New Scale Predicts Dementia Onset in Parkinson Patients

The Montreal Parkinson Risk of Dementia Scale can effectively predict the onset of dementia in patients with Parkinson disease (PD) and may be more accurate than some existing algorithms, according to new study findings.

From May 2005 to June 2016, researchers evaluated 717 patients with PD enrolled in 4 cohorts. Of these patients, 607 were free of dementia at baseline. Follow-up lasted 4.4 years.
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The relationship between individual baseline scale variables and eventual dementia risk was determined. In addition, receiver operating characteristic curves were calculated, and selected biomarkers were examined.

Of the 607 patients without dementia at baseline, 70 had converted to dementia over the course of follow-up. Findings from the study revealed that all 8 items of the Montreal Parkinson Risk of Dementia Scale effectively predicted dementia development at the 5% significance level.

Overall, predictive validity based on the area under the receiver operating characteristic curve was calculated as 0.877 for all cohorts. The researchers noted that a cutoff of 4 or more resulted in a sensitivity of 77.1%, a specificity of 87.2%, a positive predictive value of 43.90%, and a negative predictive value of 96.70%. In addition, the positive likelihood ratio was calculated as 5.94, and the negative likelihood ratio was calculated as 0.26.

The researchers noted that scale results correlated with Alzheimer pathology markers, as well as neuropsychological test results.

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

—Christina Vogt

Reference:

Dawson BK, Fereshtehnejad SM, Anang JBM, et al. Office-based screening for dementia in Parkinson disease: the Montreal Parkinson Risk of Dementia Scale in 4 longitudinal cohorts [Published online March 26, 2018]. JAMA Neurol. doi:10.1001/jamaneurol.2018.0254.