Six Visual Rating Scales as A Biomarker for Monitoring Atrophied Brain Volume in Parkinson's Disease

Abstract

The focus of our investigation was to determine the feasibility of using six visual rating scales as whole-brain imaging markers for monitoring atrophied brain volume in Parkinson's disease (PD). This was a prospective cross-sectional single-center observational study. A total of 98 PD patients were enrolled and underwent an MRI scan and a battery of neuropsychological evaluations. The brain volume was calculated using the online resource MRICloud. Brain atrophy was rated based on six visual rating scales. Correlation analysis was performed between visual rating scores and brain volume and clinical features. We found a significant negative correlation between the total scores of visual rating scores and quantitative brain volume, indicating that six visual rating scales reliably reflect whole brain atrophy in PD. Multiple linear regression-based analyses indicated severer non-motor symptoms were significantly associated with higher scores on the visual rating scales. Furthermore, we performed sample size calculations to evaluate the superiority of visual rating scales; the result show that using total scores of visual rating scales as an outcome measure, sample sizes for differentiating cognition injury require significantly fewer subjects (n = 177) compared with using total brain volume (n = 2524). Our data support the use of the total visual rating scores rather than quantitative brain volume as a biomarker for monitoring cerebral atrophy.

Keywords: Parkinson’s disease; clinical trials; structural image; visual rating scale; whole brain atrophy.

Figure 1.

Trial profile. (A) Diagrammatic sketch of the screening process; (B) Brain volume as quantified by MRICloud and examples of scoring of six visual rating scales. Red coloring indicates the segmentation region at level 1. The yellow frame indicates each region for image assessment. PDD and PD patients with dementia; nPDD and PD patients without dementia. OF = orbitofrontal cortex; AC = anterior cingulate; FI = frontoinsula; AT = anterior temporal; MT= medial temporal lobe; PA = posterior cortex.

Figure 2.

Scatter-plots showing the associations between total visual rating scores and brain volume in the total PD sample and subset group. (A) Total PD samples, (B) Patients with dementia, (C) Patients without dementia. Data were analyzed using the spearman rank correlation test.

Figure 3.

Sample size per treatment arm using brain volume and visual rating scales. The calculation was based on the assumption that cognitive state of PD patients changed from non-cognition injury to cognition injury; an 80% power level was used, and a one-side 0.05 level was considered significant.