are educationally biased also have a higher sensitivity to dementia as both characteristics are a result of a higher level of item difficulty,” according to the investigators. [Int J Geriatr Psychiatry 2000;15:21-30]

“As such, it will be valuable to investigate if instruments like the ECAQ can maintain high sensitivity with sufficient specificity, especially for mild dementia, in highly educated populations. Another method to reduce the education bias in cognitive testing may be to develop educationally adjusted cut-off scores. Alternatively, the combination of cognitive score and the informant’s report can also effectively reduce the education bias and is closer to clinical practice,” they continued. [Int J Geriatr Psychiatry 2000;15:521-531]

In closing, the investigators called for additional studies to compare the CSI-D, CMMSE, and ECAQ in a detailed item-by-item analysis. This will help assess the influences of education, language, and culture on performance on these screening tools and, in turn, contribute to the development of a shorter instrument suitable for clinical settings and the bedside, they said.