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Simple tool predicts dementia better than previous tests

Benjamin K. Dawson

The Montreal Parkinson Risk of Dementia Scale displayed a predictive validity that was identical or greater than previously described algorithms that utilized biomarker assessments, according to findings recently published in JAMA Neurology.

 “To our knowledge, there is still no inexpensive and noninvasive tool that can predict dementia risk [in patients with Parkinson’s disease] within a single office visit,” Benjamin K. Dawson, BSc, of the department of neurology and neurosurgery at McGill University in Montreal Canada and colleagues wrote. “Currently, prediction scores that integrate genetic and neuroimaging data are resource-intensive and so are difficult to apply to typical clinical settings.”

Researchers reviewed literature and data from 607 patients with Parkinson’s disease who were dementia-free at baseline and followed-up for at least 1 year during a 4.4 year period to develop what they called the eight simple criteria to make up the Montreal Parkinson Risk of Dementia Scale:

• Age older than 70;
• Male sex;
• History of rapid eye movement sleep behavior disorder
• Orthostatic hypotension;
• Mild cognitive impairment;
• Bilateral disease onset;
• Visual hallucinations; and
• Falls and/or freezing.

Researchers found that 70 of the 607 patients converted to dementia. In addition, all the items on the Montreal Parkinson Risk of Dementia Scale independently foretold the development of dementia with a significance level of 5%.

In addition, 14.9% of the patients with a Montreal Parkinson Risk of Dementia Scale score of greater than 5 converted to dementia vs. 5.8% of those with scores between 4 and 5 vs. 0.6% of those with scores between 0 and 3. The overall predictive validity by the area under the receiver operating characteristic curve was 0.877 across all the patients, whereas a cutoff of 4 or greater produced a specificity of 87.2%, a sensitivity of 77.1%, a negative predictive value of 96.7% and a positive predictive value of 43.9%. The negative likelihood ratio was 0.26% and the positive likelihood ratio was 5.94%.

“Despite its simplicity, the Montreal Parkinson Risk of Dementia Scale demonstrated predictive validity equal or greater to previously described algorithms using biomarker assessments,” Dawson and colleagues wrote. “Future studies using head-to-head comparisons or refinement of weighting would be of interest.”

The Montreal Parkinson Risk of Dementia Scale displayed a predictive validity that was identical or greater than previously described algorithms that utilized biomarker assessments, according to findings recently published in JAMA Neurology. 

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He added in an interview that the findings may be applicable to a variety of medical professionals.

“The big feature of this scale is that every item in it can be assessed in primary care, and calculated in a single office visit without any statistical software. Although no scale is perfect, we now have some pretty simple methods to predict dementia risk in Parkinson’s patients.,” Dawson said. “For neurologists treating these patients, it's important to be aware of the medium-term dementia risk to help plan treatment. And for those who will be able to plan dementia-prevention trials, we hope this will help identify those most likely to benefit from treatment.” - by Janel Miller

Reference: “MDS-developed rating scales.” https://pdbp.ninds.nih.gov. Accessed March 23, 2018.

Disclosure: Dawson reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.