Tuesday, December 5, 2017

New Geriatric Cognition Chart May Improve Dementia Monitoring

Researchers at Laval University in Quebec and colleagues have devised an assessment chart called QuoCo (for cognitive quotient) to track patient cognition, offering a new method they say can help identify dementia during the earliest stages. The study was published yesterday in the Canadian Medical Association Journal.

“Similar to the ‘growth charts’ that are used in pediatrics, cognitive charts allow physicians to position any patient based on age, education, and Mini-Mental State Examination [MMSE] scores, and simply track the longitudinal profile of cognitive decline over time,” wrote lead study author Patrick Bernier, M.D., Ph.D., and colleagues. Such a chart “could prompt earlier intervention for an older adult who ‘fell off’ the curve,” the authors noted.

The MMSE is commonly used to screen for dementia, but there is no consensus on how best to determine whether changes in MMSE scores over time reflect age-associated cognitive decline or represent mild cognitive impairment or dementia. Also, previous studies show MMSE cut-off scores are less reliable for some populations, particularly for older adults with less formal education.

Bernier and colleagues analyzed data from a longitudinal study of older adults known as the Canadian Study of Health and Aging. They assessed 7,569 participants aged 65 years or older who completed an MMSE at study baseline, and then 5 and 10 years later.

By comparing score results of the 6,411 participants who remained cognitively healthy during the follow-up with the 1,158 who developed dementia, while controlling for age and education, the investigators developed QuoCo scores. Similar to charts used to monitor infant growth, the researchers developed a chart that reflected optimal rates of gradual cognitive decline with age, divided into five broad percentile zones. Any patient who dropped by more than one percentile zone on the QuoCo following their initial visit was classified as having dementia.

Bernier and colleagues found that the model could distinguish healthy participants from those with dementia with a specificity of 89% and a sensitivity of 80%. The QuoCo was about 12% better overall than only using an MMSE score of 24 or less as a dementia cutoff; however, while using the cognitive charts improved the classification of patients with dementia, it also increased the misclassification of some patients with normal cognition.

To read more on this topic, see the Psychiatric News article “Dual-Task Gait Testing Identifies MCI Patients Likely to Develop Dementia.”

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