Dealing with severe dementia in clinical practice: A validity and reliability study of Severe Mini-Mental State Examination in Greek population

Objective: Considering the floor effect problems of many cognitive instruments administered in patients with dementia, we aimed to evaluate the validity and reliability of the Severe Mini-Mental State Examination (SMMSE) for monitoring patients with moderate to severe dementia in the Greek population. Methods: We included 210 patients with dementia, mostly diagnosed with Alzheimer's disease, and administered the SMMSE, the Mini-Mental State Examination (MMSE), the Global Deterioration Scale, and the Katz Activities of Daily Living Scale (ADL). Demographic effects on SMMSE, validity, and reliability properties were initially tested for the total sample; SMMSE diagnostic accuracy was examined between subgroups of patients according to their MMSE performance; longitudinal changes over a 6-month period were assessed for a subgroup of 100 patients. Results: None of the demographic variables correlated with SMMSE score. Reliability analysis revealed high indices regarding internal consistency, inter-rater, and test-retest reliability. Validity analysis showed high correlation coefficients between SMMSE, MMSE, Global Deterioration Scale, and Katz Activities of Daily Living Scale (concurrent validity) and excellent discriminant validity of SMMSE to correctly categorize patients based on their MMSE score. In the longitudinal analysis, we found significant differences (1) only on SMMSE for patients with an MMSE = 0 to 6 at baseline and (2) both on SMMSE and MMSE for patients with an MMSE = 7 to 16 at baseline. No differences were detected for patients with an MMSE = 17 to 22 at baseline. Conclusions: We suggest the SMMSE as quick, reliable, valid, and insensitive to demographic effects psychometric instrument to monitor cognitive changes in patients with profoundly severe dementia.