Diagnostic performance of Short Portable Mental Status Questionnaire for screening dementia among patients attending cognitive assessment clinics in Singapore

Abstract

Introduction: The Short Portable Mental Status Questionnaire (SPMSQ) is a brief cognitive screening instrument, which is easy to use by a healthcare worker with little training. However, the validity of this instrument has not been established in Singapore. Thus, the primary aim of this study was to determine the diagnostic performance of SPMSQ for screening dementia among patients attending outpatient cognitive assessment clinics and to assess whether the appropriate cut-off score varies by patient's age and education. A secondary aim of the study was to map the SPMSQ scores with Mini-Mental State Examination (MMSE) scores. Materials and Methods: SPMSQ and MMSE were administered by a trained interviewer to 127 patients visiting outpatient cognitive assessment clinics at the Singapore General Hospital, Changi General Hospital and Tan Tock Seng Hospital. The geriatricians at these clinics then diagnosed these patients with dementia or no dementia (reference standard). Sensitivity and specifi city of SPMSQ with different cut-off points (number of errors) were calculated and compared to the reference standard using the Receiver Operator Characteristic (ROC) analysis. Correlation coeffi cient was also calculated between MMSE and SPMSQ scores. Results: Based on the ROC analysis and a balance of sensitivity and specifi city, the appropriate cut-off for SPMSQ was found to be 5 or more errors (sensitivity 78%, specifi city 75%). The cut-off varied by education, but not by patient's age. There was a high correlation between SPMSQ and MMSE scores (r = 0.814, P <0.0001). Conclusion: Despite the advantage of being a brief screening instrument for dementia, the use of SPMSQ is limited by its low sensitivity and specifi city, especially among patients with less than 6 years of education.