Assessing dementia severity

The Mini-mental State Examination [MMSE] and Standardised Mini-Mental State Examination [SMMSE]) are moderately correlated with functional impairment in Alzheimer disease and have been used to assess its severity in drug trials. The Australian Pharmaceutical Benefits Scheme (PBS) uses these tests to determine Alzheimer disease severity. A MMSE score between 21 and 24 (out of 30) is generally accepted to indicate mild Alzheimer disease, a score between 10 and 20 indicates moderate Alzheimer disease and a score less than 10 indicates severe Alzheimer disease.

The MMSE and SMMSE have limited real-world applications. Some patients (eg those with intellectual disabilities, poor education level, illiteracy, innumeracy, sensory impairments, or those from linguistically or culturally diverse backgrounds) may be unable to take these tests or record a misleadingly low result. Although the MMSE and SMMSE are suitable to assess Alzheimer disease, they are not suitable to assess most other types of dementia because they primarily assess cognition (executive function is not adequately tested).

Note: In practice, dementia severity is based on the impact of functional and cognitive impairment and behavioural and psychological symptoms, and previous cognitive functioning.

In practice, dementia severity is based on the impact of functional and cognitive impairment, behavioural and psychological symptoms, and previous cognitive functioning. For example, a person with early frontotemporal dementia who has limited cognitive impairment (eg a MMSE score of 24) but significant behavioural problems necessitating institutional care would be considered to have severe dementia. Whereas, a patient with early Alzheimer disease who has limited education may appear to have significant cognitive impairment on testing (eg a MMSE score of 13), but may not be functionally impaired and would be considered to have mild dementia.