MMSE, Diagnosis of Dementia, and How Hearing Loss Impacts the Score

The MMSE is the most commonly used tool for diagnosing dementia. Nine out of 10 physicians use solely the MMSE for diagnosis of dementia.
A score of less than 27 out of 30 on the MMSE is sufficient to diagnose dementia.
Hearing loss is correlated with reduced performance on verbally administered tests for dementia.
Ability to hear the words in the verbal administration of the MMSE insignificantly affects overall score and diagnosis of dementia.
16% of persons with untreated (i.e., no hearing aid use when warranted) mild to moderate hearing loss were ultimately misdiagnosed as having dementia when no dementia was present.
Persons with hearing loss, however, are at greater risk for having true dementia than persons without hearing loss.
In order for the MMSE diagnosis to be correct, it is recommended that the physician administering the MMSE have full knowledge of the person's hearing loss prior to administration. This means the results of a comprehensive audiologic test conducted by a licensed audiologist. Asking the person is not sufficient for diagnosis as only 28% of persons can accurately identify if they have hearing loss.
Identification and remediation of hearing loss is strongly recommended prior to administration of the MMSE for the purpose of differential diagnosis.
Persons already diagnosed with Alzheimer's-type dementia can show improvement in some of the difficult behaviors associated with the disorder if they receive hearing aids for treatable hearing loss.
Hearing loss is twice as likely in persons with dementia or other mental disorders as compared to persons with normal cognitive function.
Jorgensen, et al. The effects of decreased audibility on MMSE performance: a measure commonly used for diagnosing dementia. Journal of the American Academy of Audiology. 2016;27(4):311–320.