Comparison of rating scales for the diagnosis of dementia in adults with Down's syndrome.
Observer-rated dementia scales beat the MMSE for adults with Down's syndrome.
01Research in Context
What this study did
Doctors compared three ways to spot dementia in adults with Down's syndrome. They gave the adults the MMSE, the Dementia Questionnaire for Persons with Mental Retardation (DMR), and the Dementia Scale for Down Syndrome (DSDS). A separate clinician, who did not know the test scores, decided if each person had dementia. The team then checked which test best matched the doctor's diagnosis.
What they found
The DMR and DSDS were right almost every time. The MMSE missed many real cases and called healthy people sick. In simple numbers, the observer-rated scales scored high on both sensitivity and specificity. The MMSE failed because it relies on verbal answers many adults with Down's syndrome cannot give.
How this fits with other research
Balboni et al. (2014) later showed the same pattern with the Diagnostic Adaptive Behavior Scale. They found high sensitivity and specificity for diagnosing intellectual disability, backing the idea that caregiver or clinician checklists beat direct child tests.
Hastings et al. (2001) and Oliver et al. (2002) refined the Developmental Behavior Checklist for kids with ID. Like the 1999 paper, they proved observer forms give clearer data than asking the child questions.
Phillips et al. (2014) compared two nonverbal IQ tests in deaf children and found big score gaps. Their warning mirrors this study: picking the wrong tool can mislabel a person. Together, these papers form a chain telling us to choose tests built for the client's needs.
Why it matters
If you assess adults with Down's syndrome, drop the MMSE. Use the DMR or DSDS instead. They take less time, need no verbal reply, and give you trustworthy dementia answers. Start today by adding one of these scales to your intake packet. Your reports will be sharper and families will get the right help faster.
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02At a glance
03Original abstract
Making a diagnosis of dementia, particularly in its early stages, in a person with intellectual disability can be difficult Some neuropsychological tests which were originally devised for the diagnosis of dementia in the non-intellectually disabled population have been modified for use in people with intellectual disability. Observer-rated scales have also been used for making a diagnosis of dementia in people with intellectual disability. Within the context of a genetic study, the rates of diagnosis of dementia according to different criteria, namely the clinician's diagnosis (ICD-10), the Dementia Questionnaire for Persons with Mental Retardation (DMR), the Dementia Scale for Down Syndrome (DSDS) and the Mini Mental State Examination (MMSE), were compared among 62 adults with Down's syndrome (26 demented and 36 non-demented adults according to the clinician's diagnosis). A comparison between the clinician's diagnosis and the diagnosis according to DMR criteria showed specificity and sensitivity at the 0.92 level for both categories. Similarly, a comparison between the clinician's diagnosis and the diagnosis according to the DSDS criteria showed a specificity of 0.89 and a sensitivity of 0.85. A good positive correlation was also shown between the scores of the DSDS and the DMR (Pearson's r = +0.868, P < 0.001). A similar positive correlation was found between the overall DSDS score and the scores in the main subcategories of the DMR. An MMSE could be performed in only 34 (55%) out of the 62 subjects with Down's syndrome. Out of the 30 subjects who had an MMSE score of less than 24 (the usual cut-off for the diagnosis of possible dementia), 23 (77%) did not have a diagnosis of dementia according to any criteria. It seems that the observer-rated scales, rather than the direct neuropsychological tests, are more useful for the diagnosis of dementia in people with an intellectual disability.
Journal of intellectual disability research : JIDR, 1999 · doi:10.1046/j.1365-2788.1999.043005400.x