Objective: To predict total disease severity in Parkinson’s disease (PD) for online assessments.

Background: Assessment (and hence management) of PD has largely been affected by COVID-19, with a shift from in-person to online and virtual forms of assessment. This presents a challenge as not all motor symptoms can be assessed virtually. Two of the most important symptoms of PD (rigidity and postural instability) cannot be assessed virtually using the gold-standard Unified Parkinson’s Disease Rating Scale (UPDRS-III). As a result, an accurate total disease severity score cannot be computed from the remaining subsections. A recent study advised that in order for accurate scores to be calculated, only three values of the UPDRS-III could be absent. Virtually, six values (five rigidity scores and one postural stability score) are unable to be evaluated with online assessments. This inability to compute a total disease severity score may result in poor disease management. Given the shift to increased virtual assessments, an equation was developed to predict total disease severity based on the partial scores that would typically be available in a virtual assessment.

Method: Total disease severity scores from N=234 individuals with idiopathic Parkinson’s were retrospectively analyzed. A linear regression was conducted to develop a regression equation using partial scores as the predictor variables and full scores as the outcome variable. The derived equation was tested on an independent sample of N=1168 participants to predict total disease severity.

Results: The regression analysis resulted in the Almeida-Sang equation to predict total disease severity in PD. Pearson correlation between the predicted full UPDRS-III scores and the actual UPDRS-III scores of the independent data set indicated a strong correlation (R2=0.994, p<0.001).

Conclusion: In conclusion, the Almeida-Sang equation may be essential for the continued management of PD with the limitations brought on by COVID-19, making in-person assessments more challenging. These results have important implications during a pandemic, but also for outreach into rural communities where specialists may not be readily available.

Preprint abstract: SSRN 11 Feb 2021 (not peer reviewed).

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MDS Abstracts - https://www.mdsabstracts.org/abstract/responding-to-covid-19-the-almeida-sang-equation-to-predict-total-disease-severity-in-parkinsons/