"Recent estimates suggest that, depending on the specific type of residential care and assisted living facility, the percentage of residents with dementia ranges from 63% to 81%," Dr. Sheryl Zimmerman, of the University of North Carolina at Chapel Hill, and colleagues write.

If these individuals could be identified, appropriate care plans and secondary preventive measures could be affected to slow their cognitive decline and better meet their needs, the researchers note in their paper published in the September issue of the Journal of the American Geriatrics Society.

They examined the results of the MDS-COGS in detecting undiagnosed dementia in elderly subjects living in 14 residential care or assisted living facilities in North Carolina.

Fifty residential care and assisted living facility staff members, who were trained to administer the MDS-COGS, evaluated 166 residents. Two neurologists reviewed data collected on each patient by research interviewers and a neuropsychologist, and the results were compared.

According to the neurologists, 37.7% of the residents had probable dementia. In addition, 52.0% had mild cognitive impairment, and 10.3% were cognitively intact.

When a cut-point of 2 was used, the MDS-COGS was highly specific (0.97) but not very sensitive (0.49). "Test-retest and interrater agreement for a negative screen were high (88% and 93%, respectively)," the researchers report.

Dr. Zimmerman's group concludes that staff members at residential care and assisted living facilities can use the MDS-COGS to "identify with high specificity a subset of residents with undetected dementia." However, caution is needed "in light of its low sensitivity, because some with milder dementia will not be detected."

Additional work will also be needed to see if the use of this test helps guide treatment plans and lead to better patient care and outcomes.

J Am Geriatr Soc 2007;55:1349-1355.